Files
nats-server/server/jetstream_chaos_kv_test.go
2022-08-22 18:36:15 -07:00

457 lines
13 KiB
Go

// Copyright 2022 The NATS 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:build js_chaos_tests
// +build js_chaos_tests
package server
import (
"fmt"
"math/rand"
"strings"
"sync"
"testing"
"time"
"github.com/nats-io/nats.go"
)
const (
chaosKvTestsClusterName = "KV_CHAOS_TEST"
chaosKvTestsBucketName = "KV_CHAOS_TEST_BUCKET"
chaosKvTestsSubject = "foo"
chaosKvTestsDebug = false
)
// Creates KV store (a.k.a. bucket).
func createBucketForKvChaosTest(t *testing.T, c *cluster, replicas int) {
t.Helper()
pubNc, pubJs := jsClientConnectCluster(t, c)
defer pubNc.Close()
config := nats.KeyValueConfig{
Bucket: chaosKvTestsBucketName,
Replicas: replicas,
Description: "Test bucket",
}
kvs, err := pubJs.CreateKeyValue(&config)
if err != nil {
t.Fatalf("Error creating bucket: %v", err)
}
status, err := kvs.Status()
if err != nil {
t.Fatalf("Error retrieving bucket status: %v", err)
}
t.Logf("Bucket created: %s", status.Bucket())
}
// Single client performs a set of PUT on a single key.
// If PUT is successful, perform a GET on the same key.
// If GET is successful, ensure key revision and value match the most recent successful write.
func TestJetStreamChaosKvPutGet(t *testing.T) {
const numOps = 100_000
const clusterSize = 3
const replicas = 3
const key = "key"
const staleReadsOk = true // Set to false to check for violations of 'read committed' consistency
c := createJetStreamClusterExplicit(t, chaosKvTestsClusterName, clusterSize)
defer c.shutdown()
createBucketForKvChaosTest(t, c, replicas)
chaos := createClusterChaosMonkeyController(
t,
c,
&clusterBouncerChaosMonkey{
minDowntime: 0 * time.Second,
maxDowntime: 2 * time.Second,
minDownServers: clusterSize, // Whole cluster outage
maxDownServers: clusterSize,
pause: 1 * time.Second,
},
)
nc, js := jsClientConnectCluster(t, c)
defer nc.Close()
// Create KV bucket
kv, err := js.KeyValue(chaosKvTestsBucketName)
if err != nil {
t.Fatalf("Failed to get KV store: %v", err)
}
// Initialize the only key
firstRevision, err := kv.Create(key, []byte("INITIAL VALUE"))
if err != nil {
t.Fatalf("Failed to create key: %v", err)
} else if firstRevision != 1 {
t.Fatalf("Unexpected revision: %d", firstRevision)
}
// Start chaos
chaos.start()
defer chaos.stop()
staleReadsCount := uint64(0)
successCount := uint64(0)
previousRevision := firstRevision
putGetLoop:
for i := 1; i <= numOps; i++ {
if i%1000 == 0 {
t.Logf("Completed %d/%d PUT+GET operations", i, numOps)
}
// PUT a value
putValue := fmt.Sprintf("value-%d", i)
putRevision, err := kv.Put(key, []byte(putValue))
if err != nil {
t.Logf("PUT error: %v", err)
continue putGetLoop
}
// Check revision is monotonically increasing
if putRevision <= previousRevision {
t.Fatalf("PUT produced revision %d which is not greater than the previous successful PUT revision: %d", putRevision, previousRevision)
}
previousRevision = putRevision
// If PUT was successful, GET the same
kve, err := kv.Get(key)
if err == nats.ErrKeyNotFound {
t.Fatalf("GET key not found, but key does exists (last PUT revision: %d)", putRevision)
} else if err != nil {
t.Logf("GET error: %v", err)
continue putGetLoop
}
getValue := string(kve.Value())
getRevision := kve.Revision()
if putRevision > getRevision {
// Stale read, violates 'read committed' consistency criteria
if !staleReadsOk {
t.Fatalf("PUT value %s (rev: %d) then read value %s (rev: %d)", putValue, putRevision, getValue, getRevision)
} else {
staleReadsCount += 1
}
} else if putRevision < getRevision {
// Returned revision is higher than any ever written, this should never happen
t.Fatalf("GET returned revision %d, but most recent expected revision is %d", getRevision, putRevision)
} else if putValue != getValue {
// Returned revision matches latest, but values do not, this should never happen
t.Fatalf("GET returned revision %d with value %s, but value %s was just committed for that same revision", getRevision, getValue, putValue)
} else {
// Get returned the latest revision/value
successCount += 1
if chaosKvTestsDebug {
t.Logf("PUT+GET %s=%s (rev: %d)", key, putValue, putRevision)
}
}
}
t.Logf("Completed %d PUT+GET cycles of which %d successful, %d GETs returned a stale value", numOps, successCount, staleReadsCount)
}
// A variant TestJetStreamChaosKvPutGet where PUT is retried until successful, and GET is retried until it returns the latest known key revision.
