Add experimental gRPC-Web folder

vendor/google.golang.org/grpc/.travis.yml

@@ -0,0 +1,24 @@
+language: go
+
+go:
+  - 1.6.x
+  - 1.7.x
+  - 1.8.x
+  - 1.9.x
+  - 1.10.x
+
+matrix:
+  include:
+  - go: 1.10.x
+    env: RUN386=1
+
+go_import_path: google.golang.org/grpc
+
+before_install:
+  - if [[ -n "$RUN386" ]]; then export GOARCH=386; fi
+  - if [[ "$TRAVIS_GO_VERSION" = 1.10* && "$GOARCH" != "386" ]]; then ./vet.sh -install || exit 1; fi
+
+script:
+  - if [[ "$TRAVIS_GO_VERSION" = 1.10* && "$GOARCH" != "386" ]]; then ./vet.sh || exit 1; fi
+  - make test || exit 1
+  - if [[ "$GOARCH" != "386" ]]; then make testrace; fi

vendor/google.golang.org/grpc/AUTHORS

@@ -0,0 +1 @@
+Google Inc.

vendor/google.golang.org/grpc/CONTRIBUTING.md

@@ -0,0 +1,36 @@
+# How to contribute
+
+We definitely welcome your patches and contributions to gRPC!
+
+If you are new to github, please start by reading [Pull Request howto](https://help.github.com/articles/about-pull-requests/)
+
+## Legal requirements
+
+In order to protect both you and ourselves, you will need to sign the
+[Contributor License Agreement](https://identity.linuxfoundation.org/projects/cncf).
+
+## Guidelines for Pull Requests
+How to get your contributions merged smoothly and quickly.
+ 
+- Create **small PRs** that are narrowly focused on **addressing a single concern**. We often times receive PRs that are trying to fix several things at a time, but only one fix is considered acceptable, nothing gets merged and both author's & review's time is wasted. Create more PRs to address different concerns and everyone will be happy.
+ 
+- For speculative changes, consider opening an issue and discussing it first. If you are suggesting a behavioral or API change, consider starting with a [gRFC proposal](https://github.com/grpc/proposal). 
+ 
+- Provide a good **PR description** as a record of **what** change is being made and **why** it was made. Link to a github issue if it exists.
+ 
+- Don't fix code style and formatting unless you are already changing that line to address an issue. PRs with irrelevant changes won't be merged. If you do want to fix formatting or style, do that in a separate PR.
+ 
+- Unless your PR is trivial, you should expect there will be reviewer comments that you'll need to address before merging. We expect you to be reasonably responsive to those comments, otherwise the PR will be closed after 2-3 weeks of inactivity.
+ 
+- Maintain **clean commit history** and use **meaningful commit messages**. PRs with messy commit history are difficult to review and won't be merged. Use `rebase -i upstream/master` to curate your commit history and/or to bring in latest changes from master (but avoid rebasing in the middle of a code review).
+ 
+- Keep your PR up to date with upstream/master (if there are merge conflicts, we can't really merge your change).
+ 
+- **All tests need to be passing** before your change can be merged. We recommend you **run tests locally** before creating your PR to catch breakages early on.
+  - `make all` to test everything, OR
+  - `make vet` to catch vet errors
+  - `make test` to run the tests
+  - `make testrace` to run tests in race mode
+
+- Exceptions to the rules can be made if there's a compelling reason for doing so.
+ 

vendor/google.golang.org/grpc/LICENSE

@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+      outstanding shares, or (iii) beneficial ownership of such entity.
+
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+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+   8. Limitation of Liability. In no event and under no legal theory,
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+
+   Unless required by applicable law or agreed to in writing, software
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+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/google.golang.org/grpc/Makefile

@@ -0,0 +1,48 @@
+all: vet test testrace
+
+deps:
+	go get -d -v google.golang.org/grpc/...
+
+updatedeps:
+	go get -d -v -u -f google.golang.org/grpc/...
+
+testdeps:
+	go get -d -v -t google.golang.org/grpc/...
+
+updatetestdeps:
+	go get -d -v -t -u -f google.golang.org/grpc/...
+
+build: deps
+	go build google.golang.org/grpc/...
+
+proto:
+	@ if ! which protoc > /dev/null; then \
+		echo "error: protoc not installed" >&2; \
+		exit 1; \
+	fi
+	go generate google.golang.org/grpc/...
+
+vet:
+	./vet.sh
+
+test: testdeps
+	go test -cpu 1,4 -timeout 5m google.golang.org/grpc/...
+
+testrace: testdeps
+	go test -race -cpu 1,4 -timeout 7m google.golang.org/grpc/...
+
+clean:
+	go clean -i google.golang.org/grpc/...
+
+.PHONY: \
+	all \
+	deps \
+	updatedeps \
+	testdeps \
+	updatetestdeps \
+	build \
+	proto \
+	vet \
+	test \
+	testrace \
+	clean

vendor/google.golang.org/grpc/README.md

@@ -0,0 +1,45 @@
+# gRPC-Go
+
+[![Build Status](https://travis-ci.org/grpc/grpc-go.svg)](https://travis-ci.org/grpc/grpc-go) [![GoDoc](https://godoc.org/google.golang.org/grpc?status.svg)](https://godoc.org/google.golang.org/grpc) [![GoReportCard](https://goreportcard.com/badge/grpc/grpc-go)](https://goreportcard.com/report/github.com/grpc/grpc-go)
+
+The Go implementation of [gRPC](https://grpc.io/): A high performance, open source, general RPC framework that puts mobile and HTTP/2 first. For more information see the [gRPC Quick Start: Go](https://grpc.io/docs/quickstart/go.html) guide.
+
+Installation
+------------
+
+To install this package, you need to install Go and setup your Go workspace on your computer. The simplest way to install the library is to run:
+
+```
+$ go get -u google.golang.org/grpc
+```
+
+Prerequisites
+-------------
+
+This requires Go 1.6 or later. Go 1.7 will be required soon.
+
+Constraints
+-----------
+The grpc package should only depend on standard Go packages and a small number of exceptions. If your contribution introduces new dependencies which are NOT in the [list](http://godoc.org/google.golang.org/grpc?imports), you need a discussion with gRPC-Go authors and consultants.
+
+Documentation
+-------------
+See [API documentation](https://godoc.org/google.golang.org/grpc) for package and API descriptions and find examples in the [examples directory](examples/).
+
+Performance
+-----------
+See the current benchmarks for some of the languages supported in [this dashboard](https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5652536396611584&widget=490377658&container=1286539696).
+
+Status
+------
+General Availability [Google Cloud Platform Launch Stages](https://cloud.google.com/terms/launch-stages).
+
+FAQ
+---
+
+#### Compiling error, undefined: grpc.SupportPackageIsVersion
+
+Please update proto package, gRPC package and rebuild the proto files:
+ - `go get -u github.com/golang/protobuf/{proto,protoc-gen-go}`
+ - `go get -u google.golang.org/grpc`
+ - `protoc --go_out=plugins=grpc:. *.proto`

vendor/google.golang.org/grpc/backoff.go

@@ -0,0 +1,96 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"math/rand"
+	"time"
+)
+
+// DefaultBackoffConfig uses values specified for backoff in
+// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
+var DefaultBackoffConfig = BackoffConfig{
+	MaxDelay:  120 * time.Second,
+	baseDelay: 1.0 * time.Second,
+	factor:    1.6,
+	jitter:    0.2,
+}
+
+// backoffStrategy defines the methodology for backing off after a grpc
+// connection failure.
+//
+// This is unexported until the gRPC project decides whether or not to allow
+// alternative backoff strategies. Once a decision is made, this type and its
+// method may be exported.
+type backoffStrategy interface {
+	// backoff returns the amount of time to wait before the next retry given
+	// the number of consecutive failures.
+	backoff(retries int) time.Duration
+}
+
+// BackoffConfig defines the parameters for the default gRPC backoff strategy.
+type BackoffConfig struct {
+	// MaxDelay is the upper bound of backoff delay.
+	MaxDelay time.Duration
+
+	// TODO(stevvooe): The following fields are not exported, as allowing
+	// changes would violate the current gRPC specification for backoff. If
+	// gRPC decides to allow more interesting backoff strategies, these fields
+	// may be opened up in the future.
+
+	// baseDelay is the amount of time to wait before retrying after the first
+	// failure.
+	baseDelay time.Duration
+
+	// factor is applied to the backoff after each retry.
+	factor float64
+
+	// jitter provides a range to randomize backoff delays.
+	jitter float64
+}
+
+func setDefaults(bc *BackoffConfig) {
+	md := bc.MaxDelay
+	*bc = DefaultBackoffConfig
+
+	if md > 0 {
+		bc.MaxDelay = md
+	}
+}
+
+func (bc BackoffConfig) backoff(retries int) time.Duration {
+	if retries == 0 {
+		return bc.baseDelay
+	}
+	backoff, max := float64(bc.baseDelay), float64(bc.MaxDelay)
+	for backoff < max && retries > 0 {
+		backoff *= bc.factor
+		retries--
+	}
+	if backoff > max {
+		backoff = max
+	}
+	// Randomize backoff delays so that if a cluster of requests start at
+	// the same time, they won't operate in lockstep.
+	backoff *= 1 + bc.jitter*(rand.Float64()*2-1)
+	if backoff < 0 {
+		return 0
+	}
+	return time.Duration(backoff)
+}

vendor/google.golang.org/grpc/balancer.go

@@ -0,0 +1,416 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"net"
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/naming"
+	"google.golang.org/grpc/status"
+)
+
+// Address represents a server the client connects to.
+//
+// Deprecated: please use package balancer.
+type Address struct {
+	// Addr is the server address on which a connection will be established.
+	Addr string
+	// Metadata is the information associated with Addr, which may be used
+	// to make load balancing decision.
+	Metadata interface{}
+}
+
+// BalancerConfig specifies the configurations for Balancer.
+//
+// Deprecated: please use package balancer.
+type BalancerConfig struct {
+	// DialCreds is the transport credential the Balancer implementation can
+	// use to dial to a remote load balancer server. The Balancer implementations
+	// can ignore this if it does not need to talk to another party securely.
+	DialCreds credentials.TransportCredentials
+	// Dialer is the custom dialer the Balancer implementation can use to dial
+	// to a remote load balancer server. The Balancer implementations
+	// can ignore this if it doesn't need to talk to remote balancer.
+	Dialer func(context.Context, string) (net.Conn, error)
+}
+
+// BalancerGetOptions configures a Get call.
+//
+// Deprecated: please use package balancer.
+type BalancerGetOptions struct {
+	// BlockingWait specifies whether Get should block when there is no
+	// connected address.
+	BlockingWait bool
+}
+
+// Balancer chooses network addresses for RPCs.
+//
+// Deprecated: please use package balancer.
+type Balancer interface {
+	// Start does the initialization work to bootstrap a Balancer. For example,
+	// this function may start the name resolution and watch the updates. It will
+	// be called when dialing.
+	Start(target string, config BalancerConfig) error
+	// Up informs the Balancer that gRPC has a connection to the server at
+	// addr. It returns down which is called once the connection to addr gets
+	// lost or closed.
+	// TODO: It is not clear how to construct and take advantage of the meaningful error
+	// parameter for down. Need realistic demands to guide.
+	Up(addr Address) (down func(error))
+	// Get gets the address of a server for the RPC corresponding to ctx.
+	// i) If it returns a connected address, gRPC internals issues the RPC on the
+	// connection to this address;
+	// ii) If it returns an address on which the connection is under construction
+	// (initiated by Notify(...)) but not connected, gRPC internals
+	//  * fails RPC if the RPC is fail-fast and connection is in the TransientFailure or
+	//  Shutdown state;
+	//  or
+	//  * issues RPC on the connection otherwise.
+	// iii) If it returns an address on which the connection does not exist, gRPC
+	// internals treats it as an error and will fail the corresponding RPC.
+	//
+	// Therefore, the following is the recommended rule when writing a custom Balancer.
+	// If opts.BlockingWait is true, it should return a connected address or
+	// block if there is no connected address. It should respect the timeout or
+	// cancellation of ctx when blocking. If opts.BlockingWait is false (for fail-fast
+	// RPCs), it should return an address it has notified via Notify(...) immediately
+	// instead of blocking.
+	//
+	// The function returns put which is called once the rpc has completed or failed.
+	// put can collect and report RPC stats to a remote load balancer.
+	//
+	// This function should only return the errors Balancer cannot recover by itself.
+	// gRPC internals will fail the RPC if an error is returned.
+	Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error)
+	// Notify returns a channel that is used by gRPC internals to watch the addresses
+	// gRPC needs to connect. The addresses might be from a name resolver or remote
+	// load balancer. gRPC internals will compare it with the existing connected
+	// addresses. If the address Balancer notified is not in the existing connected
+	// addresses, gRPC starts to connect the address. If an address in the existing
+	// connected addresses is not in the notification list, the corresponding connection
+	// is shutdown gracefully. Otherwise, there are no operations to take. Note that
+	// the Address slice must be the full list of the Addresses which should be connected.
+	// It is NOT delta.
+	Notify() <-chan []Address
+	// Close shuts down the balancer.
+	Close() error
+}
+
+// downErr implements net.Error. It is constructed by gRPC internals and passed to the down
+// call of Balancer.
+type downErr struct {
+	timeout   bool
+	temporary bool
+	desc      string
+}
+
+func (e downErr) Error() string   { return e.desc }
+func (e downErr) Timeout() bool   { return e.timeout }
+func (e downErr) Temporary() bool { return e.temporary }
+
+func downErrorf(timeout, temporary bool, format string, a ...interface{}) downErr {
+	return downErr{
+		timeout:   timeout,
+		temporary: temporary,
+		desc:      fmt.Sprintf(format, a...),
+	}
+}
+
+// RoundRobin returns a Balancer that selects addresses round-robin. It uses r to watch
+// the name resolution updates and updates the addresses available correspondingly.
+//
+// Deprecated: please use package balancer/roundrobin.
+func RoundRobin(r naming.Resolver) Balancer {
+	return &roundRobin{r: r}
+}
+
+type addrInfo struct {
+	addr      Address
+	connected bool
+}
+
+type roundRobin struct {
+	r      naming.Resolver
+	w      naming.Watcher
+	addrs  []*addrInfo // all the addresses the client should potentially connect
+	mu     sync.Mutex
+	addrCh chan []Address // the channel to notify gRPC internals the list of addresses the client should connect to.
+	next   int            // index of the next address to return for Get()
+	waitCh chan struct{}  // the channel to block when there is no connected address available
+	done   bool           // The Balancer is closed.
+}
+
+func (rr *roundRobin) watchAddrUpdates() error {
+	updates, err := rr.w.Next()
+	if err != nil {
+		grpclog.Warningf("grpc: the naming watcher stops working due to %v.", err)
+		return err
+	}
+	rr.mu.Lock()
+	defer rr.mu.Unlock()
+	for _, update := range updates {
+		addr := Address{
+			Addr:     update.Addr,
+			Metadata: update.Metadata,
+		}
+		switch update.Op {
+		case naming.Add:
+			var exist bool
+			for _, v := range rr.addrs {
+				if addr == v.addr {
+					exist = true
+					grpclog.Infoln("grpc: The name resolver wanted to add an existing address: ", addr)
+					break
+				}
+			}
+			if exist {
+				continue
+			}
+			rr.addrs = append(rr.addrs, &addrInfo{addr: addr})
+		case naming.Delete:
+			for i, v := range rr.addrs {
+				if addr == v.addr {
+					copy(rr.addrs[i:], rr.addrs[i+1:])
+					rr.addrs = rr.addrs[:len(rr.addrs)-1]
+					break
+				}
+			}
+		default:
+			grpclog.Errorln("Unknown update.Op ", update.Op)
+		}
+	}
+	// Make a copy of rr.addrs and write it onto rr.addrCh so that gRPC internals gets notified.
+	open := make([]Address, len(rr.addrs))
+	for i, v := range rr.addrs {
+		open[i] = v.addr
+	}
+	if rr.done {
+		return ErrClientConnClosing
+	}
+	select {
+	case <-rr.addrCh:
+	default:
+	}
+	rr.addrCh <- open
+	return nil
+}
+
+func (rr *roundRobin) Start(target string, config BalancerConfig) error {
+	rr.mu.Lock()
+	defer rr.mu.Unlock()
+	if rr.done {
+		return ErrClientConnClosing
+	}
+	if rr.r == nil {
+		// If there is no name resolver installed, it is not needed to
+		// do name resolution. In this case, target is added into rr.addrs
+		// as the only address available and rr.addrCh stays nil.
+		rr.addrs = append(rr.addrs, &addrInfo{addr: Address{Addr: target}})
+		return nil
+	}
+	w, err := rr.r.Resolve(target)
+	if err != nil {
+		return err
+	}
+	rr.w = w
+	rr.addrCh = make(chan []Address, 1)
+	go func() {
+		for {
+			if err := rr.watchAddrUpdates(); err != nil {
+				return
+			}
+		}
+	}()
+	return nil
+}
+
+// Up sets the connected state of addr and sends notification if there are pending
+// Get() calls.
+func (rr *roundRobin) Up(addr Address) func(error) {
+	rr.mu.Lock()
+	defer rr.mu.Unlock()
+	var cnt int
+	for _, a := range rr.addrs {
+		if a.addr == addr {
+			if a.connected {
+				return nil
+			}
+			a.connected = true
+		}
+		if a.connected {
+			cnt++
+		}
+	}
+	// addr is only one which is connected. Notify the Get() callers who are blocking.
+	if cnt == 1 && rr.waitCh != nil {
+		close(rr.waitCh)
+		rr.waitCh = nil
+	}
+	return func(err error) {
+		rr.down(addr, err)
+	}
+}
+
+// down unsets the connected state of addr.
+func (rr *roundRobin) down(addr Address, err error) {
+	rr.mu.Lock()
+	defer rr.mu.Unlock()
+	for _, a := range rr.addrs {
+		if addr == a.addr {
+			a.connected = false
+			break
+		}
+	}
+}
+
+// Get returns the next addr in the rotation.
+func (rr *roundRobin) Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error) {
+	var ch chan struct{}
+	rr.mu.Lock()
+	if rr.done {
+		rr.mu.Unlock()
+		err = ErrClientConnClosing
+		return
+	}
+
+	if len(rr.addrs) > 0 {
+		if rr.next >= len(rr.addrs) {
+			rr.next = 0
+		}
+		next := rr.next
+		for {
+			a := rr.addrs[next]
+			next = (next + 1) % len(rr.addrs)
+			if a.connected {
+				addr = a.addr
+				rr.next = next
+				rr.mu.Unlock()
+				return
+			}
+			if next == rr.next {
+				// Has iterated all the possible address but none is connected.
+				break
+			}
+		}
+	}
+	if !opts.BlockingWait {
+		if len(rr.addrs) == 0 {
+			rr.mu.Unlock()
+			err = status.Errorf(codes.Unavailable, "there is no address available")
+			return
+		}
+		// Returns the next addr on rr.addrs for failfast RPCs.
+		addr = rr.addrs[rr.next].addr
+		rr.next++
+		rr.mu.Unlock()
+		return
+	}
+	// Wait on rr.waitCh for non-failfast RPCs.
+	if rr.waitCh == nil {
+		ch = make(chan struct{})
+		rr.waitCh = ch
+	} else {
+		ch = rr.waitCh
+	}
+	rr.mu.Unlock()
+	for {
+		select {
+		case <-ctx.Done():
+			err = ctx.Err()
+			return
+		case <-ch:
+			rr.mu.Lock()
+			if rr.done {
+				rr.mu.Unlock()
+				err = ErrClientConnClosing
+				return
+			}
+
+			if len(rr.addrs) > 0 {
+				if rr.next >= len(rr.addrs) {
+					rr.next = 0
+				}
+				next := rr.next
+				for {
+					a := rr.addrs[next]
+					next = (next + 1) % len(rr.addrs)
+					if a.connected {
+						addr = a.addr
+						rr.next = next
+						rr.mu.Unlock()
+						return
+					}
+					if next == rr.next {
+						// Has iterated all the possible address but none is connected.
+						break
+					}
+				}
+			}
+			// The newly added addr got removed by Down() again.
+			if rr.waitCh == nil {
+				ch = make(chan struct{})
+				rr.waitCh = ch
+			} else {
+				ch = rr.waitCh
+			}
+			rr.mu.Unlock()
+		}
+	}
+}
+
+func (rr *roundRobin) Notify() <-chan []Address {
+	return rr.addrCh
+}
+
+func (rr *roundRobin) Close() error {
+	rr.mu.Lock()
+	defer rr.mu.Unlock()
+	if rr.done {
+		return errBalancerClosed
+	}
+	rr.done = true
+	if rr.w != nil {
+		rr.w.Close()
+	}
+	if rr.waitCh != nil {
+		close(rr.waitCh)
+		rr.waitCh = nil
+	}
+	if rr.addrCh != nil {
+		close(rr.addrCh)
+	}
+	return nil
+}
+
+// pickFirst is used to test multi-addresses in one addrConn in which all addresses share the same addrConn.
+// It is a wrapper around roundRobin balancer. The logic of all methods works fine because balancer.Get()
+// returns the only address Up by resetTransport().
+type pickFirst struct {
+	*roundRobin
+}
+
+func pickFirstBalancerV1(r naming.Resolver) Balancer {
+	return &pickFirst{&roundRobin{r: r}}
+}

vendor/google.golang.org/grpc/balancer/balancer.go

@@ -0,0 +1,228 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package balancer defines APIs for load balancing in gRPC.
+// All APIs in this package are experimental.
+package balancer
+
+import (
+	"errors"
+	"net"
+	"strings"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/resolver"
+)
+
+var (
+	// m is a map from name to balancer builder.
+	m = make(map[string]Builder)
+)
+
+// Register registers the balancer builder to the balancer map. b.Name
+// (lowercased) will be used as the name registered with this builder.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple Balancers are
+// registered with the same name, the one registered last will take effect.
+func Register(b Builder) {
+	m[strings.ToLower(b.Name())] = b
+}
+
+// Get returns the resolver builder registered with the given name.
+// Note that the compare is done in a case-insenstive fashion.
+// If no builder is register with the name, nil will be returned.
+func Get(name string) Builder {
+	if b, ok := m[strings.ToLower(name)]; ok {
+		return b
+	}
+	return nil
+}
+
+// SubConn represents a gRPC sub connection.
+// Each sub connection contains a list of addresses. gRPC will
+// try to connect to them (in sequence), and stop trying the
+// remainder once one connection is successful.
+//
+// The reconnect backoff will be applied on the list, not a single address.
+// For example, try_on_all_addresses -> backoff -> try_on_all_addresses.
+//
+// All SubConns start in IDLE, and will not try to connect. To trigger
+// the connecting, Balancers must call Connect.
+// When the connection encounters an error, it will reconnect immediately.
+// When the connection becomes IDLE, it will not reconnect unless Connect is
+// called.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
+type SubConn interface {
+	// UpdateAddresses updates the addresses used in this SubConn.
+	// gRPC checks if currently-connected address is still in the new list.
+	// If it's in the list, the connection will be kept.
+	// If it's not in the list, the connection will gracefully closed, and
+	// a new connection will be created.
+	//
+	// This will trigger a state transition for the SubConn.
+	UpdateAddresses([]resolver.Address)
+	// Connect starts the connecting for this SubConn.
+	Connect()
+}
+
+// NewSubConnOptions contains options to create new SubConn.
+type NewSubConnOptions struct{}
+
+// ClientConn represents a gRPC ClientConn.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
+type ClientConn interface {
+	// NewSubConn is called by balancer to create a new SubConn.
+	// It doesn't block and wait for the connections to be established.
+	// Behaviors of the SubConn can be controlled by options.
+	NewSubConn([]resolver.Address, NewSubConnOptions) (SubConn, error)
+	// RemoveSubConn removes the SubConn from ClientConn.
+	// The SubConn will be shutdown.
+	RemoveSubConn(SubConn)
+
+	// UpdateBalancerState is called by balancer to nofity gRPC that some internal
+	// state in balancer has changed.
+	//
+	// gRPC will update the connectivity state of the ClientConn, and will call pick
+	// on the new picker to pick new SubConn.
+	UpdateBalancerState(s connectivity.State, p Picker)
+
+	// ResolveNow is called by balancer to notify gRPC to do a name resolving.
+	ResolveNow(resolver.ResolveNowOption)
+
+	// Target returns the dial target for this ClientConn.
+	Target() string
+}
+
+// BuildOptions contains additional information for Build.
+type BuildOptions struct {
+	// DialCreds is the transport credential the Balancer implementation can
+	// use to dial to a remote load balancer server. The Balancer implementations
+	// can ignore this if it does not need to talk to another party securely.
+	DialCreds credentials.TransportCredentials
+	// Dialer is the custom dialer the Balancer implementation can use to dial
+	// to a remote load balancer server. The Balancer implementations
+	// can ignore this if it doesn't need to talk to remote balancer.
+	Dialer func(context.Context, string) (net.Conn, error)
+	// ChannelzParentID is the entity parent's channelz unique identification number.
+	ChannelzParentID int64
+}
+
+// Builder creates a balancer.
+type Builder interface {
+	// Build creates a new balancer with the ClientConn.
+	Build(cc ClientConn, opts BuildOptions) Balancer
+	// Name returns the name of balancers built by this builder.
+	// It will be used to pick balancers (for example in service config).
+	Name() string
+}
+
+// PickOptions contains addition information for the Pick operation.
+type PickOptions struct{}
+
+// DoneInfo contains additional information for done.
+type DoneInfo struct {
+	// Err is the rpc error the RPC finished with. It could be nil.
+	Err error
+	// BytesSent indicates if any bytes have been sent to the server.
+	BytesSent bool
+	// BytesReceived indicates if any byte has been received from the server.
+	BytesReceived bool
+}
+
+var (
+	// ErrNoSubConnAvailable indicates no SubConn is available for pick().
+	// gRPC will block the RPC until a new picker is available via UpdateBalancerState().
+	ErrNoSubConnAvailable = errors.New("no SubConn is available")
+	// ErrTransientFailure indicates all SubConns are in TransientFailure.
+	// WaitForReady RPCs will block, non-WaitForReady RPCs will fail.
+	ErrTransientFailure = errors.New("all SubConns are in TransientFailure")
+)
+
+// Picker is used by gRPC to pick a SubConn to send an RPC.
+// Balancer is expected to generate a new picker from its snapshot every time its
+// internal state has changed.
+//
+// The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState().
+type Picker interface {
+	// Pick returns the SubConn to be used to send the RPC.
+	// The returned SubConn must be one returned by NewSubConn().
+	//
+	// This functions is expected to return:
+	// - a SubConn that is known to be READY;
+	// - ErrNoSubConnAvailable if no SubConn is available, but progress is being
+	//   made (for example, some SubConn is in CONNECTING mode);
+	// - other errors if no active connecting is happening (for example, all SubConn
+	//   are in TRANSIENT_FAILURE mode).
+	//
+	// If a SubConn is returned:
+	// - If it is READY, gRPC will send the RPC on it;
+	// - If it is not ready, or becomes not ready after it's returned, gRPC will block
+	//   until UpdateBalancerState() is called and will call pick on the new picker.
+	//
+	// If the returned error is not nil:
+	// - If the error is ErrNoSubConnAvailable, gRPC will block until UpdateBalancerState()
+	// - If the error is ErrTransientFailure:
+	//   - If the RPC is wait-for-ready, gRPC will block until UpdateBalancerState()
+	//     is called to pick again;
+	//   - Otherwise, RPC will fail with unavailable error.
+	// - Else (error is other non-nil error):
+	//   - The RPC will fail with unavailable error.
+	//
+	// The returned done() function will be called once the rpc has finished, with the
+	// final status of that RPC.
+	// done may be nil if balancer doesn't care about the RPC status.
+	Pick(ctx context.Context, opts PickOptions) (conn SubConn, done func(DoneInfo), err error)
+}
+
+// Balancer takes input from gRPC, manages SubConns, and collects and aggregates
+// the connectivity states.
+//
+// It also generates and updates the Picker used by gRPC to pick SubConns for RPCs.
+//
+// HandleSubConnectionStateChange, HandleResolvedAddrs and Close are guaranteed
+// to be called synchronously from the same goroutine.
+// There's no guarantee on picker.Pick, it may be called anytime.
+type Balancer interface {
+	// HandleSubConnStateChange is called by gRPC when the connectivity state
+	// of sc has changed.
+	// Balancer is expected to aggregate all the state of SubConn and report
+	// that back to gRPC.
+	// Balancer should also generate and update Pickers when its internal state has
+	// been changed by the new state.
+	HandleSubConnStateChange(sc SubConn, state connectivity.State)
+	// HandleResolvedAddrs is called by gRPC to send updated resolved addresses to
+	// balancers.
+	// Balancer can create new SubConn or remove SubConn with the addresses.
+	// An empty address slice and a non-nil error will be passed if the resolver returns
+	// non-nil error to gRPC.
+	HandleResolvedAddrs([]resolver.Address, error)
+	// Close closes the balancer. The balancer is not required to call
+	// ClientConn.RemoveSubConn for its existing SubConns.
+	Close()
+}

vendor/google.golang.org/grpc/balancer/base/balancer.go

@@ -0,0 +1,208 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package base
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+type baseBuilder struct {
+	name          string
+	pickerBuilder PickerBuilder
+}
+
+func (bb *baseBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
+	return &baseBalancer{
+		cc:            cc,
+		pickerBuilder: bb.pickerBuilder,
+
+		subConns: make(map[resolver.Address]balancer.SubConn),
+		scStates: make(map[balancer.SubConn]connectivity.State),
+		csEvltr:  &connectivityStateEvaluator{},
+		// Initialize picker to a picker that always return
+		// ErrNoSubConnAvailable, because when state of a SubConn changes, we
+		// may call UpdateBalancerState with this picker.
+		picker: NewErrPicker(balancer.ErrNoSubConnAvailable),
+	}
+}
+
+func (bb *baseBuilder) Name() string {
+	return bb.name
+}
+
+type baseBalancer struct {
+	cc            balancer.ClientConn
+	pickerBuilder PickerBuilder
+
+	csEvltr *connectivityStateEvaluator
+	state   connectivity.State
+
+	subConns map[resolver.Address]balancer.SubConn
+	scStates map[balancer.SubConn]connectivity.State
+	picker   balancer.Picker
+}
+
+func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+	if err != nil {
+		grpclog.Infof("base.baseBalancer: HandleResolvedAddrs called with error %v", err)
+		return
+	}
+	grpclog.Infoln("base.baseBalancer: got new resolved addresses: ", addrs)
+	// addrsSet is the set converted from addrs, it's used for quick lookup of an address.
+	addrsSet := make(map[resolver.Address]struct{})
+	for _, a := range addrs {
+		addrsSet[a] = struct{}{}
+		if _, ok := b.subConns[a]; !ok {
+			// a is a new address (not existing in b.subConns).
+			sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
+			if err != nil {
+				grpclog.Warningf("base.baseBalancer: failed to create new SubConn: %v", err)
+				continue
+			}
+			b.subConns[a] = sc
+			b.scStates[sc] = connectivity.Idle
+			sc.Connect()
+		}
+	}
+	for a, sc := range b.subConns {
+		// a was removed by resolver.
+		if _, ok := addrsSet[a]; !ok {
+			b.cc.RemoveSubConn(sc)
+			delete(b.subConns, a)
+			// Keep the state of this sc in b.scStates until sc's state becomes Shutdown.
+			// The entry will be deleted in HandleSubConnStateChange.
+		}
+	}
+}
+
+// regeneratePicker takes a snapshot of the balancer, and generates a picker
+// from it. The picker is
+//  - errPicker with ErrTransientFailure if the balancer is in TransientFailure,
+//  - built by the pickerBuilder with all READY SubConns otherwise.
+func (b *baseBalancer) regeneratePicker() {
+	if b.state == connectivity.TransientFailure {
+		b.picker = NewErrPicker(balancer.ErrTransientFailure)
+		return
+	}
+	readySCs := make(map[resolver.Address]balancer.SubConn)
+
+	// Filter out all ready SCs from full subConn map.
+	for addr, sc := range b.subConns {
+		if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
+			readySCs[addr] = sc
+		}
+	}
+	b.picker = b.pickerBuilder.Build(readySCs)
+}
+
+func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
+	oldS, ok := b.scStates[sc]
+	if !ok {
+		grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
+		return
+	}
+	b.scStates[sc] = s
+	switch s {
+	case connectivity.Idle:
+		sc.Connect()
+	case connectivity.Shutdown:
+		// When an address was removed by resolver, b called RemoveSubConn but
+		// kept the sc's state in scStates. Remove state for this sc here.
+		delete(b.scStates, sc)
+	}
+
+	oldAggrState := b.state
+	b.state = b.csEvltr.recordTransition(oldS, s)
+
+	// Regenerate picker when one of the following happens:
+	//  - this sc became ready from not-ready
+	//  - this sc became not-ready from ready
+	//  - the aggregated state of balancer became TransientFailure from non-TransientFailure
+	//  - the aggregated state of balancer became non-TransientFailure from TransientFailure
+	if (s == connectivity.Ready) != (oldS == connectivity.Ready) ||
+		(b.state == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) {
+		b.regeneratePicker()
+	}
+
+	b.cc.UpdateBalancerState(b.state, b.picker)
+}
+
+// Close is a nop because base balancer doesn't have internal state to clean up,
+// and it doesn't need to call RemoveSubConn for the SubConns.
+func (b *baseBalancer) Close() {
+}
+
+// NewErrPicker returns a picker that always returns err on Pick().
+func NewErrPicker(err error) balancer.Picker {
+	return &errPicker{err: err}
+}
+
+type errPicker struct {
+	err error // Pick() always returns this err.
+}
+
+func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	return nil, nil, p.err
+}
+
+// connectivityStateEvaluator gets updated by addrConns when their
+// states transition, based on which it evaluates the state of
+// ClientConn.
+type connectivityStateEvaluator struct {
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+// recordTransition records state change happening in every subConn and based on
+// that it evaluates what aggregated state should be.
+// It can only transition between Ready, Connecting and TransientFailure. Other states,
+// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
+// before any subConn is created ClientConn is in idle state. In the end when ClientConn
+// closes it is in Shutdown state.
+//
+// recordTransition should only be called synchronously from the same goroutine.
+func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
+	// Update counters.
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			cse.numReady += updateVal
+		case connectivity.Connecting:
+			cse.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			cse.numTransientFailure += updateVal
+		}
+	}
+
+	// Evaluate.
+	if cse.numReady > 0 {
+		return connectivity.Ready
+	}
+	if cse.numConnecting > 0 {
+		return connectivity.Connecting
+	}
+	return connectivity.TransientFailure
+}

vendor/google.golang.org/grpc/balancer/base/base.go

@@ -0,0 +1,52 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package base defines a balancer base that can be used to build balancers with
+// different picking algorithms.
+//
+// The base balancer creates a new SubConn for each resolved address. The
+// provided picker will only be notified about READY SubConns.
+//
+// This package is the base of round_robin balancer, its purpose is to be used
+// to build round_robin like balancers with complex picking algorithms.
+// Balancers with more complicated logic should try to implement a balancer
+// builder from scratch.
+//
+// All APIs in this package are experimental.
+package base
+
+import (
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/resolver"
+)
+
+// PickerBuilder creates balancer.Picker.
+type PickerBuilder interface {
+	// Build takes a slice of ready SubConns, and returns a picker that will be
+	// used by gRPC to pick a SubConn.
+	Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker
+}
+
+// NewBalancerBuilder returns a balancer builder. The balancers
+// built by this builder will use the picker builder to build pickers.
+func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder {
+	return &baseBuilder{
+		name:          name,
+		pickerBuilder: pb,
+	}
+}

vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go

@@ -0,0 +1,79 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package roundrobin defines a roundrobin balancer. Roundrobin balancer is
+// installed as one of the default balancers in gRPC, users don't need to
+// explicitly install this balancer.
+package roundrobin
+
+import (
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/balancer/base"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// Name is the name of round_robin balancer.
+const Name = "round_robin"
+
+// newBuilder creates a new roundrobin balancer builder.
+func newBuilder() balancer.Builder {
+	return base.NewBalancerBuilder(Name, &rrPickerBuilder{})
+}
+
+func init() {
+	balancer.Register(newBuilder())
+}
+
+type rrPickerBuilder struct{}
+
+func (*rrPickerBuilder) Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker {
+	grpclog.Infof("roundrobinPicker: newPicker called with readySCs: %v", readySCs)
+	var scs []balancer.SubConn
+	for _, sc := range readySCs {
+		scs = append(scs, sc)
+	}
+	return &rrPicker{
+		subConns: scs,
+	}
+}
+
+type rrPicker struct {
+	// subConns is the snapshot of the roundrobin balancer when this picker was
+	// created. The slice is immutable. Each Get() will do a round robin
+	// selection from it and return the selected SubConn.
+	subConns []balancer.SubConn
+
+	mu   sync.Mutex
+	next int
+}
+
+func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	if len(p.subConns) <= 0 {
+		return nil, nil, balancer.ErrNoSubConnAvailable
+	}
+
+	p.mu.Lock()
+	sc := p.subConns[p.next]
+	p.next = (p.next + 1) % len(p.subConns)
+	p.mu.Unlock()
+	return sc, nil, nil
+}

vendor/google.golang.org/grpc/balancer_conn_wrappers.go

@@ -0,0 +1,300 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"sync"
+
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// scStateUpdate contains the subConn and the new state it changed to.
+type scStateUpdate struct {
+	sc    balancer.SubConn
+	state connectivity.State
+}
+
+// scStateUpdateBuffer is an unbounded channel for scStateChangeTuple.
+// TODO make a general purpose buffer that uses interface{}.
+type scStateUpdateBuffer struct {
+	c       chan *scStateUpdate
+	mu      sync.Mutex
+	backlog []*scStateUpdate
+}
+
+func newSCStateUpdateBuffer() *scStateUpdateBuffer {
+	return &scStateUpdateBuffer{
+		c: make(chan *scStateUpdate, 1),
+	}
+}
+
+func (b *scStateUpdateBuffer) put(t *scStateUpdate) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if len(b.backlog) == 0 {
+		select {
+		case b.c <- t:
+			return
+		default:
+		}
+	}
+	b.backlog = append(b.backlog, t)
+}
+
+func (b *scStateUpdateBuffer) load() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if len(b.backlog) > 0 {
+		select {
+		case b.c <- b.backlog[0]:
+			b.backlog[0] = nil
+			b.backlog = b.backlog[1:]
+		default:
+		}
+	}
+}
+
+// get returns the channel that the scStateUpdate will be sent to.
+//
+// Upon receiving, the caller should call load to send another
+// scStateChangeTuple onto the channel if there is any.
+func (b *scStateUpdateBuffer) get() <-chan *scStateUpdate {
+	return b.c
+}
+
+// resolverUpdate contains the new resolved addresses or error if there's
+// any.
+type resolverUpdate struct {
+	addrs []resolver.Address
+	err   error
+}
+
+// ccBalancerWrapper is a wrapper on top of cc for balancers.
+// It implements balancer.ClientConn interface.
+type ccBalancerWrapper struct {
+	cc               *ClientConn
+	balancer         balancer.Balancer
+	stateChangeQueue *scStateUpdateBuffer
+	resolverUpdateCh chan *resolverUpdate
+	done             chan struct{}
+
+	mu       sync.Mutex
+	subConns map[*acBalancerWrapper]struct{}
+}
+
+func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper {
+	ccb := &ccBalancerWrapper{
+		cc:               cc,
+		stateChangeQueue: newSCStateUpdateBuffer(),
+		resolverUpdateCh: make(chan *resolverUpdate, 1),
+		done:             make(chan struct{}),
+		subConns:         make(map[*acBalancerWrapper]struct{}),
+	}
+	go ccb.watcher()
+	ccb.balancer = b.Build(ccb, bopts)
+	return ccb
+}
+
+// watcher balancer functions sequentially, so the balancer can be implemented
+// lock-free.
+func (ccb *ccBalancerWrapper) watcher() {
+	for {
+		select {
+		case t := <-ccb.stateChangeQueue.get():
+			ccb.stateChangeQueue.load()
+			select {
+			case <-ccb.done:
+				ccb.balancer.Close()
+				return
+			default:
+			}
+			ccb.balancer.HandleSubConnStateChange(t.sc, t.state)
+		case t := <-ccb.resolverUpdateCh:
+			select {
+			case <-ccb.done:
+				ccb.balancer.Close()
+				return
+			default:
+			}
+			ccb.balancer.HandleResolvedAddrs(t.addrs, t.err)
+		case <-ccb.done:
+		}
+
+		select {
+		case <-ccb.done:
+			ccb.balancer.Close()
+			ccb.mu.Lock()
+			scs := ccb.subConns
+			ccb.subConns = nil
+			ccb.mu.Unlock()
+			for acbw := range scs {
+				ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+			}
+			return
+		default:
+		}
+	}
+}
+
+func (ccb *ccBalancerWrapper) close() {
+	close(ccb.done)
+}
+
+func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	// When updating addresses for a SubConn, if the address in use is not in
+	// the new addresses, the old ac will be tearDown() and a new ac will be
+	// created. tearDown() generates a state change with Shutdown state, we
+	// don't want the balancer to receive this state change. So before
+	// tearDown() on the old ac, ac.acbw (acWrapper) will be set to nil, and
+	// this function will be called with (nil, Shutdown). We don't need to call
+	// balancer method in this case.
+	if sc == nil {
+		return
+	}
+	ccb.stateChangeQueue.put(&scStateUpdate{
+		sc:    sc,
+		state: s,
+	})
+}
+
+func (ccb *ccBalancerWrapper) handleResolvedAddrs(addrs []resolver.Address, err error) {
+	select {
+	case <-ccb.resolverUpdateCh:
+	default:
+	}
+	ccb.resolverUpdateCh <- &resolverUpdate{
+		addrs: addrs,
+		err:   err,
+	}
+}
+
+func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
+	if len(addrs) <= 0 {
+		return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list")
+	}
+	ccb.mu.Lock()
+	defer ccb.mu.Unlock()
+	if ccb.subConns == nil {
+		return nil, fmt.Errorf("grpc: ClientConn balancer wrapper was closed")
+	}
+	ac, err := ccb.cc.newAddrConn(addrs)
+	if err != nil {
+		return nil, err
+	}
+	acbw := &acBalancerWrapper{ac: ac}
+	acbw.ac.mu.Lock()
+	ac.acbw = acbw
+	acbw.ac.mu.Unlock()
+	ccb.subConns[acbw] = struct{}{}
+	return acbw, nil
+}
+
+func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) {
+	acbw, ok := sc.(*acBalancerWrapper)
+	if !ok {
+		return
+	}
+	ccb.mu.Lock()
+	defer ccb.mu.Unlock()
+	if ccb.subConns == nil {
+		return
+	}
+	delete(ccb.subConns, acbw)
+	ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+}
+
+func (ccb *ccBalancerWrapper) UpdateBalancerState(s connectivity.State, p balancer.Picker) {
+	ccb.mu.Lock()
+	defer ccb.mu.Unlock()
+	if ccb.subConns == nil {
+		return
+	}
+	ccb.cc.csMgr.updateState(s)
+	ccb.cc.blockingpicker.updatePicker(p)
+}
+
+func (ccb *ccBalancerWrapper) ResolveNow(o resolver.ResolveNowOption) {
+	ccb.cc.resolveNow(o)
+}
+
+func (ccb *ccBalancerWrapper) Target() string {
+	return ccb.cc.target
+}
+
+// acBalancerWrapper is a wrapper on top of ac for balancers.
+// It implements balancer.SubConn interface.
+type acBalancerWrapper struct {
+	mu sync.Mutex
+	ac *addrConn
+}
+
+func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) {
+	acbw.mu.Lock()
+	defer acbw.mu.Unlock()
+	if len(addrs) <= 0 {
+		acbw.ac.tearDown(errConnDrain)
+		return
+	}
+	if !acbw.ac.tryUpdateAddrs(addrs) {
+		cc := acbw.ac.cc
+		acbw.ac.mu.Lock()
+		// Set old ac.acbw to nil so the Shutdown state update will be ignored
+		// by balancer.
+		//
+		// TODO(bar) the state transition could be wrong when tearDown() old ac
+		// and creating new ac, fix the transition.
+		acbw.ac.acbw = nil
+		acbw.ac.mu.Unlock()
+		acState := acbw.ac.getState()
+		acbw.ac.tearDown(errConnDrain)
+
+		if acState == connectivity.Shutdown {
+			return
+		}
+
+		ac, err := cc.newAddrConn(addrs)
+		if err != nil {
+			grpclog.Warningf("acBalancerWrapper: UpdateAddresses: failed to newAddrConn: %v", err)
+			return
+		}
+		acbw.ac = ac
+		ac.mu.Lock()
+		ac.acbw = acbw
+		ac.mu.Unlock()
+		if acState != connectivity.Idle {
+			ac.connect()
+		}
+	}
+}
+
+func (acbw *acBalancerWrapper) Connect() {
+	acbw.mu.Lock()
+	defer acbw.mu.Unlock()
+	acbw.ac.connect()
+}
+
+func (acbw *acBalancerWrapper) getAddrConn() *addrConn {
+	acbw.mu.Lock()
+	defer acbw.mu.Unlock()
+	return acbw.ac
+}

vendor/google.golang.org/grpc/balancer_v1_wrapper.go

@@ -0,0 +1,372 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"strings"
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+	"google.golang.org/grpc/status"
+)
+
+type balancerWrapperBuilder struct {
+	b Balancer // The v1 balancer.
+}
+
+func (bwb *balancerWrapperBuilder) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer {
+	targetAddr := cc.Target()
+	targetSplitted := strings.Split(targetAddr, ":///")
+	if len(targetSplitted) >= 2 {
+		targetAddr = targetSplitted[1]
+	}
+
+	bwb.b.Start(targetAddr, BalancerConfig{
+		DialCreds: opts.DialCreds,
+		Dialer:    opts.Dialer,
+	})
+	_, pickfirst := bwb.b.(*pickFirst)
+	bw := &balancerWrapper{
+		balancer:   bwb.b,
+		pickfirst:  pickfirst,
+		cc:         cc,
+		targetAddr: targetAddr,
+		startCh:    make(chan struct{}),
+		conns:      make(map[resolver.Address]balancer.SubConn),
+		connSt:     make(map[balancer.SubConn]*scState),
+		csEvltr:    &connectivityStateEvaluator{},
+		state:      connectivity.Idle,
+	}
+	cc.UpdateBalancerState(connectivity.Idle, bw)
+	go bw.lbWatcher()
+	return bw
+}
+
+func (bwb *balancerWrapperBuilder) Name() string {
+	return "wrapper"
+}
+
+type scState struct {
+	addr Address // The v1 address type.
+	s    connectivity.State
+	down func(error)
+}
+
+type balancerWrapper struct {
+	balancer  Balancer // The v1 balancer.
+	pickfirst bool
+
+	cc         balancer.ClientConn
+	targetAddr string // Target without the scheme.
+
+	// To aggregate the connectivity state.
+	csEvltr *connectivityStateEvaluator
+	state   connectivity.State
+
+	mu     sync.Mutex
+	conns  map[resolver.Address]balancer.SubConn
+	connSt map[balancer.SubConn]*scState
+	// This channel is closed when handling the first resolver result.
+	// lbWatcher blocks until this is closed, to avoid race between
+	// - NewSubConn is created, cc wants to notify balancer of state changes;
+	// - Build hasn't return, cc doesn't have access to balancer.
+	startCh chan struct{}
+}
+
+// lbWatcher watches the Notify channel of the balancer and manages
+// connections accordingly.
+func (bw *balancerWrapper) lbWatcher() {
+	<-bw.startCh
+	notifyCh := bw.balancer.Notify()
+	if notifyCh == nil {
+		// There's no resolver in the balancer. Connect directly.
+		a := resolver.Address{
+			Addr: bw.targetAddr,
+			Type: resolver.Backend,
+		}
+		sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
+		if err != nil {
+			grpclog.Warningf("Error creating connection to %v. Err: %v", a, err)
+		} else {
+			bw.mu.Lock()
+			bw.conns[a] = sc
+			bw.connSt[sc] = &scState{
+				addr: Address{Addr: bw.targetAddr},
+				s:    connectivity.Idle,
+			}
+			bw.mu.Unlock()
+			sc.Connect()
+		}
+		return
+	}
+
+	for addrs := range notifyCh {
+		grpclog.Infof("balancerWrapper: got update addr from Notify: %v\n", addrs)
+		if bw.pickfirst {
+			var (
+				oldA  resolver.Address
+				oldSC balancer.SubConn
+			)
+			bw.mu.Lock()
+			for oldA, oldSC = range bw.conns {
+				break
+			}
+			bw.mu.Unlock()
+			if len(addrs) <= 0 {
+				if oldSC != nil {
+					// Teardown old sc.
+					bw.mu.Lock()
+					delete(bw.conns, oldA)
+					delete(bw.connSt, oldSC)
+					bw.mu.Unlock()
+					bw.cc.RemoveSubConn(oldSC)
+				}
+				continue
+			}
+
+			var newAddrs []resolver.Address
+			for _, a := range addrs {
+				newAddr := resolver.Address{
+					Addr:       a.Addr,
+					Type:       resolver.Backend, // All addresses from balancer are all backends.
+					ServerName: "",
+					Metadata:   a.Metadata,
+				}
+				newAddrs = append(newAddrs, newAddr)
+			}
+			if oldSC == nil {
+				// Create new sc.
+				sc, err := bw.cc.NewSubConn(newAddrs, balancer.NewSubConnOptions{})
+				if err != nil {
+					grpclog.Warningf("Error creating connection to %v. Err: %v", newAddrs, err)
+				} else {
+					bw.mu.Lock()
+					// For pickfirst, there should be only one SubConn, so the
+					// address doesn't matter. All states updating (up and down)
+					// and picking should all happen on that only SubConn.
+					bw.conns[resolver.Address{}] = sc
+					bw.connSt[sc] = &scState{
+						addr: addrs[0], // Use the first address.
+						s:    connectivity.Idle,
+					}
+					bw.mu.Unlock()
+					sc.Connect()
+				}
+			} else {
+				bw.mu.Lock()
+				bw.connSt[oldSC].addr = addrs[0]
+				bw.mu.Unlock()
+				oldSC.UpdateAddresses(newAddrs)
+			}
+		} else {
+			var (
+				add []resolver.Address // Addresses need to setup connections.
+				del []balancer.SubConn // Connections need to tear down.
+			)
+			resAddrs := make(map[resolver.Address]Address)
+			for _, a := range addrs {
+				resAddrs[resolver.Address{
+					Addr:       a.Addr,
+					Type:       resolver.Backend, // All addresses from balancer are all backends.
+					ServerName: "",
+					Metadata:   a.Metadata,
+				}] = a
+			}
+			bw.mu.Lock()
+			for a := range resAddrs {
+				if _, ok := bw.conns[a]; !ok {
+					add = append(add, a)
+				}
+			}
+			for a, c := range bw.conns {
+				if _, ok := resAddrs[a]; !ok {
+					del = append(del, c)
+					delete(bw.conns, a)
+					// Keep the state of this sc in bw.connSt until its state becomes Shutdown.
+				}
+			}
+			bw.mu.Unlock()
+			for _, a := range add {
+				sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
+				if err != nil {
+					grpclog.Warningf("Error creating connection to %v. Err: %v", a, err)
+				} else {
+					bw.mu.Lock()
+					bw.conns[a] = sc
+					bw.connSt[sc] = &scState{
+						addr: resAddrs[a],
+						s:    connectivity.Idle,
+					}
+					bw.mu.Unlock()
+					sc.Connect()
+				}
+			}
+			for _, c := range del {
+				bw.cc.RemoveSubConn(c)
+			}
+		}
+	}
+}
+
+func (bw *balancerWrapper) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	scSt, ok := bw.connSt[sc]
+	if !ok {
+		return
+	}
+	if s == connectivity.Idle {
+		sc.Connect()
+	}
+	oldS := scSt.s
+	scSt.s = s
+	if oldS != connectivity.Ready && s == connectivity.Ready {
+		scSt.down = bw.balancer.Up(scSt.addr)
+	} else if oldS == connectivity.Ready && s != connectivity.Ready {
+		if scSt.down != nil {
+			scSt.down(errConnClosing)
+		}
+	}
+	sa := bw.csEvltr.recordTransition(oldS, s)
+	if bw.state != sa {
+		bw.state = sa
+	}
+	bw.cc.UpdateBalancerState(bw.state, bw)
+	if s == connectivity.Shutdown {
+		// Remove state for this sc.
+		delete(bw.connSt, sc)
+	}
+}
+
+func (bw *balancerWrapper) HandleResolvedAddrs([]resolver.Address, error) {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	select {
+	case <-bw.startCh:
+	default:
+		close(bw.startCh)
+	}
+	// There should be a resolver inside the balancer.
+	// All updates here, if any, are ignored.
+}
+
+func (bw *balancerWrapper) Close() {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	select {
+	case <-bw.startCh:
+	default:
+		close(bw.startCh)
+	}
+	bw.balancer.Close()
+}
+
+// The picker is the balancerWrapper itself.
+// Pick should never return ErrNoSubConnAvailable.
+// It either blocks or returns error, consistent with v1 balancer Get().
+func (bw *balancerWrapper) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	failfast := true // Default failfast is true.
+	if ss, ok := rpcInfoFromContext(ctx); ok {
+		failfast = ss.failfast
+	}
+	a, p, err := bw.balancer.Get(ctx, BalancerGetOptions{BlockingWait: !failfast})
+	if err != nil {
+		return nil, nil, err
+	}
+	var done func(balancer.DoneInfo)
+	if p != nil {
+		done = func(i balancer.DoneInfo) { p() }
+	}
+	var sc balancer.SubConn
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	if bw.pickfirst {
+		// Get the first sc in conns.
+		for _, sc = range bw.conns {
+			break
+		}
+	} else {
+		var ok bool
+		sc, ok = bw.conns[resolver.Address{
+			Addr:       a.Addr,
+			Type:       resolver.Backend,
+			ServerName: "",
+			Metadata:   a.Metadata,
+		}]
+		if !ok && failfast {
+			return nil, nil, status.Errorf(codes.Unavailable, "there is no connection available")
+		}
+		if s, ok := bw.connSt[sc]; failfast && (!ok || s.s != connectivity.Ready) {
+			// If the returned sc is not ready and RPC is failfast,
+			// return error, and this RPC will fail.
+			return nil, nil, status.Errorf(codes.Unavailable, "there is no connection available")
+		}
+	}
+
+	return sc, done, nil
+}
+
+// connectivityStateEvaluator gets updated by addrConns when their
+// states transition, based on which it evaluates the state of
+// ClientConn.
+type connectivityStateEvaluator struct {
+	mu                  sync.Mutex
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+// recordTransition records state change happening in every subConn and based on
+// that it evaluates what aggregated state should be.
+// It can only transition between Ready, Connecting and TransientFailure. Other states,
+// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
+// before any subConn is created ClientConn is in idle state. In the end when ClientConn
+// closes it is in Shutdown state.
+// TODO Note that in later releases, a ClientConn with no activity will be put into an Idle state.
+func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
+	cse.mu.Lock()
+	defer cse.mu.Unlock()
+
+	// Update counters.
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			cse.numReady += updateVal
+		case connectivity.Connecting:
+			cse.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			cse.numTransientFailure += updateVal
+		}
+	}
+
+	// Evaluate.
+	if cse.numReady > 0 {
+		return connectivity.Ready
+	}
+	if cse.numConnecting > 0 {
+		return connectivity.Connecting
+	}
+	return connectivity.TransientFailure
+}

