Merge pull request #114236 from dgrisonnet/fix-eventseries-race

Fix data race when emitting similar Events consecutively

Kubernetes-commit: ca858e0c961db6ef8b22ecc3e257a02757261ea1

tools/events/event_broadcaster.go

@@ -184,19 +184,21 @@ func (e *eventBroadcasterImpl) recordToSink(event *eventsv1.Event, clock clock.C
 					Count:            1,
 					LastObservedTime: metav1.MicroTime{Time: clock.Now()},
 				}
-				return isomorphicEvent
+				// Make a copy of the Event to make sure that recording it
+				// doesn't mess with the object stored in cache.
+				return isomorphicEvent.DeepCopy()
 			}
 			e.eventCache[eventKey] = eventCopy
-			return eventCopy
+			// Make a copy of the Event to make sure that recording it doesn't
+			// mess with the object stored in cache.
+			return eventCopy.DeepCopy()
 		}()
 		if evToRecord != nil {
-			recordedEvent := e.attemptRecording(evToRecord)
-			if recordedEvent != nil {
-				recordedEventKey := getKey(recordedEvent)
-				e.mu.Lock()
-				defer e.mu.Unlock()
-				e.eventCache[recordedEventKey] = recordedEvent
-			}
+			// TODO: Add a metric counting the number of recording attempts
+			e.attemptRecording(evToRecord)
+			// We don't want the new recorded Event to be reflected in the
+			// client's cache because server-side mutations could mess with the
+			// aggregation mechanism used by the client.
 		}
 	}()
 }

tools/events/eventseries_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package events
 
 import (
+	"context"
 	"strconv"
 	"testing"
 	"time"
@@ -29,6 +30,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	k8sruntime "k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
+	fake "k8s.io/client-go/kubernetes/fake"
 	"k8s.io/client-go/kubernetes/scheme"
 	restclient "k8s.io/client-go/rest"
 	ref "k8s.io/client-go/tools/reference"
@@ -185,6 +187,44 @@ func TestEventSeriesf(t *testing.T) {
 	close(stopCh)
 }
 
+// TestEventSeriesWithEventSinkImplRace verifies that when Events are emitted to
+// an EventSink consecutively there is no data race.  This test is meant to be
+// run with the `-race` option.
+func TestEventSeriesWithEventSinkImplRace(t *testing.T) {
+	kubeClient := fake.NewSimpleClientset()
+
+	eventSink := &EventSinkImpl{Interface: kubeClient.EventsV1()}
+	eventBroadcaster := NewBroadcaster(eventSink)
+
+	stopCh := make(chan struct{})
+	eventBroadcaster.StartRecordingToSink(stopCh)
+
+	recorder := eventBroadcaster.NewRecorder(scheme.Scheme, "test")
+
+	recorder.Eventf(&v1.ObjectReference{}, nil, v1.EventTypeNormal, "reason", "action", "", "")
+	recorder.Eventf(&v1.ObjectReference{}, nil, v1.EventTypeNormal, "reason", "action", "", "")
+
+	err := wait.PollImmediate(100*time.Millisecond, 5*time.Second, func() (done bool, err error) {
+		events, err := kubeClient.EventsV1().Events(metav1.NamespaceDefault).List(context.TODO(), metav1.ListOptions{})
+		if err != nil {
+			return false, err
+		}
+
+		if len(events.Items) != 1 {
+			return false, nil
+		}
+
+		if events.Items[0].Series == nil {
+			return false, nil
+		}
+
+		return true, nil
+	})
+	if err != nil {
+		t.Fatal("expected that 2 identical Eventf calls would result in the creation of an Event with a Serie")
+	}
+}
+
 func validateEvent(messagePrefix string, expectedUpdate bool, actualEvent *eventsv1.Event, expectedEvent *eventsv1.Event, t *testing.T) {
 	recvEvent := *actualEvent