client-go: don't wait too long after EventBroadcaster.Shutdown

When Shutdown was called, delivery of each pending event would still be retried
12 times with a delay of ~10s between each retry. In apiserver integration
tests that caused the goroutine to linger long after the corresponding
apiserver of the test was shut down.

Kubernetes-commit: 15b01af9c18a0840d71e2bb7dff4d8c29b158aad

tools/record/event.go

@@ -17,6 +17,7 @@ limitations under the License.
 package record
 
 import (
+	"context"
 	"fmt"
 	"math/rand"
 	"time"
@@ -132,7 +133,9 @@ type EventBroadcaster interface {
 	// with the event source set to the given event source.
 	NewRecorder(scheme *runtime.Scheme, source v1.EventSource) EventRecorder
 
-	// Shutdown shuts down the broadcaster
+	// Shutdown shuts down the broadcaster. Once the broadcaster is shut
+	// down, it will only try to record an event in a sink once before
+	// giving up on it with an error message.
 	Shutdown()
 }
 
@@ -157,31 +160,34 @@ func (a *EventRecorderAdapter) Eventf(regarding, _ runtime.Object, eventtype, re
 
 // Creates a new event broadcaster.
 func NewBroadcaster() EventBroadcaster {
-	return &eventBroadcasterImpl{
-		Broadcaster:   watch.NewLongQueueBroadcaster(maxQueuedEvents, watch.DropIfChannelFull),
-		sleepDuration: defaultSleepDuration,
-	}
+	return newEventBroadcaster(watch.NewLongQueueBroadcaster(maxQueuedEvents, watch.DropIfChannelFull), defaultSleepDuration)
 }
 
 func NewBroadcasterForTests(sleepDuration time.Duration) EventBroadcaster {
-	return &eventBroadcasterImpl{
-		Broadcaster:   watch.NewLongQueueBroadcaster(maxQueuedEvents, watch.DropIfChannelFull),
-		sleepDuration: sleepDuration,
-	}
+	return newEventBroadcaster(watch.NewLongQueueBroadcaster(maxQueuedEvents, watch.DropIfChannelFull), sleepDuration)
 }
 
 func NewBroadcasterWithCorrelatorOptions(options CorrelatorOptions) EventBroadcaster {
-	return &eventBroadcasterImpl{
-		Broadcaster:   watch.NewLongQueueBroadcaster(maxQueuedEvents, watch.DropIfChannelFull),
-		sleepDuration: defaultSleepDuration,
-		options:       options,
+	eventBroadcaster := newEventBroadcaster(watch.NewLongQueueBroadcaster(maxQueuedEvents, watch.DropIfChannelFull), defaultSleepDuration)
+	eventBroadcaster.options = options
+	return eventBroadcaster
+}
+
+func newEventBroadcaster(broadcaster *watch.Broadcaster, sleepDuration time.Duration) *eventBroadcasterImpl {
+	eventBroadcaster := &eventBroadcasterImpl{
+		Broadcaster:   broadcaster,
+		sleepDuration: sleepDuration,
 	}
+	eventBroadcaster.cancelationCtx, eventBroadcaster.cancel = context.WithCancel(context.Background())
+	return eventBroadcaster
 }
 
 type eventBroadcasterImpl struct {
 	*watch.Broadcaster
-	sleepDuration time.Duration
-	options       CorrelatorOptions
+	sleepDuration  time.Duration
+	options        CorrelatorOptions
+	cancelationCtx context.Context
+	cancel         func()
 }
 
 // StartRecordingToSink starts sending events received from the specified eventBroadcaster to the given sink.
@@ -191,15 +197,16 @@ func (e *eventBroadcasterImpl) StartRecordingToSink(sink EventSink) watch.Interf
 	eventCorrelator := NewEventCorrelatorWithOptions(e.options)
 	return e.StartEventWatcher(
 		func(event *v1.Event) {
-			recordToSink(sink, event, eventCorrelator, e.sleepDuration)
+			e.recordToSink(sink, event, eventCorrelator)
 		})
 }
 
 func (e *eventBroadcasterImpl) Shutdown() {
 	e.Broadcaster.Shutdown()
+	e.cancel()
 }
 
-func recordToSink(sink EventSink, event *v1.Event, eventCorrelator *EventCorrelator, sleepDuration time.Duration) {
+func (e *eventBroadcasterImpl) recordToSink(sink EventSink, event *v1.Event, eventCorrelator *EventCorrelator) {
 	// Make a copy before modification, because there could be multiple listeners.
 	// Events are safe to copy like this.
 	eventCopy := *event
@@ -221,12 +228,18 @@ func recordToSink(sink EventSink, event *v1.Event, eventCorrelator *EventCorrela
 			klog.Errorf("Unable to write event '%#v' (retry limit exceeded!)", event)
 			break
 		}
+
 		// Randomize the first sleep so that various clients won't all be
 		// synced up if the master goes down.
+		delay := e.sleepDuration
 		if tries == 1 {
-			time.Sleep(time.Duration(float64(sleepDuration) * rand.Float64()))
-		} else {
-			time.Sleep(sleepDuration)
+			delay = time.Duration(float64(delay) * rand.Float64())
+		}
+		select {
+		case <-e.cancelationCtx.Done():
+			klog.Errorf("Unable to write event '%#v' (broadcaster is shut down)", event)
+			return
+		case <-time.After(delay):
 		}
 	}
 }

tools/record/event_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package record
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -452,7 +453,12 @@ func TestWriteEventError(t *testing.T) {
 			},
 		}
 		ev := &v1.Event{}
-		recordToSink(sink, ev, eventCorrelator, 0)
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		e := eventBroadcasterImpl{
+			cancelationCtx: ctx,
+		}
+		e.recordToSink(sink, ev, eventCorrelator)
 		if attempts != ent.attemptsWanted {
 			t.Errorf("case %v: wanted %d, got %d attempts", caseName, ent.attemptsWanted, attempts)
 		}
@@ -482,7 +488,12 @@ func TestUpdateExpiredEvent(t *testing.T) {
 	ev := &v1.Event{}
 	ev.ResourceVersion = "updated-resource-version"
 	ev.Count = 2
-	recordToSink(sink, ev, eventCorrelator, 0)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	e := eventBroadcasterImpl{
+		cancelationCtx: ctx,
+	}
+	e.recordToSink(sink, ev, eventCorrelator)
 
 	if createdEvent == nil {
 		t.Error("Event did not get created after patch failed")
@@ -494,6 +505,33 @@ func TestUpdateExpiredEvent(t *testing.T) {
 	}
 }
 
+func TestCancelEvent(t *testing.T) {
+	clock := testclocks.SimpleIntervalClock{Time: time.Now(), Duration: time.Second}
+	eventCorrelator := NewEventCorrelator(&clock)
+
+	attempts := 0
+	sink := &testEventSink{
+		OnCreate: func(event *v1.Event) (*v1.Event, error) {
+			attempts++
+			return nil, &errors.UnexpectedObjectError{}
+		},
+	}
+
+	ev := &v1.Event{}
+
+	// Cancel before even calling recordToSink.
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	e := eventBroadcasterImpl{
+		cancelationCtx: ctx,
+		sleepDuration:  time.Second,
+	}
+	e.recordToSink(sink, ev, eventCorrelator)
+	if attempts != 1 {
+		t.Errorf("recordToSink should have tried once, then given up immediately. Instead it tried %d times.", attempts)
+	}
+}
+
 func TestLotsOfEvents(t *testing.T) {
 	recorderCalled := make(chan struct{})
 	loggerCalled := make(chan struct{})