Compress recurring events in to a single event to optimize etcd storage

pkg/client/events.go

@@ -34,6 +34,7 @@ type EventNamespacer interface {
 // EventInterface has methods to work with Event resources
 type EventInterface interface {
 	Create(event *api.Event) (*api.Event, error)
+	Update(event *api.Event) (*api.Event, error)
 	List(label, field labels.Selector) (*api.EventList, error)
 	Get(name string) (*api.Event, error)
 	Watch(label, field labels.Selector, resourceVersion string) (watch.Interface, error)
@@ -73,6 +74,26 @@ func (e *events) Create(event *api.Event) (*api.Event, error) {
 	return result, err
 }
 
+// Update modifies an existing event. It returns the copy of the event that the server returns,
+// or an error. The namespace and key to update the event within is deduced from the event. The
+// namespace must either match this event client's namespace, or this event client must have been
+// created with the "" namespace. Update also requires the ResourceVersion to be set in the event
+// object.
+func (e *events) Update(event *api.Event) (*api.Event, error) {
+	if len(event.ResourceVersion) == 0 {
+		return nil, fmt.Errorf("invalid event update object, missing resource version: %#v", event)
+	}
+	result := &api.Event{}
+	err := e.client.Put().
+		Namespace(event.Namespace).
+		Resource("events").
+		Name(event.Name).
+		Body(event).
+		Do().
+		Into(result)
+	return result, err
+}
+
 // List returns a list of events matching the selectors.
 func (e *events) List(label, field labels.Selector) (*api.EventList, error) {
 	result := &api.EventList{}

pkg/client/fake_events.go

@@ -35,6 +35,12 @@ func (c *FakeEvents) Create(event *api.Event) (*api.Event, error) {
 	return &api.Event{}, nil
 }
 
+// Update replaces an existing event. Returns the copy of the event the server returns, or an error.
+func (c *FakeEvents) Update(event *api.Event) (*api.Event, error) {
+	c.Fake.Actions = append(c.Fake.Actions, FakeAction{Action: "update-event", Value: event.Name})
+	return &api.Event{}, nil
+}
+
 // List returns a list of events matching the selectors.
 func (c *FakeEvents) List(label, field labels.Selector) (*api.EventList, error) {
 	c.Fake.Actions = append(c.Fake.Actions, FakeAction{Action: "list-events"})

pkg/client/record/event.go

@@ -41,6 +41,7 @@ var sleepDuration = 10 * time.Second
 // pkg/client's REST client.
 type EventRecorder interface {
 	Create(event *api.Event) (*api.Event, error)
+	Update(event *api.Event) (*api.Event, error)
 }
 
 // StartRecording starts sending events to recorder. Call once while initializing
@@ -58,9 +59,18 @@ func StartRecording(recorder EventRecorder, source api.EventSource) watch.Interf
 		event = &eventCopy
 		event.Source = source
 
+		previousEvent := GetEvent(event)
+		updateExistingEvent := previousEvent.Count > 0
+		if updateExistingEvent {
+			event.Count = previousEvent.Count + 1
+			event.FirstTimestamp = previousEvent.FirstTimestamp
+			event.Name = previousEvent.Name
+			event.ResourceVersion = previousEvent.ResourceVersion
+		}
+
 		tries := 0
 		for {
-			if recordEvent(recorder, event) {
+			if recordEvent(recorder, event, updateExistingEvent) {
 				break
 			}
 			tries++
@@ -81,11 +91,21 @@ func StartRecording(recorder EventRecorder, source api.EventSource) watch.Interf
 
 // recordEvent attempts to write event to recorder. It returns true if the event
 // was successfully recorded or discarded, false if it should be retried.
-func recordEvent(recorder EventRecorder, event *api.Event) bool {
-	_, err := recorder.Create(event)
+// If updateExistingEvent is false, it creates a new event, otherwise it updates
+// existing event.
+func recordEvent(recorder EventRecorder, event *api.Event, updateExistingEvent bool) bool {
+	var newEvent *api.Event
+	var err error
+	if updateExistingEvent {
+		newEvent, err = recorder.Update(event)
+	} else {
+		newEvent, err = recorder.Create(event)
+	}
 	if err == nil {
+		AddOrUpdateEvent(newEvent)
 		return true
 	}
+
 	// If we can't contact the server, then hold everything while we keep trying.
 	// Otherwise, something about the event is malformed and we should abandon it.
 	giveUp := false