vendor/google.golang.org/grpc/call.go

@@ -0,0 +1,93 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"golang.org/x/net/context"
+)
+
+// Invoke sends the RPC request on the wire and returns after response is
+// received.  This is typically called by generated code.
+//
+// All errors returned by Invoke are compatible with the status package.
+func (cc *ClientConn) Invoke(ctx context.Context, method string, args, reply interface{}, opts ...CallOption) error {
+	// allow interceptor to see all applicable call options, which means those
+	// configured as defaults from dial option as well as per-call options
+	opts = combine(cc.dopts.callOptions, opts)
+
+	if cc.dopts.unaryInt != nil {
+		return cc.dopts.unaryInt(ctx, method, args, reply, cc, invoke, opts...)
+	}
+	return invoke(ctx, method, args, reply, cc, opts...)
+}
+
+func combine(o1 []CallOption, o2 []CallOption) []CallOption {
+	// we don't use append because o1 could have extra capacity whose
+	// elements would be overwritten, which could cause inadvertent
+	// sharing (and race connditions) between concurrent calls
+	if len(o1) == 0 {
+		return o2
+	} else if len(o2) == 0 {
+		return o1
+	}
+	ret := make([]CallOption, len(o1)+len(o2))
+	copy(ret, o1)
+	copy(ret[len(o1):], o2)
+	return ret
+}
+
+// Invoke sends the RPC request on the wire and returns after response is
+// received.  This is typically called by generated code.
+//
+// DEPRECATED: Use ClientConn.Invoke instead.
+func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) error {
+	return cc.Invoke(ctx, method, args, reply, opts...)
+}
+
+var unaryStreamDesc = &StreamDesc{ServerStreams: false, ClientStreams: false}
+
+func invoke(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error {
+	// TODO: implement retries in clientStream and make this simply
+	// newClientStream, SendMsg, RecvMsg.
+	firstAttempt := true
+	for {
+		csInt, err := newClientStream(ctx, unaryStreamDesc, cc, method, opts...)
+		if err != nil {
+			return err
+		}
+		cs := csInt.(*clientStream)
+		if err := cs.SendMsg(req); err != nil {
+			if !cs.c.failFast && cs.attempt.s.Unprocessed() && firstAttempt {
+				// TODO: Add a field to header for grpc-transparent-retry-attempts
+				firstAttempt = false
+				continue
+			}
+			return err
+		}
+		if err := cs.RecvMsg(reply); err != nil {
+			if !cs.c.failFast && cs.attempt.s.Unprocessed() && firstAttempt {
+				// TODO: Add a field to header for grpc-transparent-retry-attempts
+				firstAttempt = false
+				continue
+			}
+			return err
+		}
+		return nil
+	}
+}

vendor/google.golang.org/grpc/channelz/funcs.go

@@ -0,0 +1,573 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package channelz defines APIs for enabling channelz service, entry
+// registration/deletion, and accessing channelz data. It also defines channelz
+// metric struct formats.
+//
+// All APIs in this package are experimental.
+package channelz
+
+import (
+	"sort"
+	"sync"
+	"sync/atomic"
+
+	"google.golang.org/grpc/grpclog"
+)
+
+var (
+	db    dbWrapper
+	idGen idGenerator
+	// EntryPerPage defines the number of channelz entries to be shown on a web page.
+	EntryPerPage = 50
+	curState     int32
+)
+
+// TurnOn turns on channelz data collection.
+func TurnOn() {
+	if !IsOn() {
+		NewChannelzStorage()
+		atomic.StoreInt32(&curState, 1)
+	}
+}
+
+// IsOn returns whether channelz data collection is on.
+func IsOn() bool {
+	return atomic.CompareAndSwapInt32(&curState, 1, 1)
+}
+
+// dbWarpper wraps around a reference to internal channelz data storage, and
+// provide synchronized functionality to set and get the reference.
+type dbWrapper struct {
+	mu sync.RWMutex
+	DB *channelMap
+}
+
+func (d *dbWrapper) set(db *channelMap) {
+	d.mu.Lock()
+	d.DB = db
+	d.mu.Unlock()
+}
+
+func (d *dbWrapper) get() *channelMap {
+	d.mu.RLock()
+	defer d.mu.RUnlock()
+	return d.DB
+}
+
+// NewChannelzStorage initializes channelz data storage and id generator.
+//
+// Note: This function is exported for testing purpose only. User should not call
+// it in most cases.
+func NewChannelzStorage() {
+	db.set(&channelMap{
+		topLevelChannels: make(map[int64]struct{}),
+		channels:         make(map[int64]*channel),
+		listenSockets:    make(map[int64]*listenSocket),
+		normalSockets:    make(map[int64]*normalSocket),
+		servers:          make(map[int64]*server),
+		subChannels:      make(map[int64]*subChannel),
+	})
+	idGen.reset()
+}
+
+// GetTopChannels returns a slice of top channel's ChannelMetric, along with a
+// boolean indicating whether there's more top channels to be queried for.
+//
+// The arg id specifies that only top channel with id at or above it will be included
+// in the result. The returned slice is up to a length of EntryPerPage, and is
+// sorted in ascending id order.
+func GetTopChannels(id int64) ([]*ChannelMetric, bool) {
+	return db.get().GetTopChannels(id)
+}
+
+// GetServers returns a slice of server's ServerMetric, along with a
+// boolean indicating whether there's more servers to be queried for.
+//
+// The arg id specifies that only server with id at or above it will be included
+// in the result. The returned slice is up to a length of EntryPerPage, and is
+// sorted in ascending id order.
+func GetServers(id int64) ([]*ServerMetric, bool) {
+	return db.get().GetServers(id)
+}
+
+// GetServerSockets returns a slice of server's (identified by id) normal socket's
+// SocketMetric, along with a boolean indicating whether there's more sockets to
+// be queried for.
+//
+// The arg startID specifies that only sockets with id at or above it will be
+// included in the result. The returned slice is up to a length of EntryPerPage,
+// and is sorted in ascending id order.
+func GetServerSockets(id int64, startID int64) ([]*SocketMetric, bool) {
+	return db.get().GetServerSockets(id, startID)
+}
+
+// GetChannel returns the ChannelMetric for the channel (identified by id).
+func GetChannel(id int64) *ChannelMetric {
+	return db.get().GetChannel(id)
+}
+
+// GetSubChannel returns the SubChannelMetric for the subchannel (identified by id).
+func GetSubChannel(id int64) *SubChannelMetric {
+	return db.get().GetSubChannel(id)
+}
+
+// GetSocket returns the SocketInternalMetric for the socket (identified by id).
+func GetSocket(id int64) *SocketMetric {
+	return db.get().GetSocket(id)
+}
+
+// RegisterChannel registers the given channel c in channelz database with ref
+// as its reference name, and add it to the child list of its parent (identified
+// by pid). pid = 0 means no parent. It returns the unique channelz tracking id
+// assigned to this channel.
+func RegisterChannel(c Channel, pid int64, ref string) int64 {
+	id := idGen.genID()
+	cn := &channel{
+		refName:     ref,
+		c:           c,
+		subChans:    make(map[int64]string),
+		nestedChans: make(map[int64]string),
+		id:          id,
+		pid:         pid,
+	}
+	if pid == 0 {
+		db.get().addChannel(id, cn, true, pid, ref)
+	} else {
+		db.get().addChannel(id, cn, false, pid, ref)
+	}
+	return id
+}
+
+// RegisterSubChannel registers the given channel c in channelz database with ref
+// as its reference name, and add it to the child list of its parent (identified
+// by pid). It returns the unique channelz tracking id assigned to this subchannel.
+func RegisterSubChannel(c Channel, pid int64, ref string) int64 {
+	if pid == 0 {
+		grpclog.Error("a SubChannel's parent id cannot be 0")
+		return 0
+	}
+	id := idGen.genID()
+	sc := &subChannel{
+		refName: ref,
+		c:       c,
+		sockets: make(map[int64]string),
+		id:      id,
+		pid:     pid,
+	}
+	db.get().addSubChannel(id, sc, pid, ref)
+	return id
+}
+
+// RegisterServer registers the given server s in channelz database. It returns
+// the unique channelz tracking id assigned to this server.
+func RegisterServer(s Server, ref string) int64 {
+	id := idGen.genID()
+	svr := &server{
+		refName:       ref,
+		s:             s,
+		sockets:       make(map[int64]string),
+		listenSockets: make(map[int64]string),
+		id:            id,
+	}
+	db.get().addServer(id, svr)
+	return id
+}
+
+// RegisterListenSocket registers the given listen socket s in channelz database
+// with ref as its reference name, and add it to the child list of its parent
+// (identified by pid). It returns the unique channelz tracking id assigned to
+// this listen socket.
+func RegisterListenSocket(s Socket, pid int64, ref string) int64 {
+	if pid == 0 {
+		grpclog.Error("a ListenSocket's parent id cannot be 0")
+		return 0
+	}
+	id := idGen.genID()
+	ls := &listenSocket{refName: ref, s: s, id: id, pid: pid}
+	db.get().addListenSocket(id, ls, pid, ref)
+	return id
+}
+
+// RegisterNormalSocket registers the given normal socket s in channelz database
+// with ref as its reference name, and add it to the child list of its parent
+// (identified by pid). It returns the unique channelz tracking id assigned to
+// this normal socket.
+func RegisterNormalSocket(s Socket, pid int64, ref string) int64 {
+	if pid == 0 {
+		grpclog.Error("a NormalSocket's parent id cannot be 0")
+		return 0
+	}
+	id := idGen.genID()
+	ns := &normalSocket{refName: ref, s: s, id: id, pid: pid}
+	db.get().addNormalSocket(id, ns, pid, ref)
+	return id
+}
+
+// RemoveEntry removes an entry with unique channelz trakcing id to be id from
+// channelz database.
+func RemoveEntry(id int64) {
+	db.get().removeEntry(id)
+}
+
+// channelMap is the storage data structure for channelz.
+// Methods of channelMap can be divided in two two categories with respect to locking.
+// 1. Methods acquire the global lock.
+// 2. Methods that can only be called when global lock is held.
+// A second type of method need always to be called inside a first type of method.
+type channelMap struct {
+	mu               sync.RWMutex
+	topLevelChannels map[int64]struct{}
+	servers          map[int64]*server
+	channels         map[int64]*channel
+	subChannels      map[int64]*subChannel
+	listenSockets    map[int64]*listenSocket
+	normalSockets    map[int64]*normalSocket
+}
+
+func (c *channelMap) addServer(id int64, s *server) {
+	c.mu.Lock()
+	s.cm = c
+	c.servers[id] = s
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addChannel(id int64, cn *channel, isTopChannel bool, pid int64, ref string) {
+	c.mu.Lock()
+	cn.cm = c
+	c.channels[id] = cn
+	if isTopChannel {
+		c.topLevelChannels[id] = struct{}{}
+	} else {
+		c.findEntry(pid).addChild(id, cn)
+	}
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addSubChannel(id int64, sc *subChannel, pid int64, ref string) {
+	c.mu.Lock()
+	sc.cm = c
+	c.subChannels[id] = sc
+	c.findEntry(pid).addChild(id, sc)
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addListenSocket(id int64, ls *listenSocket, pid int64, ref string) {
+	c.mu.Lock()
+	ls.cm = c
+	c.listenSockets[id] = ls
+	c.findEntry(pid).addChild(id, ls)
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addNormalSocket(id int64, ns *normalSocket, pid int64, ref string) {
+	c.mu.Lock()
+	ns.cm = c
+	c.normalSockets[id] = ns
+	c.findEntry(pid).addChild(id, ns)
+	c.mu.Unlock()
+}
+
+// removeEntry triggers the removal of an entry, which may not indeed delete the
+// entry, if it has to wait on the deletion of its children, or may lead to a chain
+// of entry deletion. For example, deleting the last socket of a gracefully shutting
+// down server will lead to the server being also deleted.
+func (c *channelMap) removeEntry(id int64) {
+	c.mu.Lock()
+	c.findEntry(id).triggerDelete()
+	c.mu.Unlock()
+}
+
+// c.mu must be held by the caller.
+func (c *channelMap) findEntry(id int64) entry {
+	var v entry
+	var ok bool
+	if v, ok = c.channels[id]; ok {
+		return v
+	}
+	if v, ok = c.subChannels[id]; ok {
+		return v
+	}
+	if v, ok = c.servers[id]; ok {
+		return v
+	}
+	if v, ok = c.listenSockets[id]; ok {
+		return v
+	}
+	if v, ok = c.normalSockets[id]; ok {
+		return v
+	}
+	return &dummyEntry{idNotFound: id}
+}
+
+// c.mu must be held by the caller
+// deleteEntry simply deletes an entry from the channelMap. Before calling this
+// method, caller must check this entry is ready to be deleted, i.e removeEntry()
+// has been called on it, and no children still exist.
+// Conditionals are ordered by the expected frequency of deletion of each entity
+// type, in order to optimize performance.
+func (c *channelMap) deleteEntry(id int64) {
+	var ok bool
+	if _, ok = c.normalSockets[id]; ok {
+		delete(c.normalSockets, id)
+		return
+	}
+	if _, ok = c.subChannels[id]; ok {
+		delete(c.subChannels, id)
+		return
+	}
+	if _, ok = c.channels[id]; ok {
+		delete(c.channels, id)
+		delete(c.topLevelChannels, id)
+		return
+	}
+	if _, ok = c.listenSockets[id]; ok {
+		delete(c.listenSockets, id)
+		return
+	}
+	if _, ok = c.servers[id]; ok {
+		delete(c.servers, id)
+		return
+	}
+}
+
+type int64Slice []int64
+
+func (s int64Slice) Len() int           { return len(s) }
+func (s int64Slice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s int64Slice) Less(i, j int) bool { return s[i] < s[j] }
+
+func copyMap(m map[int64]string) map[int64]string {
+	n := make(map[int64]string)
+	for k, v := range m {
+		n[k] = v
+	}
+	return n
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func (c *channelMap) GetTopChannels(id int64) ([]*ChannelMetric, bool) {
+	c.mu.RLock()
+	l := len(c.topLevelChannels)
+	ids := make([]int64, 0, l)
+	cns := make([]*channel, 0, min(l, EntryPerPage))
+
+	for k := range c.topLevelChannels {
+		ids = append(ids, k)
+	}
+	sort.Sort(int64Slice(ids))
+	idx := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+	count := 0
+	var end bool
+	var t []*ChannelMetric
+	for i, v := range ids[idx:] {
+		if count == EntryPerPage {
+			break
+		}
+		if cn, ok := c.channels[v]; ok {
+			cns = append(cns, cn)
+			t = append(t, &ChannelMetric{
+				NestedChans: copyMap(cn.nestedChans),
+				SubChans:    copyMap(cn.subChans),
+			})
+			count++
+		}
+		if i == len(ids[idx:])-1 {
+			end = true
+			break
+		}
+	}
+	c.mu.RUnlock()
+	if count == 0 {
+		end = true
+	}
+
+	for i, cn := range cns {
+		t[i].ChannelData = cn.c.ChannelzMetric()
+		t[i].ID = cn.id
+		t[i].RefName = cn.refName
+	}
+	return t, end
+}
+
+func (c *channelMap) GetServers(id int64) ([]*ServerMetric, bool) {
+	c.mu.RLock()
+	l := len(c.servers)
+	ids := make([]int64, 0, l)
+	ss := make([]*server, 0, min(l, EntryPerPage))
+	for k := range c.servers {
+		ids = append(ids, k)
+	}
+	sort.Sort(int64Slice(ids))
+	idx := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+	count := 0
+	var end bool
+	var s []*ServerMetric
+	for i, v := range ids[idx:] {
+		if count == EntryPerPage {
+			break
+		}
+		if svr, ok := c.servers[v]; ok {
+			ss = append(ss, svr)
+			s = append(s, &ServerMetric{
+				ListenSockets: copyMap(svr.listenSockets),
+			})
+			count++
+		}
+		if i == len(ids[idx:])-1 {
+			end = true
+			break
+		}
+	}
+	c.mu.RUnlock()
+	if count == 0 {
+		end = true
+	}
+
+	for i, svr := range ss {
+		s[i].ServerData = svr.s.ChannelzMetric()
+		s[i].ID = svr.id
+		s[i].RefName = svr.refName
+	}
+	return s, end
+}
+
+func (c *channelMap) GetServerSockets(id int64, startID int64) ([]*SocketMetric, bool) {
+	var svr *server
+	var ok bool
+	c.mu.RLock()
+	if svr, ok = c.servers[id]; !ok {
+		// server with id doesn't exist.
+		c.mu.RUnlock()
+		return nil, true
+	}
+	svrskts := svr.sockets
+	l := len(svrskts)
+	ids := make([]int64, 0, l)
+	sks := make([]*normalSocket, 0, min(l, EntryPerPage))
+	for k := range svrskts {
+		ids = append(ids, k)
+	}
+	sort.Sort((int64Slice(ids)))
+	idx := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+	count := 0
+	var end bool
+	for i, v := range ids[idx:] {
+		if count == EntryPerPage {
+			break
+		}
+		if ns, ok := c.normalSockets[v]; ok {
+			sks = append(sks, ns)
+			count++
+		}
+		if i == len(ids[idx:])-1 {
+			end = true
+			break
+		}
+	}
+	c.mu.RUnlock()
+	if count == 0 {
+		end = true
+	}
+	var s []*SocketMetric
+	for _, ns := range sks {
+		sm := &SocketMetric{}
+		sm.SocketData = ns.s.ChannelzMetric()
+		sm.ID = ns.id
+		sm.RefName = ns.refName
+		s = append(s, sm)
+	}
+	return s, end
+}
+
+func (c *channelMap) GetChannel(id int64) *ChannelMetric {
+	cm := &ChannelMetric{}
+	var cn *channel
+	var ok bool
+	c.mu.RLock()
+	if cn, ok = c.channels[id]; !ok {
+		// channel with id doesn't exist.
+		c.mu.RUnlock()
+		return nil
+	}
+	cm.NestedChans = copyMap(cn.nestedChans)
+	cm.SubChans = copyMap(cn.subChans)
+	c.mu.RUnlock()
+	cm.ChannelData = cn.c.ChannelzMetric()
+	cm.ID = cn.id
+	cm.RefName = cn.refName
+	return cm
+}
+
+func (c *channelMap) GetSubChannel(id int64) *SubChannelMetric {
+	cm := &SubChannelMetric{}
+	var sc *subChannel
+	var ok bool
+	c.mu.RLock()
+	if sc, ok = c.subChannels[id]; !ok {
+		// subchannel with id doesn't exist.
+		c.mu.RUnlock()
+		return nil
+	}
+	cm.Sockets = copyMap(sc.sockets)
+	c.mu.RUnlock()
+	cm.ChannelData = sc.c.ChannelzMetric()
+	cm.ID = sc.id
+	cm.RefName = sc.refName
+	return cm
+}
+
+func (c *channelMap) GetSocket(id int64) *SocketMetric {
+	sm := &SocketMetric{}
+	c.mu.RLock()
+	if ls, ok := c.listenSockets[id]; ok {
+		c.mu.RUnlock()
+		sm.SocketData = ls.s.ChannelzMetric()
+		sm.ID = ls.id
+		sm.RefName = ls.refName
+		return sm
+	}
+	if ns, ok := c.normalSockets[id]; ok {
+		c.mu.RUnlock()
+		sm.SocketData = ns.s.ChannelzMetric()
+		sm.ID = ns.id
+		sm.RefName = ns.refName
+		return sm
+	}
+	c.mu.RUnlock()
+	return nil
+}
+
+type idGenerator struct {
+	id int64
+}
+
+func (i *idGenerator) reset() {
+	atomic.StoreInt64(&i.id, 0)
+}
+
+func (i *idGenerator) genID() int64 {
+	return atomic.AddInt64(&i.id, 1)
+}

vendor/google.golang.org/grpc/channelz/types.go

@@ -0,0 +1,418 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package channelz
+
+import (
+	"net"
+	"time"
+
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+)
+
+// entry represents a node in the channelz database.
+type entry interface {
+	// addChild adds a child e, whose channelz id is id to child list
+	addChild(id int64, e entry)
+	// deleteChild deletes a child with channelz id to be id from child list
+	deleteChild(id int64)
+	// triggerDelete tries to delete self from channelz database. However, if child
+	// list is not empty, then deletion from the database is on hold until the last
+	// child is deleted from database.
+	triggerDelete()
+	// deleteSelfIfReady check whether triggerDelete() has been called before, and whether child
+	// list is now empty. If both conditions are met, then delete self from database.
+	deleteSelfIfReady()
+}
+
+// dummyEntry is a fake entry to handle entry not found case.
+type dummyEntry struct {
+	idNotFound int64
+}
+
+func (d *dummyEntry) addChild(id int64, e entry) {
+	// Note: It is possible for a normal program to reach here under race condition.
+	// For example, there could be a race between ClientConn.Close() info being propagated
+	// to addrConn and http2Client. ClientConn.Close() cancel the context and result
+	// in http2Client to error. The error info is then caught by transport monitor
+	// and before addrConn.tearDown() is called in side ClientConn.Close(). Therefore,
+	// the addrConn will create a new transport. And when registering the new transport in
+	// channelz, its parent addrConn could have already been torn down and deleted
+	// from channelz tracking, and thus reach the code here.
+	grpclog.Infof("attempt to add child of type %T with id %d to a parent (id=%d) that doesn't currently exist", e, id, d.idNotFound)
+}
+
+func (d *dummyEntry) deleteChild(id int64) {
+	// It is possible for a normal program to reach here under race condition.
+	// Refer to the example described in addChild().
+	grpclog.Infof("attempt to delete child with id %d from a parent (id=%d) that doesn't currently exist", id, d.idNotFound)
+}
+
+func (d *dummyEntry) triggerDelete() {
+	grpclog.Warningf("attempt to delete an entry (id=%d) that doesn't currently exist", d.idNotFound)
+}
+
+func (*dummyEntry) deleteSelfIfReady() {
+	// code should not reach here. deleteSelfIfReady is always called on an existing entry.
+}
+
+// ChannelMetric defines the info channelz provides for a specific Channel, which
+// includes ChannelInternalMetric and channelz-specific data, such as channelz id,
+// child list, etc.
+type ChannelMetric struct {
+	// ID is the channelz id of this channel.
+	ID int64
+	// RefName is the human readable reference string of this channel.
+	RefName string
+	// ChannelData contains channel internal metric reported by the channel through
+	// ChannelzMetric().
+	ChannelData *ChannelInternalMetric
+	// NestedChans tracks the nested channel type children of this channel in the format of
+	// a map from nested channel channelz id to corresponding reference string.
+	NestedChans map[int64]string
+	// SubChans tracks the subchannel type children of this channel in the format of a
+	// map from subchannel channelz id to corresponding reference string.
+	SubChans map[int64]string
+	// Sockets tracks the socket type children of this channel in the format of a map
+	// from socket channelz id to corresponding reference string.
+	// Note current grpc implementation doesn't allow channel having sockets directly,
+	// therefore, this is field is unused.
+	Sockets map[int64]string
+}
+
+// SubChannelMetric defines the info channelz provides for a specific SubChannel,
+// which includes ChannelInternalMetric and channelz-specific data, such as
+// channelz id, child list, etc.
+type SubChannelMetric struct {
+	// ID is the channelz id of this subchannel.
+	ID int64
+	// RefName is the human readable reference string of this subchannel.
+	RefName string
+	// ChannelData contains subchannel internal metric reported by the subchannel
+	// through ChannelzMetric().
+	ChannelData *ChannelInternalMetric
+	// NestedChans tracks the nested channel type children of this subchannel in the format of
+	// a map from nested channel channelz id to corresponding reference string.
+	// Note current grpc implementation doesn't allow subchannel to have nested channels
+	// as children, therefore, this field is unused.
+	NestedChans map[int64]string
+	// SubChans tracks the subchannel type children of this subchannel in the format of a
+	// map from subchannel channelz id to corresponding reference string.
+	// Note current grpc implementation doesn't allow subchannel to have subchannels
+	// as children, therefore, this field is unused.
+	SubChans map[int64]string
+	// Sockets tracks the socket type children of this subchannel in the format of a map
+	// from socket channelz id to corresponding reference string.
+	Sockets map[int64]string
+}
+
+// ChannelInternalMetric defines the struct that the implementor of Channel interface
+// should return from ChannelzMetric().
+type ChannelInternalMetric struct {
+	// current connectivity state of the channel.
+	State connectivity.State
+	// The target this channel originally tried to connect to.  May be absent
+	Target string
+	// The number of calls started on the channel.
+	CallsStarted int64
+	// The number of calls that have completed with an OK status.
+	CallsSucceeded int64
+	// The number of calls that have a completed with a non-OK status.
+	CallsFailed int64
+	// The last time a call was started on the channel.
+	LastCallStartedTimestamp time.Time
+	//TODO: trace
+}
+
+// Channel is the interface that should be satisfied in order to be tracked by
+// channelz as Channel or SubChannel.
+type Channel interface {
+	ChannelzMetric() *ChannelInternalMetric
+}
+
+type channel struct {
+	refName     string
+	c           Channel
+	closeCalled bool
+	nestedChans map[int64]string
+	subChans    map[int64]string
+	id          int64
+	pid         int64
+	cm          *channelMap
+}
+
+func (c *channel) addChild(id int64, e entry) {
+	switch v := e.(type) {
+	case *subChannel:
+		c.subChans[id] = v.refName
+	case *channel:
+		c.nestedChans[id] = v.refName
+	default:
+		grpclog.Errorf("cannot add a child (id = %d) of type %T to a channel", id, e)
+	}
+}
+
+func (c *channel) deleteChild(id int64) {
+	delete(c.subChans, id)
+	delete(c.nestedChans, id)
+	c.deleteSelfIfReady()
+}
+
+func (c *channel) triggerDelete() {
+	c.closeCalled = true
+	c.deleteSelfIfReady()
+}
+
+func (c *channel) deleteSelfIfReady() {
+	if !c.closeCalled || len(c.subChans)+len(c.nestedChans) != 0 {
+		return
+	}
+	c.cm.deleteEntry(c.id)
+	// not top channel
+	if c.pid != 0 {
+		c.cm.findEntry(c.pid).deleteChild(c.id)
+	}
+}
+
+type subChannel struct {
+	refName     string
+	c           Channel
+	closeCalled bool
+	sockets     map[int64]string
+	id          int64
+	pid         int64
+	cm          *channelMap
+}
+
+func (sc *subChannel) addChild(id int64, e entry) {
+	if v, ok := e.(*normalSocket); ok {
+		sc.sockets[id] = v.refName
+	} else {
+		grpclog.Errorf("cannot add a child (id = %d) of type %T to a subChannel", id, e)
+	}
+}
+
+func (sc *subChannel) deleteChild(id int64) {
+	delete(sc.sockets, id)
+	sc.deleteSelfIfReady()
+}
+
+func (sc *subChannel) triggerDelete() {
+	sc.closeCalled = true
+	sc.deleteSelfIfReady()
+}
+
+func (sc *subChannel) deleteSelfIfReady() {
+	if !sc.closeCalled || len(sc.sockets) != 0 {
+		return
+	}
+	sc.cm.deleteEntry(sc.id)
+	sc.cm.findEntry(sc.pid).deleteChild(sc.id)
+}
+
+// SocketMetric defines the info channelz provides for a specific Socket, which
+// includes SocketInternalMetric and channelz-specific data, such as channelz id, etc.
+type SocketMetric struct {
+	// ID is the channelz id of this socket.
+	ID int64
+	// RefName is the human readable reference string of this socket.
+	RefName string
+	// SocketData contains socket internal metric reported by the socket through
+	// ChannelzMetric().
+	SocketData *SocketInternalMetric
+}
+
+// SocketInternalMetric defines the struct that the implementor of Socket interface
+// should return from ChannelzMetric().
+type SocketInternalMetric struct {
+	// The number of streams that have been started.
+	StreamsStarted int64
+	// The number of streams that have ended successfully:
+	// On client side, receiving frame with eos bit set.
+	// On server side, sending frame with eos bit set.
+	StreamsSucceeded int64
+	// The number of streams that have ended unsuccessfully:
+	// On client side, termination without receiving frame with eos bit set.
+	// On server side, termination without sending frame with eos bit set.
+	StreamsFailed int64
+	// The number of messages successfully sent on this socket.
+	MessagesSent     int64
+	MessagesReceived int64
+	// The number of keep alives sent.  This is typically implemented with HTTP/2
+	// ping messages.
+	KeepAlivesSent int64
+	// The last time a stream was created by this endpoint.  Usually unset for
+	// servers.
+	LastLocalStreamCreatedTimestamp time.Time
+	// The last time a stream was created by the remote endpoint.  Usually unset
+	// for clients.
+	LastRemoteStreamCreatedTimestamp time.Time
+	// The last time a message was sent by this endpoint.
+	LastMessageSentTimestamp time.Time
+	// The last time a message was received by this endpoint.
+	LastMessageReceivedTimestamp time.Time
+	// The amount of window, granted to the local endpoint by the remote endpoint.
+	// This may be slightly out of date due to network latency.  This does NOT
+	// include stream level or TCP level flow control info.
+	LocalFlowControlWindow int64
+	// The amount of window, granted to the remote endpoint by the local endpoint.
+	// This may be slightly out of date due to network latency.  This does NOT
+	// include stream level or TCP level flow control info.
+	RemoteFlowControlWindow int64
+	// The locally bound address.
+	LocalAddr net.Addr
+	// The remote bound address.  May be absent.
+	RemoteAddr net.Addr
+	// Optional, represents the name of the remote endpoint, if different than
+	// the original target name.
+	RemoteName string
+	//TODO: socket options
+	//TODO: Security
+}
+
+// Socket is the interface that should be satisfied in order to be tracked by
+// channelz as Socket.
+type Socket interface {
+	ChannelzMetric() *SocketInternalMetric
+}
+
+type listenSocket struct {
+	refName string
+	s       Socket
+	id      int64
+	pid     int64
+	cm      *channelMap
+}
+
+func (ls *listenSocket) addChild(id int64, e entry) {
+	grpclog.Errorf("cannot add a child (id = %d) of type %T to a listen socket", id, e)
+}
+
+func (ls *listenSocket) deleteChild(id int64) {
+	grpclog.Errorf("cannot delete a child (id = %d) from a listen socket", id)
+}
+
+func (ls *listenSocket) triggerDelete() {
+	ls.cm.deleteEntry(ls.id)
+	ls.cm.findEntry(ls.pid).deleteChild(ls.id)
+}
+
+func (ls *listenSocket) deleteSelfIfReady() {
+	grpclog.Errorf("cannot call deleteSelfIfReady on a listen socket")
+}
+
+type normalSocket struct {
+	refName string
+	s       Socket
+	id      int64
+	pid     int64
+	cm      *channelMap
+}
+
+func (ns *normalSocket) addChild(id int64, e entry) {
+	grpclog.Errorf("cannot add a child (id = %d) of type %T to a normal socket", id, e)
+}
+
+func (ns *normalSocket) deleteChild(id int64) {
+	grpclog.Errorf("cannot delete a child (id = %d) from a normal socket", id)
+}
+
+func (ns *normalSocket) triggerDelete() {
+	ns.cm.deleteEntry(ns.id)
+	ns.cm.findEntry(ns.pid).deleteChild(ns.id)
+}
+
+func (ns *normalSocket) deleteSelfIfReady() {
+	grpclog.Errorf("cannot call deleteSelfIfReady on a normal socket")
+}
+
+// ServerMetric defines the info channelz provides for a specific Server, which
+// includes ServerInternalMetric and channelz-specific data, such as channelz id,
+// child list, etc.
+type ServerMetric struct {
+	// ID is the channelz id of this server.
+	ID int64
+	// RefName is the human readable reference string of this server.
+	RefName string
+	// ServerData contains server internal metric reported by the server through
+	// ChannelzMetric().
+	ServerData *ServerInternalMetric
+	// ListenSockets tracks the listener socket type children of this server in the
+	// format of a map from socket channelz id to corresponding reference string.
+	ListenSockets map[int64]string
+}
+
+// ServerInternalMetric defines the struct that the implementor of Server interface
+// should return from ChannelzMetric().
+type ServerInternalMetric struct {
+	// The number of incoming calls started on the server.
+	CallsStarted int64
+	// The number of incoming calls that have completed with an OK status.
+	CallsSucceeded int64
+	// The number of incoming calls that have a completed with a non-OK status.
+	CallsFailed int64
+	// The last time a call was started on the server.
+	LastCallStartedTimestamp time.Time
+	//TODO: trace
+}
+
+// Server is the interface to be satisfied in order to be tracked by channelz as
+// Server.
+type Server interface {
+	ChannelzMetric() *ServerInternalMetric
+}
+
+type server struct {
+	refName       string
+	s             Server
+	closeCalled   bool
+	sockets       map[int64]string
+	listenSockets map[int64]string
+	id            int64
+	cm            *channelMap
+}
+
+func (s *server) addChild(id int64, e entry) {
+	switch v := e.(type) {
+	case *normalSocket:
+		s.sockets[id] = v.refName
+	case *listenSocket:
+		s.listenSockets[id] = v.refName
+	default:
+		grpclog.Errorf("cannot add a child (id = %d) of type %T to a server", id, e)
+	}
+}
+
+func (s *server) deleteChild(id int64) {
+	delete(s.sockets, id)
+	delete(s.listenSockets, id)
+	s.deleteSelfIfReady()
+}
+
+func (s *server) triggerDelete() {
+	s.closeCalled = true
+	s.deleteSelfIfReady()
+}
+
+func (s *server) deleteSelfIfReady() {
+	if !s.closeCalled || len(s.sockets)+len(s.listenSockets) != 0 {
+		return
+	}
+	s.cm.deleteEntry(s.id)
+}

vendor/google.golang.org/grpc/codec.go

@@ -0,0 +1,50 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"google.golang.org/grpc/encoding"
+	_ "google.golang.org/grpc/encoding/proto" // to register the Codec for "proto"
+)
+
+// baseCodec contains the functionality of both Codec and encoding.Codec, but
+// omits the name/string, which vary between the two and are not needed for
+// anything besides the registry in the encoding package.
+type baseCodec interface {
+	Marshal(v interface{}) ([]byte, error)
+	Unmarshal(data []byte, v interface{}) error
+}
+
+var _ baseCodec = Codec(nil)
+var _ baseCodec = encoding.Codec(nil)
+
+// Codec defines the interface gRPC uses to encode and decode messages.
+// Note that implementations of this interface must be thread safe;
+// a Codec's methods can be called from concurrent goroutines.
+//
+// Deprecated: use encoding.Codec instead.
+type Codec interface {
+	// Marshal returns the wire format of v.
+	Marshal(v interface{}) ([]byte, error)
+	// Unmarshal parses the wire format into v.
+	Unmarshal(data []byte, v interface{}) error
+	// String returns the name of the Codec implementation.  This is unused by
+	// gRPC.
+	String() string
+}

vendor/google.golang.org/grpc/codegen.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+# This script serves as an example to demonstrate how to generate the gRPC-Go
+# interface and the related messages from .proto file.
+#
+# It assumes the installation of i) Google proto buffer compiler at
+# https://github.com/google/protobuf (after v2.6.1) and ii) the Go codegen
+# plugin at https://github.com/golang/protobuf (after 2015-02-20). If you have
+# not, please install them first.
+#
+# We recommend running this script at $GOPATH/src.
+#
+# If this is not what you need, feel free to make your own scripts. Again, this
+# script is for demonstration purpose.
+#
+proto=$1
+protoc --go_out=plugins=grpc:. $proto

vendor/google.golang.org/grpc/codes/code_string.go

@@ -0,0 +1,62 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package codes
+
+import "strconv"
+
+func (c Code) String() string {
+	switch c {
+	case OK:
+		return "OK"
+	case Canceled:
+		return "Canceled"
+	case Unknown:
+		return "Unknown"
+	case InvalidArgument:
+		return "InvalidArgument"
+	case DeadlineExceeded:
+		return "DeadlineExceeded"
+	case NotFound:
+		return "NotFound"
+	case AlreadyExists:
+		return "AlreadyExists"
+	case PermissionDenied:
+		return "PermissionDenied"
+	case ResourceExhausted:
+		return "ResourceExhausted"
+	case FailedPrecondition:
+		return "FailedPrecondition"
+	case Aborted:
+		return "Aborted"
+	case OutOfRange:
+		return "OutOfRange"
+	case Unimplemented:
+		return "Unimplemented"
+	case Internal:
+		return "Internal"
+	case Unavailable:
+		return "Unavailable"
+	case DataLoss:
+		return "DataLoss"
+	case Unauthenticated:
+		return "Unauthenticated"
+	default:
+		return "Code(" + strconv.FormatInt(int64(c), 10) + ")"
+	}
+}

vendor/google.golang.org/grpc/codes/codes.go

@@ -0,0 +1,184 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package codes defines the canonical error codes used by gRPC. It is
+// consistent across various languages.
+package codes // import "google.golang.org/grpc/codes"
+
+import (
+	"fmt"
+)
+
+// A Code is an unsigned 32-bit error code as defined in the gRPC spec.
+type Code uint32
+
+const (
+	// OK is returned on success.
+	OK Code = 0
+
+	// Canceled indicates the operation was canceled (typically by the caller).
+	Canceled Code = 1
+
+	// Unknown error. An example of where this error may be returned is
+	// if a Status value received from another address space belongs to
+	// an error-space that is not known in this address space. Also
+	// errors raised by APIs that do not return enough error information
+	// may be converted to this error.
+	Unknown Code = 2
+
+	// InvalidArgument indicates client specified an invalid argument.
+	// Note that this differs from FailedPrecondition. It indicates arguments
+	// that are problematic regardless of the state of the system
+	// (e.g., a malformed file name).
+	InvalidArgument Code = 3
+
+	// DeadlineExceeded means operation expired before completion.
+	// For operations that change the state of the system, this error may be
+	// returned even if the operation has completed successfully. For
+	// example, a successful response from a server could have been delayed
+	// long enough for the deadline to expire.
+	DeadlineExceeded Code = 4
+
+	// NotFound means some requested entity (e.g., file or directory) was
+	// not found.
+	NotFound Code = 5
+
+	// AlreadyExists means an attempt to create an entity failed because one
+	// already exists.
+	AlreadyExists Code = 6
+
+	// PermissionDenied indicates the caller does not have permission to
+	// execute the specified operation. It must not be used for rejections
+	// caused by exhausting some resource (use ResourceExhausted
+	// instead for those errors). It must not be
+	// used if the caller cannot be identified (use Unauthenticated
+	// instead for those errors).
+	PermissionDenied Code = 7
+
+	// ResourceExhausted indicates some resource has been exhausted, perhaps
+	// a per-user quota, or perhaps the entire file system is out of space.
+	ResourceExhausted Code = 8
+
+	// FailedPrecondition indicates operation was rejected because the
+	// system is not in a state required for the operation's execution.
+	// For example, directory to be deleted may be non-empty, an rmdir
+	// operation is applied to a non-directory, etc.
+	//
+	// A litmus test that may help a service implementor in deciding
+	// between FailedPrecondition, Aborted, and Unavailable:
+	//  (a) Use Unavailable if the client can retry just the failing call.
+	//  (b) Use Aborted if the client should retry at a higher-level
+	//      (e.g., restarting a read-modify-write sequence).
+	//  (c) Use FailedPrecondition if the client should not retry until
+	//      the system state has been explicitly fixed. E.g., if an "rmdir"
+	//      fails because the directory is non-empty, FailedPrecondition
+	//      should be returned since the client should not retry unless
+	//      they have first fixed up the directory by deleting files from it.
+	//  (d) Use FailedPrecondition if the client performs conditional
+	//      REST Get/Update/Delete on a resource and the resource on the
+	//      server does not match the condition. E.g., conflicting
+	//      read-modify-write on the same resource.
+	FailedPrecondition Code = 9
+
+	// Aborted indicates the operation was aborted, typically due to a
+	// concurrency issue like sequencer check failures, transaction aborts,
+	// etc.
+	//
+	// See litmus test above for deciding between FailedPrecondition,
+	// Aborted, and Unavailable.
+	Aborted Code = 10
+
+	// OutOfRange means operation was attempted past the valid range.
+	// E.g., seeking or reading past end of file.
+	//
+	// Unlike InvalidArgument, this error indicates a problem that may
+	// be fixed if the system state changes. For example, a 32-bit file
+	// system will generate InvalidArgument if asked to read at an
+	// offset that is not in the range [0,2^32-1], but it will generate
+	// OutOfRange if asked to read from an offset past the current
+	// file size.
+	//
+	// There is a fair bit of overlap between FailedPrecondition and
+	// OutOfRange. We recommend using OutOfRange (the more specific
+	// error) when it applies so that callers who are iterating through
+	// a space can easily look for an OutOfRange error to detect when
+	// they are done.
+	OutOfRange Code = 11
+
+	// Unimplemented indicates operation is not implemented or not
+	// supported/enabled in this service.
+	Unimplemented Code = 12
+
+	// Internal errors. Means some invariants expected by underlying
+	// system has been broken. If you see one of these errors,
+	// something is very broken.
+	Internal Code = 13
+
+	// Unavailable indicates the service is currently unavailable.
+	// This is a most likely a transient condition and may be corrected
+	// by retrying with a backoff.
+	//
+	// See litmus test above for deciding between FailedPrecondition,
+	// Aborted, and Unavailable.
+	Unavailable Code = 14
+
+	// DataLoss indicates unrecoverable data loss or corruption.
+	DataLoss Code = 15
+
+	// Unauthenticated indicates the request does not have valid
+	// authentication credentials for the operation.
+	Unauthenticated Code = 16
+)
+
+var strToCode = map[string]Code{
+	`"OK"`: OK,
+	`"CANCELLED"`:/* [sic] */ Canceled,
+	`"UNKNOWN"`:             Unknown,
+	`"INVALID_ARGUMENT"`:    InvalidArgument,
+	`"DEADLINE_EXCEEDED"`:   DeadlineExceeded,
+	`"NOT_FOUND"`:           NotFound,
+	`"ALREADY_EXISTS"`:      AlreadyExists,
+	`"PERMISSION_DENIED"`:   PermissionDenied,
+	`"RESOURCE_EXHAUSTED"`:  ResourceExhausted,
+	`"FAILED_PRECONDITION"`: FailedPrecondition,
+	`"ABORTED"`:             Aborted,
+	`"OUT_OF_RANGE"`:        OutOfRange,
+	`"UNIMPLEMENTED"`:       Unimplemented,
+	`"INTERNAL"`:            Internal,
+	`"UNAVAILABLE"`:         Unavailable,
+	`"DATA_LOSS"`:           DataLoss,
+	`"UNAUTHENTICATED"`:     Unauthenticated,
+}
+
+// UnmarshalJSON unmarshals b into the Code.
+func (c *Code) UnmarshalJSON(b []byte) error {
+	// From json.Unmarshaler: By convention, to approximate the behavior of
+	// Unmarshal itself, Unmarshalers implement UnmarshalJSON([]byte("null")) as
+	// a no-op.
+	if string(b) == "null" {
+		return nil
+	}
+	if c == nil {
+		return fmt.Errorf("nil receiver passed to UnmarshalJSON")
+	}
+	if jc, ok := strToCode[string(b)]; ok {
+		*c = jc
+		return nil
+	}
+	return fmt.Errorf("invalid code: %q", string(b))
+}

vendor/google.golang.org/grpc/connectivity/connectivity.go

@@ -0,0 +1,72 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package connectivity defines connectivity semantics.
+// For details, see https://github.com/grpc/grpc/blob/master/doc/connectivity-semantics-and-api.md.
+// All APIs in this package are experimental.
+package connectivity
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/grpclog"
+)
+
+// State indicates the state of connectivity.
+// It can be the state of a ClientConn or SubConn.
+type State int
+
+func (s State) String() string {
+	switch s {
+	case Idle:
+		return "IDLE"
+	case Connecting:
+		return "CONNECTING"
+	case Ready:
+		return "READY"
+	case TransientFailure:
+		return "TRANSIENT_FAILURE"
+	case Shutdown:
+		return "SHUTDOWN"
+	default:
+		grpclog.Errorf("unknown connectivity state: %d", s)
+		return "Invalid-State"
+	}
+}
+
+const (
+	// Idle indicates the ClientConn is idle.
+	Idle State = iota
+	// Connecting indicates the ClienConn is connecting.
+	Connecting
+	// Ready indicates the ClientConn is ready for work.
+	Ready
+	// TransientFailure indicates the ClientConn has seen a failure but expects to recover.
+	TransientFailure
+	// Shutdown indicates the ClientConn has started shutting down.
+	Shutdown
+)
+
+// Reporter reports the connectivity states.
+type Reporter interface {
+	// CurrentState returns the current state of the reporter.
+	CurrentState() State
+	// WaitForStateChange blocks until the reporter's state is different from the given state,
+	// and returns true.
+	// It returns false if <-ctx.Done() can proceed (ctx got timeout or got canceled).
+	WaitForStateChange(context.Context, State) bool
+}

vendor/google.golang.org/grpc/credentials/credentials.go

@@ -0,0 +1,220 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package credentials implements various credentials supported by gRPC library,
+// which encapsulate all the state needed by a client to authenticate with a
+// server and make various assertions, e.g., about the client's identity, role,
+// or whether it is authorized to make a particular call.
+package credentials // import "google.golang.org/grpc/credentials"
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+// alpnProtoStr are the specified application level protocols for gRPC.
+var alpnProtoStr = []string{"h2"}
+
+// PerRPCCredentials defines the common interface for the credentials which need to
+// attach security information to every RPC (e.g., oauth2).
+type PerRPCCredentials interface {
+	// GetRequestMetadata gets the current request metadata, refreshing
+	// tokens if required. This should be called by the transport layer on
+	// each request, and the data should be populated in headers or other
+	// context. If a status code is returned, it will be used as the status
+	// for the RPC. uri is the URI of the entry point for the request.
+	// When supported by the underlying implementation, ctx can be used for
+	// timeout and cancellation.
+	// TODO(zhaoq): Define the set of the qualified keys instead of leaving
+	// it as an arbitrary string.
+	GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error)
+	// RequireTransportSecurity indicates whether the credentials requires
+	// transport security.
+	RequireTransportSecurity() bool
+}
+
+// ProtocolInfo provides information regarding the gRPC wire protocol version,
+// security protocol, security protocol version in use, server name, etc.
+type ProtocolInfo struct {
+	// ProtocolVersion is the gRPC wire protocol version.
+	ProtocolVersion string
+	// SecurityProtocol is the security protocol in use.
+	SecurityProtocol string
+	// SecurityVersion is the security protocol version.
+	SecurityVersion string
+	// ServerName is the user-configured server name.
+	ServerName string
+}
+
+// AuthInfo defines the common interface for the auth information the users are interested in.
+type AuthInfo interface {
+	AuthType() string
+}
+
+// ErrConnDispatched indicates that rawConn has been dispatched out of gRPC
+// and the caller should not close rawConn.
+var ErrConnDispatched = errors.New("credentials: rawConn is dispatched out of gRPC")
+
+// TransportCredentials defines the common interface for all the live gRPC wire
+// protocols and supported transport security protocols (e.g., TLS, SSL).
+type TransportCredentials interface {
+	// ClientHandshake does the authentication handshake specified by the corresponding
+	// authentication protocol on rawConn for clients. It returns the authenticated
+	// connection and the corresponding auth information about the connection.
+	// Implementations must use the provided context to implement timely cancellation.
+	// gRPC will try to reconnect if the error returned is a temporary error
+	// (io.EOF, context.DeadlineExceeded or err.Temporary() == true).
+	// If the returned error is a wrapper error, implementations should make sure that
+	// the error implements Temporary() to have the correct retry behaviors.
+	//
+	// If the returned net.Conn is closed, it MUST close the net.Conn provided.
+	ClientHandshake(context.Context, string, net.Conn) (net.Conn, AuthInfo, error)
+	// ServerHandshake does the authentication handshake for servers. It returns
+	// the authenticated connection and the corresponding auth information about
+	// the connection.
+	//
+	// If the returned net.Conn is closed, it MUST close the net.Conn provided.
+	ServerHandshake(net.Conn) (net.Conn, AuthInfo, error)
+	// Info provides the ProtocolInfo of this TransportCredentials.
+	Info() ProtocolInfo
+	// Clone makes a copy of this TransportCredentials.
+	Clone() TransportCredentials
+	// OverrideServerName overrides the server name used to verify the hostname on the returned certificates from the server.
+	// gRPC internals also use it to override the virtual hosting name if it is set.
+	// It must be called before dialing. Currently, this is only used by grpclb.
+	OverrideServerName(string) error
+}
+
+// TLSInfo contains the auth information for a TLS authenticated connection.
+// It implements the AuthInfo interface.
+type TLSInfo struct {
+	State tls.ConnectionState
+}
+
+// AuthType returns the type of TLSInfo as a string.
+func (t TLSInfo) AuthType() string {
+	return "tls"
+}
+
+// tlsCreds is the credentials required for authenticating a connection using TLS.
+type tlsCreds struct {
+	// TLS configuration
+	config *tls.Config
+}
+
+func (c tlsCreds) Info() ProtocolInfo {
+	return ProtocolInfo{
+		SecurityProtocol: "tls",
+		SecurityVersion:  "1.2",
+		ServerName:       c.config.ServerName,
+	}
+}
+
+func (c *tlsCreds) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (_ net.Conn, _ AuthInfo, err error) {
+	// use local cfg to avoid clobbering ServerName if using multiple endpoints
+	cfg := cloneTLSConfig(c.config)
+	if cfg.ServerName == "" {
+		colonPos := strings.LastIndex(authority, ":")
+		if colonPos == -1 {
+			colonPos = len(authority)
+		}
+		cfg.ServerName = authority[:colonPos]
+	}
+	conn := tls.Client(rawConn, cfg)
+	errChannel := make(chan error, 1)
+	go func() {
+		errChannel <- conn.Handshake()
+	}()
+	select {
+	case err := <-errChannel:
+		if err != nil {
+			return nil, nil, err
+		}
+	case <-ctx.Done():
+		return nil, nil, ctx.Err()
+	}
+	return conn, TLSInfo{conn.ConnectionState()}, nil
+}
+
+func (c *tlsCreds) ServerHandshake(rawConn net.Conn) (net.Conn, AuthInfo, error) {
+	conn := tls.Server(rawConn, c.config)
+	if err := conn.Handshake(); err != nil {
+		return nil, nil, err
+	}
+	return conn, TLSInfo{conn.ConnectionState()}, nil
+}
+
+func (c *tlsCreds) Clone() TransportCredentials {
+	return NewTLS(c.config)
+}
+
+func (c *tlsCreds) OverrideServerName(serverNameOverride string) error {
+	c.config.ServerName = serverNameOverride
+	return nil
+}
+
+// NewTLS uses c to construct a TransportCredentials based on TLS.
+func NewTLS(c *tls.Config) TransportCredentials {
+	tc := &tlsCreds{cloneTLSConfig(c)}
+	tc.config.NextProtos = alpnProtoStr
+	return tc
+}
+
+// NewClientTLSFromCert constructs TLS credentials from the input certificate for client.
+// serverNameOverride is for testing only. If set to a non empty string,
+// it will override the virtual host name of authority (e.g. :authority header field) in requests.
+func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverride string) TransportCredentials {
+	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp})
+}
+
+// NewClientTLSFromFile constructs TLS credentials from the input certificate file for client.
+// serverNameOverride is for testing only. If set to a non empty string,
+// it will override the virtual host name of authority (e.g. :authority header field) in requests.
+func NewClientTLSFromFile(certFile, serverNameOverride string) (TransportCredentials, error) {
+	b, err := ioutil.ReadFile(certFile)
+	if err != nil {
+		return nil, err
+	}
+	cp := x509.NewCertPool()
+	if !cp.AppendCertsFromPEM(b) {
+		return nil, fmt.Errorf("credentials: failed to append certificates")
+	}
+	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp}), nil
+}
+
+// NewServerTLSFromCert constructs TLS credentials from the input certificate for server.
+func NewServerTLSFromCert(cert *tls.Certificate) TransportCredentials {
+	return NewTLS(&tls.Config{Certificates: []tls.Certificate{*cert}})
+}
+
+// NewServerTLSFromFile constructs TLS credentials from the input certificate file and key
+// file for server.
+func NewServerTLSFromFile(certFile, keyFile string) (TransportCredentials, error) {
+	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		return nil, err
+	}
+	return NewTLS(&tls.Config{Certificates: []tls.Certificate{cert}}), nil
+}

