Updated README

.gitignore

@@ -3,5 +3,6 @@
 
 /coverage.txt
 /bitcask
+/bitcaskd
 /tmp
 /dist

.goreleaser.yml

@@ -1,10 +1,18 @@
 builds:
   - 
+    binary: bitcask
     main: ./cmd/bitcask
     flags: -tags "static_build"
     ldflags: -w -X .Version={{.Version}} -X .Commit={{.Commit}}
     env:
       - CGO_ENABLED=0
+  - 
+    binary: bitcaskd
+    main: ./cmd/bitcaskd
+    flags: -tags "static_build"
+    ldflags: -w -X .Version={{.Version}} -X .Commit={{.Commit}}
+    env:
+      - CGO_ENABLED=0
 sign:
   artifacts: checksum
 archive:

Makefile

@@ -1,18 +1,24 @@
 .PHONY: dev build generate install image release profile bench test clean
 
 CGO_ENABLED=0
+VERSION=$(shell git describe --abbrev=0 --tags)
 COMMIT=$(shell git rev-parse --short HEAD)
 
 all: dev
 
 dev: build
 	@./bitcask --version
+	@./bitcaskd --version
 
 build: clean generate
 	@go build \
 		-tags "netgo static_build" -installsuffix netgo \
-		-ldflags "-w -X $(shell go list)/.Commit=$(COMMIT)" \
+		-ldflags "-w -X $(shell go list).Version=$(VERSION) -X $(shell go list).Commit=$(COMMIT)" \
 		./cmd/bitcask/...
+	@go build \
+		-tags "netgo static_build" -installsuffix netgo \
+		-ldflags "-w -X $(shell go list).Version=$(VERSION) -X $(shell go list).Commit=$(COMMIT)" \
+		./cmd/bitcaskd/...
 
 generate:
 	@go generate $(shell go list)/...

README.md

@@ -12,6 +12,9 @@ A Bitcask (LSM+WAL) Key/Value Store written in Go.
 
 * Embeddable
 * Builtin CLI
+* Predictable read/write performance
+* Low latecny
+* High throughput (See: [Performance](README.md#Performance)
 
 ## Install
 
@@ -54,6 +57,38 @@ $ bitcask -p /tmp/db get Hello
 World
 ```
 
+## Usage (server)
+
+There is also a builtin very  simple Redis-compatible server called `bitcaskd`:
+
+```#!bash
+$ ./bitcaskd ./tmp
+INFO[0000] starting bitcaskd v0.0.7@146f777              bind=":6379" path=./tmp
+```
+
+Example session:
+
+```
+$ telnet localhost 6379
+Trying ::1...
+Connected to localhost.
+Escape character is '^]'.
+SET foo bar
++OK
+GET foo
+$3
+bar
+DEL foo
+:1
+GET foo
+$-1
+PING
++PONG
+QUIT
++OK
+Connection closed by foreign host.
+```
+
 ## Performance
 
 Benchmarks run on a 11" Macbook with a 1.4Ghz Intel Core i7:
@@ -65,8 +100,7 @@ BenchmarkGet-4   	  300000	      5065 ns/op	     144 B/op	       4 allocs/op
 BenchmarkPut-4   	  100000	     14640 ns/op	     699 B/op	       7 allocs/op
 ```
 
-* ~30,000 reads/sec for non-active data
+* ~180,000 reads/sec
-* ~180,000 reads/sec for active data
 * ~60,000 writes/sec
 
 ## License

bitcask.go

@@ -11,6 +11,8 @@ import (
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/gofrs/flock"
 )
 
 const (
@@ -18,18 +20,29 @@ const (
 )
 
 var (
-	ErrKeyNotFound = errors.New("error: key not found")
+	ErrKeyNotFound       = errors.New("error: key not found")
+	ErrCannotAcquireLock = errors.New("error: cannot acquire lock")
 )
 
 type Bitcask struct {
-	path   string
+	*flock.Flock
-	curr   *Datafile
+
-	keydir *Keydir
+	path      string
+	curr      *Datafile
+	keydir    *Keydir
+	datafiles []*Datafile
 
 	maxDatafileSize int64
 }
 
 func (b *Bitcask) Close() error {
+	defer func() {
+		b.Flock.Unlock()
+	}()
+
+	for _, df := range b.datafiles {
+		df.Close()
+	}
 	return b.curr.Close()
 }
 
@@ -38,26 +51,17 @@ func (b *Bitcask) Sync() error {
 }
 
 func (b *Bitcask) Get(key string) ([]byte, error) {
+	var df *Datafile
+
 	item, ok := b.keydir.Get(key)
 	if !ok {
 		return nil, ErrKeyNotFound
 	}
 
