reflector: simplify reading the resourceVersion

staging/src/k8s.io/client-go/tools/cache/reflector.go

@@ -253,10 +253,8 @@ func (r *Reflector) resyncChan() (<-chan time.Time, func() bool) {
 // It returns error if ListAndWatch didn't even try to initialize watch.
 func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 	klog.V(3).Infof("Listing and watching %v from %s", r.expectedTypeName, r.name)
-	var resourceVersion string
-	var err error
 
-	resourceVersion, err = r.list(stopCh)
+	err := r.list(stopCh)
 	if err != nil {
 		return err
 	}
@@ -299,7 +297,7 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 
 		timeoutSeconds := int64(minWatchTimeout.Seconds() * (rand.Float64() + 1.0))
 		options := metav1.ListOptions{
-			ResourceVersion: resourceVersion,
+			ResourceVersion: r.LastSyncResourceVersion(),
 			// We want to avoid situations of hanging watchers. Stop any watchers that do not
 			// receive any events within the timeout window.
 			TimeoutSeconds: &timeoutSeconds,
@@ -325,7 +323,7 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			return err
 		}
 
-		if err := watchHandler(start, w, r.store, r.expectedType, r.expectedGVK, r.name, r.expectedTypeName, r.setLastSyncResourceVersion, r.clock, &resourceVersion, resyncerrc, stopCh); err != nil {
+		if err := watchHandler(start, w, r.store, r.expectedType, r.expectedGVK, r.name, r.expectedTypeName, r.setLastSyncResourceVersion, r.clock, resyncerrc, stopCh); err != nil {
 			if err != errorStopRequested {
 				switch {
 				case isExpiredError(err):
@@ -346,9 +344,9 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 	}
 }
 
-// list simply lists all items and gets a resource version obtained from the server at the moment of the call.
+// list simply lists all items and records a resource version obtained from the server at the moment of the call.
 // the resource version can be used for further progress notification (aka. watch).
-func (r *Reflector) list(stopCh <-chan struct{}) (string, error) {
+func (r *Reflector) list(stopCh <-chan struct{}) error {
 	var resourceVersion string
 	options := metav1.ListOptions{ResourceVersion: r.relistResourceVersion()}
 
@@ -408,15 +406,15 @@ func (r *Reflector) list(stopCh <-chan struct{}) (string, error) {
 	}()
 	select {
 	case <-stopCh:
-		return "", nil
+		return nil
 	case r := <-panicCh:
 		panic(r)
 	case <-listCh:
 	}
 	initTrace.Step("Objects listed", trace.Field{Key: "error", Value: err})
 	if err != nil {
 		klog.Warningf("%s: failed to list %v: %v", r.name, r.expectedTypeName, err)
-		return "", fmt.Errorf("failed to list %v: %w", r.expectedTypeName, err)
+		return fmt.Errorf("failed to list %v: %w", r.expectedTypeName, err)
 	}
 
 	// We check if the list was paginated and if so set the paginatedResult based on that.
@@ -436,22 +434,22 @@ func (r *Reflector) list(stopCh <-chan struct{}) (string, error) {
 	r.setIsLastSyncResourceVersionUnavailable(false) // list was successful
 	listMetaInterface, err := meta.ListAccessor(list)
 	if err != nil {
-		return "", fmt.Errorf("unable to understand list result %#v: %v", list, err)
+		return fmt.Errorf("unable to understand list result %#v: %v", list, err)
 	}
 	resourceVersion = listMetaInterface.GetResourceVersion()
 	initTrace.Step("Resource version extracted")
 	items, err := meta.ExtractList(list)
 	if err != nil {
-		return "", fmt.Errorf("unable to understand list result %#v (%v)", list, err)
+		return fmt.Errorf("unable to understand list result %#v (%v)", list, err)
 	}
 	initTrace.Step("Objects extracted")
 	if err := r.syncWith(items, resourceVersion); err != nil {
-		return "", fmt.Errorf("unable to sync list result: %v", err)
+		return fmt.Errorf("unable to sync list result: %v", err)
 	}
 	initTrace.Step("SyncWith done")
 	r.setLastSyncResourceVersion(resourceVersion)
 	initTrace.Step("Resource version updated")
-	return resourceVersion, nil
+	return nil
 }
 
 // syncWith replaces the store's items with the given list.
@@ -463,7 +461,7 @@ func (r *Reflector) syncWith(items []runtime.Object, resourceVersion string) err
 	return r.store.Replace(found, resourceVersion)
 }
 