vendor/google.golang.org/grpc/credentials/credentials_util_go17.go

@@ -0,0 +1,60 @@
+// +build go1.7
+// +build !go1.8
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+)
+
+// cloneTLSConfig returns a shallow clone of the exported
+// fields of cfg, ignoring the unexported sync.Once, which
+// contains a mutex and must not be copied.
+//
+// If cfg is nil, a new zero tls.Config is returned.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return &tls.Config{
+		Rand:                        cfg.Rand,
+		Time:                        cfg.Time,
+		Certificates:                cfg.Certificates,
+		NameToCertificate:           cfg.NameToCertificate,
+		GetCertificate:              cfg.GetCertificate,
+		RootCAs:                     cfg.RootCAs,
+		NextProtos:                  cfg.NextProtos,
+		ServerName:                  cfg.ServerName,
+		ClientAuth:                  cfg.ClientAuth,
+		ClientCAs:                   cfg.ClientCAs,
+		InsecureSkipVerify:          cfg.InsecureSkipVerify,
+		CipherSuites:                cfg.CipherSuites,
+		PreferServerCipherSuites:    cfg.PreferServerCipherSuites,
+		SessionTicketsDisabled:      cfg.SessionTicketsDisabled,
+		SessionTicketKey:            cfg.SessionTicketKey,
+		ClientSessionCache:          cfg.ClientSessionCache,
+		MinVersion:                  cfg.MinVersion,
+		MaxVersion:                  cfg.MaxVersion,
+		CurvePreferences:            cfg.CurvePreferences,
+		DynamicRecordSizingDisabled: cfg.DynamicRecordSizingDisabled,
+		Renegotiation:               cfg.Renegotiation,
+	}
+}

vendor/google.golang.org/grpc/credentials/credentials_util_go18.go

@@ -0,0 +1,38 @@
+// +build go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+)
+
+// cloneTLSConfig returns a shallow clone of the exported
+// fields of cfg, ignoring the unexported sync.Once, which
+// contains a mutex and must not be copied.
+//
+// If cfg is nil, a new zero tls.Config is returned.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+
+	return cfg.Clone()
+}

vendor/google.golang.org/grpc/credentials/credentials_util_pre_go17.go

@@ -0,0 +1,57 @@
+// +build !go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+)
+
+// cloneTLSConfig returns a shallow clone of the exported
+// fields of cfg, ignoring the unexported sync.Once, which
+// contains a mutex and must not be copied.
+//
+// If cfg is nil, a new zero tls.Config is returned.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return &tls.Config{
+		Rand:                     cfg.Rand,
+		Time:                     cfg.Time,
+		Certificates:             cfg.Certificates,
+		NameToCertificate:        cfg.NameToCertificate,
+		GetCertificate:           cfg.GetCertificate,
+		RootCAs:                  cfg.RootCAs,
+		NextProtos:               cfg.NextProtos,
+		ServerName:               cfg.ServerName,
+		ClientAuth:               cfg.ClientAuth,
+		ClientCAs:                cfg.ClientCAs,
+		InsecureSkipVerify:       cfg.InsecureSkipVerify,
+		CipherSuites:             cfg.CipherSuites,
+		PreferServerCipherSuites: cfg.PreferServerCipherSuites,
+		SessionTicketsDisabled:   cfg.SessionTicketsDisabled,
+		SessionTicketKey:         cfg.SessionTicketKey,
+		ClientSessionCache:       cfg.ClientSessionCache,
+		MinVersion:               cfg.MinVersion,
+		MaxVersion:               cfg.MaxVersion,
+		CurvePreferences:         cfg.CurvePreferences,
+	}
+}

vendor/google.golang.org/grpc/doc.go

@@ -0,0 +1,24 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+/*
+Package grpc implements an RPC system called gRPC.
+
+See grpc.io for more information about gRPC.
+*/
+package grpc // import "google.golang.org/grpc"

vendor/google.golang.org/grpc/encoding/encoding.go

@@ -0,0 +1,118 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package encoding defines the interface for the compressor and codec, and
+// functions to register and retrieve compressors and codecs.
+//
+// This package is EXPERIMENTAL.
+package encoding
+
+import (
+	"io"
+	"strings"
+)
+
+// Identity specifies the optional encoding for uncompressed streams.
+// It is intended for grpc internal use only.
+const Identity = "identity"
+
+// Compressor is used for compressing and decompressing when sending or
+// receiving messages.
+type Compressor interface {
+	// Compress writes the data written to wc to w after compressing it.  If an
+	// error occurs while initializing the compressor, that error is returned
+	// instead.
+	Compress(w io.Writer) (io.WriteCloser, error)
+	// Decompress reads data from r, decompresses it, and provides the
+	// uncompressed data via the returned io.Reader.  If an error occurs while
+	// initializing the decompressor, that error is returned instead.
+	Decompress(r io.Reader) (io.Reader, error)
+	// Name is the name of the compression codec and is used to set the content
+	// coding header.  The result must be static; the result cannot change
+	// between calls.
+	Name() string
+}
+
+var registeredCompressor = make(map[string]Compressor)
+
+// RegisterCompressor registers the compressor with gRPC by its name.  It can
+// be activated when sending an RPC via grpc.UseCompressor().  It will be
+// automatically accessed when receiving a message based on the content coding
+// header.  Servers also use it to send a response with the same encoding as
+// the request.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCompressor(c Compressor) {
+	registeredCompressor[c.Name()] = c
+}
+
+// GetCompressor returns Compressor for the given compressor name.
+func GetCompressor(name string) Compressor {
+	return registeredCompressor[name]
+}
+
+// Codec defines the interface gRPC uses to encode and decode messages.  Note
+// that implementations of this interface must be thread safe; a Codec's
+// methods can be called from concurrent goroutines.
+type Codec interface {
+	// Marshal returns the wire format of v.
+	Marshal(v interface{}) ([]byte, error)
+	// Unmarshal parses the wire format into v.
+	Unmarshal(data []byte, v interface{}) error
+	// Name returns the name of the Codec implementation. The returned string
+	// will be used as part of content type in transmission.  The result must be
+	// static; the result cannot change between calls.
+	Name() string
+}
+
+var registeredCodecs = make(map[string]Codec)
+
+// RegisterCodec registers the provided Codec for use with all gRPC clients and
+// servers.
+//
+// The Codec will be stored and looked up by result of its Name() method, which
+// should match the content-subtype of the encoding handled by the Codec.  This
+// is case-insensitive, and is stored and looked up as lowercase.  If the
+// result of calling Name() is an empty string, RegisterCodec will panic. See
+// Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCodec(codec Codec) {
+	if codec == nil {
+		panic("cannot register a nil Codec")
+	}
+	contentSubtype := strings.ToLower(codec.Name())
+	if contentSubtype == "" {
+		panic("cannot register Codec with empty string result for String()")
+	}
+	registeredCodecs[contentSubtype] = codec
+}
+
+// GetCodec gets a registered Codec by content-subtype, or nil if no Codec is
+// registered for the content-subtype.
+//
+// The content-subtype is expected to be lowercase.
+func GetCodec(contentSubtype string) Codec {
+	return registeredCodecs[contentSubtype]
+}

vendor/google.golang.org/grpc/encoding/proto/proto.go

@@ -0,0 +1,110 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package proto defines the protobuf codec. Importing this package will
+// register the codec.
+package proto
+
+import (
+	"math"
+	"sync"
+
+	"github.com/golang/protobuf/proto"
+	"google.golang.org/grpc/encoding"
+)
+
+// Name is the name registered for the proto compressor.
+const Name = "proto"
+
+func init() {
+	encoding.RegisterCodec(codec{})
+}
+
+// codec is a Codec implementation with protobuf. It is the default codec for gRPC.
+type codec struct{}
+
+type cachedProtoBuffer struct {
+	lastMarshaledSize uint32
+	proto.Buffer
+}
+
+func capToMaxInt32(val int) uint32 {
+	if val > math.MaxInt32 {
+		return uint32(math.MaxInt32)
+	}
+	return uint32(val)
+}
+
+func marshal(v interface{}, cb *cachedProtoBuffer) ([]byte, error) {
+	protoMsg := v.(proto.Message)
+	newSlice := make([]byte, 0, cb.lastMarshaledSize)
+
+	cb.SetBuf(newSlice)
+	cb.Reset()
+	if err := cb.Marshal(protoMsg); err != nil {
+		return nil, err
+	}
+	out := cb.Bytes()
+	cb.lastMarshaledSize = capToMaxInt32(len(out))
+	return out, nil
+}
+
+func (codec) Marshal(v interface{}) ([]byte, error) {
+	if pm, ok := v.(proto.Marshaler); ok {
+		// object can marshal itself, no need for buffer
+		return pm.Marshal()
+	}
+
+	cb := protoBufferPool.Get().(*cachedProtoBuffer)
+	out, err := marshal(v, cb)
+
+	// put back buffer and lose the ref to the slice
+	cb.SetBuf(nil)
+	protoBufferPool.Put(cb)
+	return out, err
+}
+
+func (codec) Unmarshal(data []byte, v interface{}) error {
+	protoMsg := v.(proto.Message)
+	protoMsg.Reset()
+
+	if pu, ok := protoMsg.(proto.Unmarshaler); ok {
+		// object can unmarshal itself, no need for buffer
+		return pu.Unmarshal(data)
+	}
+
+	cb := protoBufferPool.Get().(*cachedProtoBuffer)
+	cb.SetBuf(data)
+	err := cb.Unmarshal(protoMsg)
+	cb.SetBuf(nil)
+	protoBufferPool.Put(cb)
+	return err
+}
+
+func (codec) Name() string {
+	return Name
+}
+
+var protoBufferPool = &sync.Pool{
+	New: func() interface{} {
+		return &cachedProtoBuffer{
+			Buffer:            proto.Buffer{},
+			lastMarshaledSize: 16,
+		}
+	},
+}

vendor/google.golang.org/grpc/envconfig.go

@@ -0,0 +1,37 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"os"
+	"strings"
+)
+
+const (
+	envConfigPrefix        = "GRPC_GO_"
+	envConfigStickinessStr = envConfigPrefix + "STICKINESS"
+)
+
+var (
+	envConfigStickinessOn bool
+)
+
+func init() {
+	envConfigStickinessOn = strings.EqualFold(os.Getenv(envConfigStickinessStr), "on")
+}

vendor/google.golang.org/grpc/go16.go

@@ -0,0 +1,70 @@
+// +build go1.6,!go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
+}
+
+func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
+	req.Cancel = ctx.Done()
+	if err := req.Write(conn); err != nil {
+		return fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+	return nil
+}
+
+// toRPCErr converts an error into an error from the status package.
+func toRPCErr(err error) error {
+	if err == nil || err == io.EOF {
+		return err
+	}
+	if _, ok := status.FromError(err); ok {
+		return err
+	}
+	switch e := err.(type) {
+	case transport.StreamError:
+		return status.Error(e.Code, e.Desc)
+	case transport.ConnectionError:
+		return status.Error(codes.Unavailable, e.Desc)
+	default:
+		switch err {
+		case context.DeadlineExceeded:
+			return status.Error(codes.DeadlineExceeded, err.Error())
+		case context.Canceled:
+			return status.Error(codes.Canceled, err.Error())
+		}
+	}
+	return status.Error(codes.Unknown, err.Error())
+}

vendor/google.golang.org/grpc/go17.go

@@ -0,0 +1,71 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+
+	netctx "golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{}).DialContext(ctx, network, address)
+}
+
+func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
+	req = req.WithContext(ctx)
+	if err := req.Write(conn); err != nil {
+		return fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+	return nil
+}
+
+// toRPCErr converts an error into an error from the status package.
+func toRPCErr(err error) error {
+	if err == nil || err == io.EOF {
+		return err
+	}
+	if _, ok := status.FromError(err); ok {
+		return err
+	}
+	switch e := err.(type) {
+	case transport.StreamError:
+		return status.Error(e.Code, e.Desc)
+	case transport.ConnectionError:
+		return status.Error(codes.Unavailable, e.Desc)
+	default:
+		switch err {
+		case context.DeadlineExceeded, netctx.DeadlineExceeded:
+			return status.Error(codes.DeadlineExceeded, err.Error())
+		case context.Canceled, netctx.Canceled:
+			return status.Error(codes.Canceled, err.Error())
+		}
+	}
+	return status.Error(codes.Unknown, err.Error())
+}

vendor/google.golang.org/grpc/grpclb.go

@@ -0,0 +1,341 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	lbpb "google.golang.org/grpc/grpclb/grpc_lb_v1/messages"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+const (
+	lbTokeyKey             = "lb-token"
+	defaultFallbackTimeout = 10 * time.Second
+	grpclbName             = "grpclb"
+)
+
+func convertDuration(d *lbpb.Duration) time.Duration {
+	if d == nil {
+		return 0
+	}
+	return time.Duration(d.Seconds)*time.Second + time.Duration(d.Nanos)*time.Nanosecond
+}
+
+// Client API for LoadBalancer service.
+// Mostly copied from generated pb.go file.
+// To avoid circular dependency.
+type loadBalancerClient struct {
+	cc *ClientConn
+}
+
+func (c *loadBalancerClient) BalanceLoad(ctx context.Context, opts ...CallOption) (*balanceLoadClientStream, error) {
+	desc := &StreamDesc{
+		StreamName:    "BalanceLoad",
+		ServerStreams: true,
+		ClientStreams: true,
+	}
+	stream, err := c.cc.NewStream(ctx, desc, "/grpc.lb.v1.LoadBalancer/BalanceLoad", opts...)
+	if err != nil {
+		return nil, err
+	}
+	x := &balanceLoadClientStream{stream}
+	return x, nil
+}
+
+type balanceLoadClientStream struct {
+	ClientStream
+}
+
+func (x *balanceLoadClientStream) Send(m *lbpb.LoadBalanceRequest) error {
+	return x.ClientStream.SendMsg(m)
+}
+
+func (x *balanceLoadClientStream) Recv() (*lbpb.LoadBalanceResponse, error) {
+	m := new(lbpb.LoadBalanceResponse)
+	if err := x.ClientStream.RecvMsg(m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func init() {
+	balancer.Register(newLBBuilder())
+}
+
+// newLBBuilder creates a builder for grpclb.
+func newLBBuilder() balancer.Builder {
+	return NewLBBuilderWithFallbackTimeout(defaultFallbackTimeout)
+}
+
+// NewLBBuilderWithFallbackTimeout creates a grpclb builder with the given
+// fallbackTimeout. If no response is received from the remote balancer within
+// fallbackTimeout, the backend addresses from the resolved address list will be
+// used.
+//
+// Only call this function when a non-default fallback timeout is needed.
+func NewLBBuilderWithFallbackTimeout(fallbackTimeout time.Duration) balancer.Builder {
+	return &lbBuilder{
+		fallbackTimeout: fallbackTimeout,
+	}
+}
+
+type lbBuilder struct {
+	fallbackTimeout time.Duration
+}
+
+func (b *lbBuilder) Name() string {
+	return grpclbName
+}
+
+func (b *lbBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
+	// This generates a manual resolver builder with a random scheme. This
+	// scheme will be used to dial to remote LB, so we can send filtered address
+	// updates to remote LB ClientConn using this manual resolver.
+	scheme := "grpclb_internal_" + strconv.FormatInt(time.Now().UnixNano(), 36)
+	r := &lbManualResolver{scheme: scheme, ccb: cc}
+
+	var target string
+	targetSplitted := strings.Split(cc.Target(), ":///")
+	if len(targetSplitted) < 2 {
+		target = cc.Target()
+	} else {
+		target = targetSplitted[1]
+	}
+
+	lb := &lbBalancer{
+		cc:              newLBCacheClientConn(cc),
+		target:          target,
+		opt:             opt,
+		fallbackTimeout: b.fallbackTimeout,
+		doneCh:          make(chan struct{}),
+
+		manualResolver: r,
+		csEvltr:        &connectivityStateEvaluator{},
+		subConns:       make(map[resolver.Address]balancer.SubConn),
+		scStates:       make(map[balancer.SubConn]connectivity.State),
+		picker:         &errPicker{err: balancer.ErrNoSubConnAvailable},
+		clientStats:    &rpcStats{},
+	}
+
+	return lb
+}
+
+type lbBalancer struct {
+	cc              *lbCacheClientConn
+	target          string
+	opt             balancer.BuildOptions
+	fallbackTimeout time.Duration
+	doneCh          chan struct{}
+
+	// manualResolver is used in the remote LB ClientConn inside grpclb. When
+	// resolved address updates are received by grpclb, filtered updates will be
+	// send to remote LB ClientConn through this resolver.
+	manualResolver *lbManualResolver
+	// The ClientConn to talk to the remote balancer.
+	ccRemoteLB *ClientConn
+
+	// Support client side load reporting. Each picker gets a reference to this,
+	// and will update its content.
+	clientStats *rpcStats
+
+	mu sync.Mutex // guards everything following.
+	// The full server list including drops, used to check if the newly received
+	// serverList contains anything new. Each generate picker will also have
+	// reference to this list to do the first layer pick.
+	fullServerList []*lbpb.Server
+	// All backends addresses, with metadata set to nil. This list contains all
+	// backend addresses in the same order and with the same duplicates as in
+	// serverlist. When generating picker, a SubConn slice with the same order
+	// but with only READY SCs will be gerenated.
+	backendAddrs []resolver.Address
+	// Roundrobin functionalities.
+	csEvltr  *connectivityStateEvaluator
+	state    connectivity.State
+	subConns map[resolver.Address]balancer.SubConn   // Used to new/remove SubConn.
+	scStates map[balancer.SubConn]connectivity.State // Used to filter READY SubConns.
+	picker   balancer.Picker
+	// Support fallback to resolved backend addresses if there's no response
+	// from remote balancer within fallbackTimeout.
+	fallbackTimerExpired bool
+	serverListReceived   bool
+	// resolvedBackendAddrs is resolvedAddrs minus remote balancers. It's set
+	// when resolved address updates are received, and read in the goroutine
+	// handling fallback.
+	resolvedBackendAddrs []resolver.Address
+}
+
+// regeneratePicker takes a snapshot of the balancer, and generates a picker from
+// it. The picker
+//  - always returns ErrTransientFailure if the balancer is in TransientFailure,
+//  - does two layer roundrobin pick otherwise.
+// Caller must hold lb.mu.
+func (lb *lbBalancer) regeneratePicker() {
+	if lb.state == connectivity.TransientFailure {
+		lb.picker = &errPicker{err: balancer.ErrTransientFailure}
+		return
+	}
+	var readySCs []balancer.SubConn
+	for _, a := range lb.backendAddrs {
+		if sc, ok := lb.subConns[a]; ok {
+			if st, ok := lb.scStates[sc]; ok && st == connectivity.Ready {
+				readySCs = append(readySCs, sc)
+			}
+		}
+	}
+
+	if len(lb.fullServerList) <= 0 {
+		if len(readySCs) <= 0 {
+			lb.picker = &errPicker{err: balancer.ErrNoSubConnAvailable}
+			return
+		}
+		lb.picker = &rrPicker{subConns: readySCs}
+		return
+	}
+	lb.picker = &lbPicker{
+		serverList: lb.fullServerList,
+		subConns:   readySCs,
+		stats:      lb.clientStats,
+	}
+}
+
+func (lb *lbBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	grpclog.Infof("lbBalancer: handle SubConn state change: %p, %v", sc, s)
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+
+	oldS, ok := lb.scStates[sc]
+	if !ok {
+		grpclog.Infof("lbBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
+		return
+	}
+	lb.scStates[sc] = s
+	switch s {
+	case connectivity.Idle:
+		sc.Connect()
+	case connectivity.Shutdown:
+		// When an address was removed by resolver, b called RemoveSubConn but
+		// kept the sc's state in scStates. Remove state for this sc here.
+		delete(lb.scStates, sc)
+	}
+
+	oldAggrState := lb.state
+	lb.state = lb.csEvltr.recordTransition(oldS, s)
+
+	// Regenerate picker when one of the following happens:
+	//  - this sc became ready from not-ready
+	//  - this sc became not-ready from ready
+	//  - the aggregated state of balancer became TransientFailure from non-TransientFailure
+	//  - the aggregated state of balancer became non-TransientFailure from TransientFailure
+	if (oldS == connectivity.Ready) != (s == connectivity.Ready) ||
+		(lb.state == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) {
+		lb.regeneratePicker()
+	}
+
+	lb.cc.UpdateBalancerState(lb.state, lb.picker)
+}
+
+// fallbackToBackendsAfter blocks for fallbackTimeout and falls back to use
+// resolved backends (backends received from resolver, not from remote balancer)
+// if no connection to remote balancers was successful.
+func (lb *lbBalancer) fallbackToBackendsAfter(fallbackTimeout time.Duration) {
+	timer := time.NewTimer(fallbackTimeout)
+	defer timer.Stop()
+	select {
+	case <-timer.C:
+	case <-lb.doneCh:
+		return
+	}
+	lb.mu.Lock()
+	if lb.serverListReceived {
+		lb.mu.Unlock()
+		return
+	}
+	lb.fallbackTimerExpired = true
+	lb.refreshSubConns(lb.resolvedBackendAddrs)
+	lb.mu.Unlock()
+}
+
+// HandleResolvedAddrs sends the updated remoteLB addresses to remoteLB
+// clientConn. The remoteLB clientConn will handle creating/removing remoteLB
+// connections.
+func (lb *lbBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+	grpclog.Infof("lbBalancer: handleResolvedResult: %+v", addrs)
+	if len(addrs) <= 0 {
+		return
+	}
+
+	var remoteBalancerAddrs, backendAddrs []resolver.Address
+	for _, a := range addrs {
+		if a.Type == resolver.GRPCLB {
+			remoteBalancerAddrs = append(remoteBalancerAddrs, a)
+		} else {
+			backendAddrs = append(backendAddrs, a)
+		}
+	}
+
+	if lb.ccRemoteLB == nil {
+		if len(remoteBalancerAddrs) <= 0 {
+			grpclog.Errorf("grpclb: no remote balancer address is available, should never happen")
+			return
+		}
+		// First time receiving resolved addresses, create a cc to remote
+		// balancers.
+		lb.dialRemoteLB(remoteBalancerAddrs[0].ServerName)
+		// Start the fallback goroutine.
+		go lb.fallbackToBackendsAfter(lb.fallbackTimeout)
+	}
+
+	// cc to remote balancers uses lb.manualResolver. Send the updated remote
+	// balancer addresses to it through manualResolver.
+	lb.manualResolver.NewAddress(remoteBalancerAddrs)
+
+	lb.mu.Lock()
+	lb.resolvedBackendAddrs = backendAddrs
+	// If serverListReceived is true, connection to remote balancer was
+	// successful and there's no need to do fallback anymore.
+	// If fallbackTimerExpired is false, fallback hasn't happened yet.
+	if !lb.serverListReceived && lb.fallbackTimerExpired {
+		// This means we received a new list of resolved backends, and we are
+		// still in fallback mode. Need to update the list of backends we are
+		// using to the new list of backends.
+		lb.refreshSubConns(lb.resolvedBackendAddrs)
+	}
+	lb.mu.Unlock()
+}
+
+func (lb *lbBalancer) Close() {
+	select {
+	case <-lb.doneCh:
+		return
+	default:
+	}
+	close(lb.doneCh)
+	if lb.ccRemoteLB != nil {
+		lb.ccRemoteLB.Close()
+	}
+	lb.cc.close()
+}

vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.pb.go

@@ -0,0 +1,799 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: grpc_lb_v1/messages/messages.proto
+
+package messages // import "google.golang.org/grpc/grpclb/grpc_lb_v1/messages"
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+
+type Duration struct {
+	// Signed seconds of the span of time. Must be from -315,576,000,000
+	// to +315,576,000,000 inclusive.
+	Seconds int64 `protobuf:"varint,1,opt,name=seconds" json:"seconds,omitempty"`
+	// Signed fractions of a second at nanosecond resolution of the span
+	// of time. Durations less than one second are represented with a 0
+	// `seconds` field and a positive or negative `nanos` field. For durations
+	// of one second or more, a non-zero value for the `nanos` field must be
+	// of the same sign as the `seconds` field. Must be from -999,999,999
+	// to +999,999,999 inclusive.
+	Nanos                int32    `protobuf:"varint,2,opt,name=nanos" json:"nanos,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Duration) Reset()         { *m = Duration{} }
+func (m *Duration) String() string { return proto.CompactTextString(m) }
+func (*Duration) ProtoMessage()    {}
+func (*Duration) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{0}
+}
+func (m *Duration) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Duration.Unmarshal(m, b)
+}
+func (m *Duration) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Duration.Marshal(b, m, deterministic)
+}
+func (dst *Duration) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Duration.Merge(dst, src)
+}
+func (m *Duration) XXX_Size() int {
+	return xxx_messageInfo_Duration.Size(m)
+}
+func (m *Duration) XXX_DiscardUnknown() {
+	xxx_messageInfo_Duration.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Duration proto.InternalMessageInfo
+
+func (m *Duration) GetSeconds() int64 {
+	if m != nil {
+		return m.Seconds
+	}
+	return 0
+}
+
+func (m *Duration) GetNanos() int32 {
+	if m != nil {
+		return m.Nanos
+	}
+	return 0
+}
+
+type Timestamp struct {
+	// Represents seconds of UTC time since Unix epoch
+	// 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
+	// 9999-12-31T23:59:59Z inclusive.
+	Seconds int64 `protobuf:"varint,1,opt,name=seconds" json:"seconds,omitempty"`
+	// Non-negative fractions of a second at nanosecond resolution. Negative
+	// second values with fractions must still have non-negative nanos values
+	// that count forward in time. Must be from 0 to 999,999,999
+	// inclusive.
+	Nanos                int32    `protobuf:"varint,2,opt,name=nanos" json:"nanos,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Timestamp) Reset()         { *m = Timestamp{} }
+func (m *Timestamp) String() string { return proto.CompactTextString(m) }
+func (*Timestamp) ProtoMessage()    {}
+func (*Timestamp) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{1}
+}
+func (m *Timestamp) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Timestamp.Unmarshal(m, b)
+}
+func (m *Timestamp) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Timestamp.Marshal(b, m, deterministic)
+}
+func (dst *Timestamp) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Timestamp.Merge(dst, src)
+}
+func (m *Timestamp) XXX_Size() int {
+	return xxx_messageInfo_Timestamp.Size(m)
+}
+func (m *Timestamp) XXX_DiscardUnknown() {
+	xxx_messageInfo_Timestamp.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Timestamp proto.InternalMessageInfo
+
+func (m *Timestamp) GetSeconds() int64 {
+	if m != nil {
+		return m.Seconds
+	}
+	return 0
+}
+
+func (m *Timestamp) GetNanos() int32 {
+	if m != nil {
+		return m.Nanos
+	}
+	return 0
+}
+
+type LoadBalanceRequest struct {
+	// Types that are valid to be assigned to LoadBalanceRequestType:
+	//	*LoadBalanceRequest_InitialRequest
+	//	*LoadBalanceRequest_ClientStats
+	LoadBalanceRequestType isLoadBalanceRequest_LoadBalanceRequestType `protobuf_oneof:"load_balance_request_type"`
+	XXX_NoUnkeyedLiteral   struct{}                                    `json:"-"`
+	XXX_unrecognized       []byte                                      `json:"-"`
+	XXX_sizecache          int32                                       `json:"-"`
+}
+
+func (m *LoadBalanceRequest) Reset()         { *m = LoadBalanceRequest{} }
+func (m *LoadBalanceRequest) String() string { return proto.CompactTextString(m) }
+func (*LoadBalanceRequest) ProtoMessage()    {}
+func (*LoadBalanceRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{2}
+}
+func (m *LoadBalanceRequest) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_LoadBalanceRequest.Unmarshal(m, b)
+}
+func (m *LoadBalanceRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_LoadBalanceRequest.Marshal(b, m, deterministic)
+}
+func (dst *LoadBalanceRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LoadBalanceRequest.Merge(dst, src)
+}
+func (m *LoadBalanceRequest) XXX_Size() int {
+	return xxx_messageInfo_LoadBalanceRequest.Size(m)
+}
+func (m *LoadBalanceRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_LoadBalanceRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LoadBalanceRequest proto.InternalMessageInfo
+
+type isLoadBalanceRequest_LoadBalanceRequestType interface {
+	isLoadBalanceRequest_LoadBalanceRequestType()
+}
+
+type LoadBalanceRequest_InitialRequest struct {
+	InitialRequest *InitialLoadBalanceRequest `protobuf:"bytes,1,opt,name=initial_request,json=initialRequest,oneof"`
+}
+type LoadBalanceRequest_ClientStats struct {
+	ClientStats *ClientStats `protobuf:"bytes,2,opt,name=client_stats,json=clientStats,oneof"`
+}
+
+func (*LoadBalanceRequest_InitialRequest) isLoadBalanceRequest_LoadBalanceRequestType() {}
+func (*LoadBalanceRequest_ClientStats) isLoadBalanceRequest_LoadBalanceRequestType()    {}
+
+func (m *LoadBalanceRequest) GetLoadBalanceRequestType() isLoadBalanceRequest_LoadBalanceRequestType {
+	if m != nil {
+		return m.LoadBalanceRequestType
+	}
+	return nil
+}
+
+func (m *LoadBalanceRequest) GetInitialRequest() *InitialLoadBalanceRequest {
+	if x, ok := m.GetLoadBalanceRequestType().(*LoadBalanceRequest_InitialRequest); ok {
+		return x.InitialRequest
+	}
+	return nil
+}
+
+func (m *LoadBalanceRequest) GetClientStats() *ClientStats {
+	if x, ok := m.GetLoadBalanceRequestType().(*LoadBalanceRequest_ClientStats); ok {
+		return x.ClientStats
+	}
+	return nil
+}
+
+// XXX_OneofFuncs is for the internal use of the proto package.
+func (*LoadBalanceRequest) XXX_OneofFuncs() (func(msg proto.Message, b *proto.Buffer) error, func(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error), func(msg proto.Message) (n int), []interface{}) {
+	return _LoadBalanceRequest_OneofMarshaler, _LoadBalanceRequest_OneofUnmarshaler, _LoadBalanceRequest_OneofSizer, []interface{}{
+		(*LoadBalanceRequest_InitialRequest)(nil),
+		(*LoadBalanceRequest_ClientStats)(nil),
+	}
+}
+
+func _LoadBalanceRequest_OneofMarshaler(msg proto.Message, b *proto.Buffer) error {
+	m := msg.(*LoadBalanceRequest)
+	// load_balance_request_type
+	switch x := m.LoadBalanceRequestType.(type) {
+	case *LoadBalanceRequest_InitialRequest:
+		b.EncodeVarint(1<<3 | proto.WireBytes)
+		if err := b.EncodeMessage(x.InitialRequest); err != nil {
+			return err
+		}
+	case *LoadBalanceRequest_ClientStats:
+		b.EncodeVarint(2<<3 | proto.WireBytes)
+		if err := b.EncodeMessage(x.ClientStats); err != nil {
+			return err
+		}
+	case nil:
+	default:
+		return fmt.Errorf("LoadBalanceRequest.LoadBalanceRequestType has unexpected type %T", x)
+	}
+	return nil
+}
+
+func _LoadBalanceRequest_OneofUnmarshaler(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error) {
+	m := msg.(*LoadBalanceRequest)
+	switch tag {
+	case 1: // load_balance_request_type.initial_request
+		if wire != proto.WireBytes {
+			return true, proto.ErrInternalBadWireType
+		}
+		msg := new(InitialLoadBalanceRequest)
+		err := b.DecodeMessage(msg)
+		m.LoadBalanceRequestType = &LoadBalanceRequest_InitialRequest{msg}
+		return true, err
+	case 2: // load_balance_request_type.client_stats
+		if wire != proto.WireBytes {
+			return true, proto.ErrInternalBadWireType
+		}
+		msg := new(ClientStats)
+		err := b.DecodeMessage(msg)
+		m.LoadBalanceRequestType = &LoadBalanceRequest_ClientStats{msg}
+		return true, err
+	default:
+		return false, nil
+	}
+}
+
+func _LoadBalanceRequest_OneofSizer(msg proto.Message) (n int) {
+	m := msg.(*LoadBalanceRequest)
+	// load_balance_request_type
+	switch x := m.LoadBalanceRequestType.(type) {
+	case *LoadBalanceRequest_InitialRequest:
+		s := proto.Size(x.InitialRequest)
+		n += 1 // tag and wire
+		n += proto.SizeVarint(uint64(s))
+		n += s
+	case *LoadBalanceRequest_ClientStats:
+		s := proto.Size(x.ClientStats)
+		n += 1 // tag and wire
+		n += proto.SizeVarint(uint64(s))
+		n += s
+	case nil:
+	default:
+		panic(fmt.Sprintf("proto: unexpected type %T in oneof", x))
+	}
+	return n
+}
+
+type InitialLoadBalanceRequest struct {
+	// Name of load balanced service (IE, balancer.service.com)
+	// length should be less than 256 bytes.
+	Name                 string   `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *InitialLoadBalanceRequest) Reset()         { *m = InitialLoadBalanceRequest{} }
+func (m *InitialLoadBalanceRequest) String() string { return proto.CompactTextString(m) }
+func (*InitialLoadBalanceRequest) ProtoMessage()    {}
+func (*InitialLoadBalanceRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{3}
+}
+func (m *InitialLoadBalanceRequest) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_InitialLoadBalanceRequest.Unmarshal(m, b)
+}
+func (m *InitialLoadBalanceRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_InitialLoadBalanceRequest.Marshal(b, m, deterministic)
+}
+func (dst *InitialLoadBalanceRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_InitialLoadBalanceRequest.Merge(dst, src)
+}
+func (m *InitialLoadBalanceRequest) XXX_Size() int {
+	return xxx_messageInfo_InitialLoadBalanceRequest.Size(m)
+}
+func (m *InitialLoadBalanceRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_InitialLoadBalanceRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_InitialLoadBalanceRequest proto.InternalMessageInfo
+
+func (m *InitialLoadBalanceRequest) GetName() string {
+	if m != nil {
+		return m.Name
+	}
+	return ""
+}
+
+// Contains client level statistics that are useful to load balancing. Each
+// count except the timestamp should be reset to zero after reporting the stats.
+type ClientStats struct {
+	// The timestamp of generating the report.
+	Timestamp *Timestamp `protobuf:"bytes,1,opt,name=timestamp" json:"timestamp,omitempty"`
+	// The total number of RPCs that started.
+	NumCallsStarted int64 `protobuf:"varint,2,opt,name=num_calls_started,json=numCallsStarted" json:"num_calls_started,omitempty"`
+	// The total number of RPCs that finished.
+	NumCallsFinished int64 `protobuf:"varint,3,opt,name=num_calls_finished,json=numCallsFinished" json:"num_calls_finished,omitempty"`
+	// The total number of RPCs that were dropped by the client because of rate
+	// limiting.
+	NumCallsFinishedWithDropForRateLimiting int64 `protobuf:"varint,4,opt,name=num_calls_finished_with_drop_for_rate_limiting,json=numCallsFinishedWithDropForRateLimiting" json:"num_calls_finished_with_drop_for_rate_limiting,omitempty"`
+	// The total number of RPCs that were dropped by the client because of load
+	// balancing.
+	NumCallsFinishedWithDropForLoadBalancing int64 `protobuf:"varint,5,opt,name=num_calls_finished_with_drop_for_load_balancing,json=numCallsFinishedWithDropForLoadBalancing" json:"num_calls_finished_with_drop_for_load_balancing,omitempty"`
+	// The total number of RPCs that failed to reach a server except dropped RPCs.
+	NumCallsFinishedWithClientFailedToSend int64 `protobuf:"varint,6,opt,name=num_calls_finished_with_client_failed_to_send,json=numCallsFinishedWithClientFailedToSend" json:"num_calls_finished_with_client_failed_to_send,omitempty"`
+	// The total number of RPCs that finished and are known to have been received
+	// by a server.
+	NumCallsFinishedKnownReceived int64    `protobuf:"varint,7,opt,name=num_calls_finished_known_received,json=numCallsFinishedKnownReceived" json:"num_calls_finished_known_received,omitempty"`
+	XXX_NoUnkeyedLiteral          struct{} `json:"-"`
+	XXX_unrecognized              []byte   `json:"-"`
+	XXX_sizecache                 int32    `json:"-"`
+}
+
+func (m *ClientStats) Reset()         { *m = ClientStats{} }
+func (m *ClientStats) String() string { return proto.CompactTextString(m) }
+func (*ClientStats) ProtoMessage()    {}
+func (*ClientStats) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{4}
+}
+func (m *ClientStats) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_ClientStats.Unmarshal(m, b)
+}
+func (m *ClientStats) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_ClientStats.Marshal(b, m, deterministic)
+}
+func (dst *ClientStats) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ClientStats.Merge(dst, src)
+}
+func (m *ClientStats) XXX_Size() int {
+	return xxx_messageInfo_ClientStats.Size(m)
+}
+func (m *ClientStats) XXX_DiscardUnknown() {
+	xxx_messageInfo_ClientStats.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ClientStats proto.InternalMessageInfo
+
+func (m *ClientStats) GetTimestamp() *Timestamp {
+	if m != nil {
+		return m.Timestamp
+	}
+	return nil
+}
+
+func (m *ClientStats) GetNumCallsStarted() int64 {
+	if m != nil {
+		return m.NumCallsStarted
+	}
+	return 0
+}
+
+func (m *ClientStats) GetNumCallsFinished() int64 {
+	if m != nil {
+		return m.NumCallsFinished
+	}
+	return 0
+}
+
+func (m *ClientStats) GetNumCallsFinishedWithDropForRateLimiting() int64 {
+	if m != nil {
+		return m.NumCallsFinishedWithDropForRateLimiting
+	}
+	return 0
+}
+
+func (m *ClientStats) GetNumCallsFinishedWithDropForLoadBalancing() int64 {
+	if m != nil {
+		return m.NumCallsFinishedWithDropForLoadBalancing
+	}
+	return 0
+}
+
+func (m *ClientStats) GetNumCallsFinishedWithClientFailedToSend() int64 {
+	if m != nil {
+		return m.NumCallsFinishedWithClientFailedToSend
+	}
+	return 0
+}
+
+func (m *ClientStats) GetNumCallsFinishedKnownReceived() int64 {
+	if m != nil {
+		return m.NumCallsFinishedKnownReceived
+	}
+	return 0
+}
+
+type LoadBalanceResponse struct {
+	// Types that are valid to be assigned to LoadBalanceResponseType:
+	//	*LoadBalanceResponse_InitialResponse
+	//	*LoadBalanceResponse_ServerList
+	LoadBalanceResponseType isLoadBalanceResponse_LoadBalanceResponseType `protobuf_oneof:"load_balance_response_type"`
+	XXX_NoUnkeyedLiteral    struct{}                                      `json:"-"`
+	XXX_unrecognized        []byte                                        `json:"-"`
+	XXX_sizecache           int32                                         `json:"-"`
+}
+
+func (m *LoadBalanceResponse) Reset()         { *m = LoadBalanceResponse{} }
+func (m *LoadBalanceResponse) String() string { return proto.CompactTextString(m) }
+func (*LoadBalanceResponse) ProtoMessage()    {}
+func (*LoadBalanceResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{5}
+}
+func (m *LoadBalanceResponse) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_LoadBalanceResponse.Unmarshal(m, b)
+}
+func (m *LoadBalanceResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_LoadBalanceResponse.Marshal(b, m, deterministic)
+}
+func (dst *LoadBalanceResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LoadBalanceResponse.Merge(dst, src)
+}
+func (m *LoadBalanceResponse) XXX_Size() int {
+	return xxx_messageInfo_LoadBalanceResponse.Size(m)
+}
+func (m *LoadBalanceResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_LoadBalanceResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LoadBalanceResponse proto.InternalMessageInfo
+
+type isLoadBalanceResponse_LoadBalanceResponseType interface {
+	isLoadBalanceResponse_LoadBalanceResponseType()
+}
+
+type LoadBalanceResponse_InitialResponse struct {
+	InitialResponse *InitialLoadBalanceResponse `protobuf:"bytes,1,opt,name=initial_response,json=initialResponse,oneof"`
+}
+type LoadBalanceResponse_ServerList struct {
+	ServerList *ServerList `protobuf:"bytes,2,opt,name=server_list,json=serverList,oneof"`
+}
+
+func (*LoadBalanceResponse_InitialResponse) isLoadBalanceResponse_LoadBalanceResponseType() {}
+func (*LoadBalanceResponse_ServerList) isLoadBalanceResponse_LoadBalanceResponseType()      {}
+
+func (m *LoadBalanceResponse) GetLoadBalanceResponseType() isLoadBalanceResponse_LoadBalanceResponseType {
+	if m != nil {
+		return m.LoadBalanceResponseType
+	}
+	return nil
+}
+
+func (m *LoadBalanceResponse) GetInitialResponse() *InitialLoadBalanceResponse {
+	if x, ok := m.GetLoadBalanceResponseType().(*LoadBalanceResponse_InitialResponse); ok {
+		return x.InitialResponse
+	}
+	return nil
+}
+
+func (m *LoadBalanceResponse) GetServerList() *ServerList {
+	if x, ok := m.GetLoadBalanceResponseType().(*LoadBalanceResponse_ServerList); ok {
+		return x.ServerList
+	}
+	return nil
+}
+
+// XXX_OneofFuncs is for the internal use of the proto package.
+func (*LoadBalanceResponse) XXX_OneofFuncs() (func(msg proto.Message, b *proto.Buffer) error, func(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error), func(msg proto.Message) (n int), []interface{}) {
+	return _LoadBalanceResponse_OneofMarshaler, _LoadBalanceResponse_OneofUnmarshaler, _LoadBalanceResponse_OneofSizer, []interface{}{
+		(*LoadBalanceResponse_InitialResponse)(nil),
+		(*LoadBalanceResponse_ServerList)(nil),
+	}
+}
+
+func _LoadBalanceResponse_OneofMarshaler(msg proto.Message, b *proto.Buffer) error {
+	m := msg.(*LoadBalanceResponse)
+	// load_balance_response_type
+	switch x := m.LoadBalanceResponseType.(type) {
+	case *LoadBalanceResponse_InitialResponse:
+		b.EncodeVarint(1<<3 | proto.WireBytes)
+		if err := b.EncodeMessage(x.InitialResponse); err != nil {
+			return err
+		}
+	case *LoadBalanceResponse_ServerList:
+		b.EncodeVarint(2<<3 | proto.WireBytes)
+		if err := b.EncodeMessage(x.ServerList); err != nil {
+			return err
+		}
+	case nil:
+	default:
+		return fmt.Errorf("LoadBalanceResponse.LoadBalanceResponseType has unexpected type %T", x)
+	}
+	return nil
+}
+
+func _LoadBalanceResponse_OneofUnmarshaler(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error) {
+	m := msg.(*LoadBalanceResponse)
+	switch tag {
+	case 1: // load_balance_response_type.initial_response
+		if wire != proto.WireBytes {
+			return true, proto.ErrInternalBadWireType
+		}
+		msg := new(InitialLoadBalanceResponse)
+		err := b.DecodeMessage(msg)
+		m.LoadBalanceResponseType = &LoadBalanceResponse_InitialResponse{msg}
+		return true, err
+	case 2: // load_balance_response_type.server_list
+		if wire != proto.WireBytes {
+			return true, proto.ErrInternalBadWireType
+		}
+		msg := new(ServerList)
+		err := b.DecodeMessage(msg)
+		m.LoadBalanceResponseType = &LoadBalanceResponse_ServerList{msg}
+		return true, err
+	default:
+		return false, nil
+	}
+}
+
+func _LoadBalanceResponse_OneofSizer(msg proto.Message) (n int) {
+	m := msg.(*LoadBalanceResponse)
+	// load_balance_response_type
+	switch x := m.LoadBalanceResponseType.(type) {
+	case *LoadBalanceResponse_InitialResponse:
+		s := proto.Size(x.InitialResponse)
+		n += 1 // tag and wire
+		n += proto.SizeVarint(uint64(s))
+		n += s
+	case *LoadBalanceResponse_ServerList:
+		s := proto.Size(x.ServerList)
+		n += 1 // tag and wire
+		n += proto.SizeVarint(uint64(s))
+		n += s
+	case nil:
+	default:
+		panic(fmt.Sprintf("proto: unexpected type %T in oneof", x))
+	}
+	return n
+}
+
+type InitialLoadBalanceResponse struct {
+	// This is an application layer redirect that indicates the client should use
+	// the specified server for load balancing. When this field is non-empty in
+	// the response, the client should open a separate connection to the
+	// load_balancer_delegate and call the BalanceLoad method. Its length should
+	// be less than 64 bytes.
+	LoadBalancerDelegate string `protobuf:"bytes,1,opt,name=load_balancer_delegate,json=loadBalancerDelegate" json:"load_balancer_delegate,omitempty"`
+	// This interval defines how often the client should send the client stats
+	// to the load balancer. Stats should only be reported when the duration is
+	// positive.
+	ClientStatsReportInterval *Duration `protobuf:"bytes,2,opt,name=client_stats_report_interval,json=clientStatsReportInterval" json:"client_stats_report_interval,omitempty"`
+	XXX_NoUnkeyedLiteral      struct{}  `json:"-"`
+	XXX_unrecognized          []byte    `json:"-"`
+	XXX_sizecache             int32     `json:"-"`
+}
+
+func (m *InitialLoadBalanceResponse) Reset()         { *m = InitialLoadBalanceResponse{} }
+func (m *InitialLoadBalanceResponse) String() string { return proto.CompactTextString(m) }
+func (*InitialLoadBalanceResponse) ProtoMessage()    {}
+func (*InitialLoadBalanceResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{6}
+}
+func (m *InitialLoadBalanceResponse) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_InitialLoadBalanceResponse.Unmarshal(m, b)
+}
+func (m *InitialLoadBalanceResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_InitialLoadBalanceResponse.Marshal(b, m, deterministic)
+}
+func (dst *InitialLoadBalanceResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_InitialLoadBalanceResponse.Merge(dst, src)
+}
+func (m *InitialLoadBalanceResponse) XXX_Size() int {
+	return xxx_messageInfo_InitialLoadBalanceResponse.Size(m)
+}
+func (m *InitialLoadBalanceResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_InitialLoadBalanceResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_InitialLoadBalanceResponse proto.InternalMessageInfo
+
+func (m *InitialLoadBalanceResponse) GetLoadBalancerDelegate() string {
+	if m != nil {
+		return m.LoadBalancerDelegate
+	}
+	return ""
+}
+
+func (m *InitialLoadBalanceResponse) GetClientStatsReportInterval() *Duration {
+	if m != nil {
+		return m.ClientStatsReportInterval
+	}
+	return nil
+}
+
+type ServerList struct {
+	// Contains a list of servers selected by the load balancer. The list will
+	// be updated when server resolutions change or as needed to balance load
+	// across more servers. The client should consume the server list in order
+	// unless instructed otherwise via the client_config.
+	Servers              []*Server `protobuf:"bytes,1,rep,name=servers" json:"servers,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
+}
+
+func (m *ServerList) Reset()         { *m = ServerList{} }
+func (m *ServerList) String() string { return proto.CompactTextString(m) }
+func (*ServerList) ProtoMessage()    {}
+func (*ServerList) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{7}
+}
+func (m *ServerList) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_ServerList.Unmarshal(m, b)
+}
+func (m *ServerList) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_ServerList.Marshal(b, m, deterministic)
+}
+func (dst *ServerList) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ServerList.Merge(dst, src)
+}
+func (m *ServerList) XXX_Size() int {
+	return xxx_messageInfo_ServerList.Size(m)
+}
+func (m *ServerList) XXX_DiscardUnknown() {
+	xxx_messageInfo_ServerList.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ServerList proto.InternalMessageInfo
+
+func (m *ServerList) GetServers() []*Server {
+	if m != nil {
+		return m.Servers
+	}
+	return nil
+}
+
+// Contains server information. When none of the [drop_for_*] fields are true,
+// use the other fields. When drop_for_rate_limiting is true, ignore all other
+// fields. Use drop_for_load_balancing only when it is true and
+// drop_for_rate_limiting is false.
+type Server struct {
+	// A resolved address for the server, serialized in network-byte-order. It may
+	// either be an IPv4 or IPv6 address.
+	IpAddress []byte `protobuf:"bytes,1,opt,name=ip_address,json=ipAddress,proto3" json:"ip_address,omitempty"`
+	// A resolved port number for the server.
+	Port int32 `protobuf:"varint,2,opt,name=port" json:"port,omitempty"`
+	// An opaque but printable token given to the frontend for each pick. All
+	// frontend requests for that pick must include the token in its initial
+	// metadata. The token is used by the backend to verify the request and to
+	// allow the backend to report load to the gRPC LB system.
+	//
+	// Its length is variable but less than 50 bytes.
+	LoadBalanceToken string `protobuf:"bytes,3,opt,name=load_balance_token,json=loadBalanceToken" json:"load_balance_token,omitempty"`
+	// Indicates whether this particular request should be dropped by the client
+	// for rate limiting.
+	DropForRateLimiting bool `protobuf:"varint,4,opt,name=drop_for_rate_limiting,json=dropForRateLimiting" json:"drop_for_rate_limiting,omitempty"`
+	// Indicates whether this particular request should be dropped by the client
+	// for load balancing.
+	DropForLoadBalancing bool     `protobuf:"varint,5,opt,name=drop_for_load_balancing,json=dropForLoadBalancing" json:"drop_for_load_balancing,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Server) Reset()         { *m = Server{} }
+func (m *Server) String() string { return proto.CompactTextString(m) }
+func (*Server) ProtoMessage()    {}
+func (*Server) Descriptor() ([]byte, []int) {
+	return fileDescriptor_messages_b81c731f0e83edbd, []int{8}
+}
+func (m *Server) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Server.Unmarshal(m, b)
+}
+func (m *Server) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Server.Marshal(b, m, deterministic)
+}
+func (dst *Server) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Server.Merge(dst, src)
+}
+func (m *Server) XXX_Size() int {
+	return xxx_messageInfo_Server.Size(m)
+}
+func (m *Server) XXX_DiscardUnknown() {
+	xxx_messageInfo_Server.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Server proto.InternalMessageInfo
+
+func (m *Server) GetIpAddress() []byte {
+	if m != nil {
+		return m.IpAddress
+	}
+	return nil
+}
+
+func (m *Server) GetPort() int32 {
+	if m != nil {
+		return m.Port
+	}
+	return 0
+}
+
+func (m *Server) GetLoadBalanceToken() string {
+	if m != nil {
+		return m.LoadBalanceToken
+	}
+	return ""
+}
+
+func (m *Server) GetDropForRateLimiting() bool {
+	if m != nil {
+		return m.DropForRateLimiting
+	}
+	return false
+}
+
+func (m *Server) GetDropForLoadBalancing() bool {
+	if m != nil {
+		return m.DropForLoadBalancing
+	}
+	return false
+}
+
+func init() {
+	proto.RegisterType((*Duration)(nil), "grpc.lb.v1.Duration")
+	proto.RegisterType((*Timestamp)(nil), "grpc.lb.v1.Timestamp")
+	proto.RegisterType((*LoadBalanceRequest)(nil), "grpc.lb.v1.LoadBalanceRequest")
+	proto.RegisterType((*InitialLoadBalanceRequest)(nil), "grpc.lb.v1.InitialLoadBalanceRequest")
+	proto.RegisterType((*ClientStats)(nil), "grpc.lb.v1.ClientStats")
+	proto.RegisterType((*LoadBalanceResponse)(nil), "grpc.lb.v1.LoadBalanceResponse")
+	proto.RegisterType((*InitialLoadBalanceResponse)(nil), "grpc.lb.v1.InitialLoadBalanceResponse")
+	proto.RegisterType((*ServerList)(nil), "grpc.lb.v1.ServerList")
+	proto.RegisterType((*Server)(nil), "grpc.lb.v1.Server")
+}
+
+func init() {
+	proto.RegisterFile("grpc_lb_v1/messages/messages.proto", fileDescriptor_messages_b81c731f0e83edbd)
+}
+
+var fileDescriptor_messages_b81c731f0e83edbd = []byte{
+	// 731 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x94, 0x55, 0xdd, 0x4e, 0x1b, 0x39,
+	0x14, 0x26, 0x9b, 0x00, 0xc9, 0x09, 0x5a, 0xb2, 0x26, 0x0b, 0x81, 0x05, 0x89, 0x1d, 0x69, 0xd9,
+	0x68, 0xc5, 0x4e, 0x04, 0xd9, 0xbd, 0xe8, 0xcf, 0x45, 0x1b, 0x10, 0x0a, 0x2d, 0x17, 0x95, 0x43,
+	0x55, 0xa9, 0x52, 0x65, 0x39, 0x19, 0x33, 0x58, 0x38, 0xf6, 0xd4, 0x76, 0x82, 0xfa, 0x08, 0x7d,
+	0x94, 0x3e, 0x46, 0xd5, 0x67, 0xe8, 0xfb, 0x54, 0xe3, 0x99, 0xc9, 0x0c, 0x10, 0x40, 0xbd, 0x89,
+	0xec, 0xe3, 0xef, 0x7c, 0xdf, 0xf1, 0x89, 0xbf, 0x33, 0xe0, 0x85, 0x3a, 0x1a, 0x11, 0x31, 0x24,
+	0xd3, 0x83, 0xce, 0x98, 0x19, 0x43, 0x43, 0x66, 0x66, 0x0b, 0x3f, 0xd2, 0xca, 0x2a, 0x04, 0x31,
+	0xc6, 0x17, 0x43, 0x7f, 0x7a, 0xe0, 0x3d, 0x85, 0xea, 0xf1, 0x44, 0x53, 0xcb, 0x95, 0x44, 0x2d,
+	0x58, 0x36, 0x6c, 0xa4, 0x64, 0x60, 0x5a, 0xa5, 0xdd, 0x52, 0xbb, 0x8c, 0xb3, 0x2d, 0x6a, 0xc2,
+	0xa2, 0xa4, 0x52, 0x99, 0xd6, 0x2f, 0xbb, 0xa5, 0xf6, 0x22, 0x4e, 0x36, 0xde, 0x33, 0xa8, 0x9d,
+	0xf3, 0x31, 0x33, 0x96, 0x8e, 0xa3, 0x9f, 0x4e, 0xfe, 0x5a, 0x02, 0x74, 0xa6, 0x68, 0xd0, 0xa3,
+	0x82, 0xca, 0x11, 0xc3, 0xec, 0xe3, 0x84, 0x19, 0x8b, 0xde, 0xc0, 0x2a, 0x97, 0xdc, 0x72, 0x2a,
+	0x88, 0x4e, 0x42, 0x8e, 0xae, 0x7e, 0xf8, 0x97, 0x9f, 0x57, 0xed, 0x9f, 0x26, 0x90, 0xbb, 0xf9,
+	0xfd, 0x05, 0xfc, 0x6b, 0x9a, 0x9f, 0x31, 0x3e, 0x87, 0x95, 0x91, 0xe0, 0x4c, 0x5a, 0x62, 0x2c,
+	0xb5, 0x49, 0x15, 0xf5, 0xc3, 0x8d, 0x22, 0xdd, 0x91, 0x3b, 0x1f, 0xc4, 0xc7, 0xfd, 0x05, 0x5c,
+	0x1f, 0xe5, 0xdb, 0xde, 0x1f, 0xb0, 0x29, 0x14, 0x0d, 0xc8, 0x30, 0x91, 0xc9, 0x8a, 0x22, 0xf6,
+	0x53, 0xc4, 0xbc, 0x0e, 0x6c, 0xde, 0x5b, 0x09, 0x42, 0x50, 0x91, 0x74, 0xcc, 0x5c, 0xf9, 0x35,
+	0xec, 0xd6, 0xde, 0xe7, 0x0a, 0xd4, 0x0b, 0x62, 0xa8, 0x0b, 0x35, 0x9b, 0x75, 0x30, 0xbd, 0xe7,
+	0xef, 0xc5, 0xc2, 0x66, 0xed, 0xc5, 0x39, 0x0e, 0xfd, 0x03, 0xbf, 0xc9, 0xc9, 0x98, 0x8c, 0xa8,
+	0x10, 0x26, 0xbe, 0x93, 0xb6, 0x2c, 0x70, 0xb7, 0x2a, 0xe3, 0x55, 0x39, 0x19, 0x1f, 0xc5, 0xf1,
+	0x41, 0x12, 0x46, 0xfb, 0x80, 0x72, 0xec, 0x05, 0x97, 0xdc, 0x5c, 0xb2, 0xa0, 0x55, 0x76, 0xe0,
+	0x46, 0x06, 0x3e, 0x49, 0xe3, 0x88, 0x80, 0x7f, 0x17, 0x4d, 0xae, 0xb9, 0xbd, 0x24, 0x81, 0x56,
+	0x11, 0xb9, 0x50, 0x9a, 0x68, 0x6a, 0x19, 0x11, 0x7c, 0xcc, 0x2d, 0x97, 0x61, 0xab, 0xe2, 0x98,
+	0xfe, 0xbe, 0xcd, 0xf4, 0x8e, 0xdb, 0xcb, 0x63, 0xad, 0xa2, 0x13, 0xa5, 0x31, 0xb5, 0xec, 0x2c,
+	0x85, 0x23, 0x0a, 0x9d, 0x47, 0x05, 0x0a, 0xed, 0x8e, 0x15, 0x16, 0x9d, 0x42, 0xfb, 0x01, 0x85,
+	0xbc, 0xf7, 0xb1, 0xc4, 0x07, 0xf8, 0xf7, 0x3e, 0x89, 0xf4, 0x19, 0x5c, 0x50, 0x2e, 0x58, 0x40,
+	0xac, 0x22, 0x86, 0xc9, 0xa0, 0xb5, 0xe4, 0x04, 0xf6, 0xe6, 0x09, 0x24, 0x7f, 0xd5, 0x89, 0xc3,
+	0x9f, 0xab, 0x01, 0x93, 0x01, 0xea, 0xc3, 0x9f, 0x73, 0xe8, 0xaf, 0xa4, 0xba, 0x96, 0x44, 0xb3,
+	0x11, 0xe3, 0x53, 0x16, 0xb4, 0x96, 0x1d, 0xe5, 0xce, 0x6d, 0xca, 0xd7, 0x31, 0x0a, 0xa7, 0x20,
+	0xef, 0x5b, 0x09, 0xd6, 0x6e, 0x3c, 0x1b, 0x13, 0x29, 0x69, 0x18, 0x1a, 0x40, 0x23, 0x77, 0x40,
+	0x12, 0x4b, 0x9f, 0xc6, 0xde, 0x63, 0x16, 0x48, 0xd0, 0xfd, 0x05, 0xbc, 0x3a, 0xf3, 0x40, 0x4a,
+	0xfa, 0x04, 0xea, 0x86, 0xe9, 0x29, 0xd3, 0x44, 0x70, 0x63, 0x53, 0x0f, 0xac, 0x17, 0xf9, 0x06,
+	0xee, 0xf8, 0x8c, 0x3b, 0x0f, 0x81, 0x99, 0xed, 0x7a, 0xdb, 0xb0, 0x75, 0xcb, 0x01, 0x09, 0x67,
+	0x62, 0x81, 0x2f, 0x25, 0xd8, 0xba, 0xbf, 0x14, 0xf4, 0x1f, 0xac, 0x17, 0x93, 0x35, 0x09, 0x98,
+	0x60, 0x21, 0xb5, 0x99, 0x2d, 0x9a, 0x22, 0x4f, 0xd2, 0xc7, 0xe9, 0x19, 0x7a, 0x0b, 0xdb, 0x45,
+	0xcb, 0x12, 0xcd, 0x22, 0xa5, 0x2d, 0xe1, 0xd2, 0x32, 0x3d, 0xa5, 0x22, 0x2d, 0xbf, 0x59, 0x2c,
+	0x3f, 0x1b, 0x62, 0x78, 0xb3, 0xe0, 0x5e, 0xec, 0xf2, 0x4e, 0xd3, 0x34, 0xef, 0x05, 0x40, 0x7e,
+	0x4b, 0xb4, 0x1f, 0x0f, 0xac, 0x78, 0x17, 0x0f, 0xac, 0x72, 0xbb, 0x7e, 0x88, 0xee, 0xb6, 0x03,
+	0x67, 0x90, 0x57, 0x95, 0x6a, 0xb9, 0x51, 0xf1, 0xbe, 0x97, 0x60, 0x29, 0x39, 0x41, 0x3b, 0x00,
+	0x3c, 0x22, 0x34, 0x08, 0x34, 0x33, 0xc9, 0xc8, 0x5b, 0xc1, 0x35, 0x1e, 0xbd, 0x4c, 0x02, 0xb1,
+	0xfb, 0x63, 0xed, 0x74, 0xe6, 0xb9, 0x75, 0x6c, 0xc6, 0x1b, 0x9d, 0xb4, 0xea, 0x8a, 0x49, 0x67,
+	0xc6, 0x1a, 0x6e, 0x14, 0x1a, 0x71, 0x1e, 0xc7, 0x51, 0x17, 0xd6, 0x1f, 0x30, 0x5d, 0x15, 0xaf,
+	0x05, 0x73, 0x0c, 0xf6, 0x3f, 0x6c, 0x3c, 0x64, 0xa4, 0x2a, 0x6e, 0x06, 0x73, 0x4c, 0xd3, 0xeb,
+	0xbe, 0x3f, 0x08, 0x95, 0x0a, 0x05, 0xf3, 0x43, 0x25, 0xa8, 0x0c, 0x7d, 0xa5, 0xc3, 0x4e, 0xdc,
+	0x0d, 0xf7, 0x23, 0x86, 0x9d, 0x39, 0x5f, 0x95, 0xe1, 0x92, 0xfb, 0x9a, 0x74, 0x7f, 0x04, 0x00,
+	0x00, 0xff, 0xff, 0x8e, 0xd0, 0x70, 0xb7, 0x73, 0x06, 0x00, 0x00,
+}

vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.proto

@@ -0,0 +1,155 @@
+// Copyright 2016 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package grpc.lb.v1;
+option go_package = "google.golang.org/grpc/grpclb/grpc_lb_v1/messages";
+
+message Duration {
+  // Signed seconds of the span of time. Must be from -315,576,000,000
+  // to +315,576,000,000 inclusive.
+  int64 seconds = 1;
+
+  // Signed fractions of a second at nanosecond resolution of the span
+  // of time. Durations less than one second are represented with a 0
+  // `seconds` field and a positive or negative `nanos` field. For durations
+  // of one second or more, a non-zero value for the `nanos` field must be
+  // of the same sign as the `seconds` field. Must be from -999,999,999
+  // to +999,999,999 inclusive.
+  int32 nanos = 2;
+}
+
+message Timestamp {
+  // Represents seconds of UTC time since Unix epoch
+  // 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
+  // 9999-12-31T23:59:59Z inclusive.
+  int64 seconds = 1;
+
+  // Non-negative fractions of a second at nanosecond resolution. Negative
+  // second values with fractions must still have non-negative nanos values
+  // that count forward in time. Must be from 0 to 999,999,999
+  // inclusive.
+  int32 nanos = 2;
+}
+
+message LoadBalanceRequest {
+  oneof load_balance_request_type {
+    // This message should be sent on the first request to the load balancer.
+    InitialLoadBalanceRequest initial_request = 1;
+
+    // The client stats should be periodically reported to the load balancer
+    // based on the duration defined in the InitialLoadBalanceResponse.
+    ClientStats client_stats = 2;
+  }
+}
+
+message InitialLoadBalanceRequest {
+  // Name of load balanced service (IE, balancer.service.com)
+  // length should be less than 256 bytes.
+  string name = 1;
+}
+
+// Contains client level statistics that are useful to load balancing. Each
+// count except the timestamp should be reset to zero after reporting the stats.
+message ClientStats {
+  // The timestamp of generating the report.
+  Timestamp timestamp = 1;
+
+  // The total number of RPCs that started.
+  int64 num_calls_started = 2;
+
+  // The total number of RPCs that finished.
+  int64 num_calls_finished = 3;
+
+  // The total number of RPCs that were dropped by the client because of rate
+  // limiting.
+  int64 num_calls_finished_with_drop_for_rate_limiting = 4;
+
+  // The total number of RPCs that were dropped by the client because of load
+  // balancing.
+  int64 num_calls_finished_with_drop_for_load_balancing = 5;
+
+  // The total number of RPCs that failed to reach a server except dropped RPCs.
+  int64 num_calls_finished_with_client_failed_to_send = 6;
+
+  // The total number of RPCs that finished and are known to have been received
+  // by a server.
+  int64 num_calls_finished_known_received = 7;
+}
+
+message LoadBalanceResponse {
+  oneof load_balance_response_type {
+    // This message should be sent on the first response to the client.
+    InitialLoadBalanceResponse initial_response = 1;
+
+    // Contains the list of servers selected by the load balancer. The client
+    // should send requests to these servers in the specified order.
+    ServerList server_list = 2;
+  }
+}
+
+message InitialLoadBalanceResponse {
+  // This is an application layer redirect that indicates the client should use
+  // the specified server for load balancing. When this field is non-empty in
+  // the response, the client should open a separate connection to the
+  // load_balancer_delegate and call the BalanceLoad method. Its length should
+  // be less than 64 bytes.
+  string load_balancer_delegate = 1;
+
+  // This interval defines how often the client should send the client stats
+  // to the load balancer. Stats should only be reported when the duration is
+  // positive.
+  Duration client_stats_report_interval = 2;
+}
+
+message ServerList {
+  // Contains a list of servers selected by the load balancer. The list will
+  // be updated when server resolutions change or as needed to balance load
+  // across more servers. The client should consume the server list in order
+  // unless instructed otherwise via the client_config.
+  repeated Server servers = 1;
+
+  // Was google.protobuf.Duration expiration_interval.
+  reserved 3;
+}
+
+// Contains server information. When none of the [drop_for_*] fields are true,
+// use the other fields. When drop_for_rate_limiting is true, ignore all other
+// fields. Use drop_for_load_balancing only when it is true and
+// drop_for_rate_limiting is false.
+message Server {
+  // A resolved address for the server, serialized in network-byte-order. It may
+  // either be an IPv4 or IPv6 address.
+  bytes ip_address = 1;
+
+  // A resolved port number for the server.
+  int32 port = 2;
+
+  // An opaque but printable token given to the frontend for each pick. All
+  // frontend requests for that pick must include the token in its initial
+  // metadata. The token is used by the backend to verify the request and to
+  // allow the backend to report load to the gRPC LB system.
+  //
+  // Its length is variable but less than 50 bytes.
+  string load_balance_token = 3;
+
+  // Indicates whether this particular request should be dropped by the client
+  // for rate limiting.
+  bool drop_for_rate_limiting = 4;
+
+  // Indicates whether this particular request should be dropped by the client
+  // for load balancing.
+  bool drop_for_load_balancing = 5;
+}

vendor/google.golang.org/grpc/grpclb_picker.go

@@ -0,0 +1,159 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/codes"
+	lbpb "google.golang.org/grpc/grpclb/grpc_lb_v1/messages"
+	"google.golang.org/grpc/status"
+)
+
+type rpcStats struct {
+	NumCallsStarted                          int64
+	NumCallsFinished                         int64
+	NumCallsFinishedWithDropForRateLimiting  int64
+	NumCallsFinishedWithDropForLoadBalancing int64
+	NumCallsFinishedWithClientFailedToSend   int64
+	NumCallsFinishedKnownReceived            int64
+}
+
+// toClientStats converts rpcStats to lbpb.ClientStats, and clears rpcStats.
+func (s *rpcStats) toClientStats() *lbpb.ClientStats {
+	stats := &lbpb.ClientStats{
+		NumCallsStarted:                          atomic.SwapInt64(&s.NumCallsStarted, 0),
+		NumCallsFinished:                         atomic.SwapInt64(&s.NumCallsFinished, 0),
+		NumCallsFinishedWithDropForRateLimiting:  atomic.SwapInt64(&s.NumCallsFinishedWithDropForRateLimiting, 0),
+		NumCallsFinishedWithDropForLoadBalancing: atomic.SwapInt64(&s.NumCallsFinishedWithDropForLoadBalancing, 0),
+		NumCallsFinishedWithClientFailedToSend:   atomic.SwapInt64(&s.NumCallsFinishedWithClientFailedToSend, 0),
+		NumCallsFinishedKnownReceived:            atomic.SwapInt64(&s.NumCallsFinishedKnownReceived, 0),
+	}
+	return stats
+}
+
+func (s *rpcStats) dropForRateLimiting() {
+	atomic.AddInt64(&s.NumCallsStarted, 1)
+	atomic.AddInt64(&s.NumCallsFinishedWithDropForRateLimiting, 1)
+	atomic.AddInt64(&s.NumCallsFinished, 1)
+}
+
+func (s *rpcStats) dropForLoadBalancing() {
+	atomic.AddInt64(&s.NumCallsStarted, 1)
+	atomic.AddInt64(&s.NumCallsFinishedWithDropForLoadBalancing, 1)
+	atomic.AddInt64(&s.NumCallsFinished, 1)
+}
+
+func (s *rpcStats) failedToSend() {
+	atomic.AddInt64(&s.NumCallsStarted, 1)
+	atomic.AddInt64(&s.NumCallsFinishedWithClientFailedToSend, 1)
+	atomic.AddInt64(&s.NumCallsFinished, 1)
+}
+
+func (s *rpcStats) knownReceived() {
+	atomic.AddInt64(&s.NumCallsStarted, 1)
+	atomic.AddInt64(&s.NumCallsFinishedKnownReceived, 1)
+	atomic.AddInt64(&s.NumCallsFinished, 1)
+}
+
+type errPicker struct {
+	// Pick always returns this err.
+	err error
+}
+
+func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	return nil, nil, p.err
+}
+
+// rrPicker does roundrobin on subConns. It's typically used when there's no
+// response from remote balancer, and grpclb falls back to the resolved
+// backends.
+//
+// It guaranteed that len(subConns) > 0.
+type rrPicker struct {
+	mu           sync.Mutex
+	subConns     []balancer.SubConn // The subConns that were READY when taking the snapshot.
+	subConnsNext int
+}
+
+func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	sc := p.subConns[p.subConnsNext]
+	p.subConnsNext = (p.subConnsNext + 1) % len(p.subConns)
+	return sc, nil, nil
+}
+
+// lbPicker does two layers of picks:
+//
+// First layer: roundrobin on all servers in serverList, including drops and backends.
+// - If it picks a drop, the RPC will fail as being dropped.
+// - If it picks a backend, do a second layer pick to pick the real backend.
+//
+// Second layer: roundrobin on all READY backends.
+//
+// It's guaranteed that len(serverList) > 0.
+type lbPicker struct {
+	mu             sync.Mutex
+	serverList     []*lbpb.Server
+	serverListNext int
+	subConns       []balancer.SubConn // The subConns that were READY when taking the snapshot.
+	subConnsNext   int
+
+	stats *rpcStats
+}
+
+func (p *lbPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	// Layer one roundrobin on serverList.
+	s := p.serverList[p.serverListNext]
+	p.serverListNext = (p.serverListNext + 1) % len(p.serverList)
+
+	// If it's a drop, return an error and fail the RPC.
+	if s.DropForRateLimiting {
+		p.stats.dropForRateLimiting()
+		return nil, nil, status.Errorf(codes.Unavailable, "request dropped by grpclb")
+	}
+	if s.DropForLoadBalancing {
+		p.stats.dropForLoadBalancing()
+		return nil, nil, status.Errorf(codes.Unavailable, "request dropped by grpclb")
+	}
+
+	// If not a drop but there's no ready subConns.
+	if len(p.subConns) <= 0 {
+		return nil, nil, balancer.ErrNoSubConnAvailable
+	}
+
+	// Return the next ready subConn in the list, also collect rpc stats.
+	sc := p.subConns[p.subConnsNext]
+	p.subConnsNext = (p.subConnsNext + 1) % len(p.subConns)
+	done := func(info balancer.DoneInfo) {
+		if !info.BytesSent {
+			p.stats.failedToSend()
+		} else if info.BytesReceived {
+			p.stats.knownReceived()
+		}
+	}
+	return sc, done, nil
+}

vendor/google.golang.org/grpc/grpclb_remote_balancer.go

@@ -0,0 +1,266 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"net"
+	"reflect"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/channelz"
+
+	"google.golang.org/grpc/connectivity"
+	lbpb "google.golang.org/grpc/grpclb/grpc_lb_v1/messages"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/resolver"
+)
+
+// processServerList updates balaner's internal state, create/remove SubConns
+// and regenerates picker using the received serverList.
+func (lb *lbBalancer) processServerList(l *lbpb.ServerList) {
+	grpclog.Infof("lbBalancer: processing server list: %+v", l)
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+
+	// Set serverListReceived to true so fallback will not take effect if it has
+	// not hit timeout.
+	lb.serverListReceived = true
+
+	// If the new server list == old server list, do nothing.
+	if reflect.DeepEqual(lb.fullServerList, l.Servers) {
+		grpclog.Infof("lbBalancer: new serverlist same as the previous one, ignoring")
+		return
+	}
+	lb.fullServerList = l.Servers
+
+	var backendAddrs []resolver.Address
+	for _, s := range l.Servers {
+		if s.DropForLoadBalancing || s.DropForRateLimiting {
+			continue
+		}
+
+		md := metadata.Pairs(lbTokeyKey, s.LoadBalanceToken)
+		ip := net.IP(s.IpAddress)
+		ipStr := ip.String()
+		if ip.To4() == nil {
+			// Add square brackets to ipv6 addresses, otherwise net.Dial() and
+			// net.SplitHostPort() will return too many colons error.
+			ipStr = fmt.Sprintf("[%s]", ipStr)
+		}
+		addr := resolver.Address{
+			Addr:     fmt.Sprintf("%s:%d", ipStr, s.Port),
+			Metadata: &md,
+		}
+
+		backendAddrs = append(backendAddrs, addr)
+	}
+
+	// Call refreshSubConns to create/remove SubConns.
+	lb.refreshSubConns(backendAddrs)
+	// Regenerate and update picker no matter if there's update on backends (if
+	// any SubConn will be newed/removed). Because since the full serverList was
+	// different, there might be updates in drops or pick weights(different
+	// number of duplicates). We need to update picker with the fulllist.
+	//
+	// Now with cache, even if SubConn was newed/removed, there might be no
+	// state changes.
+	lb.regeneratePicker()
+	lb.cc.UpdateBalancerState(lb.state, lb.picker)
+}
+
+// refreshSubConns creates/removes SubConns with backendAddrs. It returns a bool
+// indicating whether the backendAddrs are different from the cached
+// backendAddrs (whether any SubConn was newed/removed).
+// Caller must hold lb.mu.
+func (lb *lbBalancer) refreshSubConns(backendAddrs []resolver.Address) bool {
+	lb.backendAddrs = nil
+	var backendsUpdated bool
+	// addrsSet is the set converted from backendAddrs, it's used to quick
+	// lookup for an address.
+	addrsSet := make(map[resolver.Address]struct{})
+	// Create new SubConns.
+	for _, addr := range backendAddrs {
+		addrWithoutMD := addr
+		addrWithoutMD.Metadata = nil
+		addrsSet[addrWithoutMD] = struct{}{}
+		lb.backendAddrs = append(lb.backendAddrs, addrWithoutMD)
+
+		if _, ok := lb.subConns[addrWithoutMD]; !ok {
+			backendsUpdated = true
+
+			// Use addrWithMD to create the SubConn.
+			sc, err := lb.cc.NewSubConn([]resolver.Address{addr}, balancer.NewSubConnOptions{})
+			if err != nil {
+				grpclog.Warningf("roundrobinBalancer: failed to create new SubConn: %v", err)
+				continue
+			}
+			lb.subConns[addrWithoutMD] = sc // Use the addr without MD as key for the map.
+			if _, ok := lb.scStates[sc]; !ok {
+				// Only set state of new sc to IDLE. The state could already be
+				// READY for cached SubConns.
+				lb.scStates[sc] = connectivity.Idle
+			}
+			sc.Connect()
+		}
+	}
+
+	for a, sc := range lb.subConns {
+		// a was removed by resolver.
+		if _, ok := addrsSet[a]; !ok {
+			backendsUpdated = true
+
+			lb.cc.RemoveSubConn(sc)
+			delete(lb.subConns, a)
+			// Keep the state of this sc in b.scStates until sc's state becomes Shutdown.
+			// The entry will be deleted in HandleSubConnStateChange.
+		}
+	}
+
+	return backendsUpdated
+}
+
+func (lb *lbBalancer) readServerList(s *balanceLoadClientStream) error {
+	for {
+		reply, err := s.Recv()
+		if err != nil {
+			return fmt.Errorf("grpclb: failed to recv server list: %v", err)
+		}
+		if serverList := reply.GetServerList(); serverList != nil {
+			lb.processServerList(serverList)
+		}
+	}
+}
+
+func (lb *lbBalancer) sendLoadReport(s *balanceLoadClientStream, interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ticker.C:
+		case <-s.Context().Done():
+			return
+		}
+		stats := lb.clientStats.toClientStats()
+		t := time.Now()
+		stats.Timestamp = &lbpb.Timestamp{
+			Seconds: t.Unix(),
+			Nanos:   int32(t.Nanosecond()),
+		}
+		if err := s.Send(&lbpb.LoadBalanceRequest{
+			LoadBalanceRequestType: &lbpb.LoadBalanceRequest_ClientStats{
+				ClientStats: stats,
+			},
+		}); err != nil {
+			return
+		}
+	}
+}
+
+func (lb *lbBalancer) callRemoteBalancer() error {
+	lbClient := &loadBalancerClient{cc: lb.ccRemoteLB}
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	stream, err := lbClient.BalanceLoad(ctx, FailFast(false))
+	if err != nil {
+		return fmt.Errorf("grpclb: failed to perform RPC to the remote balancer %v", err)
+	}
+
+	// grpclb handshake on the stream.
+	initReq := &lbpb.LoadBalanceRequest{
+		LoadBalanceRequestType: &lbpb.LoadBalanceRequest_InitialRequest{
+			InitialRequest: &lbpb.InitialLoadBalanceRequest{
+				Name: lb.target,
+			},
+		},
+	}
+	if err := stream.Send(initReq); err != nil {
+		return fmt.Errorf("grpclb: failed to send init request: %v", err)
+	}
+	reply, err := stream.Recv()
+	if err != nil {
+		return fmt.Errorf("grpclb: failed to recv init response: %v", err)
+	}
+	initResp := reply.GetInitialResponse()
+	if initResp == nil {
+		return fmt.Errorf("grpclb: reply from remote balancer did not include initial response")
+	}
+	if initResp.LoadBalancerDelegate != "" {
+		return fmt.Errorf("grpclb: Delegation is not supported")
+	}
+
+	go func() {
+		if d := convertDuration(initResp.ClientStatsReportInterval); d > 0 {
+			lb.sendLoadReport(stream, d)
+		}
+	}()
+	return lb.readServerList(stream)
+}
+
+func (lb *lbBalancer) watchRemoteBalancer() {
+	for {
+		err := lb.callRemoteBalancer()
+		select {
+		case <-lb.doneCh:
+			return
+		default:
+			if err != nil {
+				grpclog.Error(err)
+			}
+		}
+
+	}
+}
+
+func (lb *lbBalancer) dialRemoteLB(remoteLBName string) {
+	var dopts []DialOption
+	if creds := lb.opt.DialCreds; creds != nil {
+		if err := creds.OverrideServerName(remoteLBName); err == nil {
+			dopts = append(dopts, WithTransportCredentials(creds))
+		} else {
+			grpclog.Warningf("grpclb: failed to override the server name in the credentials: %v, using Insecure", err)
+			dopts = append(dopts, WithInsecure())
+		}
+	} else {
+		dopts = append(dopts, WithInsecure())
+	}
+	if lb.opt.Dialer != nil {
+		// WithDialer takes a different type of function, so we instead use a
+		// special DialOption here.
+		dopts = append(dopts, withContextDialer(lb.opt.Dialer))
+	}
+	// Explicitly set pickfirst as the balancer.
+	dopts = append(dopts, WithBalancerName(PickFirstBalancerName))
+	dopts = append(dopts, withResolverBuilder(lb.manualResolver))
+	if channelz.IsOn() {
+		dopts = append(dopts, WithChannelzParentID(lb.opt.ChannelzParentID))
+	}
+
+	// DialContext using manualResolver.Scheme, which is a random scheme generated
+	// when init grpclb. The target name is not important.
+	cc, err := DialContext(context.Background(), "grpclb:///grpclb.server", dopts...)
+	if err != nil {
+		grpclog.Fatalf("failed to dial: %v", err)
+	}
+	lb.ccRemoteLB = cc
+	go lb.watchRemoteBalancer()
+}

vendor/google.golang.org/grpc/grpclb_util.go

@@ -0,0 +1,214 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/resolver"
+)
+
+// The parent ClientConn should re-resolve when grpclb loses connection to the
+// remote balancer. When the ClientConn inside grpclb gets a TransientFailure,
+// it calls lbManualResolver.ResolveNow(), which calls parent ClientConn's
+// ResolveNow, and eventually results in re-resolve happening in parent
+// ClientConn's resolver (DNS for example).
+//
+//                          parent
+//                          ClientConn
+//  +-----------------------------------------------------------------+
+//  |             parent          +---------------------------------+ |
+//  | DNS         ClientConn      |  grpclb                         | |
+//  | resolver    balancerWrapper |                                 | |
+//  | +              +            |    grpclb          grpclb       | |
+//  | |              |            |    ManualResolver  ClientConn   | |
+//  | |              |            |     +              +            | |
+//  | |              |            |     |              | Transient  | |
+//  | |              |            |     |              | Failure    | |
+//  | |              |            |     |  <---------  |            | |
+//  | |              | <--------------- |  ResolveNow  |            | |
+//  | |  <---------  | ResolveNow |     |              |            | |
+//  | |  ResolveNow  |            |     |              |            | |
+//  | |              |            |     |              |            | |
+//  | +              +            |     +              +            | |
+//  |                             +---------------------------------+ |
+//  +-----------------------------------------------------------------+
+
+// lbManualResolver is used by the ClientConn inside grpclb. It's a manual
+// resolver with a special ResolveNow() function.
+//
+// When ResolveNow() is called, it calls ResolveNow() on the parent ClientConn,
+// so when grpclb client lose contact with remote balancers, the parent
+// ClientConn's resolver will re-resolve.
+type lbManualResolver struct {
+	scheme string
+	ccr    resolver.ClientConn
+
+	ccb balancer.ClientConn
+}
+
+func (r *lbManualResolver) Build(_ resolver.Target, cc resolver.ClientConn, _ resolver.BuildOption) (resolver.Resolver, error) {
+	r.ccr = cc
+	return r, nil
+}
+
+func (r *lbManualResolver) Scheme() string {
+	return r.scheme
+}
+
+// ResolveNow calls resolveNow on the parent ClientConn.
+func (r *lbManualResolver) ResolveNow(o resolver.ResolveNowOption) {
+	r.ccb.ResolveNow(o)
+}
+
+// Close is a noop for Resolver.
+func (*lbManualResolver) Close() {}
+
+// NewAddress calls cc.NewAddress.
+func (r *lbManualResolver) NewAddress(addrs []resolver.Address) {
+	r.ccr.NewAddress(addrs)
+}
+
+// NewServiceConfig calls cc.NewServiceConfig.
+func (r *lbManualResolver) NewServiceConfig(sc string) {
+	r.ccr.NewServiceConfig(sc)
+}
+
+const subConnCacheTime = time.Second * 10
+
+// lbCacheClientConn is a wrapper balancer.ClientConn with a SubConn cache.
+// SubConns will be kept in cache for subConnCacheTime before being removed.
+//
+// Its new and remove methods are updated to do cache first.
+type lbCacheClientConn struct {
+	cc      balancer.ClientConn
+	timeout time.Duration
+
+	mu sync.Mutex
+	// subConnCache only keeps subConns that are being deleted.
+	subConnCache  map[resolver.Address]*subConnCacheEntry
+	subConnToAddr map[balancer.SubConn]resolver.Address
+}
+
+type subConnCacheEntry struct {
+	sc balancer.SubConn
+
+	cancel        func()
+	abortDeleting bool
+}
+
+func newLBCacheClientConn(cc balancer.ClientConn) *lbCacheClientConn {
+	return &lbCacheClientConn{
+		cc:            cc,
+		timeout:       subConnCacheTime,
+		subConnCache:  make(map[resolver.Address]*subConnCacheEntry),
+		subConnToAddr: make(map[balancer.SubConn]resolver.Address),
+	}
+}
+
+func (ccc *lbCacheClientConn) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
+	if len(addrs) != 1 {
+		return nil, fmt.Errorf("grpclb calling NewSubConn with addrs of length %v", len(addrs))
+	}
+	addrWithoutMD := addrs[0]
+	addrWithoutMD.Metadata = nil
+
+	ccc.mu.Lock()
+	defer ccc.mu.Unlock()
+	if entry, ok := ccc.subConnCache[addrWithoutMD]; ok {
+		// If entry is in subConnCache, the SubConn was being deleted.
+		// cancel function will never be nil.
+		entry.cancel()
+		delete(ccc.subConnCache, addrWithoutMD)
+		return entry.sc, nil
+	}
+
+	scNew, err := ccc.cc.NewSubConn(addrs, opts)
+	if err != nil {
+		return nil, err
+	}
+
+	ccc.subConnToAddr[scNew] = addrWithoutMD
+	return scNew, nil
+}
+
+func (ccc *lbCacheClientConn) RemoveSubConn(sc balancer.SubConn) {
+	ccc.mu.Lock()
+	defer ccc.mu.Unlock()
+	addr, ok := ccc.subConnToAddr[sc]
+	if !ok {
+		return
+	}
+
+	if entry, ok := ccc.subConnCache[addr]; ok {
+		if entry.sc != sc {
+			// This could happen if NewSubConn was called multiple times for the
+			// same address, and those SubConns are all removed. We remove sc
+			// immediately here.
+			delete(ccc.subConnToAddr, sc)
+			ccc.cc.RemoveSubConn(sc)
+		}
+		return
+	}
+
+	entry := &subConnCacheEntry{
+		sc: sc,
+	}
+	ccc.subConnCache[addr] = entry
+
+	timer := time.AfterFunc(ccc.timeout, func() {
+		ccc.mu.Lock()
+		if entry.abortDeleting {
+			return
+		}
+		ccc.cc.RemoveSubConn(sc)
+		delete(ccc.subConnToAddr, sc)
+		delete(ccc.subConnCache, addr)
+		ccc.mu.Unlock()
+	})
+	entry.cancel = func() {
+		if !timer.Stop() {
+			// If stop was not successful, the timer has fired (this can only
+			// happen in a race). But the deleting function is blocked on ccc.mu
+			// because the mutex was held by the caller of this function.
+			//
+			// Set abortDeleting to true to abort the deleting function. When
+			// the lock is released, the deleting function will acquire the
+			// lock, check the value of abortDeleting and return.
+			entry.abortDeleting = true
+		}
+	}
+}
+
+func (ccc *lbCacheClientConn) UpdateBalancerState(s connectivity.State, p balancer.Picker) {
+	ccc.cc.UpdateBalancerState(s, p)
+}
+
+func (ccc *lbCacheClientConn) close() {
+	ccc.mu.Lock()
+	// Only cancel all existing timers. There's no need to remove SubConns.
+	for _, entry := range ccc.subConnCache {
+		entry.cancel()
+	}
+	ccc.mu.Unlock()
+}

vendor/google.golang.org/grpc/grpclog/grpclog.go

@@ -0,0 +1,126 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package grpclog defines logging for grpc.
+//
+// All logs in transport package only go to verbose level 2.
+// All logs in other packages in grpc are logged in spite of the verbosity level.
+//
+// In the default logger,
+// severity level can be set by environment variable GRPC_GO_LOG_SEVERITY_LEVEL,
+// verbosity level can be set by GRPC_GO_LOG_VERBOSITY_LEVEL.
+package grpclog // import "google.golang.org/grpc/grpclog"
+
+import "os"
+
+var logger = newLoggerV2()
+
+// V reports whether verbosity level l is at least the requested verbose level.
+func V(l int) bool {
+	return logger.V(l)
+}
+
+// Info logs to the INFO log.
+func Info(args ...interface{}) {
+	logger.Info(args...)
+}
+
+// Infof logs to the INFO log. Arguments are handled in the manner of fmt.Printf.
+func Infof(format string, args ...interface{}) {
+	logger.Infof(format, args...)
+}
+
+// Infoln logs to the INFO log. Arguments are handled in the manner of fmt.Println.
+func Infoln(args ...interface{}) {
+	logger.Infoln(args...)
+}
+
+// Warning logs to the WARNING log.
+func Warning(args ...interface{}) {
+	logger.Warning(args...)
+}
+
+// Warningf logs to the WARNING log. Arguments are handled in the manner of fmt.Printf.
+func Warningf(format string, args ...interface{}) {
+	logger.Warningf(format, args...)
+}
+
+// Warningln logs to the WARNING log. Arguments are handled in the manner of fmt.Println.
+func Warningln(args ...interface{}) {
+	logger.Warningln(args...)
+}
+
+// Error logs to the ERROR log.
+func Error(args ...interface{}) {
+	logger.Error(args...)
+}
+
+// Errorf logs to the ERROR log. Arguments are handled in the manner of fmt.Printf.
+func Errorf(format string, args ...interface{}) {
+	logger.Errorf(format, args...)
+}
+
+// Errorln logs to the ERROR log. Arguments are handled in the manner of fmt.Println.
+func Errorln(args ...interface{}) {
+	logger.Errorln(args...)
+}
+
+// Fatal logs to the FATAL log. Arguments are handled in the manner of fmt.Print.
+// It calls os.Exit() with exit code 1.
+func Fatal(args ...interface{}) {
+	logger.Fatal(args...)
+	// Make sure fatal logs will exit.
+	os.Exit(1)
+}
+
+// Fatalf logs to the FATAL log. Arguments are handled in the manner of fmt.Printf.
+// It calles os.Exit() with exit code 1.
+func Fatalf(format string, args ...interface{}) {
+	logger.Fatalf(format, args...)
+	// Make sure fatal logs will exit.
+	os.Exit(1)
+}
+
+// Fatalln logs to the FATAL log. Arguments are handled in the manner of fmt.Println.
+// It calle os.Exit()) with exit code 1.
+func Fatalln(args ...interface{}) {
+	logger.Fatalln(args...)
+	// Make sure fatal logs will exit.
+	os.Exit(1)
+}
+
+// Print prints to the logger. Arguments are handled in the manner of fmt.Print.
+//
+// Deprecated: use Info.
+func Print(args ...interface{}) {
+	logger.Info(args...)
+}
+
+// Printf prints to the logger. Arguments are handled in the manner of fmt.Printf.
+//
+// Deprecated: use Infof.
+func Printf(format string, args ...interface{}) {
+	logger.Infof(format, args...)
+}
+
+// Println prints to the logger. Arguments are handled in the manner of fmt.Println.
+//
+// Deprecated: use Infoln.
+func Println(args ...interface{}) {
+	logger.Infoln(args...)
+}

vendor/google.golang.org/grpc/grpclog/logger.go

@@ -0,0 +1,85 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpclog
+
+// Logger mimics golang's standard Logger as an interface.
+//
+// Deprecated: use LoggerV2.
+type Logger interface {
+	Fatal(args ...interface{})
+	Fatalf(format string, args ...interface{})
+	Fatalln(args ...interface{})
+	Print(args ...interface{})
+	Printf(format string, args ...interface{})
+	Println(args ...interface{})
+}
+
+// SetLogger sets the logger that is used in grpc. Call only from
+// init() functions.
+//
+// Deprecated: use SetLoggerV2.
+func SetLogger(l Logger) {
+	logger = &loggerWrapper{Logger: l}
+}
+
+// loggerWrapper wraps Logger into a LoggerV2.
+type loggerWrapper struct {
+	Logger
+}
+
+func (g *loggerWrapper) Info(args ...interface{}) {
+	g.Logger.Print(args...)
+}
+
+func (g *loggerWrapper) Infoln(args ...interface{}) {
+	g.Logger.Println(args...)
+}
+
+func (g *loggerWrapper) Infof(format string, args ...interface{}) {
+	g.Logger.Printf(format, args...)
+}
+
+func (g *loggerWrapper) Warning(args ...interface{}) {
+	g.Logger.Print(args...)
+}
+
+func (g *loggerWrapper) Warningln(args ...interface{}) {
+	g.Logger.Println(args...)
+}
+
+func (g *loggerWrapper) Warningf(format string, args ...interface{}) {
+	g.Logger.Printf(format, args...)
+}
+
+func (g *loggerWrapper) Error(args ...interface{}) {
+	g.Logger.Print(args...)
+}
+
+func (g *loggerWrapper) Errorln(args ...interface{}) {
+	g.Logger.Println(args...)
+}
+
+func (g *loggerWrapper) Errorf(format string, args ...interface{}) {
+	g.Logger.Printf(format, args...)
+}
+
+func (g *loggerWrapper) V(l int) bool {
+	// Returns true for all verbose level.
+	return true
+}

vendor/google.golang.org/grpc/grpclog/loggerv2.go

@@ -0,0 +1,195 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpclog
+
+import (
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"strconv"
+)
+
+// LoggerV2 does underlying logging work for grpclog.
+type LoggerV2 interface {
+	// Info logs to INFO log. Arguments are handled in the manner of fmt.Print.
+	Info(args ...interface{})
+	// Infoln logs to INFO log. Arguments are handled in the manner of fmt.Println.
+	Infoln(args ...interface{})
+	// Infof logs to INFO log. Arguments are handled in the manner of fmt.Printf.
+	Infof(format string, args ...interface{})
+	// Warning logs to WARNING log. Arguments are handled in the manner of fmt.Print.
+	Warning(args ...interface{})
+	// Warningln logs to WARNING log. Arguments are handled in the manner of fmt.Println.
+	Warningln(args ...interface{})
+	// Warningf logs to WARNING log. Arguments are handled in the manner of fmt.Printf.
+	Warningf(format string, args ...interface{})
+	// Error logs to ERROR log. Arguments are handled in the manner of fmt.Print.
+	Error(args ...interface{})
+	// Errorln logs to ERROR log. Arguments are handled in the manner of fmt.Println.
+	Errorln(args ...interface{})
+	// Errorf logs to ERROR log. Arguments are handled in the manner of fmt.Printf.
+	Errorf(format string, args ...interface{})
+	// Fatal logs to ERROR log. Arguments are handled in the manner of fmt.Print.
+	// gRPC ensures that all Fatal logs will exit with os.Exit(1).
+	// Implementations may also call os.Exit() with a non-zero exit code.
+	Fatal(args ...interface{})
+	// Fatalln logs to ERROR log. Arguments are handled in the manner of fmt.Println.
+	// gRPC ensures that all Fatal logs will exit with os.Exit(1).
+	// Implementations may also call os.Exit() with a non-zero exit code.
+	Fatalln(args ...interface{})
+	// Fatalf logs to ERROR log. Arguments are handled in the manner of fmt.Printf.
+	// gRPC ensures that all Fatal logs will exit with os.Exit(1).
+	// Implementations may also call os.Exit() with a non-zero exit code.
+	Fatalf(format string, args ...interface{})
+	// V reports whether verbosity level l is at least the requested verbose level.
+	V(l int) bool
+}
+
+// SetLoggerV2 sets logger that is used in grpc to a V2 logger.
+// Not mutex-protected, should be called before any gRPC functions.
+func SetLoggerV2(l LoggerV2) {
+	logger = l
+}
+
+const (
+	// infoLog indicates Info severity.
+	infoLog int = iota
+	// warningLog indicates Warning severity.
+	warningLog
+	// errorLog indicates Error severity.
+	errorLog
+	// fatalLog indicates Fatal severity.
+	fatalLog
+)
+
+// severityName contains the string representation of each severity.
+var severityName = []string{
+	infoLog:    "INFO",
+	warningLog: "WARNING",
+	errorLog:   "ERROR",
+	fatalLog:   "FATAL",
+}
+
+// loggerT is the default logger used by grpclog.
+type loggerT struct {
+	m []*log.Logger
+	v int
+}
+
+// NewLoggerV2 creates a loggerV2 with the provided writers.
+// Fatal logs will be written to errorW, warningW, infoW, followed by exit(1).
+// Error logs will be written to errorW, warningW and infoW.
+// Warning logs will be written to warningW and infoW.
+// Info logs will be written to infoW.
+func NewLoggerV2(infoW, warningW, errorW io.Writer) LoggerV2 {
+	return NewLoggerV2WithVerbosity(infoW, warningW, errorW, 0)
+}
+
+// NewLoggerV2WithVerbosity creates a loggerV2 with the provided writers and
+// verbosity level.
+func NewLoggerV2WithVerbosity(infoW, warningW, errorW io.Writer, v int) LoggerV2 {
+	var m []*log.Logger
+	m = append(m, log.New(infoW, severityName[infoLog]+": ", log.LstdFlags))
+	m = append(m, log.New(io.MultiWriter(infoW, warningW), severityName[warningLog]+": ", log.LstdFlags))
+	ew := io.MultiWriter(infoW, warningW, errorW) // ew will be used for error and fatal.
+	m = append(m, log.New(ew, severityName[errorLog]+": ", log.LstdFlags))
+	m = append(m, log.New(ew, severityName[fatalLog]+": ", log.LstdFlags))
+	return &loggerT{m: m, v: v}
+}
+
+// newLoggerV2 creates a loggerV2 to be used as default logger.
+// All logs are written to stderr.
+func newLoggerV2() LoggerV2 {
+	errorW := ioutil.Discard
+	warningW := ioutil.Discard
+	infoW := ioutil.Discard
+
+	logLevel := os.Getenv("GRPC_GO_LOG_SEVERITY_LEVEL")
+	switch logLevel {
+	case "", "ERROR", "error": // If env is unset, set level to ERROR.
+		errorW = os.Stderr
+	case "WARNING", "warning":
+		warningW = os.Stderr
+	case "INFO", "info":
+		infoW = os.Stderr
+	}
+
+	var v int
+	vLevel := os.Getenv("GRPC_GO_LOG_VERBOSITY_LEVEL")
+	if vl, err := strconv.Atoi(vLevel); err == nil {
+		v = vl
+	}
+	return NewLoggerV2WithVerbosity(infoW, warningW, errorW, v)
+}
+
+func (g *loggerT) Info(args ...interface{}) {
+	g.m[infoLog].Print(args...)
+}
+
+func (g *loggerT) Infoln(args ...interface{}) {
+	g.m[infoLog].Println(args...)
+}
+
+func (g *loggerT) Infof(format string, args ...interface{}) {
+	g.m[infoLog].Printf(format, args...)
+}
+
+func (g *loggerT) Warning(args ...interface{}) {
+	g.m[warningLog].Print(args...)
+}
+
+func (g *loggerT) Warningln(args ...interface{}) {
+	g.m[warningLog].Println(args...)
+}
+
+func (g *loggerT) Warningf(format string, args ...interface{}) {
+	g.m[warningLog].Printf(format, args...)
+}
+
+func (g *loggerT) Error(args ...interface{}) {
+	g.m[errorLog].Print(args...)
+}
+
+func (g *loggerT) Errorln(args ...interface{}) {
+	g.m[errorLog].Println(args...)
+}
+
+func (g *loggerT) Errorf(format string, args ...interface{}) {
+	g.m[errorLog].Printf(format, args...)
+}
+
+func (g *loggerT) Fatal(args ...interface{}) {
+	g.m[fatalLog].Fatal(args...)
+	// No need to call os.Exit() again because log.Logger.Fatal() calls os.Exit().
+}
+
+func (g *loggerT) Fatalln(args ...interface{}) {
+	g.m[fatalLog].Fatalln(args...)
+	// No need to call os.Exit() again because log.Logger.Fatal() calls os.Exit().
+}
+
+func (g *loggerT) Fatalf(format string, args ...interface{}) {
+	g.m[fatalLog].Fatalf(format, args...)
+	// No need to call os.Exit() again because log.Logger.Fatal() calls os.Exit().
+}
+
+func (g *loggerT) V(l int) bool {
+	return l <= g.v
+}

vendor/google.golang.org/grpc/interceptor.go

@@ -0,0 +1,77 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"golang.org/x/net/context"
+)
+
+// UnaryInvoker is called by UnaryClientInterceptor to complete RPCs.
+type UnaryInvoker func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error
+
+// UnaryClientInterceptor intercepts the execution of a unary RPC on the client. invoker is the handler to complete the RPC
+// and it is the responsibility of the interceptor to call it.
+// This is an EXPERIMENTAL API.
+type UnaryClientInterceptor func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, invoker UnaryInvoker, opts ...CallOption) error
+
+// Streamer is called by StreamClientInterceptor to create a ClientStream.
+type Streamer func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error)
+
+// StreamClientInterceptor intercepts the creation of ClientStream. It may return a custom ClientStream to intercept all I/O
+// operations. streamer is the handler to create a ClientStream and it is the responsibility of the interceptor to call it.
+// This is an EXPERIMENTAL API.
+type StreamClientInterceptor func(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, streamer Streamer, opts ...CallOption) (ClientStream, error)
+
+// UnaryServerInfo consists of various information about a unary RPC on
+// server side. All per-rpc information may be mutated by the interceptor.
+type UnaryServerInfo struct {
+	// Server is the service implementation the user provides. This is read-only.
+	Server interface{}
+	// FullMethod is the full RPC method string, i.e., /package.service/method.
+	FullMethod string
+}
+
+// UnaryHandler defines the handler invoked by UnaryServerInterceptor to complete the normal
+// execution of a unary RPC. If a UnaryHandler returns an error, it should be produced by the
+// status package, or else gRPC will use codes.Unknown as the status code and err.Error() as
+// the status message of the RPC.
+type UnaryHandler func(ctx context.Context, req interface{}) (interface{}, error)
+
+// UnaryServerInterceptor provides a hook to intercept the execution of a unary RPC on the server. info
+// contains all the information of this RPC the interceptor can operate on. And handler is the wrapper
+// of the service method implementation. It is the responsibility of the interceptor to invoke handler
+// to complete the RPC.
+type UnaryServerInterceptor func(ctx context.Context, req interface{}, info *UnaryServerInfo, handler UnaryHandler) (resp interface{}, err error)
+
+// StreamServerInfo consists of various information about a streaming RPC on
+// server side. All per-rpc information may be mutated by the interceptor.
+type StreamServerInfo struct {
+	// FullMethod is the full RPC method string, i.e., /package.service/method.
+	FullMethod string
+	// IsClientStream indicates whether the RPC is a client streaming RPC.
+	IsClientStream bool
+	// IsServerStream indicates whether the RPC is a server streaming RPC.
+	IsServerStream bool
+}
+
+// StreamServerInterceptor provides a hook to intercept the execution of a streaming RPC on the server.
+// info contains all the information of this RPC the interceptor can operate on. And handler is the
+// service method implementation. It is the responsibility of the interceptor to invoke handler to
+// complete the RPC.
+type StreamServerInterceptor func(srv interface{}, ss ServerStream, info *StreamServerInfo, handler StreamHandler) error

vendor/google.golang.org/grpc/internal/internal.go

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package internal contains gRPC-internal code for testing, to avoid polluting
+// the godoc of the top-level grpc package.
+package internal
+
+// TestingUseHandlerImpl enables the http.Handler-based server implementation.
+// It must be called before Serve and requires TLS credentials.
+//
+// The provided grpcServer must be of type *grpc.Server. It is untyped
+// for circular dependency reasons.
+var TestingUseHandlerImpl func(grpcServer interface{})

vendor/google.golang.org/grpc/keepalive/keepalive.go

@@ -0,0 +1,65 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package keepalive defines configurable parameters for point-to-point healthcheck.
+package keepalive
+
+import (
+	"time"
+)
+
+// ClientParameters is used to set keepalive parameters on the client-side.
+// These configure how the client will actively probe to notice when a connection is broken
+// and send pings so intermediaries will be aware of the liveness of the connection.
+// Make sure these parameters are set in coordination with the keepalive policy on the server,
+// as incompatible settings can result in closing of connection.
+type ClientParameters struct {
+	// After a duration of this time if the client doesn't see any activity it pings the server to see if the transport is still alive.
+	Time time.Duration // The current default value is infinity.
+	// After having pinged for keepalive check, the client waits for a duration of Timeout and if no activity is seen even after that
+	// the connection is closed.
+	Timeout time.Duration // The current default value is 20 seconds.
+	// If true, client runs keepalive checks even with no active RPCs.
+	PermitWithoutStream bool // false by default.
+}
+
+// ServerParameters is used to set keepalive and max-age parameters on the server-side.
+type ServerParameters struct {
+	// MaxConnectionIdle is a duration for the amount of time after which an idle connection would be closed by sending a GoAway.
+	// Idleness duration is defined since the most recent time the number of outstanding RPCs became zero or the connection establishment.
+	MaxConnectionIdle time.Duration // The current default value is infinity.
+	// MaxConnectionAge is a duration for the maximum amount of time a connection may exist before it will be closed by sending a GoAway.
+	// A random jitter of +/-10% will be added to MaxConnectionAge to spread out connection storms.
+	MaxConnectionAge time.Duration // The current default value is infinity.
+	// MaxConnectinoAgeGrace is an additive period after MaxConnectionAge after which the connection will be forcibly closed.
+	MaxConnectionAgeGrace time.Duration // The current default value is infinity.
+	// After a duration of this time if the server doesn't see any activity it pings the client to see if the transport is still alive.
+	Time time.Duration // The current default value is 2 hours.
+	// After having pinged for keepalive check, the server waits for a duration of Timeout and if no activity is seen even after that
+	// the connection is closed.
+	Timeout time.Duration // The current default value is 20 seconds.
+}
+
+// EnforcementPolicy is used to set keepalive enforcement policy on the server-side.
+// Server will close connection with a client that violates this policy.
+type EnforcementPolicy struct {
+	// MinTime is the minimum amount of time a client should wait before sending a keepalive ping.
+	MinTime time.Duration // The current default value is 5 minutes.
+	// If true, server expects keepalive pings even when there are no active streams(RPCs).
+	PermitWithoutStream bool // false by default.
+}