// This validates than a confirmed PUT value is never lost, and becomes eventually visible.
func TestJetStreamChaosKvPutGetWithRetries(t *testing.T) {
const numOps = 10_000
const maxRetries = 20
const retryDelay = 100 * time.Millisecond
const clusterSize = 3
const replicas = 3
const key = "key"
c := createJetStreamClusterExplicit(t, chaosKvTestsClusterName, clusterSize)
defer c.shutdown()
createBucketForKvChaosTest(t, c, replicas)
chaos := createClusterChaosMonkeyController(
t,
c,
&clusterBouncerChaosMonkey{
minDowntime: 0 * time.Second,
maxDowntime: 2 * time.Second,
minDownServers: clusterSize, // Whole cluster outage
maxDownServers: clusterSize,
pause: 1 * time.Second,
},
)
nc, js := jsClientConnectCluster(t, c)
defer nc.Close()
kv, err := js.KeyValue(chaosKvTestsBucketName)
if err != nil {
t.Fatalf("Failed to get KV store: %v", err)
}
// Initialize key value
firstRevision, err := kv.Create(key, []byte("INITIAL VALUE"))
if err != nil {
t.Fatalf("Failed to create key: %v", err)
} else if firstRevision != 1 {
t.Fatalf("Unexpected revision: %d", firstRevision)
}
// Start chaos
chaos.start()
defer chaos.stop()
staleReadCount := 0
previousRevision := firstRevision
putGetLoop:
for i := 1; i <= numOps; i++ {
if i%1000 == 0 {
t.Logf("Completed %d/%d PUT+GET operations", i, numOps)
}
putValue := fmt.Sprintf("value-%d", i)
putRevision := uint64(0)
// Put new value for key, retry until successful or out of retries
putRetryLoop:
for r := 0; r <= maxRetries; r++ {
var putErr error
putRevision, putErr = kv.Put(key, []byte(putValue))
if putErr == nil {
break putRetryLoop
} else if r == maxRetries {
t.Fatalf("Failed to PUT (retried %d times): %v", maxRetries, putErr)
} else {
if chaosKvTestsDebug {
t.Logf("PUT error: %v", putErr)
}
time.Sleep(retryDelay)
}
}
// Ensure key version is monotonically increasing
if putRevision <= previousRevision {
t.Fatalf("Latest PUT created revision %d which is not greater than the previous revision: %d", putRevision, previousRevision)
}
previousRevision = putRevision
// Read value for key, retry until successful, and validate corresponding version and value
getRetryLoop:
for r := 0; r <= maxRetries; r++ {
var getErr error
kve, getErr := kv.Get(key)
if getErr != nil && r == maxRetries {
t.Fatalf("Failed to GET (retried %d times): %v", maxRetries, getErr)
} else if getErr != nil {
if chaosKvTestsDebug {
t.Logf("GET error: %v", getErr)
}
time.Sleep(retryDelay)
continue getRetryLoop
}
// GET successful, check revision and value
getValue := string(kve.Value())
getRevision := kve.Revision()
if putRevision == getRevision {
if putValue != getValue {
t.Fatalf("Unexpected value %s for revision %d, expected: %s", getValue, getRevision, putValue)
}
if chaosKvTestsDebug {
t.Logf("PUT+GET %s=%s (rev: %d) (retry: %d)", key, putValue, putRevision, r)
}
continue putGetLoop
} else if getRevision > putRevision {
t.Fatalf("GET returned version that should not exist yet: %d, last created: %d", getRevision, putRevision)
} else { // get revision < put revision
staleReadCount += 1
if chaosKvTestsDebug {
t.Logf("GET got stale value: %v (rev: %d, latest: %d)", getValue, getRevision, putRevision)
}
time.Sleep(retryDelay)
continue getRetryLoop
}
}
}
t.Logf("Client completed %d PUT+GET cycles, %d GET returned a stale value", numOps, staleReadCount)
}
// Multiple clients updating a finite set of keys with CAS semantics.
