Use one channel for events instead of three (#495)

Use one channel for events instead of three separate channels by event type

shared/kubernetes/mizuTapperSyncer.go

@@ -70,7 +70,7 @@ func CreateAndStartMizuTapperSyncer(ctx context.Context, kubernetesProvider *Pro
 
 func (tapperSyncer *MizuTapperSyncer) watchPodsForTapping() {
 	podWatchHelper := NewPodWatchHelper(tapperSyncer.kubernetesProvider, &tapperSyncer.config.PodFilterRegex)
-	added, modified, removed, errorChan := FilteredWatch(tapperSyncer.context, podWatchHelper, tapperSyncer.config.TargetNamespaces, podWatchHelper)
+	eventChan, errorChan := FilteredWatch(tapperSyncer.context, podWatchHelper, tapperSyncer.config.TargetNamespaces, podWatchHelper)
 
 	restartTappers := func() {
 		err, changeFound := tapperSyncer.updateCurrentlyTappedPods()
@@ -96,9 +96,9 @@ func (tapperSyncer *MizuTapperSyncer) watchPodsForTapping() {
 
 	for {
 		select {
-		case wEvent, ok := <-added:
+		case wEvent, ok := <-eventChan:
 			if !ok {
-				added = nil
+				eventChan = nil
 				continue
 			}
 
@@ -109,44 +109,28 @@ func (tapperSyncer *MizuTapperSyncer) watchPodsForTapping() {
 			}
 
 
-			logger.Log.Debugf("Added matching pod %s, ns: %s", pod.Name, pod.Namespace)
-			restartTappersDebouncer.SetOn()
-		case wEvent, ok := <-removed:
-			if !ok {
-				removed = nil
-				continue
-			}
-
-			pod, err := wEvent.ToPod()
-			if err != nil {
-				tapperSyncer.handleErrorInWatchLoop(err, restartTappersDebouncer)
-				continue
-			}
-
-			logger.Log.Debugf("Removed matching pod %s, ns: %s", pod.Name, pod.Namespace)
-			restartTappersDebouncer.SetOn()
-		case wEvent, ok := <-modified:
-			if !ok {
-				modified = nil
-				continue
-			}
-
-			pod, err := wEvent.ToPod()
-			if err != nil {
-				tapperSyncer.handleErrorInWatchLoop(err, restartTappersDebouncer)
-				continue
-			}
-
-
-			logger.Log.Debugf("Modified matching pod %s, ns: %s, phase: %s, ip: %s", pod.Name, pod.Namespace, pod.Status.Phase, pod.Status.PodIP)
-			// Act only if the modified pod has already obtained an IP address.
-			// After filtering for IPs, on a normal pod restart this includes the following events:
-			// - Pod deletion
-			// - Pod reaches start state
-			// - Pod reaches ready state
-			// Ready/unready transitions might also trigger this event.
-			if pod.Status.PodIP != "" {
+			switch wEvent.Type {
+			case EventAdded:
+				logger.Log.Debugf("Added matching pod %s, ns: %s", pod.Name, pod.Namespace)
 				restartTappersDebouncer.SetOn()
+			case EventDeleted:
+				logger.Log.Debugf("Removed matching pod %s, ns: %s", pod.Name, pod.Namespace)
+				restartTappersDebouncer.SetOn()
+			case EventModified:
+				logger.Log.Debugf("Modified matching pod %s, ns: %s, phase: %s, ip: %s", pod.Name, pod.Namespace, pod.Status.Phase, pod.Status.PodIP)
+				// Act only if the modified pod has already obtained an IP address.
+				// After filtering for IPs, on a normal pod restart this includes the following events:
+				// - Pod deletion
+				// - Pod reaches start state
+				// - Pod reaches ready state
+				// Ready/unready transitions might also trigger this event.
+				if pod.Status.PodIP != "" {
+					restartTappersDebouncer.SetOn()
+				}
+			case EventBookmark:
+				break
+			case EventError:
+				break
 			}
 		case err, ok := <-errorChan:
 			if !ok {

shared/kubernetes/watch.go

@@ -20,10 +20,8 @@ type WatchCreator interface {
 	NewWatcher(ctx context.Context, namespace string) (watch.Interface, error)
 }
 
-func FilteredWatch(ctx context.Context, watcherCreator WatchCreator, targetNamespaces []string, filterer EventFilterer) (chan *WatchEvent, chan *WatchEvent, chan *WatchEvent, chan error) {
-	addedChan := make(chan *WatchEvent)
-	modifiedChan := make(chan *WatchEvent)
-	removedChan := make(chan *WatchEvent)
+func FilteredWatch(ctx context.Context, watcherCreator WatchCreator, targetNamespaces []string, filterer EventFilterer) (<-chan *WatchEvent, <-chan error) {
+	eventChan := make(chan *WatchEvent)
 	errorChan := make(chan error)
 
 	var wg sync.WaitGroup
@@ -42,7 +40,7 @@ func FilteredWatch(ctx context.Context, watcherCreator WatchCreator, targetNames
 					break
 				}
 
-				err = startWatchLoop(ctx, watcher, filterer, addedChan, modifiedChan, removedChan) // blocking
+				err = startWatchLoop(ctx, watcher, filterer, eventChan) // blocking
 				watcher.Stop()
 
 				select {
@@ -73,16 +71,14 @@ func FilteredWatch(ctx context.Context, watcherCreator WatchCreator, targetNames
 	go func() {
 		<-ctx.Done()
 		wg.Wait()
-		close(addedChan)
-		close(modifiedChan)
-		close(removedChan)
+		close(eventChan)
 		close(errorChan)
 	}()
 
-	return addedChan, modifiedChan, removedChan, errorChan
+	return eventChan, errorChan
 }
 
-func startWatchLoop(ctx context.Context, watcher watch.Interface, filterer EventFilterer, addedChan chan *WatchEvent, modifiedChan chan *WatchEvent, removedChan chan *WatchEvent) error {
+func startWatchLoop(ctx context.Context, watcher watch.Interface, filterer EventFilterer, eventChan chan<- *WatchEvent) error {
 	resultChan := watcher.ResultChan()
 	for {
 		select {
@@ -103,14 +99,7 @@ func startWatchLoop(ctx context.Context, watcher watch.Interface, filterer Event
 				continue
 			}
 
-			switch wEvent.Type {
-			case watch.Added:
-				addedChan <- &wEvent
-			case watch.Modified:
-				modifiedChan <- &wEvent
-			case watch.Deleted:
-				removedChan <- &wEvent
-			}
+			eventChan <- &wEvent
 		case <-ctx.Done():
 			return nil
 		}

shared/kubernetes/watchEvent.go

@@ -10,6 +10,14 @@ import (
 	"k8s.io/apimachinery/pkg/watch"
 )
 
+const (
+	EventAdded    watch.EventType = watch.Added
+	EventModified watch.EventType = watch.Modified
+	EventDeleted  watch.EventType = watch.Deleted
+	EventBookmark watch.EventType = watch.Bookmark
+	EventError    watch.EventType = watch.Error
+)
+
 type InvalidObjectType struct {
 	RequestedType reflect.Type
 }