Merge pull request kubernetes#120984 from p0lyn0mial/upstream-reflector-always-fallback-to-listwatch

reflector: fallback to the previous mode on any error

Author: k8s-ci-robot

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

@@ -334,12 +334,9 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			return nil
 		}
 		if err != nil {
-			if !apierrors.IsInvalid(err) {
-				return err
-			}
-			klog.Warning("The watch-list feature is not supported by the server, falling back to the previous LIST/WATCH semantics")
+			klog.Warningf("The watchlist request ended with an error, falling back to the standard LIST/WATCH semantics because making progress is better than deadlocking, err = %v", err)
 			fallbackToList = true
-			// Ensure that we won't accidentally pass some garbage down the watch.
+			// ensure that we won't accidentally pass some garbage down the watch.
 			w = nil
 		}
 	}

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

@@ -94,18 +94,39 @@ func TestWatchList(t *testing.T) {
 			expectedStoreContent: []v1.Pod{*makePod("p1", "1")},
 		},
 		{
-			name: "returning any other error than apierrors.NewInvalid stops the reflector and reports the error",
+			name: "returning any other error than apierrors.NewInvalid forces fallback",
 			watchOptionsPredicate: func(options metav1.ListOptions) error {
-				return fmt.Errorf("dummy error")
+				if options.SendInitialEvents != nil && *options.SendInitialEvents {
+					return fmt.Errorf("dummy error")
+				}
+				return nil
+			},
+			podList: &v1.PodList{
+				ListMeta: metav1.ListMeta{ResourceVersion: "1"},
+				Items:    []v1.Pod{*makePod("p1", "1")},
+			},
+			closeAfterWatchEvents: 1,
+			watchEvents:           []watch.Event{{Type: watch.Added, Object: makePod("p2", "2")}},
+			expectedWatchRequests: 2,
+			expectedListRequests:  1,
+			expectedStoreContent:  []v1.Pod{*makePod("p1", "1"), *makePod("p2", "2")},
+			expectedRequestOptions: []metav1.ListOptions{
+				{
+					SendInitialEvents:    pointer.Bool(true),
+					AllowWatchBookmarks:  true,
+					ResourceVersionMatch: metav1.ResourceVersionMatchNotOlderThan,
+					TimeoutSeconds:       pointer.Int64(1),
+				},
+				{
+					ResourceVersion: "0",
+					Limit:           500,
+				},
+				{
+					AllowWatchBookmarks: true,
+					ResourceVersion:     "1",
+					TimeoutSeconds:      pointer.Int64(1),
+				},
 			},
-			expectedError:         fmt.Errorf("dummy error"),
-			expectedWatchRequests: 1,
-			expectedRequestOptions: []metav1.ListOptions{{
-				SendInitialEvents:    pointer.Bool(true),
-				AllowWatchBookmarks:  true,
-				ResourceVersionMatch: metav1.ResourceVersionMatchNotOlderThan,
-				TimeoutSeconds:       pointer.Int64(1),
-			}},
 		},
 		{
 			name: "the reflector can fall back to old LIST/WATCH semantics when a server doesn't support streaming",