// TODO check that revision is never lower than last one seen
// TODO check that KeyNotFound is never returned, as keys are initialized beforehand
func TestJetStreamChaosKvCAS(t *testing.T) {
const numOps = 10_000
const maxRetries = 50
const retryDelay = 300 * time.Millisecond
const clusterSize = 3
const replicas = 3
const numKeys = 15
const numClients = 5
c := createJetStreamClusterExplicit(t, chaosKvTestsClusterName, clusterSize)
defer c.shutdown()
createBucketForKvChaosTest(t, c, replicas)
chaos := createClusterChaosMonkeyController(
t,
c,
&clusterBouncerChaosMonkey{
minDowntime: 0 * time.Second,
maxDowntime: 2 * time.Second,
minDownServers: clusterSize, // Whole cluster outage
maxDownServers: clusterSize,
pause: 1 * time.Second,
},
)
nc, js := jsClientConnectCluster(t, c)
defer nc.Close()
// Create bucket
kv, err := js.KeyValue(chaosKvTestsBucketName)
if err != nil {
t.Fatalf("Failed to get KV store: %v", err)
}
// Create set of keys and initialize them with dummy value
keys := make([]string, numKeys)
for k := 0; k < numKeys; k++ {
key := fmt.Sprintf("key-%d", k)
keys[k] = key
_, err := kv.Create(key, []byte("Initial value"))
if err != nil {
t.Fatalf("Failed to create key: %v", err)
}
}
wgStart := sync.WaitGroup{}
wgComplete := sync.WaitGroup{}
// Client routine
client := func(clientId int, kv nats.KeyValue) {
defer wgComplete.Done()
rng := rand.New(rand.NewSource(int64(clientId)))
successfulUpdates := 0
casRejectUpdates := 0
otherUpdateErrors := 0
// Map to track last known revision for each of the keys
knownRevisions := map[string]uint64{}
for _, key := range keys {
knownRevisions[key] = 0
}
// Wait for all clients to reach this point before proceeding
wgStart.Done()
wgStart.Wait()
for i := 1; i <= numOps; i++ {
if i%1000 == 0 {
t.Logf("Client %d completed %d/%d updates", clientId, i, numOps)
}
// Pick random key from the set
key := keys[rng.Intn(numKeys)]
// Prepare unique value to be written
value := fmt.Sprintf("client: %d operation %d", clientId, i)
// Try to update a key with CAS
newRevision, updateErr := kv.Update(key, []byte(value), knownRevisions[key])
if updateErr == nil {
// Update successful
knownRevisions[key] = newRevision
successfulUpdates += 1
if chaosKvTestsDebug {
t.Logf("Client %d updated key %s, new revision: %d", clientId, key, newRevision)
}
} else if updateErr != nil && strings.Contains(fmt.Sprint(updateErr), "wrong last sequence") {
// CAS rejected update, learn current revision for this key
casRejectUpdates += 1
for r := 0; r <= maxRetries; r++ {
kve, getErr := kv.Get(key)
if getErr == nil {
currentRevision := kve.Revision()
if currentRevision < knownRevisions[key] {
// Revision number moved backward, this should never happen
t.Fatalf("Current revision for key %s is %d, which is lower than the last known revision %d", key, currentRevision, knownRevisions[key])
}
knownRevisions[key] = currentRevision
if chaosKvTestsDebug {
t.Logf("Client %d learn key %s revision: %d", clientId, key, currentRevision)
}
break
} else if r == maxRetries {
t.Fatalf("Failed to GET (retried %d times): %v", maxRetries, getErr)
} else {
time.Sleep(retryDelay)
}
}
} else {
// Other update error
otherUpdateErrors += 1
if chaosKvTestsDebug {
t.Logf("Client %d update error for key %s: %v", clientId, key, updateErr)
}
time.Sleep(retryDelay)
}
}
t.Logf("Client %d done, %d kv updates, %d CAS rejected, %d other errors", clientId, successfulUpdates, casRejectUpdates, otherUpdateErrors)
}
// Launch all clients
for i := 1; i <= numClients; i++ {
cNc, cJs := jsClientConnectCluster(t, c)
defer cNc.Close()
cKv, err := cJs.KeyValue(chaosKvTestsBucketName)
if err != nil {
t.Fatalf("Failed to get KV store: %v", err)
}
wgStart.Add(1)
wgComplete.Add(1)
go client(i, cKv)
}
// Wait for clients to be connected and ready
wgStart.Wait()
// Start failures
chaos.start()
defer chaos.stop()
// Wait for all clients to be done
wgComplete.Wait()
}