use Watch for single object instead of WatchList

pkg/registry/etcd/etcd.go

@@ -271,7 +271,8 @@ func (r *Registry) WatchServices(ctx api.Context, label labels.Selector, field f
 		if err != nil {
 			return nil, err
 		}
-		return r.Watch(key, version), nil
+		// TODO: use generic.SelectionPredicate
+		return r.Watch(key, version, tools.Everything)
 	}
 	if field.Empty() {
 		return r.WatchList(makeServiceListKey(ctx), version, tools.Everything)

pkg/registry/generic/etcd/etcd.go

@@ -429,18 +429,7 @@ func (e *Etcd) WatchPredicate(ctx api.Context, m generic.Matcher, resourceVersio
 		return nil, err
 	}
 
-	var watchKey string
-	if name, ok := m.MatchesSingle(); ok {
-		key, err := e.KeyFunc(ctx, name)
-		if err != nil {
-			return nil, err
-		}
-		watchKey = key
-	} else {
-		watchKey = e.KeyRootFunc(ctx)
-	}
-
-	return e.Helper.WatchList(watchKey, version, func(obj runtime.Object) bool {
+	filterFunc := func(obj runtime.Object) bool {
 		matches, err := m.Matches(obj)
 		if err != nil {
 			glog.Errorf("unable to match watch: %v", err)
@@ -453,5 +442,15 @@ func (e *Etcd) WatchPredicate(ctx api.Context, m generic.Matcher, resourceVersio
 			}
 		}
 		return matches
-	})
+	}
+
+	if name, ok := m.MatchesSingle(); ok {
+		key, err := e.KeyFunc(ctx, name)
+		if err != nil {
+			return nil, err
+		}
+		return e.Helper.Watch(key, version, filterFunc)
+	}
+
+	return e.Helper.WatchList(e.KeyRootFunc(ctx), version, filterFunc)
 }

pkg/registry/generic/etcd/etcd_test.go

@@ -690,11 +690,16 @@ func TestEtcdWatch(t *testing.T) {
 
 	for name, m := range table {
 		podA := &api.Pod{
-			ObjectMeta: api.ObjectMeta{Name: "foo", ResourceVersion: "1"},
-			Spec:       api.PodSpec{Host: "machine"},
+			ObjectMeta: api.ObjectMeta{
+				Name:            "foo",
+				Namespace:       api.NamespaceDefault,
+				ResourceVersion: "1",
+			},
+			Spec: api.PodSpec{Host: "machine"},
 		}
 		respWithPodA := &etcd.Response{
 			Node: &etcd.Node{
+				Key:           "/registry/pods/default/foo",
 				Value:         runtime.EncodeOrDie(testapi.Codec(), podA),
 				ModifiedIndex: 1,
 				CreatedIndex:  1,

pkg/tools/etcd_helper_watch.go

@@ -79,8 +79,10 @@ func (h *EtcdHelper) WatchList(key string, resourceVersion uint64, filter Filter
 // Watch begins watching the specified key. Events are decoded into
 // API objects and sent down the returned watch.Interface.
 // Errors will be sent down the channel.
-func (h *EtcdHelper) Watch(key string, resourceVersion uint64) watch.Interface {
-	return h.WatchAndTransform(key, resourceVersion, nil)
+func (h *EtcdHelper) Watch(key string, resourceVersion uint64, filter FilterFunc) (watch.Interface, error) {
+	w := newEtcdWatcher(false, nil, filter, h.Codec, h.Versioner, nil)
+	go w.etcdWatch(h.Client, key, resourceVersion)
+	return w, nil
 }
 
 // WatchAndTransform begins watching the specified key. Events are decoded into

pkg/tools/etcd_helper_watch_test.go

@@ -207,7 +207,13 @@ func TestWatchEtcdError(t *testing.T) {
 	fakeClient.WatchImmediateError = fmt.Errorf("immediate error")
 	h := EtcdHelper{fakeClient, codec, versioner}
 
-	got := <-h.Watch("/some/key", 4).ResultChan()
+	watching, err := h.Watch("/some/key", 4, Everything)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	defer watching.Stop()
+
+	got := <-watching.ResultChan()
 	if got.Type != watch.Error {
 		t.Fatalf("Unexpected non-error")
 	}
@@ -229,7 +235,10 @@ func TestWatch(t *testing.T) {
 	fakeClient.expectNotFoundGetSet["/some/key"] = struct{}{}
 	h := EtcdHelper{fakeClient, codec, versioner}
 
-	watching := h.Watch("/some/key", 0)
+	watching, err := h.Watch("/some/key", 0, Everything)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
 
 	fakeClient.WaitForWatchCompletion()
 	// when server returns not found, the watch index starts at the next value (1)
@@ -398,7 +407,11 @@ func TestWatchEtcdState(t *testing.T) {
 			fakeClient.Data[key] = value
 		}
 		h := EtcdHelper{fakeClient, codec, versioner}
-		watching := h.Watch("/somekey/foo", testCase.From)
+		watching, err := h.Watch("/somekey/foo", testCase.From, Everything)
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+
 		fakeClient.WaitForWatchCompletion()
 
 		t.Logf("Testing %v", k)
@@ -466,7 +479,10 @@ func TestWatchFromZeroIndex(t *testing.T) {
 		fakeClient.Data["/some/key"] = testCase.Response
 		h := EtcdHelper{fakeClient, codec, versioner}
 
-		watching := h.Watch("/some/key", 0)
+		watching, err := h.Watch("/some/key", 0, Everything)
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
 
 		fakeClient.WaitForWatchCompletion()
 		if e, a := testCase.Response.R.EtcdIndex+1, fakeClient.WatchIndex; e != a {
@@ -612,7 +628,10 @@ func TestWatchFromNotFound(t *testing.T) {
 	}
 	h := EtcdHelper{fakeClient, codec, versioner}
 
-	watching := h.Watch("/some/key", 0)
+	watching, err := h.Watch("/some/key", 0, Everything)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
 
 	fakeClient.WaitForWatchCompletion()
 	if fakeClient.WatchIndex != 3 {
@@ -635,7 +654,10 @@ func TestWatchFromOtherError(t *testing.T) {
 	}
 	h := EtcdHelper{fakeClient, codec, versioner}
 
-	watching := h.Watch("/some/key", 0)
+	watching, err := h.Watch("/some/key", 0, Everything)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
 
 	errEvent := <-watching.ResultChan()
 	if e, a := watch.Error, errEvent.Type; e != a {
@@ -665,7 +687,11 @@ func TestWatchPurposefulShutdown(t *testing.T) {
 	fakeClient.expectNotFoundGetSet["/some/key"] = struct{}{}
 
 	// Test purposeful shutdown
-	watching := h.Watch("/some/key", 0)
+	watching, err := h.Watch("/some/key", 0, Everything)
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+
 	fakeClient.WaitForWatchCompletion()
 	watching.Stop()
 

test/integration/etcd_tools_test.go

@@ -101,7 +101,11 @@ func TestWatch(t *testing.T) {
 		expectedVersion := resp.Node.ModifiedIndex
 
 		// watch should load the object at the current index
-		w := helper.Watch(key, 0)
+		w, err := helper.Watch(key, 0, tools.Everything)
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
+
 		event := <-w.ResultChan()
 		if event.Type != watch.Added || event.Object == nil {
 			t.Fatalf("expected first value to be set to ADDED, got %#v", event)