[8.15](backport #40572) [libbeat] Stop publisher properly

CHANGELOG.next.asciidoc

@@ -76,6 +76,8 @@ https:/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Lower logging level to debug when attempting to configure beats with unknown fields from autodiscovered events/environments {pull}[37816][37816]
 - Set timeout of 1 minute for FQDN requests {pull}37756[37756]
 - Update Go version to 1.22.6. {pull}40528[40528]
+- Aborts all active connections for Elasticsearch output. {pull}40572[40572]
+- Closes beat Publisher on beat stop and by the Agent manager. {pull}40572[40572]
 
 *Auditbeat*
 

libbeat/cmd/instance/beat.go

@@ -35,6 +35,7 @@ import (
  "runtime/debug"
  "strconv"
  "strings"
+ "sync"
  "time"
 
  "github.com/gofrs/uuid"
@@ -386,6 +387,10 @@ func (b *Beat) createBeater(bt beat.Creator) (beat.Beater, error) {
  }
  outputFactory := b.makeOutputFactory(b.Config.Output)
  settings := pipeline.Settings{
+ // Since now publisher is closed on Stop, we want to give some
+ // time to ack any pending events by default to avoid
+ // changing on stop behavior too much.
+ WaitClose: time.Second,
  Processors: b.processors,
  InputQueueSize: b.InputQueueSize,
  }
@@ -396,10 +401,6 @@ func (b *Beat) createBeater(bt beat.Creator) (beat.Beater, error) {
 
  reload.RegisterV2.MustRegisterOutput(b.makeOutputReloader(publisher.OutputReloader()))
 
- // TODO: some beats race on shutdown with publisher.Stop -> do not call Stop yet,
- // but refine publisher to disconnect clients on stop automatically
- // defer pipeline.Close()
-
  b.Publisher = publisher
  beater, err := bt(&b.Beat, sub)
  if err != nil {
@@ -512,22 +513,32 @@ func (b *Beat) launch(settings Settings, bt beat.Creator) error {
  }
 
  ctx, cancel := context.WithCancel(context.Background())
+
+ // stopBeat must be idempotent since it will be called both from a signal and by the manager.
+ // Since publisher.Close is not safe to be called more than once this is necessary.
+ var once sync.Once
  stopBeat := func() {
- b.Instrumentation.Tracer().Close()
- beater.Stop()
+ once.Do(func() {
+ b.Instrumentation.Tracer().Close()
+ // If the publisher has a Close() method, call it before stopping the beater.
+ if c, ok := b.Publisher.(io.Closer); ok {
+ c.Close()
+ }
+ beater.Stop()
+ })
  }
  svc.HandleSignals(stopBeat, cancel)
 
+ // Allow the manager to stop a currently running beats out of bound.
+ b.Manager.SetStopCallback(stopBeat)
+
  err = b.loadDashboards(ctx, false)
  if err != nil {
  return err
  }
 
  logp.Info("%s start running.", b.Info.Beat)
 
- // Allow the manager to stop a currently running beats out of bound.
- b.Manager.SetStopCallback(beater.Stop)
-
  err = beater.Run(&b.Beat)
  if b.shouldReexec {
  if err := b.reexec(); err != nil {

libbeat/esleg/eslegclient/connection.go

@@ -19,6 +19,7 @@ package eslegclient
 
 import (
  "bytes"
+ "context"
  "encoding/base64"
  "encoding/json"
  "fmt"
@@ -62,6 +63,11 @@ type Connection struct {
  responseBuffer *bytes.Buffer
 
  isServerless bool
+
+ // requests will share the same cancellable context
+ // so they can be aborted on Close()
+ reqsContext context.Context
+ cancelReqs func()
 }
 
 // ConnectionSettings are the settings needed for a Connection
@@ -178,12 +184,15 @@ func NewConnection(s ConnectionSettings) (*Connection, error) {
  logger.Info("kerberos client created")
  }
 
+ ctx, cancelFunc := context.WithCancel(context.Background())
  conn := Connection{
  ConnectionSettings: s,
  HTTP: esClient,
  Encoder: encoder,
  log: logger,
  responseBuffer: bytes.NewBuffer(nil),
+ reqsContext: ctx,
+ cancelReqs: cancelFunc,
  }
 
  if s.APIKey != "" {
@@ -317,6 +326,7 @@ func (conn *Connection) Ping() (ESPingData, error) {
 // Close closes a connection.
 func (conn *Connection) Close() error {
  conn.HTTP.CloseIdleConnections()
+ conn.cancelReqs()
  return nil
 }
 