vendor/google.golang.org/grpc/metadata/metadata.go

@@ -0,0 +1,210 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package metadata define the structure of the metadata supported by gRPC library.
+// Please refer to https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
+// for more information about custom-metadata.
+package metadata // import "google.golang.org/grpc/metadata"
+
+import (
+	"fmt"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+// DecodeKeyValue returns k, v, nil.
+//
+// Deprecated: use k and v directly instead.
+func DecodeKeyValue(k, v string) (string, string, error) {
+	return k, v, nil
+}
+
+// MD is a mapping from metadata keys to values. Users should use the following
+// two convenience functions New and Pairs to generate MD.
+type MD map[string][]string
+
+// New creates an MD from a given key-value map.
+//
+// Only the following ASCII characters are allowed in keys:
+//  - digits: 0-9
+//  - uppercase letters: A-Z (normalized to lower)
+//  - lowercase letters: a-z
+//  - special characters: -_.
+// Uppercase letters are automatically converted to lowercase.
+//
+// Keys beginning with "grpc-" are reserved for grpc-internal use only and may
+// result in errors if set in metadata.
+func New(m map[string]string) MD {
+	md := MD{}
+	for k, val := range m {
+		key := strings.ToLower(k)
+		md[key] = append(md[key], val)
+	}
+	return md
+}
+
+// Pairs returns an MD formed by the mapping of key, value ...
+// Pairs panics if len(kv) is odd.
+//
+// Only the following ASCII characters are allowed in keys:
+//  - digits: 0-9
+//  - uppercase letters: A-Z (normalized to lower)
+//  - lowercase letters: a-z
+//  - special characters: -_.
+// Uppercase letters are automatically converted to lowercase.
+//
+// Keys beginning with "grpc-" are reserved for grpc-internal use only and may
+// result in errors if set in metadata.
+func Pairs(kv ...string) MD {
+	if len(kv)%2 == 1 {
+		panic(fmt.Sprintf("metadata: Pairs got the odd number of input pairs for metadata: %d", len(kv)))
+	}
+	md := MD{}
+	var key string
+	for i, s := range kv {
+		if i%2 == 0 {
+			key = strings.ToLower(s)
+			continue
+		}
+		md[key] = append(md[key], s)
+	}
+	return md
+}
+
+// Len returns the number of items in md.
+func (md MD) Len() int {
+	return len(md)
+}
+
+// Copy returns a copy of md.
+func (md MD) Copy() MD {
+	return Join(md)
+}
+
+// Get obtains the values for a given key.
+func (md MD) Get(k string) []string {
+	k = strings.ToLower(k)
+	return md[k]
+}
+
+// Set sets the value of a given key with a slice of values.
+func (md MD) Set(k string, vals ...string) {
+	if len(vals) == 0 {
+		return
+	}
+	k = strings.ToLower(k)
+	md[k] = vals
+}
+
+// Append adds the values to key k, not overwriting what was already stored at that key.
+func (md MD) Append(k string, vals ...string) {
+	if len(vals) == 0 {
+		return
+	}
+	k = strings.ToLower(k)
+	md[k] = append(md[k], vals...)
+}
+
+// Join joins any number of mds into a single MD.
+// The order of values for each key is determined by the order in which
+// the mds containing those values are presented to Join.
+func Join(mds ...MD) MD {
+	out := MD{}
+	for _, md := range mds {
+		for k, v := range md {
+			out[k] = append(out[k], v...)
+		}
+	}
+	return out
+}
+
+type mdIncomingKey struct{}
+type mdOutgoingKey struct{}
+
+// NewIncomingContext creates a new context with incoming md attached.
+func NewIncomingContext(ctx context.Context, md MD) context.Context {
+	return context.WithValue(ctx, mdIncomingKey{}, md)
+}
+
+// NewOutgoingContext creates a new context with outgoing md attached. If used
+// in conjunction with AppendToOutgoingContext, NewOutgoingContext will
+// overwrite any previously-appended metadata.
+func NewOutgoingContext(ctx context.Context, md MD) context.Context {
+	return context.WithValue(ctx, mdOutgoingKey{}, rawMD{md: md})
+}
+
+// AppendToOutgoingContext returns a new context with the provided kv merged
+// with any existing metadata in the context. Please refer to the
+// documentation of Pairs for a description of kv.
+func AppendToOutgoingContext(ctx context.Context, kv ...string) context.Context {
+	if len(kv)%2 == 1 {
+		panic(fmt.Sprintf("metadata: AppendToOutgoingContext got an odd number of input pairs for metadata: %d", len(kv)))
+	}
+	md, _ := ctx.Value(mdOutgoingKey{}).(rawMD)
+	added := make([][]string, len(md.added)+1)
+	copy(added, md.added)
+	added[len(added)-1] = make([]string, len(kv))
+	copy(added[len(added)-1], kv)
+	return context.WithValue(ctx, mdOutgoingKey{}, rawMD{md: md.md, added: added})
+}
+
+// FromIncomingContext returns the incoming metadata in ctx if it exists.  The
+// returned MD should not be modified. Writing to it may cause races.
+// Modification should be made to copies of the returned MD.
+func FromIncomingContext(ctx context.Context) (md MD, ok bool) {
+	md, ok = ctx.Value(mdIncomingKey{}).(MD)
+	return
+}
+
+// FromOutgoingContextRaw returns the un-merged, intermediary contents
+// of rawMD. Remember to perform strings.ToLower on the keys. The returned
+// MD should not be modified. Writing to it may cause races. Modification
+// should be made to copies of the returned MD.
+//
+// This is intended for gRPC-internal use ONLY.
+func FromOutgoingContextRaw(ctx context.Context) (MD, [][]string, bool) {
+	raw, ok := ctx.Value(mdOutgoingKey{}).(rawMD)
+	if !ok {
+		return nil, nil, false
+	}
+
+	return raw.md, raw.added, true
+}
+
+// FromOutgoingContext returns the outgoing metadata in ctx if it exists.  The
+// returned MD should not be modified. Writing to it may cause races.
+// Modification should be made to copies of the returned MD.
+func FromOutgoingContext(ctx context.Context) (MD, bool) {
+	raw, ok := ctx.Value(mdOutgoingKey{}).(rawMD)
+	if !ok {
+		return nil, false
+	}
+
+	mds := make([]MD, 0, len(raw.added)+1)
+	mds = append(mds, raw.md)
+	for _, vv := range raw.added {
+		mds = append(mds, Pairs(vv...))
+	}
+	return Join(mds...), ok
+}
+
+type rawMD struct {
+	md    MD
+	added [][]string
+}

vendor/google.golang.org/grpc/naming/dns_resolver.go

@@ -0,0 +1,290 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package naming
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"strconv"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/grpclog"
+)
+
+const (
+	defaultPort = "443"
+	defaultFreq = time.Minute * 30
+)
+
+var (
+	errMissingAddr  = errors.New("missing address")
+	errWatcherClose = errors.New("watcher has been closed")
+)
+
+// NewDNSResolverWithFreq creates a DNS Resolver that can resolve DNS names, and
+// create watchers that poll the DNS server using the frequency set by freq.
+func NewDNSResolverWithFreq(freq time.Duration) (Resolver, error) {
+	return &dnsResolver{freq: freq}, nil
+}
+
+// NewDNSResolver creates a DNS Resolver that can resolve DNS names, and create
+// watchers that poll the DNS server using the default frequency defined by defaultFreq.
+func NewDNSResolver() (Resolver, error) {
+	return NewDNSResolverWithFreq(defaultFreq)
+}
+
+// dnsResolver handles name resolution for names following the DNS scheme
+type dnsResolver struct {
+	// frequency of polling the DNS server that the watchers created by this resolver will use.
+	freq time.Duration
+}
+
+// formatIP returns ok = false if addr is not a valid textual representation of an IP address.
+// If addr is an IPv4 address, return the addr and ok = true.
+// If addr is an IPv6 address, return the addr enclosed in square brackets and ok = true.
+func formatIP(addr string) (addrIP string, ok bool) {
+	ip := net.ParseIP(addr)
+	if ip == nil {
+		return "", false
+	}
+	if ip.To4() != nil {
+		return addr, true
+	}
+	return "[" + addr + "]", true
+}
+
+// parseTarget takes the user input target string, returns formatted host and port info.
+// If target doesn't specify a port, set the port to be the defaultPort.
+// If target is in IPv6 format and host-name is enclosed in sqarue brackets, brackets
+// are strippd when setting the host.
+// examples:
+// target: "www.google.com" returns host: "www.google.com", port: "443"
+// target: "ipv4-host:80" returns host: "ipv4-host", port: "80"
+// target: "[ipv6-host]" returns host: "ipv6-host", port: "443"
+// target: ":80" returns host: "localhost", port: "80"
+// target: ":" returns host: "localhost", port: "443"
+func parseTarget(target string) (host, port string, err error) {
+	if target == "" {
+		return "", "", errMissingAddr
+	}
+
+	if ip := net.ParseIP(target); ip != nil {
+		// target is an IPv4 or IPv6(without brackets) address
+		return target, defaultPort, nil
+	}
+	if host, port, err := net.SplitHostPort(target); err == nil {
+		// target has port, i.e ipv4-host:port, [ipv6-host]:port, host-name:port
+		if host == "" {
+			// Keep consistent with net.Dial(): If the host is empty, as in ":80", the local system is assumed.
+			host = "localhost"
+		}
+		if port == "" {
+			// If the port field is empty(target ends with colon), e.g. "[::1]:", defaultPort is used.
+			port = defaultPort
+		}
+		return host, port, nil
+	}
+	if host, port, err := net.SplitHostPort(target + ":" + defaultPort); err == nil {
+		// target doesn't have port
+		return host, port, nil
+	}
+	return "", "", fmt.Errorf("invalid target address %v", target)
+}
+
+// Resolve creates a watcher that watches the name resolution of the target.
+func (r *dnsResolver) Resolve(target string) (Watcher, error) {
+	host, port, err := parseTarget(target)
+	if err != nil {
+		return nil, err
+	}
+
+	if net.ParseIP(host) != nil {
+		ipWatcher := &ipWatcher{
+			updateChan: make(chan *Update, 1),
+		}
+		host, _ = formatIP(host)
+		ipWatcher.updateChan <- &Update{Op: Add, Addr: host + ":" + port}
+		return ipWatcher, nil
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	return &dnsWatcher{
+		r:      r,
+		host:   host,
+		port:   port,
+		ctx:    ctx,
+		cancel: cancel,
+		t:      time.NewTimer(0),
+	}, nil
+}
+
+// dnsWatcher watches for the name resolution update for a specific target
+type dnsWatcher struct {
+	r    *dnsResolver
+	host string
+	port string
+	// The latest resolved address set
+	curAddrs map[string]*Update
+	ctx      context.Context
+	cancel   context.CancelFunc
+	t        *time.Timer
+}
+
+// ipWatcher watches for the name resolution update for an IP address.
+type ipWatcher struct {
+	updateChan chan *Update
+}
+
+// Next returns the address resolution Update for the target. For IP address,
+// the resolution is itself, thus polling name server is unnecessary. Therefore,
+// Next() will return an Update the first time it is called, and will be blocked
+// for all following calls as no Update exists until watcher is closed.
+func (i *ipWatcher) Next() ([]*Update, error) {
+	u, ok := <-i.updateChan
+	if !ok {
+		return nil, errWatcherClose
+	}
+	return []*Update{u}, nil
+}
+
+// Close closes the ipWatcher.
+func (i *ipWatcher) Close() {
+	close(i.updateChan)
+}
+
+// AddressType indicates the address type returned by name resolution.
+type AddressType uint8
+
+const (
+	// Backend indicates the server is a backend server.
+	Backend AddressType = iota
+	// GRPCLB indicates the server is a grpclb load balancer.
+	GRPCLB
+)
+
+// AddrMetadataGRPCLB contains the information the name resolver for grpclb should provide. The
+// name resolver used by the grpclb balancer is required to provide this type of metadata in
+// its address updates.
+type AddrMetadataGRPCLB struct {
+	// AddrType is the type of server (grpc load balancer or backend).
+	AddrType AddressType
+	// ServerName is the name of the grpc load balancer. Used for authentication.
+	ServerName string
+}
+
+// compileUpdate compares the old resolved addresses and newly resolved addresses,
+// and generates an update list
+func (w *dnsWatcher) compileUpdate(newAddrs map[string]*Update) []*Update {
+	var res []*Update
+	for a, u := range w.curAddrs {
+		if _, ok := newAddrs[a]; !ok {
+			u.Op = Delete
+			res = append(res, u)
+		}
+	}
+	for a, u := range newAddrs {
+		if _, ok := w.curAddrs[a]; !ok {
+			res = append(res, u)
+		}
+	}
+	return res
+}
+
+func (w *dnsWatcher) lookupSRV() map[string]*Update {
+	newAddrs := make(map[string]*Update)
+	_, srvs, err := lookupSRV(w.ctx, "grpclb", "tcp", w.host)
+	if err != nil {
+		grpclog.Infof("grpc: failed dns SRV record lookup due to %v.\n", err)
+		return nil
+	}
+	for _, s := range srvs {
+		lbAddrs, err := lookupHost(w.ctx, s.Target)
+		if err != nil {
+			grpclog.Warningf("grpc: failed load banlacer address dns lookup due to %v.\n", err)
+			continue
+		}
+		for _, a := range lbAddrs {
+			a, ok := formatIP(a)
+			if !ok {
+				grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+				continue
+			}
+			addr := a + ":" + strconv.Itoa(int(s.Port))
+			newAddrs[addr] = &Update{Addr: addr,
+				Metadata: AddrMetadataGRPCLB{AddrType: GRPCLB, ServerName: s.Target}}
+		}
+	}
+	return newAddrs
+}
+
+func (w *dnsWatcher) lookupHost() map[string]*Update {
+	newAddrs := make(map[string]*Update)
+	addrs, err := lookupHost(w.ctx, w.host)
+	if err != nil {
+		grpclog.Warningf("grpc: failed dns A record lookup due to %v.\n", err)
+		return nil
+	}
+	for _, a := range addrs {
+		a, ok := formatIP(a)
+		if !ok {
+			grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+			continue
+		}
+		addr := a + ":" + w.port
+		newAddrs[addr] = &Update{Addr: addr}
+	}
+	return newAddrs
+}
+
+func (w *dnsWatcher) lookup() []*Update {
+	newAddrs := w.lookupSRV()
+	if newAddrs == nil {
+		// If failed to get any balancer address (either no corresponding SRV for the
+		// target, or caused by failure during resolution/parsing of the balancer target),
+		// return any A record info available.
+		newAddrs = w.lookupHost()
+	}
+	result := w.compileUpdate(newAddrs)
+	w.curAddrs = newAddrs
+	return result
+}
+
+// Next returns the resolved address update(delta) for the target. If there's no
+// change, it will sleep for 30 mins and try to resolve again after that.
+func (w *dnsWatcher) Next() ([]*Update, error) {
+	for {
+		select {
+		case <-w.ctx.Done():
+			return nil, errWatcherClose
+		case <-w.t.C:
+		}
+		result := w.lookup()
+		// Next lookup should happen after an interval defined by w.r.freq.
+		w.t.Reset(w.r.freq)
+		if len(result) > 0 {
+			return result, nil
+		}
+	}
+}
+
+func (w *dnsWatcher) Close() {
+	w.cancel()
+}

vendor/google.golang.org/grpc/naming/go17.go

@@ -0,0 +1,34 @@
+// +build go1.6,!go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package naming
+
+import (
+	"net"
+
+	"golang.org/x/net/context"
+)
+
+var (
+	lookupHost = func(ctx context.Context, host string) ([]string, error) { return net.LookupHost(host) }
+	lookupSRV  = func(ctx context.Context, service, proto, name string) (string, []*net.SRV, error) {
+		return net.LookupSRV(service, proto, name)
+	}
+)

vendor/google.golang.org/grpc/naming/go18.go

@@ -0,0 +1,28 @@
+// +build go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package naming
+
+import "net"
+
+var (
+	lookupHost = net.DefaultResolver.LookupHost
+	lookupSRV  = net.DefaultResolver.LookupSRV
+)

vendor/google.golang.org/grpc/naming/naming.go

@@ -0,0 +1,69 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package naming defines the naming API and related data structures for gRPC.
+// The interface is EXPERIMENTAL and may be suject to change.
+//
+// Deprecated: please use package resolver.
+package naming
+
+// Operation defines the corresponding operations for a name resolution change.
+//
+// Deprecated: please use package resolver.
+type Operation uint8
+
+const (
+	// Add indicates a new address is added.
+	Add Operation = iota
+	// Delete indicates an existing address is deleted.
+	Delete
+)
+
+// Update defines a name resolution update. Notice that it is not valid having both
+// empty string Addr and nil Metadata in an Update.
+//
+// Deprecated: please use package resolver.
+type Update struct {
+	// Op indicates the operation of the update.
+	Op Operation
+	// Addr is the updated address. It is empty string if there is no address update.
+	Addr string
+	// Metadata is the updated metadata. It is nil if there is no metadata update.
+	// Metadata is not required for a custom naming implementation.
+	Metadata interface{}
+}
+
+// Resolver creates a Watcher for a target to track its resolution changes.
+//
+// Deprecated: please use package resolver.
+type Resolver interface {
+	// Resolve creates a Watcher for target.
+	Resolve(target string) (Watcher, error)
+}
+
+// Watcher watches for the updates on the specified target.
+//
+// Deprecated: please use package resolver.
+type Watcher interface {
+	// Next blocks until an update or error happens. It may return one or more
+	// updates. The first call should get the full set of the results. It should
+	// return an error if and only if Watcher cannot recover.
+	Next() ([]*Update, error)
+	// Close closes the Watcher.
+	Close()
+}

vendor/google.golang.org/grpc/peer/peer.go

@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package peer defines various peer information associated with RPCs and
+// corresponding utils.
+package peer
+
+import (
+	"net"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/credentials"
+)
+
+// Peer contains the information of the peer for an RPC, such as the address
+// and authentication information.
+type Peer struct {
+	// Addr is the peer address.
+	Addr net.Addr
+	// AuthInfo is the authentication information of the transport.
+	// It is nil if there is no transport security being used.
+	AuthInfo credentials.AuthInfo
+}
+
+type peerKey struct{}
+
+// NewContext creates a new context with peer information attached.
+func NewContext(ctx context.Context, p *Peer) context.Context {
+	return context.WithValue(ctx, peerKey{}, p)
+}
+
+// FromContext returns the peer information in ctx if it exists.
+func FromContext(ctx context.Context) (p *Peer, ok bool) {
+	p, ok = ctx.Value(peerKey{}).(*Peer)
+	return
+}

vendor/google.golang.org/grpc/picker_wrapper.go

@@ -0,0 +1,331 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"io"
+	"sync"
+	"sync/atomic"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/channelz"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/resolver"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// pickerWrapper is a wrapper of balancer.Picker. It blocks on certain pick
+// actions and unblock when there's a picker update.
+type pickerWrapper struct {
+	mu         sync.Mutex
+	done       bool
+	blockingCh chan struct{}
+	picker     balancer.Picker
+
+	// The latest connection happened.
+	connErrMu sync.Mutex
+	connErr   error
+
+	stickinessMDKey atomic.Value
+	stickiness      *stickyStore
+}
+
+func newPickerWrapper() *pickerWrapper {
+	bp := &pickerWrapper{
+		blockingCh: make(chan struct{}),
+		stickiness: newStickyStore(),
+	}
+	return bp
+}
+
+func (bp *pickerWrapper) updateConnectionError(err error) {
+	bp.connErrMu.Lock()
+	bp.connErr = err
+	bp.connErrMu.Unlock()
+}
+
+func (bp *pickerWrapper) connectionError() error {
+	bp.connErrMu.Lock()
+	err := bp.connErr
+	bp.connErrMu.Unlock()
+	return err
+}
+
+func (bp *pickerWrapper) updateStickinessMDKey(newKey string) {
+	// No need to check ok because mdKey == "" if ok == false.
+	if oldKey, _ := bp.stickinessMDKey.Load().(string); oldKey != newKey {
+		bp.stickinessMDKey.Store(newKey)
+		bp.stickiness.reset(newKey)
+	}
+}
+
+func (bp *pickerWrapper) getStickinessMDKey() string {
+	// No need to check ok because mdKey == "" if ok == false.
+	mdKey, _ := bp.stickinessMDKey.Load().(string)
+	return mdKey
+}
+
+func (bp *pickerWrapper) clearStickinessState() {
+	if oldKey := bp.getStickinessMDKey(); oldKey != "" {
+		// There's no need to reset store if mdKey was "".
+		bp.stickiness.reset(oldKey)
+	}
+}
+
+// updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
+func (bp *pickerWrapper) updatePicker(p balancer.Picker) {
+	bp.mu.Lock()
+	if bp.done {
+		bp.mu.Unlock()
+		return
+	}
+	bp.picker = p
+	// bp.blockingCh should never be nil.
+	close(bp.blockingCh)
+	bp.blockingCh = make(chan struct{})
+	bp.mu.Unlock()
+}
+
+func doneChannelzWrapper(acw *acBalancerWrapper, done func(balancer.DoneInfo)) func(balancer.DoneInfo) {
+	acw.mu.Lock()
+	ac := acw.ac
+	acw.mu.Unlock()
+	ac.incrCallsStarted()
+	return func(b balancer.DoneInfo) {
+		if b.Err != nil && b.Err != io.EOF {
+			ac.incrCallsFailed()
+		} else {
+			ac.incrCallsSucceeded()
+		}
+		if done != nil {
+			done(b)
+		}
+	}
+}
+
+// pick returns the transport that will be used for the RPC.
+// It may block in the following cases:
+// - there's no picker
+// - the current picker returns ErrNoSubConnAvailable
+// - the current picker returns other errors and failfast is false.
+// - the subConn returned by the current picker is not READY
+// When one of these situations happens, pick blocks until the picker gets updated.
+func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.PickOptions) (transport.ClientTransport, func(balancer.DoneInfo), error) {
+
+	mdKey := bp.getStickinessMDKey()
+	stickyKey, isSticky := stickyKeyFromContext(ctx, mdKey)
+
+	// Potential race here: if stickinessMDKey is updated after the above two
+	// lines, and this pick is a sticky pick, the following put could add an
+	// entry to sticky store with an outdated sticky key.
+	//
+	// The solution: keep the current md key in sticky store, and at the
+	// beginning of each get/put, check the mdkey against store.curMDKey.
+	//  - Cons: one more string comparing for each get/put.
+	//  - Pros: the string matching happens inside get/put, so the overhead for
+	//  non-sticky RPCs will be minimal.
+
+	if isSticky {
+		if t, ok := bp.stickiness.get(mdKey, stickyKey); ok {
+			// Done function returned is always nil.
+			return t, nil, nil
+		}
+	}
+
+	var (
+		p  balancer.Picker
+		ch chan struct{}
+	)
+
+	for {
+		bp.mu.Lock()
+		if bp.done {
+			bp.mu.Unlock()
+			return nil, nil, ErrClientConnClosing
+		}
+
+		if bp.picker == nil {
+			ch = bp.blockingCh
+		}
+		if ch == bp.blockingCh {
+			// This could happen when either:
+			// - bp.picker is nil (the previous if condition), or
+			// - has called pick on the current picker.
+			bp.mu.Unlock()
+			select {
+			case <-ctx.Done():
+				return nil, nil, ctx.Err()
+			case <-ch:
+			}
+			continue
+		}
+
+		ch = bp.blockingCh
+		p = bp.picker
+		bp.mu.Unlock()
+
+		subConn, done, err := p.Pick(ctx, opts)
+
+		if err != nil {
+			switch err {
+			case balancer.ErrNoSubConnAvailable:
+				continue
+			case balancer.ErrTransientFailure:
+				if !failfast {
+					continue
+				}
+				return nil, nil, status.Errorf(codes.Unavailable, "%v, latest connection error: %v", err, bp.connectionError())
+			default:
+				// err is some other error.
+				return nil, nil, toRPCErr(err)
+			}
+		}
+
+		acw, ok := subConn.(*acBalancerWrapper)
+		if !ok {
+			grpclog.Infof("subconn returned from pick is not *acBalancerWrapper")
+			continue
+		}
+		if t, ok := acw.getAddrConn().getReadyTransport(); ok {
+			if isSticky {
+				bp.stickiness.put(mdKey, stickyKey, acw)
+			}
+			if channelz.IsOn() {
+				return t, doneChannelzWrapper(acw, done), nil
+			}
+			return t, done, nil
+		}
+		grpclog.Infof("blockingPicker: the picked transport is not ready, loop back to repick")
+		// If ok == false, ac.state is not READY.
+		// A valid picker always returns READY subConn. This means the state of ac
+		// just changed, and picker will be updated shortly.
+		// continue back to the beginning of the for loop to repick.
+	}
+}
+
+func (bp *pickerWrapper) close() {
+	bp.mu.Lock()
+	defer bp.mu.Unlock()
+	if bp.done {
+		return
+	}
+	bp.done = true
+	close(bp.blockingCh)
+}
+
+type stickyStoreEntry struct {
+	acw  *acBalancerWrapper
+	addr resolver.Address
+}
+
+type stickyStore struct {
+	mu sync.Mutex
+	// curMDKey is check before every get/put to avoid races. The operation will
+	// abort immediately when the given mdKey is different from the curMDKey.
+	curMDKey string
+	store    map[string]*stickyStoreEntry
+}
+
+func newStickyStore() *stickyStore {
+	return &stickyStore{
+		store: make(map[string]*stickyStoreEntry),
+	}
+}
+
+// reset clears the map in stickyStore, and set the currentMDKey to newMDKey.
+func (ss *stickyStore) reset(newMDKey string) {
+	ss.mu.Lock()
+	ss.curMDKey = newMDKey
+	ss.store = make(map[string]*stickyStoreEntry)
+	ss.mu.Unlock()
+}
+
+// stickyKey is the key to look up in store. mdKey will be checked against
+// curMDKey to avoid races.
+func (ss *stickyStore) put(mdKey, stickyKey string, acw *acBalancerWrapper) {
+	ss.mu.Lock()
+	defer ss.mu.Unlock()
+	if mdKey != ss.curMDKey {
+		return
+	}
+	// TODO(stickiness): limit the total number of entries.
+	ss.store[stickyKey] = &stickyStoreEntry{
+		acw:  acw,
+		addr: acw.getAddrConn().getCurAddr(),
+	}
+}
+
+// stickyKey is the key to look up in store. mdKey will be checked against
+// curMDKey to avoid races.
+func (ss *stickyStore) get(mdKey, stickyKey string) (transport.ClientTransport, bool) {
+	ss.mu.Lock()
+	defer ss.mu.Unlock()
+	if mdKey != ss.curMDKey {
+		return nil, false
+	}
+	entry, ok := ss.store[stickyKey]
+	if !ok {
+		return nil, false
+	}
+	ac := entry.acw.getAddrConn()
+	if ac.getCurAddr() != entry.addr {
+		delete(ss.store, stickyKey)
+		return nil, false
+	}
+	t, ok := ac.getReadyTransport()
+	if !ok {
+		delete(ss.store, stickyKey)
+		return nil, false
+	}
+	return t, true
+}
+
+// Get one value from metadata in ctx with key stickinessMDKey.
+//
+// It returns "", false if stickinessMDKey is an empty string.
+func stickyKeyFromContext(ctx context.Context, stickinessMDKey string) (string, bool) {
+	if stickinessMDKey == "" {
+		return "", false
+	}
+
+	md, added, ok := metadata.FromOutgoingContextRaw(ctx)
+	if !ok {
+		return "", false
+	}
+
+	if vv, ok := md[stickinessMDKey]; ok {
+		if len(vv) > 0 {
+			return vv[0], true
+		}
+	}
+
+	for _, ss := range added {
+		for i := 0; i < len(ss)-1; i += 2 {
+			if ss[i] == stickinessMDKey {
+				return ss[i+1], true
+			}
+		}
+	}
+
+	return "", false
+}

vendor/google.golang.org/grpc/pickfirst.go

@@ -0,0 +1,108 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// PickFirstBalancerName is the name of the pick_first balancer.
+const PickFirstBalancerName = "pick_first"
+
+func newPickfirstBuilder() balancer.Builder {
+	return &pickfirstBuilder{}
+}
+
+type pickfirstBuilder struct{}
+
+func (*pickfirstBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
+	return &pickfirstBalancer{cc: cc}
+}
+
+func (*pickfirstBuilder) Name() string {
+	return PickFirstBalancerName
+}
+
+type pickfirstBalancer struct {
+	cc balancer.ClientConn
+	sc balancer.SubConn
+}
+
+func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+	if err != nil {
+		grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
+		return
+	}
+	if b.sc == nil {
+		b.sc, err = b.cc.NewSubConn(addrs, balancer.NewSubConnOptions{})
+		if err != nil {
+			grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+			return
+		}
+		b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
+		b.sc.Connect()
+	} else {
+		b.sc.UpdateAddresses(addrs)
+		b.sc.Connect()
+	}
+}
+
+func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+	if b.sc != sc {
+		grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+		return
+	}
+	if s == connectivity.Shutdown {
+		b.sc = nil
+		return
+	}
+
+	switch s {
+	case connectivity.Ready, connectivity.Idle:
+		b.cc.UpdateBalancerState(s, &picker{sc: sc})
+	case connectivity.Connecting:
+		b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrNoSubConnAvailable})
+	case connectivity.TransientFailure:
+		b.cc.UpdateBalancerState(s, &picker{err: balancer.ErrTransientFailure})
+	}
+}
+
+func (b *pickfirstBalancer) Close() {
+}
+
+type picker struct {
+	err error
+	sc  balancer.SubConn
+}
+
+func (p *picker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	if p.err != nil {
+		return nil, nil, p.err
+	}
+	return p.sc, nil, nil
+}
+
+func init() {
+	balancer.Register(newPickfirstBuilder())
+}

vendor/google.golang.org/grpc/proxy.go

@@ -0,0 +1,130 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"golang.org/x/net/context"
+)
+
+var (
+	// errDisabled indicates that proxy is disabled for the address.
+	errDisabled = errors.New("proxy is disabled for the address")
+	// The following variable will be overwritten in the tests.
+	httpProxyFromEnvironment = http.ProxyFromEnvironment
+)
+
+func mapAddress(ctx context.Context, address string) (string, error) {
+	req := &http.Request{
+		URL: &url.URL{
+			Scheme: "https",
+			Host:   address,
+		},
+	}
+	url, err := httpProxyFromEnvironment(req)
+	if err != nil {
+		return "", err
+	}
+	if url == nil {
+		return "", errDisabled
+	}
+	return url.Host, nil
+}
+
+// To read a response from a net.Conn, http.ReadResponse() takes a bufio.Reader.
+// It's possible that this reader reads more than what's need for the response and stores
+// those bytes in the buffer.
+// bufConn wraps the original net.Conn and the bufio.Reader to make sure we don't lose the
+// bytes in the buffer.
+type bufConn struct {
+	net.Conn
+	r io.Reader
+}
+
+func (c *bufConn) Read(b []byte) (int, error) {
+	return c.r.Read(b)
+}
+
+func doHTTPConnectHandshake(ctx context.Context, conn net.Conn, addr string) (_ net.Conn, err error) {
+	defer func() {
+		if err != nil {
+			conn.Close()
+		}
+	}()
+
+	req := (&http.Request{
+		Method: http.MethodConnect,
+		URL:    &url.URL{Host: addr},
+		Header: map[string][]string{"User-Agent": {grpcUA}},
+	})
+
+	if err := sendHTTPRequest(ctx, req, conn); err != nil {
+		return nil, fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+
+	r := bufio.NewReader(conn)
+	resp, err := http.ReadResponse(r, req)
+	if err != nil {
+		return nil, fmt.Errorf("reading server HTTP response: %v", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		dump, err := httputil.DumpResponse(resp, true)
+		if err != nil {
+			return nil, fmt.Errorf("failed to do connect handshake, status code: %s", resp.Status)
+		}
+		return nil, fmt.Errorf("failed to do connect handshake, response: %q", dump)
+	}
+
+	return &bufConn{Conn: conn, r: r}, nil
+}
+
+// newProxyDialer returns a dialer that connects to proxy first if necessary.
+// The returned dialer checks if a proxy is necessary, dial to the proxy with the
+// provided dialer, does HTTP CONNECT handshake and returns the connection.
+func newProxyDialer(dialer func(context.Context, string) (net.Conn, error)) func(context.Context, string) (net.Conn, error) {
+	return func(ctx context.Context, addr string) (conn net.Conn, err error) {
+		var skipHandshake bool
+		newAddr, err := mapAddress(ctx, addr)
+		if err != nil {
+			if err != errDisabled {
+				return nil, err
+			}
+			skipHandshake = true
+			newAddr = addr
+		}
+
+		conn, err = dialer(ctx, newAddr)
+		if err != nil {
+			return
+		}
+		if !skipHandshake {
+			conn, err = doHTTPConnectHandshake(ctx, conn, addr)
+		}
+		return
+	}
+}

vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go

@@ -0,0 +1,379 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package dns implements a dns resolver to be installed as the default resolver
+// in grpc.
+package dns
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"math/rand"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+func init() {
+	resolver.Register(NewBuilder())
+}
+
+const (
+	defaultPort = "443"
+	defaultFreq = time.Minute * 30
+	golang      = "GO"
+	// In DNS, service config is encoded in a TXT record via the mechanism
+	// described in RFC-1464 using the attribute name grpc_config.
+	txtAttribute = "grpc_config="
+)
+
+var (
+	errMissingAddr = errors.New("missing address")
+	randomGen      = rand.New(rand.NewSource(time.Now().UnixNano()))
+)
+
+// NewBuilder creates a dnsBuilder which is used to factory DNS resolvers.
+func NewBuilder() resolver.Builder {
+	return &dnsBuilder{freq: defaultFreq}
+}
+
+type dnsBuilder struct {
+	// frequency of polling the DNS server.
+	freq time.Duration
+}
+
+// Build creates and starts a DNS resolver that watches the name resolution of the target.
+func (b *dnsBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+	host, port, err := parseTarget(target.Endpoint)
+	if err != nil {
+		return nil, err
+	}
+
+	// IP address.
+	if net.ParseIP(host) != nil {
+		host, _ = formatIP(host)
+		addr := []resolver.Address{{Addr: host + ":" + port}}
+		i := &ipResolver{
+			cc: cc,
+			ip: addr,
+			rn: make(chan struct{}, 1),
+			q:  make(chan struct{}),
+		}
+		cc.NewAddress(addr)
+		go i.watcher()
+		return i, nil
+	}
+
+	// DNS address (non-IP).
+	ctx, cancel := context.WithCancel(context.Background())
+	d := &dnsResolver{
+		freq:                 b.freq,
+		host:                 host,
+		port:                 port,
+		ctx:                  ctx,
+		cancel:               cancel,
+		cc:                   cc,
+		t:                    time.NewTimer(0),
+		rn:                   make(chan struct{}, 1),
+		disableServiceConfig: opts.DisableServiceConfig,
+	}
+
+	d.wg.Add(1)
+	go d.watcher()
+	return d, nil
+}
+
+// Scheme returns the naming scheme of this resolver builder, which is "dns".
+func (b *dnsBuilder) Scheme() string {
+	return "dns"
+}
+
+// ipResolver watches for the name resolution update for an IP address.
+type ipResolver struct {
+	cc resolver.ClientConn
+	ip []resolver.Address
+	// rn channel is used by ResolveNow() to force an immediate resolution of the target.
+	rn chan struct{}
+	q  chan struct{}
+}
+
+// ResolveNow resend the address it stores, no resolution is needed.
+func (i *ipResolver) ResolveNow(opt resolver.ResolveNowOption) {
+	select {
+	case i.rn <- struct{}{}:
+	default:
+	}
+}
+
+// Close closes the ipResolver.
+func (i *ipResolver) Close() {
+	close(i.q)
+}
+
+func (i *ipResolver) watcher() {
+	for {
+		select {
+		case <-i.rn:
+			i.cc.NewAddress(i.ip)
+		case <-i.q:
+			return
+		}
+	}
+}
+
+// dnsResolver watches for the name resolution update for a non-IP target.
+type dnsResolver struct {
+	freq   time.Duration
+	host   string
+	port   string
+	ctx    context.Context
+	cancel context.CancelFunc
+	cc     resolver.ClientConn
+	// rn channel is used by ResolveNow() to force an immediate resolution of the target.
+	rn chan struct{}
+	t  *time.Timer
+	// wg is used to enforce Close() to return after the watcher() goroutine has finished.
+	// Otherwise, data race will be possible. [Race Example] in dns_resolver_test we
+	// replace the real lookup functions with mocked ones to facilitate testing.
+	// If Close() doesn't wait for watcher() goroutine finishes, race detector sometimes
+	// will warns lookup (READ the lookup function pointers) inside watcher() goroutine
+	// has data race with replaceNetFunc (WRITE the lookup function pointers).
+	wg                   sync.WaitGroup
+	disableServiceConfig bool
+}
+
+// ResolveNow invoke an immediate resolution of the target that this dnsResolver watches.
+func (d *dnsResolver) ResolveNow(opt resolver.ResolveNowOption) {
+	select {
+	case d.rn <- struct{}{}:
+	default:
+	}
+}
+
+// Close closes the dnsResolver.
+func (d *dnsResolver) Close() {
+	d.cancel()
+	d.wg.Wait()
+	d.t.Stop()
+}
+
+func (d *dnsResolver) watcher() {
+	defer d.wg.Done()
+	for {
+		select {
+		case <-d.ctx.Done():
+			return
+		case <-d.t.C:
+		case <-d.rn:
+		}
+		result, sc := d.lookup()
+		// Next lookup should happen after an interval defined by d.freq.
+		d.t.Reset(d.freq)
+		d.cc.NewServiceConfig(sc)
+		d.cc.NewAddress(result)
+	}
+}
+
+func (d *dnsResolver) lookupSRV() []resolver.Address {
+	var newAddrs []resolver.Address
+	_, srvs, err := lookupSRV(d.ctx, "grpclb", "tcp", d.host)
+	if err != nil {
+		grpclog.Infof("grpc: failed dns SRV record lookup due to %v.\n", err)
+		return nil
+	}
+	for _, s := range srvs {
+		lbAddrs, err := lookupHost(d.ctx, s.Target)
+		if err != nil {
+			grpclog.Infof("grpc: failed load balancer address dns lookup due to %v.\n", err)
+			continue
+		}
+		for _, a := range lbAddrs {
+			a, ok := formatIP(a)
+			if !ok {
+				grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+				continue
+			}
+			addr := a + ":" + strconv.Itoa(int(s.Port))
+			newAddrs = append(newAddrs, resolver.Address{Addr: addr, Type: resolver.GRPCLB, ServerName: s.Target})
+		}
+	}
+	return newAddrs
+}
+
+func (d *dnsResolver) lookupTXT() string {
+	ss, err := lookupTXT(d.ctx, d.host)
+	if err != nil {
+		grpclog.Infof("grpc: failed dns TXT record lookup due to %v.\n", err)
+		return ""
+	}
+	var res string
+	for _, s := range ss {
+		res += s
+	}
+
+	// TXT record must have "grpc_config=" attribute in order to be used as service config.
+	if !strings.HasPrefix(res, txtAttribute) {
+		grpclog.Warningf("grpc: TXT record %v missing %v attribute", res, txtAttribute)
+		return ""
+	}
+	return strings.TrimPrefix(res, txtAttribute)
+}
+
+func (d *dnsResolver) lookupHost() []resolver.Address {
+	var newAddrs []resolver.Address
+	addrs, err := lookupHost(d.ctx, d.host)
+	if err != nil {
+		grpclog.Warningf("grpc: failed dns A record lookup due to %v.\n", err)
+		return nil
+	}
+	for _, a := range addrs {
+		a, ok := formatIP(a)
+		if !ok {
+			grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+			continue
+		}
+		addr := a + ":" + d.port
+		newAddrs = append(newAddrs, resolver.Address{Addr: addr})
+	}
+	return newAddrs
+}
+
+func (d *dnsResolver) lookup() ([]resolver.Address, string) {
+	newAddrs := d.lookupSRV()
+	// Support fallback to non-balancer address.
+	newAddrs = append(newAddrs, d.lookupHost()...)
+	if d.disableServiceConfig {
+		return newAddrs, ""
+	}
+	sc := d.lookupTXT()
+	return newAddrs, canaryingSC(sc)
+}
+
+// formatIP returns ok = false if addr is not a valid textual representation of an IP address.
+// If addr is an IPv4 address, return the addr and ok = true.
+// If addr is an IPv6 address, return the addr enclosed in square brackets and ok = true.
+func formatIP(addr string) (addrIP string, ok bool) {
+	ip := net.ParseIP(addr)
+	if ip == nil {
+		return "", false
+	}
+	if ip.To4() != nil {
+		return addr, true
+	}
+	return "[" + addr + "]", true
+}
+
+// parseTarget takes the user input target string, returns formatted host and port info.
+// If target doesn't specify a port, set the port to be the defaultPort.
+// If target is in IPv6 format and host-name is enclosed in sqarue brackets, brackets
+// are strippd when setting the host.
+// examples:
+// target: "www.google.com" returns host: "www.google.com", port: "443"
+// target: "ipv4-host:80" returns host: "ipv4-host", port: "80"
+// target: "[ipv6-host]" returns host: "ipv6-host", port: "443"
+// target: ":80" returns host: "localhost", port: "80"
+// target: ":" returns host: "localhost", port: "443"
+func parseTarget(target string) (host, port string, err error) {
+	if target == "" {
+		return "", "", errMissingAddr
+	}
+	if ip := net.ParseIP(target); ip != nil {
+		// target is an IPv4 or IPv6(without brackets) address
+		return target, defaultPort, nil
+	}
+	if host, port, err = net.SplitHostPort(target); err == nil {
+		// target has port, i.e ipv4-host:port, [ipv6-host]:port, host-name:port
+		if host == "" {
+			// Keep consistent with net.Dial(): If the host is empty, as in ":80", the local system is assumed.
+			host = "localhost"
+		}
+		if port == "" {
+			// If the port field is empty(target ends with colon), e.g. "[::1]:", defaultPort is used.
+			port = defaultPort
+		}
+		return host, port, nil
+	}
+	if host, port, err = net.SplitHostPort(target + ":" + defaultPort); err == nil {
+		// target doesn't have port
+		return host, port, nil
+	}
+	return "", "", fmt.Errorf("invalid target address %v, error info: %v", target, err)
+}
+
+type rawChoice struct {
+	ClientLanguage *[]string        `json:"clientLanguage,omitempty"`
+	Percentage     *int             `json:"percentage,omitempty"`
+	ClientHostName *[]string        `json:"clientHostName,omitempty"`
+	ServiceConfig  *json.RawMessage `json:"serviceConfig,omitempty"`
+}
+
+func containsString(a *[]string, b string) bool {
+	if a == nil {
+		return true
+	}
+	for _, c := range *a {
+		if c == b {
+			return true
+		}
+	}
+	return false
+}
+
+func chosenByPercentage(a *int) bool {
+	if a == nil {
+		return true
+	}
+	return randomGen.Intn(100)+1 <= *a
+}
+
+func canaryingSC(js string) string {
+	if js == "" {
+		return ""
+	}
+	var rcs []rawChoice
+	err := json.Unmarshal([]byte(js), &rcs)
+	if err != nil {
+		grpclog.Warningf("grpc: failed to parse service config json string due to %v.\n", err)
+		return ""
+	}
+	cliHostname, err := os.Hostname()
+	if err != nil {
+		grpclog.Warningf("grpc: failed to get client hostname due to %v.\n", err)
+		return ""
+	}
+	var sc string
+	for _, c := range rcs {
+		if !containsString(c.ClientLanguage, golang) ||
+			!chosenByPercentage(c.Percentage) ||
+			!containsString(c.ClientHostName, cliHostname) ||
+			c.ServiceConfig == nil {
+			continue
+		}
+		sc = string(*c.ServiceConfig)
+		break
+	}
+	return sc
+}

vendor/google.golang.org/grpc/resolver/dns/go17.go

@@ -0,0 +1,35 @@
+// +build go1.6, !go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package dns
+
+import (
+	"net"
+
+	"golang.org/x/net/context"
+)
+
+var (
+	lookupHost = func(ctx context.Context, host string) ([]string, error) { return net.LookupHost(host) }
+	lookupSRV  = func(ctx context.Context, service, proto, name string) (string, []*net.SRV, error) {
+		return net.LookupSRV(service, proto, name)
+	}
+	lookupTXT = func(ctx context.Context, name string) ([]string, error) { return net.LookupTXT(name) }
+)

vendor/google.golang.org/grpc/resolver/dns/go18.go

@@ -0,0 +1,29 @@
+// +build go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package dns
+
+import "net"
+
+var (
+	lookupHost = net.DefaultResolver.LookupHost
+	lookupSRV  = net.DefaultResolver.LookupSRV
+	lookupTXT  = net.DefaultResolver.LookupTXT
+)

vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go

@@ -0,0 +1,57 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package passthrough implements a pass-through resolver. It sends the target
+// name without scheme back to gRPC as resolved address.
+package passthrough
+
+import "google.golang.org/grpc/resolver"
+
+const scheme = "passthrough"
+
+type passthroughBuilder struct{}
+
+func (*passthroughBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+	r := &passthroughResolver{
+		target: target,
+		cc:     cc,
+	}
+	r.start()
+	return r, nil
+}
+
+func (*passthroughBuilder) Scheme() string {
+	return scheme
+}
+
+type passthroughResolver struct {
+	target resolver.Target
+	cc     resolver.ClientConn
+}
+
+func (r *passthroughResolver) start() {
+	r.cc.NewAddress([]resolver.Address{{Addr: r.target.Endpoint}})
+}
+
+func (*passthroughResolver) ResolveNow(o resolver.ResolveNowOption) {}
+
+func (*passthroughResolver) Close() {}
+
+func init() {
+	resolver.Register(&passthroughBuilder{})
+}

vendor/google.golang.org/grpc/resolver/resolver.go

@@ -0,0 +1,154 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package resolver defines APIs for name resolution in gRPC.
+// All APIs in this package are experimental.
+package resolver
+
+var (
+	// m is a map from scheme to resolver builder.
+	m = make(map[string]Builder)
+	// defaultScheme is the default scheme to use.
+	defaultScheme = "passthrough"
+)
+
+// TODO(bar) install dns resolver in init(){}.
+
+// Register registers the resolver builder to the resolver map. b.Scheme will be
+// used as the scheme registered with this builder.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple Resolvers are
+// registered with the same name, the one registered last will take effect.
+func Register(b Builder) {
+	m[b.Scheme()] = b
+}
+
+// Get returns the resolver builder registered with the given scheme.
+//
+// If no builder is register with the scheme, nil will be returned.
+func Get(scheme string) Builder {
+	if b, ok := m[scheme]; ok {
+		return b
+	}
+	return nil
+}
+
+// SetDefaultScheme sets the default scheme that will be used.
+// The default default scheme is "passthrough".
+func SetDefaultScheme(scheme string) {
+	defaultScheme = scheme
+}
+
+// GetDefaultScheme gets the default scheme that will be used.
+func GetDefaultScheme() string {
+	return defaultScheme
+}
+
+// AddressType indicates the address type returned by name resolution.
+type AddressType uint8
+
+const (
+	// Backend indicates the address is for a backend server.
+	Backend AddressType = iota
+	// GRPCLB indicates the address is for a grpclb load balancer.
+	GRPCLB
+)
+
+// Address represents a server the client connects to.
+// This is the EXPERIMENTAL API and may be changed or extended in the future.
+type Address struct {
+	// Addr is the server address on which a connection will be established.
+	Addr string
+	// Type is the type of this address.
+	Type AddressType
+	// ServerName is the name of this address.
+	//
+	// e.g. if Type is GRPCLB, ServerName should be the name of the remote load
+	// balancer, not the name of the backend.
+	ServerName string
+	// Metadata is the information associated with Addr, which may be used
+	// to make load balancing decision.
+	Metadata interface{}
+}
+
+// BuildOption includes additional information for the builder to create
+// the resolver.
+type BuildOption struct {
+	// DisableServiceConfig indicates whether resolver should fetch service config data.
+	DisableServiceConfig bool
+}
+
+// ClientConn contains the callbacks for resolver to notify any updates
+// to the gRPC ClientConn.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
+type ClientConn interface {
+	// NewAddress is called by resolver to notify ClientConn a new list
+	// of resolved addresses.
+	// The address list should be the complete list of resolved addresses.
+	NewAddress(addresses []Address)
+	// NewServiceConfig is called by resolver to notify ClientConn a new
+	// service config. The service config should be provided as a json string.
+	NewServiceConfig(serviceConfig string)
+}
+
+// Target represents a target for gRPC, as specified in:
+// https://github.com/grpc/grpc/blob/master/doc/naming.md.
+type Target struct {
+	Scheme    string
+	Authority string
+	Endpoint  string
+}
+
+// Builder creates a resolver that will be used to watch name resolution updates.
+type Builder interface {
+	// Build creates a new resolver for the given target.
+	//
+	// gRPC dial calls Build synchronously, and fails if the returned error is
+	// not nil.
+	Build(target Target, cc ClientConn, opts BuildOption) (Resolver, error)
+	// Scheme returns the scheme supported by this resolver.
+	// Scheme is defined at https://github.com/grpc/grpc/blob/master/doc/naming.md.
+	Scheme() string
+}
+
+// ResolveNowOption includes additional information for ResolveNow.
+type ResolveNowOption struct{}
+
+// Resolver watches for the updates on the specified target.
+// Updates include address updates and service config updates.
+type Resolver interface {
+	// ResolveNow will be called by gRPC to try to resolve the target name
+	// again. It's just a hint, resolver can ignore this if it's not necessary.
+	//
+	// It could be called multiple times concurrently.
+	ResolveNow(ResolveNowOption)
+	// Close closes the resolver.
+	Close()
+}
+
+// UnregisterForTesting removes the resolver builder with the given scheme from the
+// resolver map.
+// This function is for testing only.
+func UnregisterForTesting(scheme string) {
+	delete(m, scheme)
+}

vendor/google.golang.org/grpc/resolver_conn_wrapper.go

@@ -0,0 +1,158 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"strings"
+
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// ccResolverWrapper is a wrapper on top of cc for resolvers.
+// It implements resolver.ClientConnection interface.
+type ccResolverWrapper struct {
+	cc       *ClientConn
+	resolver resolver.Resolver
+	addrCh   chan []resolver.Address
+	scCh     chan string
+	done     chan struct{}
+}
+
+// split2 returns the values from strings.SplitN(s, sep, 2).
+// If sep is not found, it returns ("", s, false) instead.
+func split2(s, sep string) (string, string, bool) {
+	spl := strings.SplitN(s, sep, 2)
+	if len(spl) < 2 {
+		return "", "", false
+	}
+	return spl[0], spl[1], true
+}
+
+// parseTarget splits target into a struct containing scheme, authority and
+// endpoint.
+//
+// If target is not a valid scheme://authority/endpoint, it returns {Endpoint:
+// target}.
+func parseTarget(target string) (ret resolver.Target) {
+	var ok bool
+	ret.Scheme, ret.Endpoint, ok = split2(target, "://")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
+	ret.Authority, ret.Endpoint, ok = split2(ret.Endpoint, "/")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
+	return ret
+}
+
+// newCCResolverWrapper parses cc.target for scheme and gets the resolver
+// builder for this scheme. It then builds the resolver and starts the
+// monitoring goroutine for it.
+//
+// If withResolverBuilder dial option is set, the specified resolver will be
+// used instead.
+func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
+	rb := cc.dopts.resolverBuilder
+	if rb == nil {
+		return nil, fmt.Errorf("could not get resolver for scheme: %q", cc.parsedTarget.Scheme)
+	}
+
+	ccr := &ccResolverWrapper{
+		cc:     cc,
+		addrCh: make(chan []resolver.Address, 1),
+		scCh:   make(chan string, 1),
+		done:   make(chan struct{}),
+	}
+
+	var err error
+	ccr.resolver, err = rb.Build(cc.parsedTarget, ccr, resolver.BuildOption{DisableServiceConfig: cc.dopts.disableServiceConfig})
+	if err != nil {
+		return nil, err
+	}
+	return ccr, nil
+}
+
+func (ccr *ccResolverWrapper) start() {
+	go ccr.watcher()
+}
+
+// watcher processes address updates and service config updates sequentially.
+// Otherwise, we need to resolve possible races between address and service
+// config (e.g. they specify different balancer types).
+func (ccr *ccResolverWrapper) watcher() {
+	for {
+		select {
+		case <-ccr.done:
+			return
+		default:
+		}
+
+		select {
+		case addrs := <-ccr.addrCh:
+			select {
+			case <-ccr.done:
+				return
+			default:
+			}
+			grpclog.Infof("ccResolverWrapper: sending new addresses to cc: %v", addrs)
+			ccr.cc.handleResolvedAddrs(addrs, nil)
+		case sc := <-ccr.scCh:
+			select {
+			case <-ccr.done:
+				return
+			default:
+			}
+			grpclog.Infof("ccResolverWrapper: got new service config: %v", sc)
+			ccr.cc.handleServiceConfig(sc)
+		case <-ccr.done:
+			return
+		}
+	}
+}
+
+func (ccr *ccResolverWrapper) resolveNow(o resolver.ResolveNowOption) {
+	ccr.resolver.ResolveNow(o)
+}
+
+func (ccr *ccResolverWrapper) close() {
+	ccr.resolver.Close()
+	close(ccr.done)
+}
+
+// NewAddress is called by the resolver implemenetion to send addresses to gRPC.
+func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
+	select {
+	case <-ccr.addrCh:
+	default:
+	}
+	ccr.addrCh <- addrs
+}
+
+// NewServiceConfig is called by the resolver implemenetion to send service
+// configs to gPRC.
+func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
+	select {
+	case <-ccr.scCh:
+	default:
+	}
+	ccr.scCh <- sc
+}

