apply desired changes for handler registration

Kubernetes-commit: 92f04baac98186673c684bba419087d6285807b1

tools/cache/shared_informer.go

@@ -136,9 +136,9 @@ type SharedInformer interface {
 	// AddEventHandler adds an event handler to the shared informer using the shared informer's resync
 	// period.  Events to a single handler are delivered sequentially, but there is no coordination
 	// between different handlers.
-	// It returns a handle for the handler that can be used to remove
+	// It returns a registration handle for the handler that can be used to remove
 	// the handler again.
-	AddEventHandler(handler ResourceEventHandler) (*ResourceEventHandlerRegistration, error)
+	AddEventHandler(handler ResourceEventHandler) (ResourceEventHandlerRegistration, error)
 	// AddEventHandlerWithResyncPeriod adds an event handler to the
 	// shared informer with the requested resync period; zero means
 	// this handler does not care about resyncs.  The resync operation
@@ -153,9 +153,9 @@ type SharedInformer interface {
 	// between any two resyncs may be longer than the nominal period
 	// because the implementation takes time to do work and there may
 	// be competing load and scheduling noise.
-	// It returns a handle for the handler that can be used to remove
+	// It returns a registration handle for the handler that can be used to remove
 	// the handler again and an error if the handler cannot be added.
-	AddEventHandlerWithResyncPeriod(handler ResourceEventHandler, resyncPeriod time.Duration) (*ResourceEventHandlerRegistration, error)
+	AddEventHandlerWithResyncPeriod(handler ResourceEventHandler, resyncPeriod time.Duration) (ResourceEventHandlerRegistration, error)
 	// RemoveEventHandlerByRegistration removes a formerly added event handler given by
 	// its registration handle.
 	// If, for some reason, the same handler has been added multiple
@@ -166,7 +166,7 @@ type SharedInformer interface {
 	// Calling Remove on an already removed handle returns no error
 	// because the handler is finally (still) removed after calling this
 	// method.
-	RemoveEventHandlerByRegistration(handle *ResourceEventHandlerRegistration) error
+	RemoveEventHandlerByRegistration(handle ResourceEventHandlerRegistration) error
 	// GetStore returns the informer's local cache as a Store.
 	GetStore() Store
 	// GetController is deprecated, it does nothing useful
@@ -229,13 +229,6 @@ type ResourceEventHandlerRegistration struct {
 	listener *processorListener
 }
 
-// isActive reports whether this registration is still active
-// meaning that the handler registered with this handle is
-// still registered.
-func (h *ResourceEventHandlerRegistration) isActive() bool {
-	return h.listener != nil
-}
-
 // SharedIndexInformer provides add and get Indexers ability based on SharedInformer.
 type SharedIndexInformer interface {
 	SharedInformer
@@ -409,6 +402,10 @@ type deleteNotification struct {
 	oldObj interface{}
 }
 
+func (s *sharedIndexInformer) isRegistered(h ResourceEventHandlerRegistration) bool {
+	return s.processor.isRegistered(h.listener)
+}
+
 func (s *sharedIndexInformer) SetWatchErrorHandler(handler WatchErrorHandler) error {
 	s.startedLock.Lock()
 	defer s.startedLock.Unlock()
@@ -531,7 +528,7 @@ func (s *sharedIndexInformer) GetController() Controller {
 	return &dummyController{informer: s}
 }
 
-func (s *sharedIndexInformer) AddEventHandler(handler ResourceEventHandler) (*ResourceEventHandlerRegistration, error) {
+func (s *sharedIndexInformer) AddEventHandler(handler ResourceEventHandler) (ResourceEventHandlerRegistration, error) {
 	return s.AddEventHandlerWithResyncPeriod(handler, s.defaultEventHandlerResyncPeriod)
 }
 
@@ -552,13 +549,13 @@ func determineResyncPeriod(desired, check time.Duration) time.Duration {
 
 const minimumResyncPeriod = 1 * time.Second
 
-func (s *sharedIndexInformer) AddEventHandlerWithResyncPeriod(handler ResourceEventHandler, resyncPeriod time.Duration) (*ResourceEventHandlerRegistration, error) {
+func (s *sharedIndexInformer) AddEventHandlerWithResyncPeriod(handler ResourceEventHandler, resyncPeriod time.Duration) (ResourceEventHandlerRegistration, error) {
 	s.startedLock.Lock()
 	defer s.startedLock.Unlock()
 
 	if s.stopped {
 		klog.V(2).Infof("Handler %v is not added to shared informer because it has stopped already", handler)
-		return nil, fmt.Errorf("handler %v is not added to shared informer because it has stopped already", handler)
+		return ResourceEventHandlerRegistration{}, fmt.Errorf("handler %v is not added to shared informer because it has stopped already", handler)
 	}
 
 	if resyncPeriod > 0 {
@@ -582,7 +579,7 @@ func (s *sharedIndexInformer) AddEventHandlerWithResyncPeriod(handler ResourceEv
 	}
 
 	listener := newProcessListener(handler, resyncPeriod, determineResyncPeriod(resyncPeriod, s.resyncCheckPeriod), s.clock.Now(), initialBufferSize)
-	handle := &ResourceEventHandlerRegistration{listener}
+	handle := ResourceEventHandlerRegistration{listener}
 
 	if !s.started {
 		s.processor.addListener(listener)
@@ -663,7 +660,7 @@ func (s *sharedIndexInformer) IsStopped() bool {
 // If a handler has been added multiple times, only the actual registration for the
 // handler will be removed. Other registrations of the same handler will still be
 // active until they are explicitly removes, also.
-func (s *sharedIndexInformer) RemoveEventHandlerByRegistration(handle *ResourceEventHandlerRegistration) error {
+func (s *sharedIndexInformer) RemoveEventHandlerByRegistration(handle ResourceEventHandlerRegistration) error {
 	s.startedLock.Lock()
 	defer s.startedLock.Unlock()
 