@@ -391,7 +401,7 @@ func (conn *Connection) execRequest(
  method, url string,
  body io.Reader,
 ) (int, []byte, error) {
- req, err := http.NewRequest(method, url, body) //nolint:noctx // keep legacy behaviour
+ req, err := http.NewRequestWithContext(conn.reqsContext, method, url, body)
  if err != nil {
  conn.log.Warnf("Failed to create request %+v", err)
  return 0, nil, err

libbeat/publisher/pipeline/controller.go

@@ -113,11 +113,7 @@ func (c *outputController) WaitClose(timeout time.Duration) error {
  c.consumer.close()
  close(c.workerChan)
 
- // Signal the output workers to close. This step is a hint, and carries
- // no guarantees. For example, on close the Elasticsearch output workers
- // will close idle connections, but will not change any behavior for
- // active connections, giving any remaining events a chance to ingest
- // before we terminate.
+ // Signal the output workers to close.
  for _, out := range c.workers {
  out.Close()
  }
@@ -209,11 +205,6 @@ func (c *outputController) closeQueue(timeout time.Duration) {
  // pipeline but it was shut down before any output was set.
  // In this case, return nil and Pipeline.ConnectWith will pass on a
  // real error to the caller.
- // NOTE: under the current shutdown process, Pipeline.Close (and hence
- // outputController.Close) is ~never called. So even if we did have
- // blocked callers here, in a real shutdown they will never be woken
- // up. But in hopes of a day when the shutdown process is more robust,
- // I've decided to do the right thing here anyway.
  req.responseChan <- nil
  }
 }

libbeat/tests/integration/http_test.go

@@ -21,7 +21,7 @@ package integration
 
 import (
  "encoding/json"
- "io/ioutil"
+ "io"
  "net/http"
  "testing"
  "time"
@@ -57,12 +57,14 @@ output.console:
  mockbeat.WriteConfigFile(cfg)
  mockbeat.Start()
  mockbeat.WaitForLogs("Starting stats endpoint", 60*time.Second)
+ time.Sleep(time.Second)
 
- r, err := http.Get("http://localhost:5066")
+ r, err := http.Get("http://localhost:5066") //nolint:noctx // fine for tests
  require.NoError(t, err)
  require.Equal(t, http.StatusOK, r.StatusCode, "incorrect status code")
 
- body, err := ioutil.ReadAll(r.Body)
+ body, err := io.ReadAll(r.Body)
+ r.Body.Close()
  require.NoError(t, err)
  var m map[string]interface{}
  err = json.Unmarshal(body, &m)
@@ -88,12 +90,14 @@ output.console:
  mockbeat.WriteConfigFile(cfg)
  mockbeat.Start()
  mockbeat.WaitForLogs("Starting stats endpoint", 60*time.Second)
+ time.Sleep(time.Second)
 
- r, err := http.Get("http://localhost:5066/stats")
+ r, err := http.Get("http://localhost:5066/stats") //nolint:noctx // fine for tests
  require.NoError(t, err)
  require.Equal(t, http.StatusOK, r.StatusCode, "incorrect status code")
 
- body, err := ioutil.ReadAll(r.Body)
+ body, err := io.ReadAll(r.Body)
+ r.Body.Close()
  require.NoError(t, err)
  var m Stats
 
@@ -121,8 +125,10 @@ output.console:
  mockbeat.WriteConfigFile(cfg)
  mockbeat.Start()
  mockbeat.WaitForLogs("Starting stats endpoint", 60*time.Second)
+ time.Sleep(time.Second)
 
- r, err := http.Get("http://localhost:5066/not-exist")
+ r, err := http.Get("http://localhost:5066/not-exist") //nolint:noctx // fine for tests
+ r.Body.Close()
  require.NoError(t, err)
  require.Equal(t, http.StatusNotFound, r.StatusCode, "incorrect status code")
 }
@@ -143,8 +149,10 @@ output.console:
  mockbeat.WriteConfigFile(cfg)
  mockbeat.Start()
  mockbeat.WaitForLogs("Starting stats endpoint", 60*time.Second)
+ time.Sleep(time.Second)
 
- r, err := http.Get("http://localhost:5066/debug/pprof/")
+ r, err := http.Get("http://localhost:5066/debug/pprof/") //nolint:noctx // fine for tests
+ r.Body.Close()
  require.NoError(t, err)
  require.Equal(t, http.StatusNotFound, r.StatusCode, "incorrect status code")
 }