vendor/google.golang.org/grpc/rpc_util.go

@@ -0,0 +1,727 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"bytes"
+	"compress/gzip"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/encoding/proto"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// Compressor defines the interface gRPC uses to compress a message.
+//
+// Deprecated: use package encoding.
+type Compressor interface {
+	// Do compresses p into w.
+	Do(w io.Writer, p []byte) error
+	// Type returns the compression algorithm the Compressor uses.
+	Type() string
+}
+
+type gzipCompressor struct {
+	pool sync.Pool
+}
+
+// NewGZIPCompressor creates a Compressor based on GZIP.
+//
+// Deprecated: use package encoding/gzip.
+func NewGZIPCompressor() Compressor {
+	c, _ := NewGZIPCompressorWithLevel(gzip.DefaultCompression)
+	return c
+}
+
+// NewGZIPCompressorWithLevel is like NewGZIPCompressor but specifies the gzip compression level instead
+// of assuming DefaultCompression.
+//
+// The error returned will be nil if the level is valid.
+//
+// Deprecated: use package encoding/gzip.
+func NewGZIPCompressorWithLevel(level int) (Compressor, error) {
+	if level < gzip.DefaultCompression || level > gzip.BestCompression {
+		return nil, fmt.Errorf("grpc: invalid compression level: %d", level)
+	}
+	return &gzipCompressor{
+		pool: sync.Pool{
+			New: func() interface{} {
+				w, err := gzip.NewWriterLevel(ioutil.Discard, level)
+				if err != nil {
+					panic(err)
+				}
+				return w
+			},
+		},
+	}, nil
+}
+
+func (c *gzipCompressor) Do(w io.Writer, p []byte) error {
+	z := c.pool.Get().(*gzip.Writer)
+	defer c.pool.Put(z)
+	z.Reset(w)
+	if _, err := z.Write(p); err != nil {
+		return err
+	}
+	return z.Close()
+}
+
+func (c *gzipCompressor) Type() string {
+	return "gzip"
+}
+
+// Decompressor defines the interface gRPC uses to decompress a message.
+//
+// Deprecated: use package encoding.
+type Decompressor interface {
+	// Do reads the data from r and uncompress them.
+	Do(r io.Reader) ([]byte, error)
+	// Type returns the compression algorithm the Decompressor uses.
+	Type() string
+}
+
+type gzipDecompressor struct {
+	pool sync.Pool
+}
+
+// NewGZIPDecompressor creates a Decompressor based on GZIP.
+//
+// Deprecated: use package encoding/gzip.
+func NewGZIPDecompressor() Decompressor {
+	return &gzipDecompressor{}
+}
+
+func (d *gzipDecompressor) Do(r io.Reader) ([]byte, error) {
+	var z *gzip.Reader
+	switch maybeZ := d.pool.Get().(type) {
+	case nil:
+		newZ, err := gzip.NewReader(r)
+		if err != nil {
+			return nil, err
+		}
+		z = newZ
+	case *gzip.Reader:
+		z = maybeZ
+		if err := z.Reset(r); err != nil {
+			d.pool.Put(z)
+			return nil, err
+		}
+	}
+
+	defer func() {
+		z.Close()
+		d.pool.Put(z)
+	}()
+	return ioutil.ReadAll(z)
+}
+
+func (d *gzipDecompressor) Type() string {
+	return "gzip"
+}
+
+// callInfo contains all related configuration and information about an RPC.
+type callInfo struct {
+	compressorType        string
+	failFast              bool
+	stream                *clientStream
+	traceInfo             traceInfo // in trace.go
+	maxReceiveMessageSize *int
+	maxSendMessageSize    *int
+	creds                 credentials.PerRPCCredentials
+	contentSubtype        string
+	codec                 baseCodec
+}
+
+func defaultCallInfo() *callInfo {
+	return &callInfo{failFast: true}
+}
+
+// CallOption configures a Call before it starts or extracts information from
+// a Call after it completes.
+type CallOption interface {
+	// before is called before the call is sent to any server.  If before
+	// returns a non-nil error, the RPC fails with that error.
+	before(*callInfo) error
+
+	// after is called after the call has completed.  after cannot return an
+	// error, so any failures should be reported via output parameters.
+	after(*callInfo)
+}
+
+// EmptyCallOption does not alter the Call configuration.
+// It can be embedded in another structure to carry satellite data for use
+// by interceptors.
+type EmptyCallOption struct{}
+
+func (EmptyCallOption) before(*callInfo) error { return nil }
+func (EmptyCallOption) after(*callInfo)        {}
+
+// Header returns a CallOptions that retrieves the header metadata
+// for a unary RPC.
+func Header(md *metadata.MD) CallOption {
+	return HeaderCallOption{HeaderAddr: md}
+}
+
+// HeaderCallOption is a CallOption for collecting response header metadata.
+// The metadata field will be populated *after* the RPC completes.
+// This is an EXPERIMENTAL API.
+type HeaderCallOption struct {
+	HeaderAddr *metadata.MD
+}
+
+func (o HeaderCallOption) before(c *callInfo) error { return nil }
+func (o HeaderCallOption) after(c *callInfo) {
+	if c.stream != nil {
+		*o.HeaderAddr, _ = c.stream.Header()
+	}
+}
+
+// Trailer returns a CallOptions that retrieves the trailer metadata
+// for a unary RPC.
+func Trailer(md *metadata.MD) CallOption {
+	return TrailerCallOption{TrailerAddr: md}
+}
+
+// TrailerCallOption is a CallOption for collecting response trailer metadata.
+// The metadata field will be populated *after* the RPC completes.
+// This is an EXPERIMENTAL API.
+type TrailerCallOption struct {
+	TrailerAddr *metadata.MD
+}
+
+func (o TrailerCallOption) before(c *callInfo) error { return nil }
+func (o TrailerCallOption) after(c *callInfo) {
+	if c.stream != nil {
+		*o.TrailerAddr = c.stream.Trailer()
+	}
+}
+
+// Peer returns a CallOption that retrieves peer information for a unary RPC.
+// The peer field will be populated *after* the RPC completes.
+func Peer(p *peer.Peer) CallOption {
+	return PeerCallOption{PeerAddr: p}
+}
+
+// PeerCallOption is a CallOption for collecting the identity of the remote
+// peer. The peer field will be populated *after* the RPC completes.
+// This is an EXPERIMENTAL API.
+type PeerCallOption struct {
+	PeerAddr *peer.Peer
+}
+
+func (o PeerCallOption) before(c *callInfo) error { return nil }
+func (o PeerCallOption) after(c *callInfo) {
+	if c.stream != nil {
+		if x, ok := peer.FromContext(c.stream.Context()); ok {
+			*o.PeerAddr = *x
+		}
+	}
+}
+
+// FailFast configures the action to take when an RPC is attempted on broken
+// connections or unreachable servers.  If failFast is true, the RPC will fail
+// immediately. Otherwise, the RPC client will block the call until a
+// connection is available (or the call is canceled or times out) and will
+// retry the call if it fails due to a transient error.  gRPC will not retry if
+// data was written to the wire unless the server indicates it did not process
+// the data.  Please refer to
+// https://github.com/grpc/grpc/blob/master/doc/wait-for-ready.md.
+//
+// By default, RPCs are "Fail Fast".
+func FailFast(failFast bool) CallOption {
+	return FailFastCallOption{FailFast: failFast}
+}
+
+// FailFastCallOption is a CallOption for indicating whether an RPC should fail
+// fast or not.
+// This is an EXPERIMENTAL API.
+type FailFastCallOption struct {
+	FailFast bool
+}
+
+func (o FailFastCallOption) before(c *callInfo) error {
+	c.failFast = o.FailFast
+	return nil
+}
+func (o FailFastCallOption) after(c *callInfo) {}
+
+// MaxCallRecvMsgSize returns a CallOption which sets the maximum message size the client can receive.
+func MaxCallRecvMsgSize(s int) CallOption {
+	return MaxRecvMsgSizeCallOption{MaxRecvMsgSize: s}
+}
+
+// MaxRecvMsgSizeCallOption is a CallOption that indicates the maximum message
+// size the client can receive.
+// This is an EXPERIMENTAL API.
+type MaxRecvMsgSizeCallOption struct {
+	MaxRecvMsgSize int
+}
+
+func (o MaxRecvMsgSizeCallOption) before(c *callInfo) error {
+	c.maxReceiveMessageSize = &o.MaxRecvMsgSize
+	return nil
+}
+func (o MaxRecvMsgSizeCallOption) after(c *callInfo) {}
+
+// MaxCallSendMsgSize returns a CallOption which sets the maximum message size the client can send.
+func MaxCallSendMsgSize(s int) CallOption {
+	return MaxSendMsgSizeCallOption{MaxSendMsgSize: s}
+}
+
+// MaxSendMsgSizeCallOption is a CallOption that indicates the maximum message
+// size the client can send.
+// This is an EXPERIMENTAL API.
+type MaxSendMsgSizeCallOption struct {
+	MaxSendMsgSize int
+}
+
+func (o MaxSendMsgSizeCallOption) before(c *callInfo) error {
+	c.maxSendMessageSize = &o.MaxSendMsgSize
+	return nil
+}
+func (o MaxSendMsgSizeCallOption) after(c *callInfo) {}
+
+// PerRPCCredentials returns a CallOption that sets credentials.PerRPCCredentials
+// for a call.
+func PerRPCCredentials(creds credentials.PerRPCCredentials) CallOption {
+	return PerRPCCredsCallOption{Creds: creds}
+}
+
+// PerRPCCredsCallOption is a CallOption that indicates the per-RPC
+// credentials to use for the call.
+// This is an EXPERIMENTAL API.
+type PerRPCCredsCallOption struct {
+	Creds credentials.PerRPCCredentials
+}
+
+func (o PerRPCCredsCallOption) before(c *callInfo) error {
+	c.creds = o.Creds
+	return nil
+}
+func (o PerRPCCredsCallOption) after(c *callInfo) {}
+
+// UseCompressor returns a CallOption which sets the compressor used when
+// sending the request.  If WithCompressor is also set, UseCompressor has
+// higher priority.
+//
+// This API is EXPERIMENTAL.
+func UseCompressor(name string) CallOption {
+	return CompressorCallOption{CompressorType: name}
+}
+
+// CompressorCallOption is a CallOption that indicates the compressor to use.
+// This is an EXPERIMENTAL API.
+type CompressorCallOption struct {
+	CompressorType string
+}
+
+func (o CompressorCallOption) before(c *callInfo) error {
+	c.compressorType = o.CompressorType
+	return nil
+}
+func (o CompressorCallOption) after(c *callInfo) {}
+
+// CallContentSubtype returns a CallOption that will set the content-subtype
+// for a call. For example, if content-subtype is "json", the Content-Type over
+// the wire will be "application/grpc+json". The content-subtype is converted
+// to lowercase before being included in Content-Type. See Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// If CallCustomCodec is not also used, the content-subtype will be used to
+// look up the Codec to use in the registry controlled by RegisterCodec. See
+// the documentation on RegisterCodec for details on registration. The lookup
+// of content-subtype is case-insensitive. If no such Codec is found, the call
+// will result in an error with code codes.Internal.
+//
+// If CallCustomCodec is also used, that Codec will be used for all request and
+// response messages, with the content-subtype set to the given contentSubtype
+// here for requests.
+func CallContentSubtype(contentSubtype string) CallOption {
+	return ContentSubtypeCallOption{ContentSubtype: strings.ToLower(contentSubtype)}
+}
+
+// ContentSubtypeCallOption is a CallOption that indicates the content-subtype
+// used for marshaling messages.
+// This is an EXPERIMENTAL API.
+type ContentSubtypeCallOption struct {
+	ContentSubtype string
+}
+
+func (o ContentSubtypeCallOption) before(c *callInfo) error {
+	c.contentSubtype = o.ContentSubtype
+	return nil
+}
+func (o ContentSubtypeCallOption) after(c *callInfo) {}
+
+// CallCustomCodec returns a CallOption that will set the given Codec to be
+// used for all request and response messages for a call. The result of calling
+// String() will be used as the content-subtype in a case-insensitive manner.
+//
+// See Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details. Also see the documentation on RegisterCodec and
+// CallContentSubtype for more details on the interaction between Codec and
+// content-subtype.
+//
+// This function is provided for advanced users; prefer to use only
+// CallContentSubtype to select a registered codec instead.
+func CallCustomCodec(codec Codec) CallOption {
+	return CustomCodecCallOption{Codec: codec}
+}
+
+// CustomCodecCallOption is a CallOption that indicates the codec used for
+// marshaling messages.
+// This is an EXPERIMENTAL API.
+type CustomCodecCallOption struct {
+	Codec Codec
+}
+
+func (o CustomCodecCallOption) before(c *callInfo) error {
+	c.codec = o.Codec
+	return nil
+}
+func (o CustomCodecCallOption) after(c *callInfo) {}
+
+// The format of the payload: compressed or not?
+type payloadFormat uint8
+
+const (
+	compressionNone payloadFormat = iota // no compression
+	compressionMade
+)
+
+// parser reads complete gRPC messages from the underlying reader.
+type parser struct {
+	// r is the underlying reader.
+	// See the comment on recvMsg for the permissible
+	// error types.
+	r io.Reader
+
+	// The header of a gRPC message. Find more detail at
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
+	header [5]byte
+}
+
+// recvMsg reads a complete gRPC message from the stream.
+//
+// It returns the message and its payload (compression/encoding)
+// format. The caller owns the returned msg memory.
+//
+// If there is an error, possible values are:
+//   * io.EOF, when no messages remain
+//   * io.ErrUnexpectedEOF
+//   * of type transport.ConnectionError
+//   * of type transport.StreamError
+// No other error values or types must be returned, which also means
+// that the underlying io.Reader must not return an incompatible
+// error.
+func (p *parser) recvMsg(maxReceiveMessageSize int) (pf payloadFormat, msg []byte, err error) {
+	if _, err := p.r.Read(p.header[:]); err != nil {
+		return 0, nil, err
+	}
+
+	pf = payloadFormat(p.header[0])
+	length := binary.BigEndian.Uint32(p.header[1:])
+
+	if length == 0 {
+		return pf, nil, nil
+	}
+	if int64(length) > int64(maxInt) {
+		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max length allowed on current machine (%d vs. %d)", length, maxInt)
+	}
+	if int(length) > maxReceiveMessageSize {
+		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", length, maxReceiveMessageSize)
+	}
+	// TODO(bradfitz,zhaoq): garbage. reuse buffer after proto decoding instead
+	// of making it for each message:
+	msg = make([]byte, int(length))
+	if _, err := p.r.Read(msg); err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return 0, nil, err
+	}
+	return pf, msg, nil
+}
+
+// encode serializes msg and returns a buffer of message header and a buffer of msg.
+// If msg is nil, it generates the message header and an empty msg buffer.
+// TODO(ddyihai): eliminate extra Compressor parameter.
+func encode(c baseCodec, msg interface{}, cp Compressor, outPayload *stats.OutPayload, compressor encoding.Compressor) ([]byte, []byte, error) {
+	var (
+		b    []byte
+		cbuf *bytes.Buffer
+	)
+	const (
+		payloadLen = 1
+		sizeLen    = 4
+	)
+	if msg != nil {
+		var err error
+		b, err = c.Marshal(msg)
+		if err != nil {
+			return nil, nil, status.Errorf(codes.Internal, "grpc: error while marshaling: %v", err.Error())
+		}
+		if outPayload != nil {
+			outPayload.Payload = msg
+			// TODO truncate large payload.
+			outPayload.Data = b
+			outPayload.Length = len(b)
+		}
+		if compressor != nil || cp != nil {
+			cbuf = new(bytes.Buffer)
+			// Has compressor, check Compressor is set by UseCompressor first.
+			if compressor != nil {
+				z, _ := compressor.Compress(cbuf)
+				if _, err := z.Write(b); err != nil {
+					return nil, nil, status.Errorf(codes.Internal, "grpc: error while compressing: %v", err.Error())
+				}
+				z.Close()
+			} else {
+				// If Compressor is not set by UseCompressor, use default Compressor
+				if err := cp.Do(cbuf, b); err != nil {
+					return nil, nil, status.Errorf(codes.Internal, "grpc: error while compressing: %v", err.Error())
+				}
+			}
+			b = cbuf.Bytes()
+		}
+	}
+	if uint(len(b)) > math.MaxUint32 {
+		return nil, nil, status.Errorf(codes.ResourceExhausted, "grpc: message too large (%d bytes)", len(b))
+	}
+
+	bufHeader := make([]byte, payloadLen+sizeLen)
+	if compressor != nil || cp != nil {
+		bufHeader[0] = byte(compressionMade)
+	} else {
+		bufHeader[0] = byte(compressionNone)
+	}
+
+	// Write length of b into buf
+	binary.BigEndian.PutUint32(bufHeader[payloadLen:], uint32(len(b)))
+	if outPayload != nil {
+		outPayload.WireLength = payloadLen + sizeLen + len(b)
+	}
+	return bufHeader, b, nil
+}
+
+func checkRecvPayload(pf payloadFormat, recvCompress string, haveCompressor bool) *status.Status {
+	switch pf {
+	case compressionNone:
+	case compressionMade:
+		if recvCompress == "" || recvCompress == encoding.Identity {
+			return status.New(codes.Internal, "grpc: compressed flag set with identity or empty encoding")
+		}
+		if !haveCompressor {
+			return status.Newf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", recvCompress)
+		}
+	default:
+		return status.Newf(codes.Internal, "grpc: received unexpected payload format %d", pf)
+	}
+	return nil
+}
+
+// For the two compressor parameters, both should not be set, but if they are,
+// dc takes precedence over compressor.
+// TODO(dfawley): wrap the old compressor/decompressor using the new API?
+func recv(p *parser, c baseCodec, s *transport.Stream, dc Decompressor, m interface{}, maxReceiveMessageSize int, inPayload *stats.InPayload, compressor encoding.Compressor) error {
+	pf, d, err := p.recvMsg(maxReceiveMessageSize)
+	if err != nil {
+		return err
+	}
+	if inPayload != nil {
+		inPayload.WireLength = len(d)
+	}
+
+	if st := checkRecvPayload(pf, s.RecvCompress(), compressor != nil || dc != nil); st != nil {
+		return st.Err()
+	}
+
+	if pf == compressionMade {
+		// To match legacy behavior, if the decompressor is set by WithDecompressor or RPCDecompressor,
+		// use this decompressor as the default.
+		if dc != nil {
+			d, err = dc.Do(bytes.NewReader(d))
+			if err != nil {
+				return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+			}
+		} else {
+			dcReader, err := compressor.Decompress(bytes.NewReader(d))
+			if err != nil {
+				return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+			}
+			d, err = ioutil.ReadAll(dcReader)
+			if err != nil {
+				return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+			}
+		}
+	}
+	if len(d) > maxReceiveMessageSize {
+		// TODO: Revisit the error code. Currently keep it consistent with java
+		// implementation.
+		return status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", len(d), maxReceiveMessageSize)
+	}
+	if err := c.Unmarshal(d, m); err != nil {
+		return status.Errorf(codes.Internal, "grpc: failed to unmarshal the received message %v", err)
+	}
+	if inPayload != nil {
+		inPayload.RecvTime = time.Now()
+		inPayload.Payload = m
+		// TODO truncate large payload.
+		inPayload.Data = d
+		inPayload.Length = len(d)
+	}
+	return nil
+}
+
+type rpcInfo struct {
+	failfast bool
+}
+
+type rpcInfoContextKey struct{}
+
+func newContextWithRPCInfo(ctx context.Context, failfast bool) context.Context {
+	return context.WithValue(ctx, rpcInfoContextKey{}, &rpcInfo{failfast: failfast})
+}
+
+func rpcInfoFromContext(ctx context.Context) (s *rpcInfo, ok bool) {
+	s, ok = ctx.Value(rpcInfoContextKey{}).(*rpcInfo)
+	return
+}
+
+// Code returns the error code for err if it was produced by the rpc system.
+// Otherwise, it returns codes.Unknown.
+//
+// Deprecated: use status.FromError and Code method instead.
+func Code(err error) codes.Code {
+	if s, ok := status.FromError(err); ok {
+		return s.Code()
+	}
+	return codes.Unknown
+}
+
+// ErrorDesc returns the error description of err if it was produced by the rpc system.
+// Otherwise, it returns err.Error() or empty string when err is nil.
+//
+// Deprecated: use status.FromError and Message method instead.
+func ErrorDesc(err error) string {
+	if s, ok := status.FromError(err); ok {
+		return s.Message()
+	}
+	return err.Error()
+}
+
+// Errorf returns an error containing an error code and a description;
+// Errorf returns nil if c is OK.
+//
+// Deprecated: use status.Errorf instead.
+func Errorf(c codes.Code, format string, a ...interface{}) error {
+	return status.Errorf(c, format, a...)
+}
+
+// setCallInfoCodec should only be called after CallOptions have been applied.
+func setCallInfoCodec(c *callInfo) error {
+	if c.codec != nil {
+		// codec was already set by a CallOption; use it.
+		return nil
+	}
+
+	if c.contentSubtype == "" {
+		// No codec specified in CallOptions; use proto by default.
+		c.codec = encoding.GetCodec(proto.Name)
+		return nil
+	}
+
+	// c.contentSubtype is already lowercased in CallContentSubtype
+	c.codec = encoding.GetCodec(c.contentSubtype)
+	if c.codec == nil {
+		return status.Errorf(codes.Internal, "no codec registered for content-subtype %s", c.contentSubtype)
+	}
+	return nil
+}
+
+// parseDialTarget returns the network and address to pass to dialer
+func parseDialTarget(target string) (net string, addr string) {
+	net = "tcp"
+
+	m1 := strings.Index(target, ":")
+	m2 := strings.Index(target, ":/")
+
+	// handle unix:addr which will fail with url.Parse
+	if m1 >= 0 && m2 < 0 {
+		if n := target[0:m1]; n == "unix" {
+			net = n
+			addr = target[m1+1:]
+			return net, addr
+		}
+	}
+	if m2 >= 0 {
+		t, err := url.Parse(target)
+		if err != nil {
+			return net, target
+		}
+		scheme := t.Scheme
+		addr = t.Path
+		if scheme == "unix" {
+			net = scheme
+			if addr == "" {
+				addr = t.Host
+			}
+			return net, addr
+		}
+	}
+
+	return net, target
+}
+
+// The SupportPackageIsVersion variables are referenced from generated protocol
+// buffer files to ensure compatibility with the gRPC version used.  The latest
+// support package version is 5.
+//
+// Older versions are kept for compatibility. They may be removed if
+// compatibility cannot be maintained.
+//
+// These constants should not be referenced from any other code.
+const (
+	SupportPackageIsVersion3 = true
+	SupportPackageIsVersion4 = true
+	SupportPackageIsVersion5 = true
+)
+
+// Version is the current grpc version.
+const Version = "1.12.0"
+
+const grpcUA = "grpc-go/" + Version

vendor/google.golang.org/grpc/service_config.go

@@ -0,0 +1,233 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	"google.golang.org/grpc/grpclog"
+)
+
+const maxInt = int(^uint(0) >> 1)
+
+// MethodConfig defines the configuration recommended by the service providers for a
+// particular method.
+//
+// Deprecated: Users should not use this struct. Service config should be received
+// through name resolver, as specified here
+// https://github.com/grpc/grpc/blob/master/doc/service_config.md
+type MethodConfig struct {
+	// WaitForReady indicates whether RPCs sent to this method should wait until
+	// the connection is ready by default (!failfast). The value specified via the
+	// gRPC client API will override the value set here.
+	WaitForReady *bool
+	// Timeout is the default timeout for RPCs sent to this method. The actual
+	// deadline used will be the minimum of the value specified here and the value
+	// set by the application via the gRPC client API.  If either one is not set,
+	// then the other will be used.  If neither is set, then the RPC has no deadline.
+	Timeout *time.Duration
+	// MaxReqSize is the maximum allowed payload size for an individual request in a
+	// stream (client->server) in bytes. The size which is measured is the serialized
+	// payload after per-message compression (but before stream compression) in bytes.
+	// The actual value used is the minimum of the value specified here and the value set
+	// by the application via the gRPC client API. If either one is not set, then the other
+	// will be used.  If neither is set, then the built-in default is used.
+	MaxReqSize *int
+	// MaxRespSize is the maximum allowed payload size for an individual response in a
+	// stream (server->client) in bytes.
+	MaxRespSize *int
+}
+
+// ServiceConfig is provided by the service provider and contains parameters for how
+// clients that connect to the service should behave.
+//
+// Deprecated: Users should not use this struct. Service config should be received
+// through name resolver, as specified here
+// https://github.com/grpc/grpc/blob/master/doc/service_config.md
+type ServiceConfig struct {
+	// LB is the load balancer the service providers recommends. The balancer specified
+	// via grpc.WithBalancer will override this.
+	LB *string
+	// Methods contains a map for the methods in this service.
+	// If there is an exact match for a method (i.e. /service/method) in the map, use the corresponding MethodConfig.
+	// If there's no exact match, look for the default config for the service (/service/) and use the corresponding MethodConfig if it exists.
+	// Otherwise, the method has no MethodConfig to use.
+	Methods map[string]MethodConfig
+
+	stickinessMetadataKey *string
+}
+
+func parseDuration(s *string) (*time.Duration, error) {
+	if s == nil {
+		return nil, nil
+	}
+	if !strings.HasSuffix(*s, "s") {
+		return nil, fmt.Errorf("malformed duration %q", *s)
+	}
+	ss := strings.SplitN((*s)[:len(*s)-1], ".", 3)
+	if len(ss) > 2 {
+		return nil, fmt.Errorf("malformed duration %q", *s)
+	}
+	// hasDigits is set if either the whole or fractional part of the number is
+	// present, since both are optional but one is required.
+	hasDigits := false
+	var d time.Duration
+	if len(ss[0]) > 0 {
+		i, err := strconv.ParseInt(ss[0], 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
+		}
+		d = time.Duration(i) * time.Second
+		hasDigits = true
+	}
+	if len(ss) == 2 && len(ss[1]) > 0 {
+		if len(ss[1]) > 9 {
+			return nil, fmt.Errorf("malformed duration %q", *s)
+		}
+		f, err := strconv.ParseInt(ss[1], 10, 64)
+		if err != nil {
+			return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
+		}
+		for i := 9; i > len(ss[1]); i-- {
+			f *= 10
+		}
+		d += time.Duration(f)
+		hasDigits = true
+	}
+	if !hasDigits {
+		return nil, fmt.Errorf("malformed duration %q", *s)
+	}
+
+	return &d, nil
+}
+
+type jsonName struct {
+	Service *string
+	Method  *string
+}
+
+func (j jsonName) generatePath() (string, bool) {
+	if j.Service == nil {
+		return "", false
+	}
+	res := "/" + *j.Service + "/"
+	if j.Method != nil {
+		res += *j.Method
+	}
+	return res, true
+}
+
+// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
+type jsonMC struct {
+	Name                    *[]jsonName
+	WaitForReady            *bool
+	Timeout                 *string
+	MaxRequestMessageBytes  *int64
+	MaxResponseMessageBytes *int64
+}
+
+// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
+type jsonSC struct {
+	LoadBalancingPolicy   *string
+	StickinessMetadataKey *string
+	MethodConfig          *[]jsonMC
+}
+
+func parseServiceConfig(js string) (ServiceConfig, error) {
+	var rsc jsonSC
+	err := json.Unmarshal([]byte(js), &rsc)
+	if err != nil {
+		grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
+		return ServiceConfig{}, err
+	}
+	sc := ServiceConfig{
+		LB:      rsc.LoadBalancingPolicy,
+		Methods: make(map[string]MethodConfig),
+
+		stickinessMetadataKey: rsc.StickinessMetadataKey,
+	}
+	if rsc.MethodConfig == nil {
+		return sc, nil
+	}
+
+	for _, m := range *rsc.MethodConfig {
+		if m.Name == nil {
+			continue
+		}
+		d, err := parseDuration(m.Timeout)
+		if err != nil {
+			grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
+			return ServiceConfig{}, err
+		}
+
+		mc := MethodConfig{
+			WaitForReady: m.WaitForReady,
+			Timeout:      d,
+		}
+		if m.MaxRequestMessageBytes != nil {
+			if *m.MaxRequestMessageBytes > int64(maxInt) {
+				mc.MaxReqSize = newInt(maxInt)
+			} else {
+				mc.MaxReqSize = newInt(int(*m.MaxRequestMessageBytes))
+			}
+		}
+		if m.MaxResponseMessageBytes != nil {
+			if *m.MaxResponseMessageBytes > int64(maxInt) {
+				mc.MaxRespSize = newInt(maxInt)
+			} else {
+				mc.MaxRespSize = newInt(int(*m.MaxResponseMessageBytes))
+			}
+		}
+		for _, n := range *m.Name {
+			if path, valid := n.generatePath(); valid {
+				sc.Methods[path] = mc
+			}
+		}
+	}
+
+	return sc, nil
+}
+
+func min(a, b *int) *int {
+	if *a < *b {
+		return a
+	}
+	return b
+}
+
+func getMaxSize(mcMax, doptMax *int, defaultVal int) *int {
+	if mcMax == nil && doptMax == nil {
+		return &defaultVal
+	}
+	if mcMax != nil && doptMax != nil {
+		return min(mcMax, doptMax)
+	}
+	if mcMax != nil {
+		return mcMax
+	}
+	return doptMax
+}
+
+func newInt(b int) *int {
+	return &b
+}

vendor/google.golang.org/grpc/stats/handlers.go

@@ -0,0 +1,64 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package stats
+
+import (
+	"net"
+
+	"golang.org/x/net/context"
+)
+
+// ConnTagInfo defines the relevant information needed by connection context tagger.
+type ConnTagInfo struct {
+	// RemoteAddr is the remote address of the corresponding connection.
+	RemoteAddr net.Addr
+	// LocalAddr is the local address of the corresponding connection.
+	LocalAddr net.Addr
+}
+
+// RPCTagInfo defines the relevant information needed by RPC context tagger.
+type RPCTagInfo struct {
+	// FullMethodName is the RPC method in the format of /package.service/method.
+	FullMethodName string
+	// FailFast indicates if this RPC is failfast.
+	// This field is only valid on client side, it's always false on server side.
+	FailFast bool
+}
+
+// Handler defines the interface for the related stats handling (e.g., RPCs, connections).
+type Handler interface {
+	// TagRPC can attach some information to the given context.
+	// The context used for the rest lifetime of the RPC will be derived from
+	// the returned context.
+	TagRPC(context.Context, *RPCTagInfo) context.Context
+	// HandleRPC processes the RPC stats.
+	HandleRPC(context.Context, RPCStats)
+
+	// TagConn can attach some information to the given context.
+	// The returned context will be used for stats handling.
+	// For conn stats handling, the context used in HandleConn for this
+	// connection will be derived from the context returned.
+	// For RPC stats handling,
+	//  - On server side, the context used in HandleRPC for all RPCs on this
+	// connection will be derived from the context returned.
+	//  - On client side, the context is not derived from the context returned.
+	TagConn(context.Context, *ConnTagInfo) context.Context
+	// HandleConn processes the Conn stats.
+	HandleConn(context.Context, ConnStats)
+}

vendor/google.golang.org/grpc/stats/stats.go

@@ -0,0 +1,296 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+//go:generate protoc --go_out=plugins=grpc:. grpc_testing/test.proto
+
+// Package stats is for collecting and reporting various network and RPC stats.
+// This package is for monitoring purpose only. All fields are read-only.
+// All APIs are experimental.
+package stats // import "google.golang.org/grpc/stats"
+
+import (
+	"net"
+	"time"
+
+	"golang.org/x/net/context"
+)
+
+// RPCStats contains stats information about RPCs.
+type RPCStats interface {
+	isRPCStats()
+	// IsClient returns true if this RPCStats is from client side.
+	IsClient() bool
+}
+
+// Begin contains stats when an RPC begins.
+// FailFast is only valid if this Begin is from client side.
+type Begin struct {
+	// Client is true if this Begin is from client side.
+	Client bool
+	// BeginTime is the time when the RPC begins.
+	BeginTime time.Time
+	// FailFast indicates if this RPC is failfast.
+	FailFast bool
+}
+
+// IsClient indicates if the stats information is from client side.
+func (s *Begin) IsClient() bool { return s.Client }
+
+func (s *Begin) isRPCStats() {}
+
+// InPayload contains the information for an incoming payload.
+type InPayload struct {
+	// Client is true if this InPayload is from client side.
+	Client bool
+	// Payload is the payload with original type.
+	Payload interface{}
+	// Data is the serialized message payload.
+	Data []byte
+	// Length is the length of uncompressed data.
+	Length int
+	// WireLength is the length of data on wire (compressed, signed, encrypted).
+	WireLength int
+	// RecvTime is the time when the payload is received.
+	RecvTime time.Time
+}
+
+// IsClient indicates if the stats information is from client side.
+func (s *InPayload) IsClient() bool { return s.Client }
+
+func (s *InPayload) isRPCStats() {}
+
+// InHeader contains stats when a header is received.
+type InHeader struct {
+	// Client is true if this InHeader is from client side.
+	Client bool
+	// WireLength is the wire length of header.
+	WireLength int
+
+	// The following fields are valid only if Client is false.
+	// FullMethod is the full RPC method string, i.e., /package.service/method.
+	FullMethod string
+	// RemoteAddr is the remote address of the corresponding connection.
+	RemoteAddr net.Addr
+	// LocalAddr is the local address of the corresponding connection.
+	LocalAddr net.Addr
+	// Compression is the compression algorithm used for the RPC.
+	Compression string
+}
+
+// IsClient indicates if the stats information is from client side.
+func (s *InHeader) IsClient() bool { return s.Client }
+
+func (s *InHeader) isRPCStats() {}
+
+// InTrailer contains stats when a trailer is received.
+type InTrailer struct {
+	// Client is true if this InTrailer is from client side.
+	Client bool
+	// WireLength is the wire length of trailer.
+	WireLength int
+}
+
+// IsClient indicates if the stats information is from client side.
+func (s *InTrailer) IsClient() bool { return s.Client }
+
+func (s *InTrailer) isRPCStats() {}
+
+// OutPayload contains the information for an outgoing payload.
+type OutPayload struct {
+	// Client is true if this OutPayload is from client side.
+	Client bool
+	// Payload is the payload with original type.
+	Payload interface{}
+	// Data is the serialized message payload.
+	Data []byte
+	// Length is the length of uncompressed data.
+	Length int
+	// WireLength is the length of data on wire (compressed, signed, encrypted).
+	WireLength int
+	// SentTime is the time when the payload is sent.
+	SentTime time.Time
+}
+
+// IsClient indicates if this stats information is from client side.
+func (s *OutPayload) IsClient() bool { return s.Client }
+
+func (s *OutPayload) isRPCStats() {}
+
+// OutHeader contains stats when a header is sent.
+type OutHeader struct {
+	// Client is true if this OutHeader is from client side.
+	Client bool
+
+	// The following fields are valid only if Client is true.
+	// FullMethod is the full RPC method string, i.e., /package.service/method.
+	FullMethod string
+	// RemoteAddr is the remote address of the corresponding connection.
+	RemoteAddr net.Addr
+	// LocalAddr is the local address of the corresponding connection.
+	LocalAddr net.Addr
+	// Compression is the compression algorithm used for the RPC.
+	Compression string
+}
+
+// IsClient indicates if this stats information is from client side.
+func (s *OutHeader) IsClient() bool { return s.Client }
+
+func (s *OutHeader) isRPCStats() {}
+
+// OutTrailer contains stats when a trailer is sent.
+type OutTrailer struct {
+	// Client is true if this OutTrailer is from client side.
+	Client bool
+	// WireLength is the wire length of trailer.
+	WireLength int
+}
+
+// IsClient indicates if this stats information is from client side.
+func (s *OutTrailer) IsClient() bool { return s.Client }
+
+func (s *OutTrailer) isRPCStats() {}
+
+// End contains stats when an RPC ends.
+type End struct {
+	// Client is true if this End is from client side.
+	Client bool
+	// BeginTime is the time when the RPC began.
+	BeginTime time.Time
+	// EndTime is the time when the RPC ends.
+	EndTime time.Time
+	// Error is the error the RPC ended with. It is an error generated from
+	// status.Status and can be converted back to status.Status using
+	// status.FromError if non-nil.
+	Error error
+}
+
+// IsClient indicates if this is from client side.
+func (s *End) IsClient() bool { return s.Client }
+
+func (s *End) isRPCStats() {}
+
+// ConnStats contains stats information about connections.
+type ConnStats interface {
+	isConnStats()
+	// IsClient returns true if this ConnStats is from client side.
+	IsClient() bool
+}
+
+// ConnBegin contains the stats of a connection when it is established.
+type ConnBegin struct {
+	// Client is true if this ConnBegin is from client side.
+	Client bool
+}
+
+// IsClient indicates if this is from client side.
+func (s *ConnBegin) IsClient() bool { return s.Client }
+
+func (s *ConnBegin) isConnStats() {}
+
+// ConnEnd contains the stats of a connection when it ends.
+type ConnEnd struct {
+	// Client is true if this ConnEnd is from client side.
+	Client bool
+}
+
+// IsClient indicates if this is from client side.
+func (s *ConnEnd) IsClient() bool { return s.Client }
+
+func (s *ConnEnd) isConnStats() {}
+
+type incomingTagsKey struct{}
+type outgoingTagsKey struct{}
+
+// SetTags attaches stats tagging data to the context, which will be sent in
+// the outgoing RPC with the header grpc-tags-bin.  Subsequent calls to
+// SetTags will overwrite the values from earlier calls.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release.  New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func SetTags(ctx context.Context, b []byte) context.Context {
+	return context.WithValue(ctx, outgoingTagsKey{}, b)
+}
+
+// Tags returns the tags from the context for the inbound RPC.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release.  New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func Tags(ctx context.Context) []byte {
+	b, _ := ctx.Value(incomingTagsKey{}).([]byte)
+	return b
+}
+
+// SetIncomingTags attaches stats tagging data to the context, to be read by
+// the application (not sent in outgoing RPCs).
+//
+// This is intended for gRPC-internal use ONLY.
+func SetIncomingTags(ctx context.Context, b []byte) context.Context {
+	return context.WithValue(ctx, incomingTagsKey{}, b)
+}
+
+// OutgoingTags returns the tags from the context for the outbound RPC.
+//
+// This is intended for gRPC-internal use ONLY.
+func OutgoingTags(ctx context.Context) []byte {
+	b, _ := ctx.Value(outgoingTagsKey{}).([]byte)
+	return b
+}
+
+type incomingTraceKey struct{}
+type outgoingTraceKey struct{}
+
+// SetTrace attaches stats tagging data to the context, which will be sent in
+// the outgoing RPC with the header grpc-trace-bin.  Subsequent calls to
+// SetTrace will overwrite the values from earlier calls.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release.  New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func SetTrace(ctx context.Context, b []byte) context.Context {
+	return context.WithValue(ctx, outgoingTraceKey{}, b)
+}
+
+// Trace returns the trace from the context for the inbound RPC.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release.  New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func Trace(ctx context.Context) []byte {
+	b, _ := ctx.Value(incomingTraceKey{}).([]byte)
+	return b
+}
+
+// SetIncomingTrace attaches stats tagging data to the context, to be read by
+// the application (not sent in outgoing RPCs).  It is intended for
+// gRPC-internal use.
+func SetIncomingTrace(ctx context.Context, b []byte) context.Context {
+	return context.WithValue(ctx, incomingTraceKey{}, b)
+}
+
+// OutgoingTrace returns the trace from the context for the outbound RPC.  It is
+// intended for gRPC-internal use.
+func OutgoingTrace(ctx context.Context) []byte {
+	b, _ := ctx.Value(outgoingTraceKey{}).([]byte)
+	return b
+}

vendor/google.golang.org/grpc/status/status.go

@@ -0,0 +1,189 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package status implements errors returned by gRPC.  These errors are
+// serialized and transmitted on the wire between server and client, and allow
+// for additional data to be transmitted via the Details field in the status
+// proto.  gRPC service handlers should return an error created by this
+// package, and gRPC clients should expect a corresponding error to be
+// returned from the RPC call.
+//
+// This package upholds the invariants that a non-nil error may not
+// contain an OK code, and an OK code must result in a nil error.
+package status
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/ptypes"
+	spb "google.golang.org/genproto/googleapis/rpc/status"
+	"google.golang.org/grpc/codes"
+)
+
+// statusError is an alias of a status proto.  It implements error and Status,
+// and a nil statusError should never be returned by this package.
+type statusError spb.Status
+
+func (se *statusError) Error() string {
+	p := (*spb.Status)(se)
+	return fmt.Sprintf("rpc error: code = %s desc = %s", codes.Code(p.GetCode()), p.GetMessage())
+}
+
+func (se *statusError) GRPCStatus() *Status {
+	return &Status{s: (*spb.Status)(se)}
+}
+
+// Status represents an RPC status code, message, and details.  It is immutable
+// and should be created with New, Newf, or FromProto.
+type Status struct {
+	s *spb.Status
+}
+
+// Code returns the status code contained in s.
+func (s *Status) Code() codes.Code {
+	if s == nil || s.s == nil {
+		return codes.OK
+	}
+	return codes.Code(s.s.Code)
+}
+
+// Message returns the message contained in s.
+func (s *Status) Message() string {
+	if s == nil || s.s == nil {
+		return ""
+	}
+	return s.s.Message
+}
+
+// Proto returns s's status as an spb.Status proto message.
+func (s *Status) Proto() *spb.Status {
+	if s == nil {
+		return nil
+	}
+	return proto.Clone(s.s).(*spb.Status)
+}
+
+// Err returns an immutable error representing s; returns nil if s.Code() is
+// OK.
+func (s *Status) Err() error {
+	if s.Code() == codes.OK {
+		return nil
+	}
+	return (*statusError)(s.s)
+}
+
+// New returns a Status representing c and msg.
+func New(c codes.Code, msg string) *Status {
+	return &Status{s: &spb.Status{Code: int32(c), Message: msg}}
+}
+
+// Newf returns New(c, fmt.Sprintf(format, a...)).
+func Newf(c codes.Code, format string, a ...interface{}) *Status {
+	return New(c, fmt.Sprintf(format, a...))
+}
+
+// Error returns an error representing c and msg.  If c is OK, returns nil.
+func Error(c codes.Code, msg string) error {
+	return New(c, msg).Err()
+}
+
+// Errorf returns Error(c, fmt.Sprintf(format, a...)).
+func Errorf(c codes.Code, format string, a ...interface{}) error {
+	return Error(c, fmt.Sprintf(format, a...))
+}
+
+// ErrorProto returns an error representing s.  If s.Code is OK, returns nil.
+func ErrorProto(s *spb.Status) error {
+	return FromProto(s).Err()
+}
+
+// FromProto returns a Status representing s.
+func FromProto(s *spb.Status) *Status {
+	return &Status{s: proto.Clone(s).(*spb.Status)}
+}
+
+// FromError returns a Status representing err if it was produced from this
+// package or has a method `GRPCStatus() *Status`. Otherwise, ok is false and a
+// Status is returned with codes.Unknown and the original error message.
+func FromError(err error) (s *Status, ok bool) {
+	if err == nil {
+		return &Status{s: &spb.Status{Code: int32(codes.OK)}}, true
+	}
+	if se, ok := err.(interface{ GRPCStatus() *Status }); ok {
+		return se.GRPCStatus(), true
+	}
+	return New(codes.Unknown, err.Error()), false
+}
+
+// Convert is a convenience function which removes the need to handle the
+// boolean return value from FromError.
+func Convert(err error) *Status {
+	s, _ := FromError(err)
+	return s
+}
+
+// WithDetails returns a new status with the provided details messages appended to the status.
+// If any errors are encountered, it returns nil and the first error encountered.
+func (s *Status) WithDetails(details ...proto.Message) (*Status, error) {
+	if s.Code() == codes.OK {
+		return nil, errors.New("no error details for status with code OK")
+	}
+	// s.Code() != OK implies that s.Proto() != nil.
+	p := s.Proto()
+	for _, detail := range details {
+		any, err := ptypes.MarshalAny(detail)
+		if err != nil {
+			return nil, err
+		}
+		p.Details = append(p.Details, any)
+	}
+	return &Status{s: p}, nil
+}
+
+// Details returns a slice of details messages attached to the status.
+// If a detail cannot be decoded, the error is returned in place of the detail.
+func (s *Status) Details() []interface{} {
+	if s == nil || s.s == nil {
+		return nil
+	}
+	details := make([]interface{}, 0, len(s.s.Details))
+	for _, any := range s.s.Details {
+		detail := &ptypes.DynamicAny{}
+		if err := ptypes.UnmarshalAny(any, detail); err != nil {
+			details = append(details, err)
+			continue
+		}
+		details = append(details, detail.Message)
+	}
+	return details
+}
+
+// Code returns the Code of the error if it is a Status error, codes.OK if err
+// is nil, or codes.Unknown otherwise.
+func Code(err error) codes.Code {
+	// Don't use FromError to avoid allocation of OK status.
+	if err == nil {
+		return codes.OK
+	}
+	if se, ok := err.(interface{ GRPCStatus() *Status }); ok {
+		return se.GRPCStatus().Code()
+	}
+	return codes.Unknown
+}