-	var (
-		df  *Datafile
-		err error
-	)
-
-	// Optimization
 	if item.FileID == b.curr.id {
 		df = b.curr
 	} else {
-		// TODO: Pre-open non-active Datafiles and cache the file pointers?
+		df = b.datafiles[item.FileID]
-		df, err = NewDatafile(b.path, item.FileID, true)
-		if err != nil {
-			return nil, err
-		}
-		defer df.Close()
 	}
 
 	e, err := df.ReadAt(item.Index)
@@ -111,6 +115,9 @@ func (b *Bitcask) put(key string, value []byte) (int64, error) {
 			return -1, err
 		}
 
+		df, err := NewDatafile(b.path, b.curr.id, true)
+		b.datafiles = append(b.datafiles, df)
+
 		id := b.curr.id + 1
 		curr, err := NewDatafile(b.path, id, false)
 		if err != nil {
@@ -128,7 +135,7 @@ func (b *Bitcask) setMaxDatafileSize(size int64) error {
 	return nil
 }
 
-func MaxDatafileSize(size int64) func(*Bitcask) error {
+func WithMaxDatafileSize(size int64) func(*Bitcask) error {
 	return func(b *Bitcask) error {
 		return b.setMaxDatafileSize(size)
 	}
@@ -277,8 +284,6 @@ func Open(path string, options ...func(*Bitcask) error) (*Bitcask, error) {
 		return nil, err
 	}
 
-	keydir := NewKeydir()
-
 	fns, err := getDatafiles(path)
 	if err != nil {
 		return nil, err
@@ -289,7 +294,16 @@ func Open(path string, options ...func(*Bitcask) error) (*Bitcask, error) {
 		return nil, err
 	}
 
+	keydir := NewKeydir()
+	var datafiles []*Datafile
+
 	for i, fn := range fns {
+		df, err := NewDatafile(path, ids[i], true)
+		if err != nil {
+			return nil, err
+		}
+		datafiles = append(datafiles, df)
+
 		if filepath.Ext(fn) == ".hint" {
 			f, err := os.Open(filepath.Join(path, fn))
 			if err != nil {
@@ -307,11 +321,6 @@ func Open(path string, options ...func(*Bitcask) error) (*Bitcask, error) {
 				keydir.Add(key, item.FileID, item.Index, item.Timestamp)
 			}
 		} else {
-			df, err := NewDatafile(path, ids[i], true)
-			if err != nil {
-				return nil, err
-			}
-
 			for {
 				e, err := df.Read()
 				if err != nil {
@@ -336,15 +345,18 @@ func Open(path string, options ...func(*Bitcask) error) (*Bitcask, error) {
 	if len(ids) > 0 {
 		id = ids[(len(ids) - 1)]
 	}
+
 	curr, err := NewDatafile(path, id, false)
 	if err != nil {
 		return nil, err
 	}
 
 	bitcask := &Bitcask{
-		path:   path,
+		Flock:     flock.New(filepath.Join(path, "lock")),
-		curr:   curr,
+		path:      path,
-		keydir: keydir,
+		curr:      curr,
+		keydir:    keydir,
+		datafiles: datafiles,
 
 		maxDatafileSize: DefaultMaxDatafileSize,
 	}
@@ -356,5 +368,14 @@ func Open(path string, options ...func(*Bitcask) error) (*Bitcask, error) {
 		}
 	}
 
+	locked, err := bitcask.Flock.TryLock()
+	if err != nil {
+		return nil, err
+	}
+
+	if !locked {
+		return nil, ErrCannotAcquireLock
+	}
+
 	return bitcask, nil
 }

bitcask_test.go

@@ -198,6 +198,21 @@ func TestMerge(t *testing.T) {
 	})
 }
 
+func TestLocking(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	db, err := Open(testdir)
+	assert.NoError(err)
+	defer db.Close()
+
+	_, err = Open(testdir)
+	assert.Error(err)
+	assert.Equal("error: cannot acquire lock", err.Error())
+}
+
 func BenchmarkGet(b *testing.B) {
 	testdir, err := ioutil.TempDir("", "bitcask")
 	if err != nil {