-// watchHandler watches w and keeps *resourceVersion up to date.
+// watchHandler watches w and sets setLastSyncResourceVersion
 func watchHandler(start time.Time,
 	w watch.Interface,
 	store Store,
@@ -473,7 +471,6 @@ func watchHandler(start time.Time,
 	expectedTypeName string,
 	setLastSyncResourceVersion func(string),
 	clock clock.Clock,
-	resourceVersion *string,
 	errc chan error,
 	stopCh <-chan struct{},
 ) error {
@@ -514,7 +511,7 @@ loop:
 				utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", name, event))
 				continue
 			}
-			newResourceVersion := meta.GetResourceVersion()
+			resourceVersion := meta.GetResourceVersion()
 			switch event.Type {
 			case watch.Added:
 				err := store.Add(event.Object)
@@ -539,18 +536,17 @@ loop:
 			default:
 				utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", name, event))
 			}
-			*resourceVersion = newResourceVersion
-			setLastSyncResourceVersion(newResourceVersion)
+			setLastSyncResourceVersion(resourceVersion)
 			if rvu, ok := store.(ResourceVersionUpdater); ok {
-				rvu.UpdateResourceVersion(newResourceVersion)
+				rvu.UpdateResourceVersion(resourceVersion)
 			}
 			eventCount++
 		}
 	}
 
 	watchDuration := clock.Since(start)
 	if watchDuration < 1*time.Second && eventCount == 0 {
-		return fmt.Errorf("very short watch: %s: Unexpected watch close - watch jasted less than a second and no items received", name)
+		return fmt.Errorf("very short watch: %s: Unexpected watch close - watch lasted less than a second and no items received", name)
 	}
 	klog.V(4).Infof("%s: Watch close - %v total %v items received", name, expectedTypeName, eventCount)
 	return nil

staging/src/k8s.io/client-go/tools/cache/reflector_test.go

@@ -138,8 +138,7 @@ func TestReflectorWatchHandlerError(t *testing.T) {
 	go func() {
 		fw.Stop()
 	}()
-	var resumeRV string
-	err := watchHandler(time.Now(), fw, s, g.expectedType, g.expectedGVK, g.name, g.expectedTypeName, g.setLastSyncResourceVersion, g.clock, &resumeRV, nevererrc, wait.NeverStop)
+	err := watchHandler(time.Now(), fw, s, g.expectedType, g.expectedGVK, g.name, g.expectedTypeName, g.setLastSyncResourceVersion, g.clock, nevererrc, wait.NeverStop)
 	if err == nil {
 		t.Errorf("unexpected non-error")
 	}
@@ -158,8 +157,7 @@ func TestReflectorWatchHandler(t *testing.T) {
 		fw.Add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "baz", ResourceVersion: "32"}})
 		fw.Stop()
 	}()
-	var resumeRV string
-	err := watchHandler(time.Now(), fw, s, g.expectedType, g.expectedGVK, g.name, g.expectedTypeName, g.setLastSyncResourceVersion, g.clock, &resumeRV, nevererrc, wait.NeverStop)
+	err := watchHandler(time.Now(), fw, s, g.expectedType, g.expectedGVK, g.name, g.expectedTypeName, g.setLastSyncResourceVersion, g.clock, nevererrc, wait.NeverStop)
 	if err != nil {
 		t.Errorf("unexpected error %v", err)
 	}
@@ -191,7 +189,7 @@ func TestReflectorWatchHandler(t *testing.T) {
 	}
 
 	// RV should send the last version we see.
-	if e, a := "32", resumeRV; e != a {
+	if e, a := "32", g.LastSyncResourceVersion(); e != a {
 		t.Errorf("expected %v, got %v", e, a)
 	}
 
@@ -205,10 +203,9 @@ func TestReflectorStopWatch(t *testing.T) {
 	s := NewStore(MetaNamespaceKeyFunc)
 	g := NewReflector(&testLW{}, &v1.Pod{}, s, 0)
 	fw := watch.NewFake()
-	var resumeRV string
 	stopWatch := make(chan struct{}, 1)
 	stopWatch <- struct{}{}
-	err := watchHandler(time.Now(), fw, s, g.expectedType, g.expectedGVK, g.name, g.expectedTypeName, g.setLastSyncResourceVersion, g.clock, &resumeRV, nevererrc, stopWatch)
+	err := watchHandler(time.Now(), fw, s, g.expectedType, g.expectedGVK, g.name, g.expectedTypeName, g.setLastSyncResourceVersion, g.clock, nevererrc, stopWatch)
 	if err != errorStopRequested {
 		t.Errorf("expected stop error, got %q", err)
 	}