vendor/google.golang.org/grpc/stream.go

@@ -0,0 +1,765 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"errors"
+	"io"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"golang.org/x/net/trace"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/channelz"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// StreamHandler defines the handler called by gRPC server to complete the
+// execution of a streaming RPC. If a StreamHandler returns an error, it
+// should be produced by the status package, or else gRPC will use
+// codes.Unknown as the status code and err.Error() as the status message
+// of the RPC.
+type StreamHandler func(srv interface{}, stream ServerStream) error
+
+// StreamDesc represents a streaming RPC service's method specification.
+type StreamDesc struct {
+	StreamName string
+	Handler    StreamHandler
+
+	// At least one of these is true.
+	ServerStreams bool
+	ClientStreams bool
+}
+
+// Stream defines the common interface a client or server stream has to satisfy.
+//
+// All errors returned from Stream are compatible with the status package.
+type Stream interface {
+	// Context returns the context for this stream.
+	Context() context.Context
+	// SendMsg blocks until it sends m, the stream is done or the stream
+	// breaks.
+	// On error, it aborts the stream and returns an RPC status on client
+	// side. On server side, it simply returns the error to the caller.
+	// SendMsg is called by generated code. Also Users can call SendMsg
+	// directly when it is really needed in their use cases.
+	// It's safe to have a goroutine calling SendMsg and another goroutine calling
+	// recvMsg on the same stream at the same time.
+	// But it is not safe to call SendMsg on the same stream in different goroutines.
+	SendMsg(m interface{}) error
+	// RecvMsg blocks until it receives a message or the stream is
+	// done. On client side, it returns io.EOF when the stream is done. On
+	// any other error, it aborts the stream and returns an RPC status. On
+	// server side, it simply returns the error to the caller.
+	// It's safe to have a goroutine calling SendMsg and another goroutine calling
+	// recvMsg on the same stream at the same time.
+	// But it is not safe to call RecvMsg on the same stream in different goroutines.
+	RecvMsg(m interface{}) error
+}
+
+// ClientStream defines the interface a client stream has to satisfy.
+type ClientStream interface {
+	// Header returns the header metadata received from the server if there
+	// is any. It blocks if the metadata is not ready to read.
+	Header() (metadata.MD, error)
+	// Trailer returns the trailer metadata from the server, if there is any.
+	// It must only be called after stream.CloseAndRecv has returned, or
+	// stream.Recv has returned a non-nil error (including io.EOF).
+	Trailer() metadata.MD
+	// CloseSend closes the send direction of the stream. It closes the stream
+	// when non-nil error is met.
+	CloseSend() error
+	// Stream.SendMsg() may return a non-nil error when something wrong happens sending
+	// the request. The returned error indicates the status of this sending, not the final
+	// status of the RPC.
+	//
+	// Always call Stream.RecvMsg() to drain the stream and get the final
+	// status, otherwise there could be leaked resources.
+	Stream
+}
+
+// NewStream creates a new Stream for the client side. This is typically
+// called by generated code.
+func (cc *ClientConn) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) {
+	// allow interceptor to see all applicable call options, which means those
+	// configured as defaults from dial option as well as per-call options
+	opts = combine(cc.dopts.callOptions, opts)
+
+	if cc.dopts.streamInt != nil {
+		return cc.dopts.streamInt(ctx, desc, cc, method, newClientStream, opts...)
+	}
+	return newClientStream(ctx, desc, cc, method, opts...)
+}
+
+// NewClientStream creates a new Stream for the client side. This is typically
+// called by generated code.
+//
+// DEPRECATED: Use ClientConn.NewStream instead.
+func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
+	return cc.NewStream(ctx, desc, method, opts...)
+}
+
+func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
+	if channelz.IsOn() {
+		cc.incrCallsStarted()
+		defer func() {
+			if err != nil {
+				cc.incrCallsFailed()
+			}
+		}()
+	}
+	c := defaultCallInfo()
+	mc := cc.GetMethodConfig(method)
+	if mc.WaitForReady != nil {
+		c.failFast = !*mc.WaitForReady
+	}
+
+	// Possible context leak:
+	// The cancel function for the child context we create will only be called
+	// when RecvMsg returns a non-nil error, if the ClientConn is closed, or if
+	// an error is generated by SendMsg.
+	// https://github.com/grpc/grpc-go/issues/1818.
+	var cancel context.CancelFunc
+	if mc.Timeout != nil && *mc.Timeout >= 0 {
+		ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
+	} else {
+		ctx, cancel = context.WithCancel(ctx)
+	}
+	defer func() {
+		if err != nil {
+			cancel()
+		}
+	}()
+
+	for _, o := range opts {
+		if err := o.before(c); err != nil {
+			return nil, toRPCErr(err)
+		}
+	}
+	c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
+	c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
+	if err := setCallInfoCodec(c); err != nil {
+		return nil, err
+	}
+
+	callHdr := &transport.CallHdr{
+		Host:   cc.authority,
+		Method: method,
+		// If it's not client streaming, we should already have the request to be sent,
+		// so we don't flush the header.
+		// If it's client streaming, the user may never send a request or send it any
+		// time soon, so we ask the transport to flush the header.
+		Flush:          desc.ClientStreams,
+		ContentSubtype: c.contentSubtype,
+	}
+
+	// Set our outgoing compression according to the UseCompressor CallOption, if
+	// set.  In that case, also find the compressor from the encoding package.
+	// Otherwise, use the compressor configured by the WithCompressor DialOption,
+	// if set.
+	var cp Compressor
+	var comp encoding.Compressor
+	if ct := c.compressorType; ct != "" {
+		callHdr.SendCompress = ct
+		if ct != encoding.Identity {
+			comp = encoding.GetCompressor(ct)
+			if comp == nil {
+				return nil, status.Errorf(codes.Internal, "grpc: Compressor is not installed for requested grpc-encoding %q", ct)
+			}
+		}
+	} else if cc.dopts.cp != nil {
+		callHdr.SendCompress = cc.dopts.cp.Type()
+		cp = cc.dopts.cp
+	}
+	if c.creds != nil {
+		callHdr.Creds = c.creds
+	}
+	var trInfo traceInfo
+	if EnableTracing {
+		trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
+		trInfo.firstLine.client = true
+		if deadline, ok := ctx.Deadline(); ok {
+			trInfo.firstLine.deadline = deadline.Sub(time.Now())
+		}
+		trInfo.tr.LazyLog(&trInfo.firstLine, false)
+		ctx = trace.NewContext(ctx, trInfo.tr)
+		defer func() {
+			if err != nil {
+				// Need to call tr.finish() if error is returned.
+				// Because tr will not be returned to caller.
+				trInfo.tr.LazyPrintf("RPC: [%v]", err)
+				trInfo.tr.SetError()
+				trInfo.tr.Finish()
+			}
+		}()
+	}
+	ctx = newContextWithRPCInfo(ctx, c.failFast)
+	sh := cc.dopts.copts.StatsHandler
+	var beginTime time.Time
+	if sh != nil {
+		ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
+		beginTime = time.Now()
+		begin := &stats.Begin{
+			Client:    true,
+			BeginTime: beginTime,
+			FailFast:  c.failFast,
+		}
+		sh.HandleRPC(ctx, begin)
+		defer func() {
+			if err != nil {
+				// Only handle end stats if err != nil.
+				end := &stats.End{
+					Client:    true,
+					Error:     err,
+					BeginTime: beginTime,
+					EndTime:   time.Now(),
+				}
+				sh.HandleRPC(ctx, end)
+			}
+		}()
+	}
+
+	var (
+		t    transport.ClientTransport
+		s    *transport.Stream
+		done func(balancer.DoneInfo)
+	)
+	for {
+		// Check to make sure the context has expired.  This will prevent us from
+		// looping forever if an error occurs for wait-for-ready RPCs where no data
+		// is sent on the wire.
+		select {
+		case <-ctx.Done():
+			return nil, toRPCErr(ctx.Err())
+		default:
+		}
+
+		t, done, err = cc.getTransport(ctx, c.failFast)
+		if err != nil {
+			return nil, err
+		}
+
+		s, err = t.NewStream(ctx, callHdr)
+		if err != nil {
+			if done != nil {
+				done(balancer.DoneInfo{Err: err})
+				done = nil
+			}
+			// In the event of any error from NewStream, we never attempted to write
+			// anything to the wire, so we can retry indefinitely for non-fail-fast
+			// RPCs.
+			if !c.failFast {
+				continue
+			}
+			return nil, toRPCErr(err)
+		}
+		break
+	}
+
+	cs := &clientStream{
+		opts:   opts,
+		c:      c,
+		cc:     cc,
+		desc:   desc,
+		codec:  c.codec,
+		cp:     cp,
+		comp:   comp,
+		cancel: cancel,
+		attempt: &csAttempt{
+			t:            t,
+			s:            s,
+			p:            &parser{r: s},
+			done:         done,
+			dc:           cc.dopts.dc,
+			ctx:          ctx,
+			trInfo:       trInfo,
+			statsHandler: sh,
+			beginTime:    beginTime,
+		},
+	}
+	cs.c.stream = cs
+	cs.attempt.cs = cs
+	if desc != unaryStreamDesc {
+		// Listen on cc and stream contexts to cleanup when the user closes the
+		// ClientConn or cancels the stream context.  In all other cases, an error
+		// should already be injected into the recv buffer by the transport, which
+		// the client will eventually receive, and then we will cancel the stream's
+		// context in clientStream.finish.
+		go func() {
+			select {
+			case <-cc.ctx.Done():
+				cs.finish(ErrClientConnClosing)
+			case <-ctx.Done():
+				cs.finish(toRPCErr(ctx.Err()))
+			}
+		}()
+	}
+	return cs, nil
+}
+
+// clientStream implements a client side Stream.
+type clientStream struct {
+	opts []CallOption
+	c    *callInfo
+	cc   *ClientConn
+	desc *StreamDesc
+
+	codec baseCodec
+	cp    Compressor
+	comp  encoding.Compressor
+
+	cancel context.CancelFunc // cancels all attempts
+
+	sentLast bool // sent an end stream
+
+	mu       sync.Mutex // guards finished
+	finished bool       // TODO: replace with atomic cmpxchg or sync.Once?
+
+	attempt *csAttempt // the active client stream attempt
+	// TODO(hedging): hedging will have multiple attempts simultaneously.
+}
+
+// csAttempt implements a single transport stream attempt within a
+// clientStream.
+type csAttempt struct {
+	cs   *clientStream
+	t    transport.ClientTransport
+	s    *transport.Stream
+	p    *parser
+	done func(balancer.DoneInfo)
+
+	dc        Decompressor
+	decomp    encoding.Compressor
+	decompSet bool
+
+	ctx context.Context // the application's context, wrapped by stats/tracing
+
+	mu sync.Mutex // guards trInfo.tr
+	// trInfo.tr is set when created (if EnableTracing is true),
+	// and cleared when the finish method is called.
+	trInfo traceInfo
+
+	statsHandler stats.Handler
+	beginTime    time.Time
+}
+
+func (cs *clientStream) Context() context.Context {
+	// TODO(retry): commit the current attempt (the context has peer-aware data).
+	return cs.attempt.context()
+}
+
+func (cs *clientStream) Header() (metadata.MD, error) {
+	m, err := cs.attempt.header()
+	if err != nil {
+		// TODO(retry): maybe retry on error or commit attempt on success.
+		err = toRPCErr(err)
+		cs.finish(err)
+	}
+	return m, err
+}
+
+func (cs *clientStream) Trailer() metadata.MD {
+	// TODO(retry): on error, maybe retry (trailers-only).
+	return cs.attempt.trailer()
+}
+
+func (cs *clientStream) SendMsg(m interface{}) (err error) {
+	// TODO(retry): buffer message for replaying if not committed.
+	return cs.attempt.sendMsg(m)
+}
+
+func (cs *clientStream) RecvMsg(m interface{}) (err error) {
+	// TODO(retry): maybe retry on error or commit attempt on success.
+	return cs.attempt.recvMsg(m)
+}
+
+func (cs *clientStream) CloseSend() error {
+	cs.attempt.closeSend()
+	return nil
+}
+
+func (cs *clientStream) finish(err error) {
+	if err == io.EOF {
+		// Ending a stream with EOF indicates a success.
+		err = nil
+	}
+	cs.mu.Lock()
+	if cs.finished {
+		cs.mu.Unlock()
+		return
+	}
+	cs.finished = true
+	cs.mu.Unlock()
+	if channelz.IsOn() {
+		if err != nil {
+			cs.cc.incrCallsFailed()
+		} else {
+			cs.cc.incrCallsSucceeded()
+		}
+	}
+	// TODO(retry): commit current attempt if necessary.
+	cs.attempt.finish(err)
+	for _, o := range cs.opts {
+		o.after(cs.c)
+	}
+	cs.cancel()
+}
+
+func (a *csAttempt) context() context.Context {
+	return a.s.Context()
+}
+
+func (a *csAttempt) header() (metadata.MD, error) {
+	return a.s.Header()
+}
+
+func (a *csAttempt) trailer() metadata.MD {
+	return a.s.Trailer()
+}
+
+func (a *csAttempt) sendMsg(m interface{}) (err error) {
+	// TODO Investigate how to signal the stats handling party.
+	// generate error stats if err != nil && err != io.EOF?
+	cs := a.cs
+	defer func() {
+		// For non-client-streaming RPCs, we return nil instead of EOF on success
+		// because the generated code requires it.  finish is not called; RecvMsg()
+		// will call it with the stream's status independently.
+		if err == io.EOF && !cs.desc.ClientStreams {
+			err = nil
+		}
+		if err != nil && err != io.EOF {
+			// Call finish on the client stream for errors generated by this SendMsg
+			// call, as these indicate problems created by this client.  (Transport
+			// errors are converted to an io.EOF error below; the real error will be
+			// returned from RecvMsg eventually in that case, or be retried.)
+			cs.finish(err)
+		}
+	}()
+	// TODO: Check cs.sentLast and error if we already ended the stream.
+	if EnableTracing {
+		a.mu.Lock()
+		if a.trInfo.tr != nil {
+			a.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
+		}
+		a.mu.Unlock()
+	}
+	var outPayload *stats.OutPayload
+	if a.statsHandler != nil {
+		outPayload = &stats.OutPayload{
+			Client: true,
+		}
+	}
+	hdr, data, err := encode(cs.codec, m, cs.cp, outPayload, cs.comp)
+	if err != nil {
+		return err
+	}
+	if len(data) > *cs.c.maxSendMessageSize {
+		return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(data), *cs.c.maxSendMessageSize)
+	}
+	if !cs.desc.ClientStreams {
+		cs.sentLast = true
+	}
+	err = a.t.Write(a.s, hdr, data, &transport.Options{Last: !cs.desc.ClientStreams})
+	if err == nil {
+		if outPayload != nil {
+			outPayload.SentTime = time.Now()
+			a.statsHandler.HandleRPC(a.ctx, outPayload)
+		}
+		if channelz.IsOn() {
+			a.t.IncrMsgSent()
+		}
+		return nil
+	}
+	return io.EOF
+}
+
+func (a *csAttempt) recvMsg(m interface{}) (err error) {
+	cs := a.cs
+	defer func() {
+		if err != nil || !cs.desc.ServerStreams {
+			// err != nil or non-server-streaming indicates end of stream.
+			cs.finish(err)
+		}
+	}()
+	var inPayload *stats.InPayload
+	if a.statsHandler != nil {
+		inPayload = &stats.InPayload{
+			Client: true,
+		}
+	}
+	if !a.decompSet {
+		// Block until we receive headers containing received message encoding.
+		if ct := a.s.RecvCompress(); ct != "" && ct != encoding.Identity {
+			if a.dc == nil || a.dc.Type() != ct {
+				// No configured decompressor, or it does not match the incoming
+				// message encoding; attempt to find a registered compressor that does.
+				a.dc = nil
+				a.decomp = encoding.GetCompressor(ct)
+			}
+		} else {
+			// No compression is used; disable our decompressor.
+			a.dc = nil
+		}
+		// Only initialize this state once per stream.
+		a.decompSet = true
+	}
+	err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.c.maxReceiveMessageSize, inPayload, a.decomp)
+	if err != nil {
+		if err == io.EOF {
+			if statusErr := a.s.Status().Err(); statusErr != nil {
+				return statusErr
+			}
+			return io.EOF // indicates successful end of stream.
+		}
+		return toRPCErr(err)
+	}
+	if EnableTracing {
+		a.mu.Lock()
+		if a.trInfo.tr != nil {
+			a.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
+		}
+		a.mu.Unlock()
+	}
+	if inPayload != nil {
+		a.statsHandler.HandleRPC(a.ctx, inPayload)
+	}
+	if channelz.IsOn() {
+		a.t.IncrMsgRecv()
+	}
+	if cs.desc.ServerStreams {
+		// Subsequent messages should be received by subsequent RecvMsg calls.
+		return nil
+	}
+
+	// Special handling for non-server-stream rpcs.
+	// This recv expects EOF or errors, so we don't collect inPayload.
+	err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.c.maxReceiveMessageSize, nil, a.decomp)
+	if err == nil {
+		return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
+	}
+	if err == io.EOF {
+		return a.s.Status().Err() // non-server streaming Recv returns nil on success
+	}
+	return toRPCErr(err)
+}
+
+func (a *csAttempt) closeSend() {
+	cs := a.cs
+	if cs.sentLast {
+		return
+	}
+	cs.sentLast = true
+	cs.attempt.t.Write(cs.attempt.s, nil, nil, &transport.Options{Last: true})
+	// We ignore errors from Write.  Any error it would return would also be
+	// returned by a subsequent RecvMsg call, and the user is supposed to always
+	// finish the stream by calling RecvMsg until it returns err != nil.
+}
+
+func (a *csAttempt) finish(err error) {
+	a.mu.Lock()
+	a.t.CloseStream(a.s, err)
+
+	if a.done != nil {
+		a.done(balancer.DoneInfo{
+			Err:           err,
+			BytesSent:     true,
+			BytesReceived: a.s.BytesReceived(),
+		})
+	}
+	if a.statsHandler != nil {
+		end := &stats.End{
+			Client:    true,
+			BeginTime: a.beginTime,
+			EndTime:   time.Now(),
+			Error:     err,
+		}
+		a.statsHandler.HandleRPC(a.ctx, end)
+	}
+	if a.trInfo.tr != nil {
+		if err == nil {
+			a.trInfo.tr.LazyPrintf("RPC: [OK]")
+		} else {
+			a.trInfo.tr.LazyPrintf("RPC: [%v]", err)
+			a.trInfo.tr.SetError()
+		}
+		a.trInfo.tr.Finish()
+		a.trInfo.tr = nil
+	}
+	a.mu.Unlock()
+}
+
+// ServerStream defines the interface a server stream has to satisfy.
+type ServerStream interface {
+	// SetHeader sets the header metadata. It may be called multiple times.
+	// When call multiple times, all the provided metadata will be merged.
+	// All the metadata will be sent out when one of the following happens:
+	//  - ServerStream.SendHeader() is called;
+	//  - The first response is sent out;
+	//  - An RPC status is sent out (error or success).
+	SetHeader(metadata.MD) error
+	// SendHeader sends the header metadata.
+	// The provided md and headers set by SetHeader() will be sent.
+	// It fails if called multiple times.
+	SendHeader(metadata.MD) error
+	// SetTrailer sets the trailer metadata which will be sent with the RPC status.
+	// When called more than once, all the provided metadata will be merged.
+	SetTrailer(metadata.MD)
+	Stream
+}
+
+// serverStream implements a server side Stream.
+type serverStream struct {
+	ctx   context.Context
+	t     transport.ServerTransport
+	s     *transport.Stream
+	p     *parser
+	codec baseCodec
+
+	cp     Compressor
+	dc     Decompressor
+	comp   encoding.Compressor
+	decomp encoding.Compressor
+
+	maxReceiveMessageSize int
+	maxSendMessageSize    int
+	trInfo                *traceInfo
+
+	statsHandler stats.Handler
+
+	mu sync.Mutex // protects trInfo.tr after the service handler runs.
+}
+
+func (ss *serverStream) Context() context.Context {
+	return ss.ctx
+}
+
+func (ss *serverStream) SetHeader(md metadata.MD) error {
+	if md.Len() == 0 {
+		return nil
+	}
+	return ss.s.SetHeader(md)
+}
+
+func (ss *serverStream) SendHeader(md metadata.MD) error {
+	return ss.t.WriteHeader(ss.s, md)
+}
+
+func (ss *serverStream) SetTrailer(md metadata.MD) {
+	if md.Len() == 0 {
+		return
+	}
+	ss.s.SetTrailer(md)
+}
+
+func (ss *serverStream) SendMsg(m interface{}) (err error) {
+	defer func() {
+		if ss.trInfo != nil {
+			ss.mu.Lock()
+			if ss.trInfo.tr != nil {
+				if err == nil {
+					ss.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
+				} else {
+					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
+					ss.trInfo.tr.SetError()
+				}
+			}
+			ss.mu.Unlock()
+		}
+		if err != nil && err != io.EOF {
+			st, _ := status.FromError(toRPCErr(err))
+			ss.t.WriteStatus(ss.s, st)
+		}
+		if channelz.IsOn() && err == nil {
+			ss.t.IncrMsgSent()
+		}
+	}()
+	var outPayload *stats.OutPayload
+	if ss.statsHandler != nil {
+		outPayload = &stats.OutPayload{}
+	}
+	hdr, data, err := encode(ss.codec, m, ss.cp, outPayload, ss.comp)
+	if err != nil {
+		return err
+	}
+	if len(data) > ss.maxSendMessageSize {
+		return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(data), ss.maxSendMessageSize)
+	}
+	if err := ss.t.Write(ss.s, hdr, data, &transport.Options{Last: false}); err != nil {
+		return toRPCErr(err)
+	}
+	if outPayload != nil {
+		outPayload.SentTime = time.Now()
+		ss.statsHandler.HandleRPC(ss.s.Context(), outPayload)
+	}
+	return nil
+}
+
+func (ss *serverStream) RecvMsg(m interface{}) (err error) {
+	defer func() {
+		if ss.trInfo != nil {
+			ss.mu.Lock()
+			if ss.trInfo.tr != nil {
+				if err == nil {
+					ss.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
+				} else if err != io.EOF {
+					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
+					ss.trInfo.tr.SetError()
+				}
+			}
+			ss.mu.Unlock()
+		}
+		if err != nil && err != io.EOF {
+			st, _ := status.FromError(toRPCErr(err))
+			ss.t.WriteStatus(ss.s, st)
+		}
+		if channelz.IsOn() && err == nil {
+			ss.t.IncrMsgRecv()
+		}
+	}()
+	var inPayload *stats.InPayload
+	if ss.statsHandler != nil {
+		inPayload = &stats.InPayload{}
+	}
+	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxReceiveMessageSize, inPayload, ss.decomp); err != nil {
+		if err == io.EOF {
+			return err
+		}
+		if err == io.ErrUnexpectedEOF {
+			err = status.Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
+		}
+		return toRPCErr(err)
+	}
+	if inPayload != nil {
+		ss.statsHandler.HandleRPC(ss.s.Context(), inPayload)
+	}
+	return nil
+}
+
+// MethodFromServerStream returns the method string for the input stream.
+// The returned string is in the format of "/service/method".
+func MethodFromServerStream(stream ServerStream) (string, bool) {
+	return Method(stream.Context())
+}

vendor/google.golang.org/grpc/tap/tap.go

@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package tap defines the function handles which are executed on the transport
+// layer of gRPC-Go and related information. Everything here is EXPERIMENTAL.
+package tap
+
+import (
+	"golang.org/x/net/context"
+)
+
+// Info defines the relevant information needed by the handles.
+type Info struct {
+	// FullMethodName is the string of grpc method (in the format of
+	// /package.service/method).
+	FullMethodName string
+	// TODO: More to be added.
+}
+
+// ServerInHandle defines the function which runs before a new stream is created
+// on the server side. If it returns a non-nil error, the stream will not be
+// created and a RST_STREAM will be sent back to the client with REFUSED_STREAM.
+// The client will receive an RPC error "code = Unavailable, desc = stream
+// terminated by RST_STREAM with error code: REFUSED_STREAM".
+//
+// It's intended to be used in situations where you don't want to waste the
+// resources to accept the new stream (e.g. rate-limiting). And the content of
+// the error will be ignored and won't be sent back to the client. For other
+// general usages, please use interceptors.
+//
+// Note that it is executed in the per-connection I/O goroutine(s) instead of
+// per-RPC goroutine. Therefore, users should NOT have any
+// blocking/time-consuming work in this handle. Otherwise all the RPCs would
+// slow down. Also, for the same reason, this handle won't be called
+// concurrently by gRPC.
+type ServerInHandle func(ctx context.Context, info *Info) (context.Context, error)

vendor/google.golang.org/grpc/trace.go

@@ -0,0 +1,113 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net"
+	"strings"
+	"time"
+
+	"golang.org/x/net/trace"
+)
+
+// EnableTracing controls whether to trace RPCs using the golang.org/x/net/trace package.
+// This should only be set before any RPCs are sent or received by this program.
+var EnableTracing bool
+
+// methodFamily returns the trace family for the given method.
+// It turns "/pkg.Service/GetFoo" into "pkg.Service".
+func methodFamily(m string) string {
+	m = strings.TrimPrefix(m, "/") // remove leading slash
+	if i := strings.Index(m, "/"); i >= 0 {
+		m = m[:i] // remove everything from second slash
+	}
+	if i := strings.LastIndex(m, "."); i >= 0 {
+		m = m[i+1:] // cut down to last dotted component
+	}
+	return m
+}
+
+// traceInfo contains tracing information for an RPC.
+type traceInfo struct {
+	tr        trace.Trace
+	firstLine firstLine
+}
+
+// firstLine is the first line of an RPC trace.
+type firstLine struct {
+	client     bool // whether this is a client (outgoing) RPC
+	remoteAddr net.Addr
+	deadline   time.Duration // may be zero
+}
+
+func (f *firstLine) String() string {
+	var line bytes.Buffer
+	io.WriteString(&line, "RPC: ")
+	if f.client {
+		io.WriteString(&line, "to")
+	} else {
+		io.WriteString(&line, "from")
+	}
+	fmt.Fprintf(&line, " %v deadline:", f.remoteAddr)
+	if f.deadline != 0 {
+		fmt.Fprint(&line, f.deadline)
+	} else {
+		io.WriteString(&line, "none")
+	}
+	return line.String()
+}
+
+const truncateSize = 100
+
+func truncate(x string, l int) string {
+	if l > len(x) {
+		return x
+	}
+	return x[:l]
+}
+
+// payload represents an RPC request or response payload.
+type payload struct {
+	sent bool        // whether this is an outgoing payload
+	msg  interface{} // e.g. a proto.Message
+	// TODO(dsymonds): add stringifying info to codec, and limit how much we hold here?
+}
+
+func (p payload) String() string {
+	if p.sent {
+		return truncate(fmt.Sprintf("sent: %v", p.msg), truncateSize)
+	}
+	return truncate(fmt.Sprintf("recv: %v", p.msg), truncateSize)
+}
+
+type fmtStringer struct {
+	format string
+	a      []interface{}
+}
+
+func (f *fmtStringer) String() string {
+	return fmt.Sprintf(f.format, f.a...)
+}
+
+type stringer string
+
+func (s stringer) String() string { return string(s) }

vendor/google.golang.org/grpc/transport/bdp_estimator.go

@@ -0,0 +1,140 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	// bdpLimit is the maximum value the flow control windows
+	// will be increased to.
+	bdpLimit = (1 << 20) * 4
+	// alpha is a constant factor used to keep a moving average
+	// of RTTs.
+	alpha = 0.9
+	// If the current bdp sample is greater than or equal to
+	// our beta * our estimated bdp and the current bandwidth
+	// sample is the maximum bandwidth observed so far, we
+	// increase our bbp estimate by a factor of gamma.
+	beta = 0.66
+	// To put our bdp to be smaller than or equal to twice the real BDP,
+	// we should multiply our current sample with 4/3, however to round things out
+	// we use 2 as the multiplication factor.
+	gamma = 2
+)
+
+// Adding arbitrary data to ping so that its ack can be identified.
+// Easter-egg: what does the ping message say?
+var bdpPing = &ping{data: [8]byte{2, 4, 16, 16, 9, 14, 7, 7}}
+
+type bdpEstimator struct {
+	// sentAt is the time when the ping was sent.
+	sentAt time.Time
+
+	mu sync.Mutex
+	// bdp is the current bdp estimate.
+	bdp uint32
+	// sample is the number of bytes received in one measurement cycle.
+	sample uint32
+	// bwMax is the maximum bandwidth noted so far (bytes/sec).
+	bwMax float64
+	// bool to keep track of the beginning of a new measurement cycle.
+	isSent bool
+	// Callback to update the window sizes.
+	updateFlowControl func(n uint32)
+	// sampleCount is the number of samples taken so far.
+	sampleCount uint64
+	// round trip time (seconds)
+	rtt float64
+}
+
+// timesnap registers the time bdp ping was sent out so that
+// network rtt can be calculated when its ack is received.
+// It is called (by controller) when the bdpPing is
+// being written on the wire.
+func (b *bdpEstimator) timesnap(d [8]byte) {
+	if bdpPing.data != d {
+		return
+	}
+	b.sentAt = time.Now()
+}
+
+// add adds bytes to the current sample for calculating bdp.
+// It returns true only if a ping must be sent. This can be used
+// by the caller (handleData) to make decision about batching
+// a window update with it.
+func (b *bdpEstimator) add(n uint32) bool {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if b.bdp == bdpLimit {
+		return false
+	}
+	if !b.isSent {
+		b.isSent = true
+		b.sample = n
+		b.sentAt = time.Time{}
+		b.sampleCount++
+		return true
+	}
+	b.sample += n
+	return false
+}
+
+// calculate is called when an ack for a bdp ping is received.
+// Here we calculate the current bdp and bandwidth sample and
+// decide if the flow control windows should go up.
+func (b *bdpEstimator) calculate(d [8]byte) {
+	// Check if the ping acked for was the bdp ping.
+	if bdpPing.data != d {
+		return
+	}
+	b.mu.Lock()
+	rttSample := time.Since(b.sentAt).Seconds()
+	if b.sampleCount < 10 {
+		// Bootstrap rtt with an average of first 10 rtt samples.
+		b.rtt += (rttSample - b.rtt) / float64(b.sampleCount)
+	} else {
+		// Heed to the recent past more.
+		b.rtt += (rttSample - b.rtt) * float64(alpha)
+	}
+	b.isSent = false
+	// The number of bytes accumulated so far in the sample is smaller
+	// than or equal to 1.5 times the real BDP on a saturated connection.
+	bwCurrent := float64(b.sample) / (b.rtt * float64(1.5))
+	if bwCurrent > b.bwMax {
+		b.bwMax = bwCurrent
+	}
+	// If the current sample (which is smaller than or equal to the 1.5 times the real BDP) is
+	// greater than or equal to 2/3rd our perceived bdp AND this is the maximum bandwidth seen so far, we
+	// should update our perception of the network BDP.
+	if float64(b.sample) >= beta*float64(b.bdp) && bwCurrent == b.bwMax && b.bdp != bdpLimit {
+		sampleFloat := float64(b.sample)
+		b.bdp = uint32(gamma * sampleFloat)
+		if b.bdp > bdpLimit {
+			b.bdp = bdpLimit
+		}
+		bdp := b.bdp
+		b.mu.Unlock()
+		b.updateFlowControl(bdp)
+		return
+	}
+	b.mu.Unlock()
+}

vendor/google.golang.org/grpc/transport/controlbuf.go

@@ -0,0 +1,769 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"bytes"
+	"fmt"
+	"runtime"
+	"sync"
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/hpack"
+)
+
+type itemNode struct {
+	it   interface{}
+	next *itemNode
+}
+
+type itemList struct {
+	head *itemNode
+	tail *itemNode
+}
+
+func (il *itemList) enqueue(i interface{}) {
+	n := &itemNode{it: i}
+	if il.tail == nil {
+		il.head, il.tail = n, n
+		return
+	}
+	il.tail.next = n
+	il.tail = n
+}
+
+// peek returns the first item in the list without removing it from the
+// list.
+func (il *itemList) peek() interface{} {
+	return il.head.it
+}
+
+func (il *itemList) dequeue() interface{} {
+	if il.head == nil {
+		return nil
+	}
+	i := il.head.it
+	il.head = il.head.next
+	if il.head == nil {
+		il.tail = nil
+	}
+	return i
+}
+
+func (il *itemList) dequeueAll() *itemNode {
+	h := il.head
+	il.head, il.tail = nil, nil
+	return h
+}
+
+func (il *itemList) isEmpty() bool {
+	return il.head == nil
+}
+
+// The following defines various control items which could flow through
+// the control buffer of transport. They represent different aspects of
+// control tasks, e.g., flow control, settings, streaming resetting, etc.
+
+type headerFrame struct {
+	streamID   uint32
+	hf         []hpack.HeaderField
+	endStream  bool                       // Valid on server side.
+	initStream func(uint32) (bool, error) // Used only on the client side.
+	onWrite    func()
+	wq         *writeQuota    // write quota for the stream created.
+	cleanup    *cleanupStream // Valid on the server side.
+	onOrphaned func(error)    // Valid on client-side
+}
+
+type cleanupStream struct {
+	streamID uint32
+	idPtr    *uint32
+	rst      bool
+	rstCode  http2.ErrCode
+	onWrite  func()
+}
+
+type dataFrame struct {
+	streamID  uint32
+	endStream bool
+	h         []byte
+	d         []byte
+	// onEachWrite is called every time
+	// a part of d is written out.
+	onEachWrite func()
+}
+
+type incomingWindowUpdate struct {
+	streamID  uint32
+	increment uint32
+}
+
+type outgoingWindowUpdate struct {
+	streamID  uint32
+	increment uint32
+}
+
+type incomingSettings struct {
+	ss []http2.Setting
+}
+
+type outgoingSettings struct {
+	ss []http2.Setting
+}
+
+type settingsAck struct {
+}
+
+type incomingGoAway struct {
+}
+
+type goAway struct {
+	code      http2.ErrCode
+	debugData []byte
+	headsUp   bool
+	closeConn bool
+}
+
+type ping struct {
+	ack  bool
+	data [8]byte
+}
+
+type outFlowControlSizeRequest struct {
+	resp chan uint32
+}
+
+type outStreamState int
+
+const (
+	active outStreamState = iota
+	empty
+	waitingOnStreamQuota
+)
+
+type outStream struct {
+	id               uint32
+	state            outStreamState
+	itl              *itemList
+	bytesOutStanding int
+	wq               *writeQuota
+
+	next *outStream
+	prev *outStream
+}
+
+func (s *outStream) deleteSelf() {
+	if s.prev != nil {
+		s.prev.next = s.next
+	}
+	if s.next != nil {
+		s.next.prev = s.prev
+	}
+	s.next, s.prev = nil, nil
+}
+
+type outStreamList struct {
+	// Following are sentinel objects that mark the
+	// beginning and end of the list. They do not
+	// contain any item lists. All valid objects are
+	// inserted in between them.
+	// This is needed so that an outStream object can
+	// deleteSelf() in O(1) time without knowing which
+	// list it belongs to.
+	head *outStream
+	tail *outStream
+}
+
+func newOutStreamList() *outStreamList {
+	head, tail := new(outStream), new(outStream)
+	head.next = tail
+	tail.prev = head
+	return &outStreamList{
+		head: head,
+		tail: tail,
+	}
+}
+
+func (l *outStreamList) enqueue(s *outStream) {
+	e := l.tail.prev
+	e.next = s
+	s.prev = e
+	s.next = l.tail
+	l.tail.prev = s
+}
+
+// remove from the beginning of the list.
+func (l *outStreamList) dequeue() *outStream {
+	b := l.head.next
+	if b == l.tail {
+		return nil
+	}
+	b.deleteSelf()
+	return b
+}
+
+type controlBuffer struct {
+	ch              chan struct{}
+	done            <-chan struct{}
+	mu              sync.Mutex
+	consumerWaiting bool
+	list            *itemList
+	err             error
+}
+
+func newControlBuffer(done <-chan struct{}) *controlBuffer {
+	return &controlBuffer{
+		ch:   make(chan struct{}, 1),
+		list: &itemList{},
+		done: done,
+	}
+}
+
+func (c *controlBuffer) put(it interface{}) error {
+	_, err := c.executeAndPut(nil, it)
+	return err
+}
+
+func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it interface{}) (bool, error) {
+	var wakeUp bool
+	c.mu.Lock()
+	if c.err != nil {
+		c.mu.Unlock()
+		return false, c.err
+	}
+	if f != nil {
+		if !f(it) { // f wasn't successful
+			c.mu.Unlock()
+			return false, nil
+		}
+	}
+	if c.consumerWaiting {
+		wakeUp = true
+		c.consumerWaiting = false
+	}
+	c.list.enqueue(it)
+	c.mu.Unlock()
+	if wakeUp {
+		select {
+		case c.ch <- struct{}{}:
+		default:
+		}
+	}
+	return true, nil
+}
+
+func (c *controlBuffer) get(block bool) (interface{}, error) {
+	for {
+		c.mu.Lock()
+		if c.err != nil {
+			c.mu.Unlock()
+			return nil, c.err
+		}
+		if !c.list.isEmpty() {
+			h := c.list.dequeue()
+			c.mu.Unlock()
+			return h, nil
+		}
+		if !block {
+			c.mu.Unlock()
+			return nil, nil
+		}
+		c.consumerWaiting = true
+		c.mu.Unlock()
+		select {
+		case <-c.ch:
+		case <-c.done:
+			c.finish()
+			return nil, ErrConnClosing
+		}
+	}
+}
+
+func (c *controlBuffer) finish() {
+	c.mu.Lock()
+	if c.err != nil {
+		c.mu.Unlock()
+		return
+	}
+	c.err = ErrConnClosing
+	// There may be headers for streams in the control buffer.
+	// These streams need to be cleaned out since the transport
+	// is still not aware of these yet.
+	for head := c.list.dequeueAll(); head != nil; head = head.next {
+		hdr, ok := head.it.(*headerFrame)
+		if !ok {
+			continue
+		}
+		if hdr.onOrphaned != nil { // It will be nil on the server-side.
+			hdr.onOrphaned(ErrConnClosing)
+		}
+	}
+	c.mu.Unlock()
+}
+
+type side int
+
+const (
+	clientSide side = iota
+	serverSide
+)
+
+type loopyWriter struct {
+	side          side
+	cbuf          *controlBuffer
+	sendQuota     uint32
+	oiws          uint32                // outbound initial window size.
+	estdStreams   map[uint32]*outStream // Established streams.
+	activeStreams *outStreamList        // Streams that are sending data.
+	framer        *framer
+	hBuf          *bytes.Buffer  // The buffer for HPACK encoding.
+	hEnc          *hpack.Encoder // HPACK encoder.
+	bdpEst        *bdpEstimator
+	draining      bool
+
+	// Side-specific handlers
+	ssGoAwayHandler func(*goAway) (bool, error)
+}
+
+func newLoopyWriter(s side, fr *framer, cbuf *controlBuffer, bdpEst *bdpEstimator) *loopyWriter {
+	var buf bytes.Buffer
+	l := &loopyWriter{
+		side:          s,
+		cbuf:          cbuf,
+		sendQuota:     defaultWindowSize,
+		oiws:          defaultWindowSize,
+		estdStreams:   make(map[uint32]*outStream),
+		activeStreams: newOutStreamList(),
+		framer:        fr,
+		hBuf:          &buf,
+		hEnc:          hpack.NewEncoder(&buf),
+		bdpEst:        bdpEst,
+	}
+	return l
+}
+
+const minBatchSize = 1000
+
+// run should be run in a separate goroutine.
+func (l *loopyWriter) run() {
+	var (
+		it      interface{}
+		err     error
+		isEmpty bool
+	)
+	defer func() {
+		errorf("transport: loopyWriter.run returning. Err: %v", err)
+	}()
+	for {
+		it, err = l.cbuf.get(true)
+		if err != nil {
+			return
+		}
+		if err = l.handle(it); err != nil {
+			return
+		}
+		if _, err = l.processData(); err != nil {
+			return
+		}
+		gosched := true
+	hasdata:
+		for {
+			it, err = l.cbuf.get(false)
+			if err != nil {
+				return
+			}
+			if it != nil {
+				if err = l.handle(it); err != nil {
+					return
+				}
+				if _, err = l.processData(); err != nil {
+					return
+				}
+				continue hasdata
+			}
+			if isEmpty, err = l.processData(); err != nil {
+				return
+			}
+			if !isEmpty {
+				continue hasdata
+			}
+			if gosched {
+				gosched = false
+				if l.framer.writer.offset < minBatchSize {
+					runtime.Gosched()
+					continue hasdata
+				}
+			}
+			l.framer.writer.Flush()
+			break hasdata
+
+		}
+	}
+}
+
+func (l *loopyWriter) outgoingWindowUpdateHandler(w *outgoingWindowUpdate) error {
+	return l.framer.fr.WriteWindowUpdate(w.streamID, w.increment)
+}
+
+func (l *loopyWriter) incomingWindowUpdateHandler(w *incomingWindowUpdate) error {
+	// Otherwise update the quota.
+	if w.streamID == 0 {
+		l.sendQuota += w.increment
+		return nil
+	}
+	// Find the stream and update it.
+	if str, ok := l.estdStreams[w.streamID]; ok {
+		str.bytesOutStanding -= int(w.increment)
+		if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota > 0 && str.state == waitingOnStreamQuota {
+			str.state = active
+			l.activeStreams.enqueue(str)
+			return nil
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) outgoingSettingsHandler(s *outgoingSettings) error {
+	return l.framer.fr.WriteSettings(s.ss...)
+}
+
+func (l *loopyWriter) incomingSettingsHandler(s *incomingSettings) error {
+	if err := l.applySettings(s.ss); err != nil {
+		return err
+	}
+	return l.framer.fr.WriteSettingsAck()
+}
+
+func (l *loopyWriter) headerHandler(h *headerFrame) error {
+	if l.side == serverSide {
+		if h.endStream { // Case 1.A: Server wants to close stream.
+			// Make sure it's not a trailers only response.
+			if str, ok := l.estdStreams[h.streamID]; ok {
+				if str.state != empty { // either active or waiting on stream quota.
+					// add it str's list of items.
+					str.itl.enqueue(h)
+					return nil
+				}
+			}
+			if err := l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite); err != nil {
+				return err
+			}
+			return l.cleanupStreamHandler(h.cleanup)
+		}
+		// Case 1.B: Server is responding back with headers.
+		str := &outStream{
+			state: empty,
+			itl:   &itemList{},
+			wq:    h.wq,
+		}
+		l.estdStreams[h.streamID] = str
+		return l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite)
+	}
+	// Case 2: Client wants to originate stream.
+	str := &outStream{
+		id:    h.streamID,
+		state: empty,
+		itl:   &itemList{},
+		wq:    h.wq,
+	}
+	str.itl.enqueue(h)
+	return l.originateStream(str)
+}
+
+func (l *loopyWriter) originateStream(str *outStream) error {
+	hdr := str.itl.dequeue().(*headerFrame)
+	sendPing, err := hdr.initStream(str.id)
+	if err != nil {
+		if err == ErrConnClosing {
+			return err
+		}
+		// Other errors(errStreamDrain) need not close transport.
+		return nil
+	}
+	if err = l.writeHeader(str.id, hdr.endStream, hdr.hf, hdr.onWrite); err != nil {
+		return err
+	}
+	l.estdStreams[str.id] = str
+	if sendPing {
+		return l.pingHandler(&ping{data: [8]byte{}})
+	}
+	return nil
+}
+
+func (l *loopyWriter) writeHeader(streamID uint32, endStream bool, hf []hpack.HeaderField, onWrite func()) error {
+	if onWrite != nil {
+		onWrite()
+	}
+	l.hBuf.Reset()
+	for _, f := range hf {
+		if err := l.hEnc.WriteField(f); err != nil {
+			warningf("transport: loopyWriter.writeHeader encountered error while encoding headers:", err)
+		}
+	}
+	var (
+		err               error
+		endHeaders, first bool
+	)
+	first = true
+	for !endHeaders {
+		size := l.hBuf.Len()
+		if size > http2MaxFrameLen {
+			size = http2MaxFrameLen
+		} else {
+			endHeaders = true
+		}
+		if first {
+			first = false
+			err = l.framer.fr.WriteHeaders(http2.HeadersFrameParam{
+				StreamID:      streamID,
+				BlockFragment: l.hBuf.Next(size),
+				EndStream:     endStream,
+				EndHeaders:    endHeaders,
+			})
+		} else {
+			err = l.framer.fr.WriteContinuation(
+				streamID,
+				endHeaders,
+				l.hBuf.Next(size),
+			)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) preprocessData(df *dataFrame) error {
+	str, ok := l.estdStreams[df.streamID]
+	if !ok {
+		return nil
+	}
+	// If we got data for a stream it means that
+	// stream was originated and the headers were sent out.
+	str.itl.enqueue(df)
+	if str.state == empty {
+		str.state = active
+		l.activeStreams.enqueue(str)
+	}
+	return nil
+}
+
+func (l *loopyWriter) pingHandler(p *ping) error {
+	if !p.ack {
+		l.bdpEst.timesnap(p.data)
+	}
+	return l.framer.fr.WritePing(p.ack, p.data)
+
+}
+
+func (l *loopyWriter) outFlowControlSizeRequestHandler(o *outFlowControlSizeRequest) error {
+	o.resp <- l.sendQuota
+	return nil
+}
+
+func (l *loopyWriter) cleanupStreamHandler(c *cleanupStream) error {
+	c.onWrite()
+	if str, ok := l.estdStreams[c.streamID]; ok {
+		// On the server side it could be a trailers-only response or
+		// a RST_STREAM before stream initialization thus the stream might
+		// not be established yet.
+		delete(l.estdStreams, c.streamID)
+		str.deleteSelf()
+	}
+	if c.rst { // If RST_STREAM needs to be sent.
+		if err := l.framer.fr.WriteRSTStream(c.streamID, c.rstCode); err != nil {
+			return err
+		}
+	}
+	if l.side == clientSide && l.draining && len(l.estdStreams) == 0 {
+		return ErrConnClosing
+	}
+	return nil
+}
+
+func (l *loopyWriter) incomingGoAwayHandler(*incomingGoAway) error {
+	if l.side == clientSide {
+		l.draining = true
+		if len(l.estdStreams) == 0 {
+			return ErrConnClosing
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) goAwayHandler(g *goAway) error {
+	// Handling of outgoing GoAway is very specific to side.
+	if l.ssGoAwayHandler != nil {
+		draining, err := l.ssGoAwayHandler(g)
+		if err != nil {
+			return err
+		}
+		l.draining = draining
+	}
+	return nil
+}
+
+func (l *loopyWriter) handle(i interface{}) error {
+	switch i := i.(type) {
+	case *incomingWindowUpdate:
+		return l.incomingWindowUpdateHandler(i)
+	case *outgoingWindowUpdate:
+		return l.outgoingWindowUpdateHandler(i)
+	case *incomingSettings:
+		return l.incomingSettingsHandler(i)
+	case *outgoingSettings:
+		return l.outgoingSettingsHandler(i)
+	case *headerFrame:
+		return l.headerHandler(i)
+	case *cleanupStream:
+		return l.cleanupStreamHandler(i)
+	case *incomingGoAway:
+		return l.incomingGoAwayHandler(i)
+	case *dataFrame:
+		return l.preprocessData(i)
+	case *ping:
+		return l.pingHandler(i)
+	case *goAway:
+		return l.goAwayHandler(i)
+	case *outFlowControlSizeRequest:
+		return l.outFlowControlSizeRequestHandler(i)
+	default:
+		return fmt.Errorf("transport: unknown control message type %T", i)
+	}
+}
+
+func (l *loopyWriter) applySettings(ss []http2.Setting) error {
+	for _, s := range ss {
+		switch s.ID {
+		case http2.SettingInitialWindowSize:
+			o := l.oiws
+			l.oiws = s.Val
+			if o < l.oiws {
+				// If the new limit is greater make all depleted streams active.
+				for _, stream := range l.estdStreams {
+					if stream.state == waitingOnStreamQuota {
+						stream.state = active
+						l.activeStreams.enqueue(stream)
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) processData() (bool, error) {
+	if l.sendQuota == 0 {
+		return true, nil
+	}
+	str := l.activeStreams.dequeue()
+	if str == nil {
+		return true, nil
+	}
+	dataItem := str.itl.peek().(*dataFrame)
+	if len(dataItem.h) == 0 && len(dataItem.d) == 0 {
+		// Client sends out empty data frame with endStream = true
+		if err := l.framer.fr.WriteData(dataItem.streamID, dataItem.endStream, nil); err != nil {
+			return false, err
+		}
+		str.itl.dequeue()
+		if str.itl.isEmpty() {
+			str.state = empty
+		} else if trailer, ok := str.itl.peek().(*headerFrame); ok { // the next item is trailers.
+			if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil {
+				return false, err
+			}
+			if err := l.cleanupStreamHandler(trailer.cleanup); err != nil {
+				return false, nil
+			}
+		} else {
+			l.activeStreams.enqueue(str)
+		}
+		return false, nil
+	}
+	var (
+		idx int
+		buf []byte
+	)
+	if len(dataItem.h) != 0 { // data header has not been written out yet.
+		buf = dataItem.h
+	} else {
+		idx = 1
+		buf = dataItem.d
+	}
+	size := http2MaxFrameLen
+	if len(buf) < size {
+		size = len(buf)
+	}
+	if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota <= 0 {
+		str.state = waitingOnStreamQuota
+		return false, nil
+	} else if strQuota < size {
+		size = strQuota
+	}
+
+	if l.sendQuota < uint32(size) {
+		size = int(l.sendQuota)
+	}
+	// Now that outgoing flow controls are checked we can replenish str's write quota
+	str.wq.replenish(size)
+	var endStream bool
+	// This last data message on this stream and all
+	// of it can be written in this go.
+	if dataItem.endStream && size == len(buf) {
+		// buf contains either data or it contains header but data is empty.
+		if idx == 1 || len(dataItem.d) == 0 {
+			endStream = true
+		}
+	}
+	if dataItem.onEachWrite != nil {
+		dataItem.onEachWrite()
+	}
+	if err := l.framer.fr.WriteData(dataItem.streamID, endStream, buf[:size]); err != nil {
+		return false, err
+	}
+	buf = buf[size:]
+	str.bytesOutStanding += size
+	l.sendQuota -= uint32(size)
+	if idx == 0 {
+		dataItem.h = buf
+	} else {
+		dataItem.d = buf
+	}
+
+	if len(dataItem.h) == 0 && len(dataItem.d) == 0 { // All the data from that message was written out.
+		str.itl.dequeue()
+	}
+	if str.itl.isEmpty() {
+		str.state = empty
+	} else if trailer, ok := str.itl.peek().(*headerFrame); ok { // The next item is trailers.
+		if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil {
+			return false, err
+		}
+		if err := l.cleanupStreamHandler(trailer.cleanup); err != nil {
+			return false, err
+		}
+	} else if int(l.oiws)-str.bytesOutStanding <= 0 { // Ran out of stream quota.
+		str.state = waitingOnStreamQuota
+	} else { // Otherwise add it back to the list of active streams.
+		l.activeStreams.enqueue(str)
+	}
+	return false, nil
+}

vendor/google.golang.org/grpc/transport/flowcontrol.go

@@ -0,0 +1,236 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"fmt"
+	"math"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+const (
+	// The default value of flow control window size in HTTP2 spec.
+	defaultWindowSize = 65535
+	// The initial window size for flow control.
+	initialWindowSize             = defaultWindowSize // for an RPC
+	infinity                      = time.Duration(math.MaxInt64)
+	defaultClientKeepaliveTime    = infinity
+	defaultClientKeepaliveTimeout = 20 * time.Second
+	defaultMaxStreamsClient       = 100
+	defaultMaxConnectionIdle      = infinity
+	defaultMaxConnectionAge       = infinity
+	defaultMaxConnectionAgeGrace  = infinity
+	defaultServerKeepaliveTime    = 2 * time.Hour
+	defaultServerKeepaliveTimeout = 20 * time.Second
+	defaultKeepalivePolicyMinTime = 5 * time.Minute
+	// max window limit set by HTTP2 Specs.
+	maxWindowSize = math.MaxInt32
+	// defaultWriteQuota is the default value for number of data
+	// bytes that each stream can schedule before some of it being
+	// flushed out.
+	defaultWriteQuota = 64 * 1024
+)
+
+// writeQuota is a soft limit on the amount of data a stream can
+// schedule before some of it is written out.
+type writeQuota struct {
+	quota int32
+	// get waits on read from when quota goes less than or equal to zero.
+	// replenish writes on it when quota goes positive again.
+	ch chan struct{}
+	// done is triggered in error case.
+	done <-chan struct{}
+}
+
+func newWriteQuota(sz int32, done <-chan struct{}) *writeQuota {
+	return &writeQuota{
+		quota: sz,
+		ch:    make(chan struct{}, 1),
+		done:  done,
+	}
+}
+
+func (w *writeQuota) get(sz int32) error {
+	for {
+		if atomic.LoadInt32(&w.quota) > 0 {
+			atomic.AddInt32(&w.quota, -sz)
+			return nil
+		}
+		select {
+		case <-w.ch:
+			continue
+		case <-w.done:
+			return errStreamDone
+		}
+	}
+}
+
+func (w *writeQuota) replenish(n int) {
+	sz := int32(n)
+	a := atomic.AddInt32(&w.quota, sz)
+	b := a - sz
+	if b <= 0 && a > 0 {
+		select {
+		case w.ch <- struct{}{}:
+		default:
+		}
+	}
+}
+
+type trInFlow struct {
+	limit               uint32
+	unacked             uint32
+	effectiveWindowSize uint32
+}
+
+func (f *trInFlow) newLimit(n uint32) uint32 {
+	d := n - f.limit
+	f.limit = n
+	f.updateEffectiveWindowSize()
+	return d
+}
+
+func (f *trInFlow) onData(n uint32) uint32 {
+	f.unacked += n
+	if f.unacked >= f.limit/4 {
+		w := f.unacked
+		f.unacked = 0
+		f.updateEffectiveWindowSize()
+		return w
+	}
+	f.updateEffectiveWindowSize()
+	return 0
+}
+
+func (f *trInFlow) reset() uint32 {
+	w := f.unacked
+	f.unacked = 0
+	f.updateEffectiveWindowSize()
+	return w
+}
+
+func (f *trInFlow) updateEffectiveWindowSize() {
+	atomic.StoreUint32(&f.effectiveWindowSize, f.limit-f.unacked)
+}
+
+func (f *trInFlow) getSize() uint32 {
+	return atomic.LoadUint32(&f.effectiveWindowSize)
+}
+
+// TODO(mmukhi): Simplify this code.
+// inFlow deals with inbound flow control
+type inFlow struct {
+	mu sync.Mutex
+	// The inbound flow control limit for pending data.
+	limit uint32
+	// pendingData is the overall data which have been received but not been
+	// consumed by applications.
+	pendingData uint32
+	// The amount of data the application has consumed but grpc has not sent
+	// window update for them. Used to reduce window update frequency.
+	pendingUpdate uint32
+	// delta is the extra window update given by receiver when an application
+	// is reading data bigger in size than the inFlow limit.
+	delta uint32
+}
+
+// newLimit updates the inflow window to a new value n.
+// It assumes that n is always greater than the old limit.
+func (f *inFlow) newLimit(n uint32) uint32 {
+	f.mu.Lock()
+	d := n - f.limit
+	f.limit = n
+	f.mu.Unlock()
+	return d
+}
+
+func (f *inFlow) maybeAdjust(n uint32) uint32 {
+	if n > uint32(math.MaxInt32) {
+		n = uint32(math.MaxInt32)
+	}
+	f.mu.Lock()
+	// estSenderQuota is the receiver's view of the maximum number of bytes the sender
+	// can send without a window update.
+	estSenderQuota := int32(f.limit - (f.pendingData + f.pendingUpdate))
+	// estUntransmittedData is the maximum number of bytes the sends might not have put
+	// on the wire yet. A value of 0 or less means that we have already received all or
+	// more bytes than the application is requesting to read.
+	estUntransmittedData := int32(n - f.pendingData) // Casting into int32 since it could be negative.
+	// This implies that unless we send a window update, the sender won't be able to send all the bytes
+	// for this message. Therefore we must send an update over the limit since there's an active read
+	// request from the application.
+	if estUntransmittedData > estSenderQuota {
+		// Sender's window shouldn't go more than 2^31 - 1 as specified in the HTTP spec.
+		if f.limit+n > maxWindowSize {
+			f.delta = maxWindowSize - f.limit
+		} else {
+			// Send a window update for the whole message and not just the difference between
+			// estUntransmittedData and estSenderQuota. This will be helpful in case the message
+			// is padded; We will fallback on the current available window(at least a 1/4th of the limit).
+			f.delta = n
+		}
+		f.mu.Unlock()
+		return f.delta
+	}
+	f.mu.Unlock()
+	return 0
+}
+
+// onData is invoked when some data frame is received. It updates pendingData.
+func (f *inFlow) onData(n uint32) error {
+	f.mu.Lock()
+	f.pendingData += n
+	if f.pendingData+f.pendingUpdate > f.limit+f.delta {
+		limit := f.limit
+		rcvd := f.pendingData + f.pendingUpdate
+		f.mu.Unlock()
+		return fmt.Errorf("received %d-bytes data exceeding the limit %d bytes", rcvd, limit)
+	}
+	f.mu.Unlock()
+	return nil
+}
+
+// onRead is invoked when the application reads the data. It returns the window size
+// to be sent to the peer.
+func (f *inFlow) onRead(n uint32) uint32 {
+	f.mu.Lock()
+	if f.pendingData == 0 {
+		f.mu.Unlock()
+		return 0
+	}
+	f.pendingData -= n
+	if n > f.delta {
+		n -= f.delta
+		f.delta = 0
+	} else {
+		f.delta -= n
+		n = 0
+	}
+	f.pendingUpdate += n
+	if f.pendingUpdate >= f.limit/4 {
+		wu := f.pendingUpdate
+		f.pendingUpdate = 0
+		f.mu.Unlock()
+		return wu
+	}
+	f.mu.Unlock()
+	return 0
+}

vendor/google.golang.org/grpc/transport/go16.go

@@ -0,0 +1,51 @@
+// +build go1.6,!go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"net"
+	"net/http"
+
+	"google.golang.org/grpc/codes"
+
+	"golang.org/x/net/context"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
+}
+
+// ContextErr converts the error from context package into a StreamError.
+func ContextErr(err error) StreamError {
+	switch err {
+	case context.DeadlineExceeded:
+		return streamErrorf(codes.DeadlineExceeded, "%v", err)
+	case context.Canceled:
+		return streamErrorf(codes.Canceled, "%v", err)
+	}
+	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
+}
+
+// contextFromRequest returns a background context.
+func contextFromRequest(r *http.Request) context.Context {
+	return context.Background()
+}

vendor/google.golang.org/grpc/transport/go17.go

@@ -0,0 +1,52 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"context"
+	"net"
+	"net/http"
+
+	"google.golang.org/grpc/codes"
+
+	netctx "golang.org/x/net/context"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{}).DialContext(ctx, network, address)
+}
+
+// ContextErr converts the error from context package into a StreamError.
+func ContextErr(err error) StreamError {
+	switch err {
+	case context.DeadlineExceeded, netctx.DeadlineExceeded:
+		return streamErrorf(codes.DeadlineExceeded, "%v", err)
+	case context.Canceled, netctx.Canceled:
+		return streamErrorf(codes.Canceled, "%v", err)
+	}
+	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
+}
+
+// contextFromRequest returns a context from the HTTP Request.
+func contextFromRequest(r *http.Request) context.Context {
+	return r.Context()
+}