cmd/bitcaskd/main.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+	flag "github.com/spf13/pflag"
+	"github.com/tidwall/redcon"
+
+	"github.com/prologic/bitcask"
+)
+
+var (
+	bind            string
+	debug           bool
+	version         bool
+	maxDatafileSize int64
+)
+
+func init() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage: %s [options] <path>\n", os.Args[0])
+		flag.PrintDefaults()
+	}
+
+	flag.BoolVarP(&version, "version", "v", false, "display version information")
+	flag.BoolVarP(&debug, "debug", "d", false, "enable debug logging")
+
+	flag.StringVarP(&bind, "bind", "b", ":6379", "interface and port to bind to")
+
+	flag.Int64Var(&maxDatafileSize, "max-datafile-size", 1<<20, "maximum datafile size in bytes")
+}
+
+func main() {
+	flag.Parse()
+
+	if debug {
+		log.SetLevel(log.DebugLevel)
+	} else {
+		log.SetLevel(log.InfoLevel)
+	}
+
+	if version {
+		fmt.Printf("bitcaskd version %s", bitcask.FullVersion())
+		os.Exit(0)
+	}
+
+	if len(flag.Args()) < 1 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	path := flag.Arg(0)
+
+	db, err := bitcask.Open(path, bitcask.WithMaxDatafileSize(maxDatafileSize))
+	if err != nil {
+		log.WithError(err).WithField("path", path).Error("error opening database")
+		os.Exit(1)
+	}
+
+	log.WithField("bind", bind).WithField("path", path).Infof("starting bitcaskd v%s", bitcask.FullVersion())
+
+	err = redcon.ListenAndServe(bind,
+		func(conn redcon.Conn, cmd redcon.Command) {
+			switch strings.ToLower(string(cmd.Args[0])) {
+			case "ping":
+				conn.WriteString("PONG")
+			case "quit":
+				conn.WriteString("OK")
+				conn.Close()
+			case "set":
+				if len(cmd.Args) != 3 {
+					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+					return
+				}
+				key := string(cmd.Args[1])
+				value := cmd.Args[2]
+				err = db.Put(key, value)
+				if err != nil {
+					conn.WriteString(fmt.Sprintf("ERR: %s", err))
+				} else {
+					conn.WriteString("OK")
+				}
+			case "get":
+				if len(cmd.Args) != 2 {
+					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+					return
+				}
+				key := string(cmd.Args[1])
+				value, err := db.Get(key)
+				if err != nil {
+					conn.WriteNull()
+				} else {
+					conn.WriteBulk(value)
+				}
+			case "del":
+				if len(cmd.Args) != 2 {
+					conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
+					return
+				}
+				key := string(cmd.Args[1])
+				err := db.Delete(key)
+				if err != nil {
+					conn.WriteInt(0)
+				} else {
+					conn.WriteInt(1)
+				}
+			default:
+				conn.WriteError("ERR unknown command '" + string(cmd.Args[0]) + "'")
+			}
+		},
+		func(conn redcon.Conn) bool {
+			return true
+		},
+		func(conn redcon.Conn, err error) {
+		},
+	)
+	if err != nil {
+		log.WithError(err).Fatal("oops")
+	}
+}

go.mod

@@ -1,6 +1,7 @@
 module github.com/prologic/bitcask
 
 require (
+	github.com/gofrs/flock v0.7.1
 	github.com/gogo/protobuf v1.2.1
 	github.com/golang/protobuf v1.2.0
 	github.com/gorilla/websocket v1.4.0 // indirect
@@ -11,7 +12,9 @@ require (
 	github.com/prometheus/client_golang v0.9.2 // indirect
 	github.com/sirupsen/logrus v1.3.0
 	github.com/spf13/cobra v0.0.3
+	github.com/spf13/pflag v1.0.3
 	github.com/spf13/viper v1.3.1
 	github.com/stretchr/testify v1.3.0
+	github.com/tidwall/redcon v0.9.0
 	gopkg.in/vmihailenco/msgpack.v2 v2.9.1
 )

go.sum

@@ -10,6 +10,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/gofrs/flock v0.7.1 h1:DP+LD/t0njgoPBvT5MJLeliUIVQR03hiKR6vezdwHlc=
+github.com/gofrs/flock v0.7.1/go.mod h1:F1TvTiK9OcQqauNUHlbJvyl9Qa1QvF/gOUDKA14jxHU=
 github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
@@ -65,6 +67,8 @@ github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/tidwall/redcon v0.9.0 h1:tiT9DLAoohsdNaFg9Si5dRsv9+FjvZYnhMOEtSFwBqA=
+github.com/tidwall/redcon v0.9.0/go.mod h1:bdYBm4rlcWpst2XMwKVzWDF9CoUxEbUmM7CQrKeOZas=
 github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
 github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=