@@ -682,7 +679,6 @@ func (s *sharedIndexInformer) RemoveEventHandlerByRegistration(handle *ResourceE
 	s.blockDeltas.Lock()
 	defer s.blockDeltas.Unlock()
 	s.processor.removeListener(handle.listener)
-	handle.listener = nil
 	return nil
 }
 
@@ -701,6 +697,19 @@ type sharedProcessor struct {
 	wg               wait.Group
 }
 
+func (p *sharedProcessor) isRegistered(listener *processorListener) bool {
+	p.listenersLock.Lock()
+	defer p.listenersLock.Unlock()
+
+	for i := 0; i < len(p.listeners); i++ {
+		l := p.listeners[i]
+		if l == listener {
+			return true
+		}
+	}
+	return false
+}
+
 func (p *sharedProcessor) addListener(listener *processorListener) {
 	p.listenersLock.Lock()
 	defer p.listenersLock.Unlock()
@@ -721,18 +730,21 @@ func (p *sharedProcessor) removeListener(listener *processorListener) {
 	p.listenersLock.Lock()
 	defer p.listenersLock.Unlock()
 
-	p.removeListenerLocked(listener)
+	if p.removeListenerLocked(listener) {
 		if p.listenersStarted {
 			close(listener.addCh)
 		}
+	}
 }
 
-func (p *sharedProcessor) removeListenerLocked(listener *processorListener) {
+func (p *sharedProcessor) removeListenerLocked(listener *processorListener) bool {
+	found := false
 	for i := 0; i < len(p.listeners); i++ {
 		l := p.listeners[i]
 		if l == listener {
 			p.listeners = append(p.listeners[:i], p.listeners[i+1:]...)
 			i--
+			found = true
 		}
 	}
 	for i := 0; i < len(p.syncingListeners); i++ {
@@ -742,6 +754,7 @@ func (p *sharedProcessor) removeListenerLocked(listener *processorListener) {
 			i--
 		}
 	}
+	return found
 }
 
 func (p *sharedProcessor) distribute(obj interface{}, sync bool) {

tools/cache/shared_informer_test.go

@@ -110,6 +110,11 @@ func isStarted(i SharedInformer) bool {
 	return s.started
 }
 
+func isRegistered(i SharedInformer, h ResourceEventHandlerRegistration) bool {
+	s := i.(*sharedIndexInformer)
+	return s.isRegistered(h)
+}
+
 func TestListenerResyncPeriods(t *testing.T) {
 	// source simulates an apiserver object endpoint.
 	source := fcache.NewFakeControllerSource()
@@ -494,7 +499,7 @@ func TestSharedInformerMultipleRegistration(t *testing.T) {
 		return
 	}
 
-	if !reg1.isActive() {
+	if !isRegistered(informer,reg1) {
 		t.Errorf("handle1 is not active after successful registration")
 		return
 	}
@@ -505,7 +510,7 @@ func TestSharedInformerMultipleRegistration(t *testing.T) {
 		return
 	}
 
-	if !reg2.isActive() {
+	if !isRegistered(informer,reg2) {
 		t.Errorf("handle2 is not active after successful registration")
 		return
 	}
@@ -518,11 +523,11 @@ func TestSharedInformerMultipleRegistration(t *testing.T) {
 		t.Errorf("removing of duplicate handler registration failed: %s", err)
 	}
 
-	if reg1.isActive() {
+	if isRegistered(informer,reg1) {
 		t.Errorf("handle1 is still active after successful remove")
 		return
 	}
-	if !reg2.isActive() {
+	if !isRegistered(informer, reg2) {
 		t.Errorf("handle2 is not active after removing handle1")
 		return
 	}
@@ -539,7 +544,7 @@ func TestSharedInformerMultipleRegistration(t *testing.T) {
 		t.Errorf("removing of second handler registration failed: %s", err)
 	}
 
-	if reg2.isActive() {
+	if isRegistered(informer,reg2) {
 		t.Errorf("handle2 is still active after successful remove")
 		return
 	}
@@ -565,14 +570,14 @@ func TestRemovingRemovedSharedInformer(t *testing.T) {
 		t.Errorf("removing of handler registration failed: %s", err)
 		return
 	}
-	if reg.isActive() {
+	if isRegistered(informer,reg) {
 		t.Errorf("handle is still active after successful remove")
 		return
 	}
 	if err := informer.RemoveEventHandlerByRegistration(reg); err != nil {
 		t.Errorf("removing of already removed registration yields unexpected error: %s", err)
 	}
-	if reg.isActive() {
+	if isRegistered(informer,reg) {
 		t.Errorf("handle is still active after second remove")
 		return
 	}
@@ -643,7 +648,7 @@ func TestAddOnStoppedSharedInformer(t *testing.T) {
 		return
 	}
 
-	handle, err := informer.AddEventHandlerWithResyncPeriod(listener, listener.resyncPeriod)
+	_, err := informer.AddEventHandlerWithResyncPeriod(listener, listener.resyncPeriod)
 	if err == nil {
 		t.Errorf("stopped informer did not reject add handler")
 		return
@@ -652,10 +657,6 @@ func TestAddOnStoppedSharedInformer(t *testing.T) {
 		t.Errorf("adding handler to a stopped informer yields unexpected error: %s", err)
 		return
 	}
-	if handle != nil {
-		t.Errorf("got handle for added handler on stopped informer")
-		return
-	}
 }
 
 func TestRemoveOnStoppedSharedInformer(t *testing.T) {