vendor/google.golang.org/grpc/transport/handler_server.go

@@ -0,0 +1,451 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// This file is the implementation of a gRPC server using HTTP/2 which
+// uses the standard Go http2 Server implementation (via the
+// http.Handler interface), rather than speaking low-level HTTP/2
+// frames itself. It is the implementation of *grpc.Server.ServeHTTP.
+
+package transport
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"golang.org/x/net/context"
+	"golang.org/x/net/http2"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/status"
+)
+
+// NewServerHandlerTransport returns a ServerTransport handling gRPC
+// from inside an http.Handler. It requires that the http Server
+// supports HTTP/2.
+func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request, stats stats.Handler) (ServerTransport, error) {
+	if r.ProtoMajor != 2 {
+		return nil, errors.New("gRPC requires HTTP/2")
+	}
+	if r.Method != "POST" {
+		return nil, errors.New("invalid gRPC request method")
+	}
+	contentType := r.Header.Get("Content-Type")
+	// TODO: do we assume contentType is lowercase? we did before
+	contentSubtype, validContentType := contentSubtype(contentType)
+	if !validContentType {
+		return nil, errors.New("invalid gRPC request content-type")
+	}
+	if _, ok := w.(http.Flusher); !ok {
+		return nil, errors.New("gRPC requires a ResponseWriter supporting http.Flusher")
+	}
+	if _, ok := w.(http.CloseNotifier); !ok {
+		return nil, errors.New("gRPC requires a ResponseWriter supporting http.CloseNotifier")
+	}
+
+	st := &serverHandlerTransport{
+		rw:             w,
+		req:            r,
+		closedCh:       make(chan struct{}),
+		writes:         make(chan func()),
+		contentType:    contentType,
+		contentSubtype: contentSubtype,
+		stats:          stats,
+	}
+
+	if v := r.Header.Get("grpc-timeout"); v != "" {
+		to, err := decodeTimeout(v)
+		if err != nil {
+			return nil, streamErrorf(codes.Internal, "malformed time-out: %v", err)
+		}
+		st.timeoutSet = true
+		st.timeout = to
+	}
+
+	metakv := []string{"content-type", contentType}
+	if r.Host != "" {
+		metakv = append(metakv, ":authority", r.Host)
+	}
+	for k, vv := range r.Header {
+		k = strings.ToLower(k)
+		if isReservedHeader(k) && !isWhitelistedHeader(k) {
+			continue
+		}
+		for _, v := range vv {
+			v, err := decodeMetadataHeader(k, v)
+			if err != nil {
+				return nil, streamErrorf(codes.Internal, "malformed binary metadata: %v", err)
+			}
+			metakv = append(metakv, k, v)
+		}
+	}
+	st.headerMD = metadata.Pairs(metakv...)
+
+	return st, nil
+}
+
+// serverHandlerTransport is an implementation of ServerTransport
+// which replies to exactly one gRPC request (exactly one HTTP request),
+// using the net/http.Handler interface. This http.Handler is guaranteed
+// at this point to be speaking over HTTP/2, so it's able to speak valid
+// gRPC.
+type serverHandlerTransport struct {
+	rw               http.ResponseWriter
+	req              *http.Request
+	timeoutSet       bool
+	timeout          time.Duration
+	didCommonHeaders bool
+
+	headerMD metadata.MD
+
+	closeOnce sync.Once
+	closedCh  chan struct{} // closed on Close
+
+	// writes is a channel of code to run serialized in the
+	// ServeHTTP (HandleStreams) goroutine. The channel is closed
+	// when WriteStatus is called.
+	writes chan func()
+
+	// block concurrent WriteStatus calls
+	// e.g. grpc/(*serverStream).SendMsg/RecvMsg
+	writeStatusMu sync.Mutex
+
+	// we just mirror the request content-type
+	contentType string
+	// we store both contentType and contentSubtype so we don't keep recreating them
+	// TODO make sure this is consistent across handler_server and http2_server
+	contentSubtype string
+
+	stats stats.Handler
+}
+
+func (ht *serverHandlerTransport) Close() error {
+	ht.closeOnce.Do(ht.closeCloseChanOnce)
+	return nil
+}
+
+func (ht *serverHandlerTransport) closeCloseChanOnce() { close(ht.closedCh) }
+
+func (ht *serverHandlerTransport) RemoteAddr() net.Addr { return strAddr(ht.req.RemoteAddr) }
+
+// strAddr is a net.Addr backed by either a TCP "ip:port" string, or
+// the empty string if unknown.
+type strAddr string
+
+func (a strAddr) Network() string {
+	if a != "" {
+		// Per the documentation on net/http.Request.RemoteAddr, if this is
+		// set, it's set to the IP:port of the peer (hence, TCP):
+		// https://golang.org/pkg/net/http/#Request
+		//
+		// If we want to support Unix sockets later, we can
+		// add our own grpc-specific convention within the
+		// grpc codebase to set RemoteAddr to a different
+		// format, or probably better: we can attach it to the
+		// context and use that from serverHandlerTransport.RemoteAddr.
+		return "tcp"
+	}
+	return ""
+}
+
+func (a strAddr) String() string { return string(a) }
+
+// do runs fn in the ServeHTTP goroutine.
+func (ht *serverHandlerTransport) do(fn func()) error {
+	// Avoid a panic writing to closed channel. Imperfect but maybe good enough.
+	select {
+	case <-ht.closedCh:
+		return ErrConnClosing
+	default:
+		select {
+		case ht.writes <- fn:
+			return nil
+		case <-ht.closedCh:
+			return ErrConnClosing
+		}
+	}
+}
+
+func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) error {
+	ht.writeStatusMu.Lock()
+	defer ht.writeStatusMu.Unlock()
+
+	err := ht.do(func() {
+		ht.writeCommonHeaders(s)
+
+		// And flush, in case no header or body has been sent yet.
+		// This forces a separation of headers and trailers if this is the
+		// first call (for example, in end2end tests's TestNoService).
+		ht.rw.(http.Flusher).Flush()
+
+		h := ht.rw.Header()
+		h.Set("Grpc-Status", fmt.Sprintf("%d", st.Code()))
+		if m := st.Message(); m != "" {
+			h.Set("Grpc-Message", encodeGrpcMessage(m))
+		}
+
+		if p := st.Proto(); p != nil && len(p.Details) > 0 {
+			stBytes, err := proto.Marshal(p)
+			if err != nil {
+				// TODO: return error instead, when callers are able to handle it.
+				panic(err)
+			}
+
+			h.Set("Grpc-Status-Details-Bin", encodeBinHeader(stBytes))
+		}
+
+		if md := s.Trailer(); len(md) > 0 {
+			for k, vv := range md {
+				// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
+				if isReservedHeader(k) {
+					continue
+				}
+				for _, v := range vv {
+					// http2 ResponseWriter mechanism to send undeclared Trailers after
+					// the headers have possibly been written.
+					h.Add(http2.TrailerPrefix+k, encodeMetadataHeader(k, v))
+				}
+			}
+		}
+	})
+
+	if err == nil { // transport has not been closed
+		if ht.stats != nil {
+			ht.stats.HandleRPC(s.Context(), &stats.OutTrailer{})
+		}
+		ht.Close()
+		close(ht.writes)
+	}
+	return err
+}
+
+// writeCommonHeaders sets common headers on the first write
+// call (Write, WriteHeader, or WriteStatus).
+func (ht *serverHandlerTransport) writeCommonHeaders(s *Stream) {
+	if ht.didCommonHeaders {
+		return
+	}
+	ht.didCommonHeaders = true
+
+	h := ht.rw.Header()
+	h["Date"] = nil // suppress Date to make tests happy; TODO: restore
+	h.Set("Content-Type", ht.contentType)
+
+	// Predeclare trailers we'll set later in WriteStatus (after the body).
+	// This is a SHOULD in the HTTP RFC, and the way you add (known)
+	// Trailers per the net/http.ResponseWriter contract.
+	// See https://golang.org/pkg/net/http/#ResponseWriter
+	// and https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
+	h.Add("Trailer", "Grpc-Status")
+	h.Add("Trailer", "Grpc-Message")
+	h.Add("Trailer", "Grpc-Status-Details-Bin")
+
+	if s.sendCompress != "" {
+		h.Set("Grpc-Encoding", s.sendCompress)
+	}
+}
+
+func (ht *serverHandlerTransport) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
+	return ht.do(func() {
+		ht.writeCommonHeaders(s)
+		ht.rw.Write(hdr)
+		ht.rw.Write(data)
+		if !opts.Delay {
+			ht.rw.(http.Flusher).Flush()
+		}
+	})
+}
+
+func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error {
+	err := ht.do(func() {
+		ht.writeCommonHeaders(s)
+		h := ht.rw.Header()
+		for k, vv := range md {
+			// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
+			if isReservedHeader(k) {
+				continue
+			}
+			for _, v := range vv {
+				v = encodeMetadataHeader(k, v)
+				h.Add(k, v)
+			}
+		}
+		ht.rw.WriteHeader(200)
+		ht.rw.(http.Flusher).Flush()
+	})
+
+	if err == nil {
+		if ht.stats != nil {
+			ht.stats.HandleRPC(s.Context(), &stats.OutHeader{})
+		}
+	}
+	return err
+}
+
+func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), traceCtx func(context.Context, string) context.Context) {
+	// With this transport type there will be exactly 1 stream: this HTTP request.
+
+	ctx := contextFromRequest(ht.req)
+	var cancel context.CancelFunc
+	if ht.timeoutSet {
+		ctx, cancel = context.WithTimeout(ctx, ht.timeout)
+	} else {
+		ctx, cancel = context.WithCancel(ctx)
+	}
+
+	// requestOver is closed when either the request's context is done
+	// or the status has been written via WriteStatus.
+	requestOver := make(chan struct{})
+
+	// clientGone receives a single value if peer is gone, either
+	// because the underlying connection is dead or because the
+	// peer sends an http2 RST_STREAM.
+	clientGone := ht.rw.(http.CloseNotifier).CloseNotify()
+	go func() {
+		select {
+		case <-requestOver:
+			return
+		case <-ht.closedCh:
+		case <-clientGone:
+		}
+		cancel()
+	}()
+
+	req := ht.req
+
+	s := &Stream{
+		id:             0, // irrelevant
+		requestRead:    func(int) {},
+		cancel:         cancel,
+		buf:            newRecvBuffer(),
+		st:             ht,
+		method:         req.URL.Path,
+		recvCompress:   req.Header.Get("grpc-encoding"),
+		contentSubtype: ht.contentSubtype,
+	}
+	pr := &peer.Peer{
+		Addr: ht.RemoteAddr(),
+	}
+	if req.TLS != nil {
+		pr.AuthInfo = credentials.TLSInfo{State: *req.TLS}
+	}
+	ctx = metadata.NewIncomingContext(ctx, ht.headerMD)
+	s.ctx = peer.NewContext(ctx, pr)
+	if ht.stats != nil {
+		s.ctx = ht.stats.TagRPC(s.ctx, &stats.RPCTagInfo{FullMethodName: s.method})
+		inHeader := &stats.InHeader{
+			FullMethod:  s.method,
+			RemoteAddr:  ht.RemoteAddr(),
+			Compression: s.recvCompress,
+		}
+		ht.stats.HandleRPC(s.ctx, inHeader)
+	}
+	s.trReader = &transportReader{
+		reader:        &recvBufferReader{ctx: s.ctx, ctxDone: s.ctx.Done(), recv: s.buf},
+		windowHandler: func(int) {},
+	}
+
+	// readerDone is closed when the Body.Read-ing goroutine exits.
+	readerDone := make(chan struct{})
+	go func() {
+		defer close(readerDone)
+
+		// TODO: minimize garbage, optimize recvBuffer code/ownership
+		const readSize = 8196
+		for buf := make([]byte, readSize); ; {
+			n, err := req.Body.Read(buf)
+			if n > 0 {
+				s.buf.put(recvMsg{data: buf[:n:n]})
+				buf = buf[n:]
+			}
+			if err != nil {
+				s.buf.put(recvMsg{err: mapRecvMsgError(err)})
+				return
+			}
+			if len(buf) == 0 {
+				buf = make([]byte, readSize)
+			}
+		}
+	}()
+
+	// startStream is provided by the *grpc.Server's serveStreams.
+	// It starts a goroutine serving s and exits immediately.
+	// The goroutine that is started is the one that then calls
+	// into ht, calling WriteHeader, Write, WriteStatus, Close, etc.
+	startStream(s)
+
+	ht.runStream()
+	close(requestOver)
+
+	// Wait for reading goroutine to finish.
+	req.Body.Close()
+	<-readerDone
+}
+
+func (ht *serverHandlerTransport) runStream() {
+	for {
+		select {
+		case fn, ok := <-ht.writes:
+			if !ok {
+				return
+			}
+			fn()
+		case <-ht.closedCh:
+			return
+		}
+	}
+}
+
+func (ht *serverHandlerTransport) IncrMsgSent() {}
+
+func (ht *serverHandlerTransport) IncrMsgRecv() {}
+
+func (ht *serverHandlerTransport) Drain() {
+	panic("Drain() is not implemented")
+}
+
+// mapRecvMsgError returns the non-nil err into the appropriate
+// error value as expected by callers of *grpc.parser.recvMsg.
+// In particular, in can only be:
+//   * io.EOF
+//   * io.ErrUnexpectedEOF
+//   * of type transport.ConnectionError
+//   * of type transport.StreamError
+func mapRecvMsgError(err error) error {
+	if err == io.EOF || err == io.ErrUnexpectedEOF {
+		return err
+	}
+	if se, ok := err.(http2.StreamError); ok {
+		if code, ok := http2ErrConvTab[se.Code]; ok {
+			return StreamError{
+				Code: code,
+				Desc: se.Error(),
+			}
+		}
+	}
+	return connectionErrorf(true, err, err.Error())
+}

vendor/google.golang.org/grpc/transport/http_util.go

@@ -0,0 +1,574 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"net"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/hpack"
+	spb "google.golang.org/genproto/googleapis/rpc/status"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+const (
+	// http2MaxFrameLen specifies the max length of a HTTP2 frame.
+	http2MaxFrameLen = 16384 // 16KB frame
+	// http://http2.github.io/http2-spec/#SettingValues
+	http2InitHeaderTableSize = 4096
+	// http2IOBufSize specifies the buffer size for sending frames.
+	defaultWriteBufSize = 32 * 1024
+	defaultReadBufSize  = 32 * 1024
+	// baseContentType is the base content-type for gRPC.  This is a valid
+	// content-type on it's own, but can also include a content-subtype such as
+	// "proto" as a suffix after "+" or ";".  See
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
+	// for more details.
+	baseContentType = "application/grpc"
+)
+
+var (
+	clientPreface   = []byte(http2.ClientPreface)
+	http2ErrConvTab = map[http2.ErrCode]codes.Code{
+		http2.ErrCodeNo:                 codes.Internal,
+		http2.ErrCodeProtocol:           codes.Internal,
+		http2.ErrCodeInternal:           codes.Internal,
+		http2.ErrCodeFlowControl:        codes.ResourceExhausted,
+		http2.ErrCodeSettingsTimeout:    codes.Internal,
+		http2.ErrCodeStreamClosed:       codes.Internal,
+		http2.ErrCodeFrameSize:          codes.Internal,
+		http2.ErrCodeRefusedStream:      codes.Unavailable,
+		http2.ErrCodeCancel:             codes.Canceled,
+		http2.ErrCodeCompression:        codes.Internal,
+		http2.ErrCodeConnect:            codes.Internal,
+		http2.ErrCodeEnhanceYourCalm:    codes.ResourceExhausted,
+		http2.ErrCodeInadequateSecurity: codes.PermissionDenied,
+		http2.ErrCodeHTTP11Required:     codes.Internal,
+	}
+	statusCodeConvTab = map[codes.Code]http2.ErrCode{
+		codes.Internal:          http2.ErrCodeInternal,
+		codes.Canceled:          http2.ErrCodeCancel,
+		codes.Unavailable:       http2.ErrCodeRefusedStream,
+		codes.ResourceExhausted: http2.ErrCodeEnhanceYourCalm,
+		codes.PermissionDenied:  http2.ErrCodeInadequateSecurity,
+	}
+	httpStatusConvTab = map[int]codes.Code{
+		// 400 Bad Request - INTERNAL.
+		http.StatusBadRequest: codes.Internal,
+		// 401 Unauthorized  - UNAUTHENTICATED.
+		http.StatusUnauthorized: codes.Unauthenticated,
+		// 403 Forbidden - PERMISSION_DENIED.
+		http.StatusForbidden: codes.PermissionDenied,
+		// 404 Not Found - UNIMPLEMENTED.
+		http.StatusNotFound: codes.Unimplemented,
+		// 429 Too Many Requests - UNAVAILABLE.
+		http.StatusTooManyRequests: codes.Unavailable,
+		// 502 Bad Gateway - UNAVAILABLE.
+		http.StatusBadGateway: codes.Unavailable,
+		// 503 Service Unavailable - UNAVAILABLE.
+		http.StatusServiceUnavailable: codes.Unavailable,
+		// 504 Gateway timeout - UNAVAILABLE.
+		http.StatusGatewayTimeout: codes.Unavailable,
+	}
+)
+
+// Records the states during HPACK decoding. Must be reset once the
+// decoding of the entire headers are finished.
+type decodeState struct {
+	encoding string
+	// statusGen caches the stream status received from the trailer the server
+	// sent.  Client side only.  Do not access directly.  After all trailers are
+	// parsed, use the status method to retrieve the status.
+	statusGen *status.Status
+	// rawStatusCode and rawStatusMsg are set from the raw trailer fields and are not
+	// intended for direct access outside of parsing.
+	rawStatusCode *int
+	rawStatusMsg  string
+	httpStatus    *int
+	// Server side only fields.
+	timeoutSet bool
+	timeout    time.Duration
+	method     string
+	// key-value metadata map from the peer.
+	mdata          map[string][]string
+	statsTags      []byte
+	statsTrace     []byte
+	contentSubtype string
+}
+
+// isReservedHeader checks whether hdr belongs to HTTP2 headers
+// reserved by gRPC protocol. Any other headers are classified as the
+// user-specified metadata.
+func isReservedHeader(hdr string) bool {
+	if hdr != "" && hdr[0] == ':' {
+		return true
+	}
+	switch hdr {
+	case "content-type",
+		"user-agent",
+		"grpc-message-type",
+		"grpc-encoding",
+		"grpc-message",
+		"grpc-status",
+		"grpc-timeout",
+		"grpc-status-details-bin",
+		"te":
+		return true
+	default:
+		return false
+	}
+}
+
+// isWhitelistedHeader checks whether hdr should be propagated
+// into metadata visible to users.
+func isWhitelistedHeader(hdr string) bool {
+	switch hdr {
+	case ":authority", "user-agent":
+		return true
+	default:
+		return false
+	}
+}
+
+// contentSubtype returns the content-subtype for the given content-type.  The
+// given content-type must be a valid content-type that starts with
+// "application/grpc". A content-subtype will follow "application/grpc" after a
+// "+" or ";". See
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// If contentType is not a valid content-type for gRPC, the boolean
+// will be false, otherwise true. If content-type == "application/grpc",
+// "application/grpc+", or "application/grpc;", the boolean will be true,
+// but no content-subtype will be returned.
+//
+// contentType is assumed to be lowercase already.
+func contentSubtype(contentType string) (string, bool) {
+	if contentType == baseContentType {
+		return "", true
+	}
+	if !strings.HasPrefix(contentType, baseContentType) {
+		return "", false
+	}
+	// guaranteed since != baseContentType and has baseContentType prefix
+	switch contentType[len(baseContentType)] {
+	case '+', ';':
+		// this will return true for "application/grpc+" or "application/grpc;"
+		// which the previous validContentType function tested to be valid, so we
+		// just say that no content-subtype is specified in this case
+		return contentType[len(baseContentType)+1:], true
+	default:
+		return "", false
+	}
+}
+
+// contentSubtype is assumed to be lowercase
+func contentType(contentSubtype string) string {
+	if contentSubtype == "" {
+		return baseContentType
+	}
+	return baseContentType + "+" + contentSubtype
+}
+
+func (d *decodeState) status() *status.Status {
+	if d.statusGen == nil {
+		// No status-details were provided; generate status using code/msg.
+		d.statusGen = status.New(codes.Code(int32(*(d.rawStatusCode))), d.rawStatusMsg)
+	}
+	return d.statusGen
+}
+
+const binHdrSuffix = "-bin"
+
+func encodeBinHeader(v []byte) string {
+	return base64.RawStdEncoding.EncodeToString(v)
+}
+
+func decodeBinHeader(v string) ([]byte, error) {
+	if len(v)%4 == 0 {
+		// Input was padded, or padding was not necessary.
+		return base64.StdEncoding.DecodeString(v)
+	}
+	return base64.RawStdEncoding.DecodeString(v)
+}
+
+func encodeMetadataHeader(k, v string) string {
+	if strings.HasSuffix(k, binHdrSuffix) {
+		return encodeBinHeader(([]byte)(v))
+	}
+	return v
+}
+
+func decodeMetadataHeader(k, v string) (string, error) {
+	if strings.HasSuffix(k, binHdrSuffix) {
+		b, err := decodeBinHeader(v)
+		return string(b), err
+	}
+	return v, nil
+}
+
+func (d *decodeState) decodeResponseHeader(frame *http2.MetaHeadersFrame) error {
+	for _, hf := range frame.Fields {
+		if err := d.processHeaderField(hf); err != nil {
+			return err
+		}
+	}
+
+	// If grpc status exists, no need to check further.
+	if d.rawStatusCode != nil || d.statusGen != nil {
+		return nil
+	}
+
+	// If grpc status doesn't exist and http status doesn't exist,
+	// then it's a malformed header.
+	if d.httpStatus == nil {
+		return streamErrorf(codes.Internal, "malformed header: doesn't contain status(gRPC or HTTP)")
+	}
+
+	if *(d.httpStatus) != http.StatusOK {
+		code, ok := httpStatusConvTab[*(d.httpStatus)]
+		if !ok {
+			code = codes.Unknown
+		}
+		return streamErrorf(code, http.StatusText(*(d.httpStatus)))
+	}
+
+	// gRPC status doesn't exist and http status is OK.
+	// Set rawStatusCode to be unknown and return nil error.
+	// So that, if the stream has ended this Unknown status
+	// will be propagated to the user.
+	// Otherwise, it will be ignored. In which case, status from
+	// a later trailer, that has StreamEnded flag set, is propagated.
+	code := int(codes.Unknown)
+	d.rawStatusCode = &code
+	return nil
+
+}
+
+func (d *decodeState) addMetadata(k, v string) {
+	if d.mdata == nil {
+		d.mdata = make(map[string][]string)
+	}
+	d.mdata[k] = append(d.mdata[k], v)
+}
+
+func (d *decodeState) processHeaderField(f hpack.HeaderField) error {
+	switch f.Name {
+	case "content-type":
+		contentSubtype, validContentType := contentSubtype(f.Value)
+		if !validContentType {
+			return streamErrorf(codes.Internal, "transport: received the unexpected content-type %q", f.Value)
+		}
+		d.contentSubtype = contentSubtype
+		// TODO: do we want to propagate the whole content-type in the metadata,
+		// or come up with a way to just propagate the content-subtype if it was set?
+		// ie {"content-type": "application/grpc+proto"} or {"content-subtype": "proto"}
+		// in the metadata?
+		d.addMetadata(f.Name, f.Value)
+	case "grpc-encoding":
+		d.encoding = f.Value
+	case "grpc-status":
+		code, err := strconv.Atoi(f.Value)
+		if err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed grpc-status: %v", err)
+		}
+		d.rawStatusCode = &code
+	case "grpc-message":
+		d.rawStatusMsg = decodeGrpcMessage(f.Value)
+	case "grpc-status-details-bin":
+		v, err := decodeBinHeader(f.Value)
+		if err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
+		}
+		s := &spb.Status{}
+		if err := proto.Unmarshal(v, s); err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
+		}
+		d.statusGen = status.FromProto(s)
+	case "grpc-timeout":
+		d.timeoutSet = true
+		var err error
+		if d.timeout, err = decodeTimeout(f.Value); err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed time-out: %v", err)
+		}
+	case ":path":
+		d.method = f.Value
+	case ":status":
+		code, err := strconv.Atoi(f.Value)
+		if err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed http-status: %v", err)
+		}
+		d.httpStatus = &code
+	case "grpc-tags-bin":
+		v, err := decodeBinHeader(f.Value)
+		if err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed grpc-tags-bin: %v", err)
+		}
+		d.statsTags = v
+		d.addMetadata(f.Name, string(v))
+	case "grpc-trace-bin":
+		v, err := decodeBinHeader(f.Value)
+		if err != nil {
+			return streamErrorf(codes.Internal, "transport: malformed grpc-trace-bin: %v", err)
+		}
+		d.statsTrace = v
+		d.addMetadata(f.Name, string(v))
+	default:
+		if isReservedHeader(f.Name) && !isWhitelistedHeader(f.Name) {
+			break
+		}
+		v, err := decodeMetadataHeader(f.Name, f.Value)
+		if err != nil {
+			errorf("Failed to decode metadata header (%q, %q): %v", f.Name, f.Value, err)
+			return nil
+		}
+		d.addMetadata(f.Name, v)
+	}
+	return nil
+}
+
+type timeoutUnit uint8
+
+const (
+	hour        timeoutUnit = 'H'
+	minute      timeoutUnit = 'M'
+	second      timeoutUnit = 'S'
+	millisecond timeoutUnit = 'm'
+	microsecond timeoutUnit = 'u'
+	nanosecond  timeoutUnit = 'n'
+)
+
+func timeoutUnitToDuration(u timeoutUnit) (d time.Duration, ok bool) {
+	switch u {
+	case hour:
+		return time.Hour, true
+	case minute:
+		return time.Minute, true
+	case second:
+		return time.Second, true
+	case millisecond:
+		return time.Millisecond, true
+	case microsecond:
+		return time.Microsecond, true
+	case nanosecond:
+		return time.Nanosecond, true
+	default:
+	}
+	return
+}
+
+const maxTimeoutValue int64 = 100000000 - 1
+
+// div does integer division and round-up the result. Note that this is
+// equivalent to (d+r-1)/r but has less chance to overflow.
+func div(d, r time.Duration) int64 {
+	if m := d % r; m > 0 {
+		return int64(d/r + 1)
+	}
+	return int64(d / r)
+}
+
+// TODO(zhaoq): It is the simplistic and not bandwidth efficient. Improve it.
+func encodeTimeout(t time.Duration) string {
+	if t <= 0 {
+		return "0n"
+	}
+	if d := div(t, time.Nanosecond); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "n"
+	}
+	if d := div(t, time.Microsecond); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "u"
+	}
+	if d := div(t, time.Millisecond); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "m"
+	}
+	if d := div(t, time.Second); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "S"
+	}
+	if d := div(t, time.Minute); d <= maxTimeoutValue {
+		return strconv.FormatInt(d, 10) + "M"
+	}
+	// Note that maxTimeoutValue * time.Hour > MaxInt64.
+	return strconv.FormatInt(div(t, time.Hour), 10) + "H"
+}
+
+func decodeTimeout(s string) (time.Duration, error) {
+	size := len(s)
+	if size < 2 {
+		return 0, fmt.Errorf("transport: timeout string is too short: %q", s)
+	}
+	unit := timeoutUnit(s[size-1])
+	d, ok := timeoutUnitToDuration(unit)
+	if !ok {
+		return 0, fmt.Errorf("transport: timeout unit is not recognized: %q", s)
+	}
+	t, err := strconv.ParseInt(s[:size-1], 10, 64)
+	if err != nil {
+		return 0, err
+	}
+	return d * time.Duration(t), nil
+}
+
+const (
+	spaceByte   = ' '
+	tildaByte   = '~'
+	percentByte = '%'
+)
+
+// encodeGrpcMessage is used to encode status code in header field
+// "grpc-message".
+// It checks to see if each individual byte in msg is an
+// allowable byte, and then either percent encoding or passing it through.
+// When percent encoding, the byte is converted into hexadecimal notation
+// with a '%' prepended.
+func encodeGrpcMessage(msg string) string {
+	if msg == "" {
+		return ""
+	}
+	lenMsg := len(msg)
+	for i := 0; i < lenMsg; i++ {
+		c := msg[i]
+		if !(c >= spaceByte && c < tildaByte && c != percentByte) {
+			return encodeGrpcMessageUnchecked(msg)
+		}
+	}
+	return msg
+}
+
+func encodeGrpcMessageUnchecked(msg string) string {
+	var buf bytes.Buffer
+	lenMsg := len(msg)
+	for i := 0; i < lenMsg; i++ {
+		c := msg[i]
+		if c >= spaceByte && c < tildaByte && c != percentByte {
+			buf.WriteByte(c)
+		} else {
+			buf.WriteString(fmt.Sprintf("%%%02X", c))
+		}
+	}
+	return buf.String()
+}
+
+// decodeGrpcMessage decodes the msg encoded by encodeGrpcMessage.
+func decodeGrpcMessage(msg string) string {
+	if msg == "" {
+		return ""
+	}
+	lenMsg := len(msg)
+	for i := 0; i < lenMsg; i++ {
+		if msg[i] == percentByte && i+2 < lenMsg {
+			return decodeGrpcMessageUnchecked(msg)
+		}
+	}
+	return msg
+}
+
+func decodeGrpcMessageUnchecked(msg string) string {
+	var buf bytes.Buffer
+	lenMsg := len(msg)
+	for i := 0; i < lenMsg; i++ {
+		c := msg[i]
+		if c == percentByte && i+2 < lenMsg {
+			parsed, err := strconv.ParseUint(msg[i+1:i+3], 16, 8)
+			if err != nil {
+				buf.WriteByte(c)
+			} else {
+				buf.WriteByte(byte(parsed))
+				i += 2
+			}
+		} else {
+			buf.WriteByte(c)
+		}
+	}
+	return buf.String()
+}
+
+type bufWriter struct {
+	buf       []byte
+	offset    int
+	batchSize int
+	conn      net.Conn
+	err       error
+
+	onFlush func()
+}
+
+func newBufWriter(conn net.Conn, batchSize int) *bufWriter {
+	return &bufWriter{
+		buf:       make([]byte, batchSize*2),
+		batchSize: batchSize,
+		conn:      conn,
+	}
+}
+
+func (w *bufWriter) Write(b []byte) (n int, err error) {
+	if w.err != nil {
+		return 0, w.err
+	}
+	n = copy(w.buf[w.offset:], b)
+	w.offset += n
+	if w.offset >= w.batchSize {
+		err = w.Flush()
+	}
+	return n, err
+}
+
+func (w *bufWriter) Flush() error {
+	if w.err != nil {
+		return w.err
+	}
+	if w.offset == 0 {
+		return nil
+	}
+	if w.onFlush != nil {
+		w.onFlush()
+	}
+	_, w.err = w.conn.Write(w.buf[:w.offset])
+	w.offset = 0
+	return w.err
+}
+
+type framer struct {
+	writer *bufWriter
+	fr     *http2.Framer
+}
+
+func newFramer(conn net.Conn, writeBufferSize, readBufferSize int) *framer {
+	r := bufio.NewReaderSize(conn, readBufferSize)
+	w := newBufWriter(conn, writeBufferSize)
+	f := &framer{
+		writer: w,
+		fr:     http2.NewFramer(w, r),
+	}
+	// Opt-in to Frame reuse API on framer to reduce garbage.
+	// Frames aren't safe to read from after a subsequent call to ReadFrame.
+	f.fr.SetReuseFrames()
+	f.fr.ReadMetaHeaders = hpack.NewDecoder(http2InitHeaderTableSize, nil)
+	return f
+}

vendor/google.golang.org/grpc/transport/log.go

@@ -0,0 +1,50 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// This file contains wrappers for grpclog functions.
+// The transport package only logs to verbose level 2 by default.
+
+package transport
+
+import "google.golang.org/grpc/grpclog"
+
+const logLevel = 2
+
+func infof(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Infof(format, args...)
+	}
+}
+
+func warningf(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Warningf(format, args...)
+	}
+}
+
+func errorf(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Errorf(format, args...)
+	}
+}
+
+func fatalf(format string, args ...interface{}) {
+	if grpclog.V(logLevel) {
+		grpclog.Fatalf(format, args...)
+	}
+}

vendor/google.golang.org/grpc/transport/transport.go

@@ -0,0 +1,683 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package transport defines and implements message oriented communication
+// channel to complete various transactions (e.g., an RPC).  It is meant for
+// grpc-internal usage and is not intended to be imported directly by users.
+package transport // externally used as import "google.golang.org/grpc/transport"
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"sync/atomic"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/keepalive"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/tap"
+)
+
+// recvMsg represents the received msg from the transport. All transport
+// protocol specific info has been removed.
+type recvMsg struct {
+	data []byte
+	// nil: received some data
+	// io.EOF: stream is completed. data is nil.
+	// other non-nil error: transport failure. data is nil.
+	err error
+}
+
+// recvBuffer is an unbounded channel of recvMsg structs.
+// Note recvBuffer differs from controlBuffer only in that recvBuffer
+// holds a channel of only recvMsg structs instead of objects implementing "item" interface.
+// recvBuffer is written to much more often than
+// controlBuffer and using strict recvMsg structs helps avoid allocation in "recvBuffer.put"
+type recvBuffer struct {
+	c       chan recvMsg
+	mu      sync.Mutex
+	backlog []recvMsg
+	err     error
+}
+
+func newRecvBuffer() *recvBuffer {
+	b := &recvBuffer{
+		c: make(chan recvMsg, 1),
+	}
+	return b
+}
+
+func (b *recvBuffer) put(r recvMsg) {
+	b.mu.Lock()
+	if b.err != nil {
+		b.mu.Unlock()
+		// An error had occurred earlier, don't accept more
+		// data or errors.
+		return
+	}
+	b.err = r.err
+	if len(b.backlog) == 0 {
+		select {
+		case b.c <- r:
+			b.mu.Unlock()
+			return
+		default:
+		}
+	}
+	b.backlog = append(b.backlog, r)
+	b.mu.Unlock()
+}
+
+func (b *recvBuffer) load() {
+	b.mu.Lock()
+	if len(b.backlog) > 0 {
+		select {
+		case b.c <- b.backlog[0]:
+			b.backlog[0] = recvMsg{}
+			b.backlog = b.backlog[1:]
+		default:
+		}
+	}
+	b.mu.Unlock()
+}
+
+// get returns the channel that receives a recvMsg in the buffer.
+//
+// Upon receipt of a recvMsg, the caller should call load to send another
+// recvMsg onto the channel if there is any.
+func (b *recvBuffer) get() <-chan recvMsg {
+	return b.c
+}
+
+//
+// recvBufferReader implements io.Reader interface to read the data from
+// recvBuffer.
+type recvBufferReader struct {
+	ctx     context.Context
+	ctxDone <-chan struct{} // cache of ctx.Done() (for performance).
+	recv    *recvBuffer
+	last    []byte // Stores the remaining data in the previous calls.
+	err     error
+}
+
+// Read reads the next len(p) bytes from last. If last is drained, it tries to
+// read additional data from recv. It blocks if there no additional data available
+// in recv. If Read returns any non-nil error, it will continue to return that error.
+func (r *recvBufferReader) Read(p []byte) (n int, err error) {
+	if r.err != nil {
+		return 0, r.err
+	}
+	n, r.err = r.read(p)
+	return n, r.err
+}
+
+func (r *recvBufferReader) read(p []byte) (n int, err error) {
+	if r.last != nil && len(r.last) > 0 {
+		// Read remaining data left in last call.
+		copied := copy(p, r.last)
+		r.last = r.last[copied:]
+		return copied, nil
+	}
+	select {
+	case <-r.ctxDone:
+		return 0, ContextErr(r.ctx.Err())
+	case m := <-r.recv.get():
+		r.recv.load()
+		if m.err != nil {
+			return 0, m.err
+		}
+		copied := copy(p, m.data)
+		r.last = m.data[copied:]
+		return copied, nil
+	}
+}
+
+type streamState uint32
+
+const (
+	streamActive    streamState = iota
+	streamWriteDone             // EndStream sent
+	streamReadDone              // EndStream received
+	streamDone                  // the entire stream is finished.
+)
+
+// Stream represents an RPC in the transport layer.
+type Stream struct {
+	id           uint32
+	st           ServerTransport    // nil for client side Stream
+	ctx          context.Context    // the associated context of the stream
+	cancel       context.CancelFunc // always nil for client side Stream
+	done         chan struct{}      // closed at the end of stream to unblock writers. On the client side.
+	ctxDone      <-chan struct{}    // same as done chan but for server side. Cache of ctx.Done() (for performance)
+	method       string             // the associated RPC method of the stream
+	recvCompress string
+	sendCompress string
+	buf          *recvBuffer
+	trReader     io.Reader
+	fc           *inFlow
+	recvQuota    uint32
+	wq           *writeQuota
+
+	// Callback to state application's intentions to read data. This
+	// is used to adjust flow control, if needed.
+	requestRead func(int)
+
+	headerChan chan struct{} // closed to indicate the end of header metadata.
+	headerDone uint32        // set when headerChan is closed. Used to avoid closing headerChan multiple times.
+	header     metadata.MD   // the received header metadata.
+	trailer    metadata.MD   // the key-value map of trailer metadata.
+
+	headerOk bool // becomes true from the first header is about to send
+	state    streamState
+
+	status *status.Status // the status error received from the server
+
+	bytesReceived uint32 // indicates whether any bytes have been received on this stream
+	unprocessed   uint32 // set if the server sends a refused stream or GOAWAY including this stream
+
+	// contentSubtype is the content-subtype for requests.
+	// this must be lowercase or the behavior is undefined.
+	contentSubtype string
+}
+
+func (s *Stream) swapState(st streamState) streamState {
+	return streamState(atomic.SwapUint32((*uint32)(&s.state), uint32(st)))
+}
+
+func (s *Stream) compareAndSwapState(oldState, newState streamState) bool {
+	return atomic.CompareAndSwapUint32((*uint32)(&s.state), uint32(oldState), uint32(newState))
+}
+
+func (s *Stream) getState() streamState {
+	return streamState(atomic.LoadUint32((*uint32)(&s.state)))
+}
+
+func (s *Stream) waitOnHeader() error {
+	if s.headerChan == nil {
+		// On the server headerChan is always nil since a stream originates
+		// only after having received headers.
+		return nil
+	}
+	select {
+	case <-s.ctx.Done():
+		return ContextErr(s.ctx.Err())
+	case <-s.headerChan:
+		return nil
+	}
+}
+
+// RecvCompress returns the compression algorithm applied to the inbound
+// message. It is empty string if there is no compression applied.
+func (s *Stream) RecvCompress() string {
+	if err := s.waitOnHeader(); err != nil {
+		return ""
+	}
+	return s.recvCompress
+}
+
+// SetSendCompress sets the compression algorithm to the stream.
+func (s *Stream) SetSendCompress(str string) {
+	s.sendCompress = str
+}
+
+// Done returns a chanel which is closed when it receives the final status
+// from the server.
+func (s *Stream) Done() <-chan struct{} {
+	return s.done
+}
+
+// Header acquires the key-value pairs of header metadata once it
+// is available. It blocks until i) the metadata is ready or ii) there is no
+// header metadata or iii) the stream is canceled/expired.
+func (s *Stream) Header() (metadata.MD, error) {
+	err := s.waitOnHeader()
+	// Even if the stream is closed, header is returned if available.
+	select {
+	case <-s.headerChan:
+		if s.header == nil {
+			return nil, nil
+		}
+		return s.header.Copy(), nil
+	default:
+	}
+	return nil, err
+}
+
+// Trailer returns the cached trailer metedata. Note that if it is not called
+// after the entire stream is done, it could return an empty MD. Client
+// side only.
+// It can be safely read only after stream has ended that is either read
+// or write have returned io.EOF.
+func (s *Stream) Trailer() metadata.MD {
+	c := s.trailer.Copy()
+	return c
+}
+
+// ServerTransport returns the underlying ServerTransport for the stream.
+// The client side stream always returns nil.
+func (s *Stream) ServerTransport() ServerTransport {
+	return s.st
+}
+
+// ContentSubtype returns the content-subtype for a request. For example, a
+// content-subtype of "proto" will result in a content-type of
+// "application/grpc+proto". This will always be lowercase.  See
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+func (s *Stream) ContentSubtype() string {
+	return s.contentSubtype
+}
+
+// Context returns the context of the stream.
+func (s *Stream) Context() context.Context {
+	return s.ctx
+}
+
+// Method returns the method for the stream.
+func (s *Stream) Method() string {
+	return s.method
+}
+
+// Status returns the status received from the server.
+// Status can be read safely only after the stream has ended,
+// that is, read or write has returned io.EOF.
+func (s *Stream) Status() *status.Status {
+	return s.status
+}
+
+// SetHeader sets the header metadata. This can be called multiple times.
+// Server side only.
+// This should not be called in parallel to other data writes.
+func (s *Stream) SetHeader(md metadata.MD) error {
+	if md.Len() == 0 {
+		return nil
+	}
+	if s.headerOk || atomic.LoadUint32((*uint32)(&s.state)) == uint32(streamDone) {
+		return ErrIllegalHeaderWrite
+	}
+	s.header = metadata.Join(s.header, md)
+	return nil
+}
+
+// SendHeader sends the given header metadata. The given metadata is
+// combined with any metadata set by previous calls to SetHeader and
+// then written to the transport stream.
+func (s *Stream) SendHeader(md metadata.MD) error {
+	t := s.ServerTransport()
+	return t.WriteHeader(s, md)
+}
+
+// SetTrailer sets the trailer metadata which will be sent with the RPC status
+// by the server. This can be called multiple times. Server side only.
+// This should not be called parallel to other data writes.
+func (s *Stream) SetTrailer(md metadata.MD) error {
+	if md.Len() == 0 {
+		return nil
+	}
+	s.trailer = metadata.Join(s.trailer, md)
+	return nil
+}
+
+func (s *Stream) write(m recvMsg) {
+	s.buf.put(m)
+}
+
+// Read reads all p bytes from the wire for this stream.
+func (s *Stream) Read(p []byte) (n int, err error) {
+	// Don't request a read if there was an error earlier
+	if er := s.trReader.(*transportReader).er; er != nil {
+		return 0, er
+	}
+	s.requestRead(len(p))
+	return io.ReadFull(s.trReader, p)
+}
+
+// tranportReader reads all the data available for this Stream from the transport and
+// passes them into the decoder, which converts them into a gRPC message stream.
+// The error is io.EOF when the stream is done or another non-nil error if
+// the stream broke.
+type transportReader struct {
+	reader io.Reader
+	// The handler to control the window update procedure for both this
+	// particular stream and the associated transport.
+	windowHandler func(int)
+	er            error
+}
+
+func (t *transportReader) Read(p []byte) (n int, err error) {
+	n, err = t.reader.Read(p)
+	if err != nil {
+		t.er = err
+		return
+	}
+	t.windowHandler(n)
+	return
+}
+
+// BytesReceived indicates whether any bytes have been received on this stream.
+func (s *Stream) BytesReceived() bool {
+	return atomic.LoadUint32(&s.bytesReceived) == 1
+}
+
+// Unprocessed indicates whether the server did not process this stream --
+// i.e. it sent a refused stream or GOAWAY including this stream ID.
+func (s *Stream) Unprocessed() bool {
+	return atomic.LoadUint32(&s.unprocessed) == 1
+}
+
+// GoString is implemented by Stream so context.String() won't
+// race when printing %#v.
+func (s *Stream) GoString() string {
+	return fmt.Sprintf("<stream: %p, %v>", s, s.method)
+}
+
+// state of transport
+type transportState int
+
+const (
+	reachable transportState = iota
+	closing
+	draining
+)
+
+// ServerConfig consists of all the configurations to establish a server transport.
+type ServerConfig struct {
+	MaxStreams            uint32
+	AuthInfo              credentials.AuthInfo
+	InTapHandle           tap.ServerInHandle
+	StatsHandler          stats.Handler
+	KeepaliveParams       keepalive.ServerParameters
+	KeepalivePolicy       keepalive.EnforcementPolicy
+	InitialWindowSize     int32
+	InitialConnWindowSize int32
+	WriteBufferSize       int
+	ReadBufferSize        int
+	ChannelzParentID      int64
+}
+
+// NewServerTransport creates a ServerTransport with conn or non-nil error
+// if it fails.
+func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error) {
+	return newHTTP2Server(conn, config)
+}
+
+// ConnectOptions covers all relevant options for communicating with the server.
+type ConnectOptions struct {
+	// UserAgent is the application user agent.
+	UserAgent string
+	// Authority is the :authority pseudo-header to use. This field has no effect if
+	// TransportCredentials is set.
+	Authority string
+	// Dialer specifies how to dial a network address.
+	Dialer func(context.Context, string) (net.Conn, error)
+	// FailOnNonTempDialError specifies if gRPC fails on non-temporary dial errors.
+	FailOnNonTempDialError bool
+	// PerRPCCredentials stores the PerRPCCredentials required to issue RPCs.
+	PerRPCCredentials []credentials.PerRPCCredentials
+	// TransportCredentials stores the Authenticator required to setup a client connection.
+	TransportCredentials credentials.TransportCredentials
+	// KeepaliveParams stores the keepalive parameters.
+	KeepaliveParams keepalive.ClientParameters
+	// StatsHandler stores the handler for stats.
+	StatsHandler stats.Handler
+	// InitialWindowSize sets the initial window size for a stream.
+	InitialWindowSize int32
+	// InitialConnWindowSize sets the initial window size for a connection.
+	InitialConnWindowSize int32
+	// WriteBufferSize sets the size of write buffer which in turn determines how much data can be batched before it's written on the wire.
+	WriteBufferSize int
+	// ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall.
+	ReadBufferSize int
+	// ChannelzParentID sets the addrConn id which initiate the creation of this client transport.
+	ChannelzParentID int64
+}
+
+// TargetInfo contains the information of the target such as network address and metadata.
+type TargetInfo struct {
+	Addr      string
+	Metadata  interface{}
+	Authority string
+}
+
+// NewClientTransport establishes the transport with the required ConnectOptions
+// and returns it to the caller.
+func NewClientTransport(connectCtx, ctx context.Context, target TargetInfo, opts ConnectOptions, onSuccess func()) (ClientTransport, error) {
+	return newHTTP2Client(connectCtx, ctx, target, opts, onSuccess)
+}
+
+// Options provides additional hints and information for message
+// transmission.
+type Options struct {
+	// Last indicates whether this write is the last piece for
+	// this stream.
+	Last bool
+
+	// Delay is a hint to the transport implementation for whether
+	// the data could be buffered for a batching write. The
+	// transport implementation may ignore the hint.
+	Delay bool
+}
+
+// CallHdr carries the information of a particular RPC.
+type CallHdr struct {
+	// Host specifies the peer's host.
+	Host string
+
+	// Method specifies the operation to perform.
+	Method string
+
+	// SendCompress specifies the compression algorithm applied on
+	// outbound message.
+	SendCompress string
+
+	// Creds specifies credentials.PerRPCCredentials for a call.
+	Creds credentials.PerRPCCredentials
+
+	// Flush indicates whether a new stream command should be sent
+	// to the peer without waiting for the first data. This is
+	// only a hint.
+	// If it's true, the transport may modify the flush decision
+	// for performance purposes.
+	// If it's false, new stream will never be flushed.
+	Flush bool
+
+	// ContentSubtype specifies the content-subtype for a request. For example, a
+	// content-subtype of "proto" will result in a content-type of
+	// "application/grpc+proto". The value of ContentSubtype must be all
+	// lowercase, otherwise the behavior is undefined. See
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
+	// for more details.
+	ContentSubtype string
+}
+
+// ClientTransport is the common interface for all gRPC client-side transport
+// implementations.
+type ClientTransport interface {
+	// Close tears down this transport. Once it returns, the transport
+	// should not be accessed any more. The caller must make sure this
+	// is called only once.
+	Close() error
+
+	// GracefulClose starts to tear down the transport. It stops accepting
+	// new RPCs and wait the completion of the pending RPCs.
+	GracefulClose() error
+
+	// Write sends the data for the given stream. A nil stream indicates
+	// the write is to be performed on the transport as a whole.
+	Write(s *Stream, hdr []byte, data []byte, opts *Options) error
+
+	// NewStream creates a Stream for an RPC.
+	NewStream(ctx context.Context, callHdr *CallHdr) (*Stream, error)
+
+	// CloseStream clears the footprint of a stream when the stream is
+	// not needed any more. The err indicates the error incurred when
+	// CloseStream is called. Must be called when a stream is finished
+	// unless the associated transport is closing.
+	CloseStream(stream *Stream, err error)
+
+	// Error returns a channel that is closed when some I/O error
+	// happens. Typically the caller should have a goroutine to monitor
+	// this in order to take action (e.g., close the current transport
+	// and create a new one) in error case. It should not return nil
+	// once the transport is initiated.
+	Error() <-chan struct{}
+
+	// GoAway returns a channel that is closed when ClientTransport
+	// receives the draining signal from the server (e.g., GOAWAY frame in
+	// HTTP/2).
+	GoAway() <-chan struct{}
+
+	// GetGoAwayReason returns the reason why GoAway frame was received.
+	GetGoAwayReason() GoAwayReason
+
+	// IncrMsgSent increments the number of message sent through this transport.
+	IncrMsgSent()
+
+	// IncrMsgRecv increments the number of message received through this transport.
+	IncrMsgRecv()
+}
+
+// ServerTransport is the common interface for all gRPC server-side transport
+// implementations.
+//
+// Methods may be called concurrently from multiple goroutines, but
+// Write methods for a given Stream will be called serially.
+type ServerTransport interface {
+	// HandleStreams receives incoming streams using the given handler.
+	HandleStreams(func(*Stream), func(context.Context, string) context.Context)
+
+	// WriteHeader sends the header metadata for the given stream.
+	// WriteHeader may not be called on all streams.
+	WriteHeader(s *Stream, md metadata.MD) error
+
+	// Write sends the data for the given stream.
+	// Write may not be called on all streams.
+	Write(s *Stream, hdr []byte, data []byte, opts *Options) error
+
+	// WriteStatus sends the status of a stream to the client.  WriteStatus is
+	// the final call made on a stream and always occurs.
+	WriteStatus(s *Stream, st *status.Status) error
+
+	// Close tears down the transport. Once it is called, the transport
+	// should not be accessed any more. All the pending streams and their
+	// handlers will be terminated asynchronously.
+	Close() error
+
+	// RemoteAddr returns the remote network address.
+	RemoteAddr() net.Addr
+
+	// Drain notifies the client this ServerTransport stops accepting new RPCs.
+	Drain()
+
+	// IncrMsgSent increments the number of message sent through this transport.
+	IncrMsgSent()
+
+	// IncrMsgRecv increments the number of message received through this transport.
+	IncrMsgRecv()
+}
+
+// streamErrorf creates an StreamError with the specified error code and description.
+func streamErrorf(c codes.Code, format string, a ...interface{}) StreamError {
+	return StreamError{
+		Code: c,
+		Desc: fmt.Sprintf(format, a...),
+	}
+}
+
+// connectionErrorf creates an ConnectionError with the specified error description.
+func connectionErrorf(temp bool, e error, format string, a ...interface{}) ConnectionError {
+	return ConnectionError{
+		Desc: fmt.Sprintf(format, a...),
+		temp: temp,
+		err:  e,
+	}
+}
+
+// ConnectionError is an error that results in the termination of the
+// entire connection and the retry of all the active streams.
+type ConnectionError struct {
+	Desc string
+	temp bool
+	err  error
+}
+
+func (e ConnectionError) Error() string {
+	return fmt.Sprintf("connection error: desc = %q", e.Desc)
+}
+
+// Temporary indicates if this connection error is temporary or fatal.
+func (e ConnectionError) Temporary() bool {
+	return e.temp
+}
+
+// Origin returns the original error of this connection error.
+func (e ConnectionError) Origin() error {
+	// Never return nil error here.
+	// If the original error is nil, return itself.
+	if e.err == nil {
+		return e
+	}
+	return e.err
+}
+
+var (
+	// ErrConnClosing indicates that the transport is closing.
+	ErrConnClosing = connectionErrorf(true, nil, "transport is closing")
+	// errStreamDrain indicates that the stream is rejected because the
+	// connection is draining. This could be caused by goaway or balancer
+	// removing the address.
+	errStreamDrain = streamErrorf(codes.Unavailable, "the connection is draining")
+	// errStreamDone is returned from write at the client side to indiacte application
+	// layer of an error.
+	errStreamDone = errors.New("the stream is done")
+	// StatusGoAway indicates that the server sent a GOAWAY that included this
+	// stream's ID in unprocessed RPCs.
+	statusGoAway = status.New(codes.Unavailable, "the stream is rejected because server is draining the connection")
+)
+
+// TODO: See if we can replace StreamError with status package errors.
+
+// StreamError is an error that only affects one stream within a connection.
+type StreamError struct {
+	Code codes.Code
+	Desc string
+}
+
+func (e StreamError) Error() string {
+	return fmt.Sprintf("stream error: code = %s desc = %q", e.Code, e.Desc)
+}
+
+// GoAwayReason contains the reason for the GoAway frame received.
+type GoAwayReason uint8
+
+const (
+	// GoAwayInvalid indicates that no GoAway frame is received.
+	GoAwayInvalid GoAwayReason = 0
+	// GoAwayNoReason is the default value when GoAway frame is received.
+	GoAwayNoReason GoAwayReason = 1
+	// GoAwayTooManyPings indicates that a GoAway frame with
+	// ErrCodeEnhanceYourCalm was received and that the debug data said
+	// "too_many_pings".
+	GoAwayTooManyPings GoAwayReason = 2
+)

vendor/google.golang.org/grpc/vet.sh

@@ -0,0 +1,93 @@
+#!/bin/bash
+
+if [[ `uname -a` = *"Darwin"* ]]; then
+  echo "It seems you are running on Mac. This script does not work on Mac. See https://github.com/grpc/grpc-go/issues/2047"
+  exit 1
+fi
+
+set -ex  # Exit on error; debugging enabled.
+set -o pipefail  # Fail a pipe if any sub-command fails.
+
+die() {
+  echo "$@" >&2
+  exit 1
+}
+
+PATH="$GOPATH/bin:$GOROOT/bin:$PATH"
+
+# Check proto in manual runs or cron runs.
+if [[ "$TRAVIS" != "true" || "$TRAVIS_EVENT_TYPE" = "cron" ]]; then
+  check_proto="true"
+fi
+
+if [ "$1" = "-install" ]; then
+  go get -d \
+    google.golang.org/grpc/...
+  go get -u \
+    github.com/golang/lint/golint \
+    golang.org/x/tools/cmd/goimports \
+    honnef.co/go/tools/cmd/staticcheck \
+    github.com/client9/misspell/cmd/misspell \
+    github.com/golang/protobuf/protoc-gen-go
+  if [[ "$check_proto" = "true" ]]; then
+    if [[ "$TRAVIS" = "true" ]]; then
+      PROTOBUF_VERSION=3.3.0
+      PROTOC_FILENAME=protoc-${PROTOBUF_VERSION}-linux-x86_64.zip
+      pushd /home/travis
+      wget https://github.com/google/protobuf/releases/download/v${PROTOBUF_VERSION}/${PROTOC_FILENAME}
+      unzip ${PROTOC_FILENAME}
+      bin/protoc --version
+      popd
+    elif ! which protoc > /dev/null; then
+      die "Please install protoc into your path"
+    fi
+  fi
+  exit 0
+elif [[ "$#" -ne 0 ]]; then
+  die "Unknown argument(s): $*"
+fi
+
+# TODO: Remove this check and the mangling below once "context" is imported
+# directly.
+if git status --porcelain | read; then
+  die "Uncommitted or untracked files found; commit changes first"
+fi
+
+git ls-files "*.go" | xargs grep -L "\(Copyright [0-9]\{4,\} gRPC authors\)\|DO NOT EDIT" 2>&1 | tee /dev/stderr | (! read)
+git ls-files "*.go" | xargs grep -l "\"unsafe\"" 2>&1 | (! grep -v '_test.go') | tee /dev/stderr | (! read)
+gofmt -s -d -l . 2>&1 | tee /dev/stderr | (! read)
+goimports -l . 2>&1 | tee /dev/stderr | (! read)
+golint ./... 2>&1 | (grep -vE "(_mock|\.pb)\.go:" || true) | tee /dev/stderr | (! read)
+
+# Undo any edits made by this script.
+cleanup() {
+  git reset --hard HEAD
+}
+trap cleanup EXIT
+
+# Rewrite golang.org/x/net/context -> context imports (see grpc/grpc-go#1484).
+# TODO: Remove this mangling once "context" is imported directly (grpc/grpc-go#711).
+git ls-files "*.go" | xargs sed -i 's:"golang.org/x/net/context":"context":'
+set +o pipefail
+# TODO: Stop filtering pb.go files once golang/protobuf#214 is fixed.
+go tool vet -all . 2>&1 | grep -vE '(clientconn|transport\/transport_test).go:.*cancel (function|var)' | grep -vF '.pb.go:' | tee /dev/stderr | (! read)
+set -o pipefail
+git reset --hard HEAD
+
+if [[ "$check_proto" = "true" ]]; then
+  PATH="/home/travis/bin:$PATH" make proto && \
+    git status --porcelain 2>&1 | (! read) || \
+    (git status; git --no-pager diff; exit 1)
+fi
+
+# TODO(menghanl): fix errors in transport_test.
+staticcheck -ignore '
+google.golang.org/grpc/transport/transport_test.go:SA2002
+google.golang.org/grpc/benchmark/benchmain/main.go:SA1019
+google.golang.org/grpc/stats/stats_test.go:SA1019
+google.golang.org/grpc/test/end2end_test.go:SA1019
+google.golang.org/grpc/balancer_test.go:SA1019
+google.golang.org/grpc/balancer.go:SA1019
+google.golang.org/grpc/clientconn_test.go:SA1019
+' ./...
+misspell -error .