clientv3: use default client watcher

clientv3/concurrency/key.go

@@ -40,9 +40,7 @@ func NewUniqueKey(ctx context.Context, kv v3.KV, pfx string, opts ...v3.OpOption
 }
 
 func waitUpdate(ctx context.Context, client *v3.Client, key string, opts ...v3.OpOption) error {
-	w := v3.NewWatcher(client)
-	defer w.Close()
-	wc := w.Watch(ctx, key, opts...)
+	wc := client.Watch(ctx, key, opts...)
 	if wc == nil {
 		return ctx.Err()
 	}

clientv3/example_watch_test.go

@@ -32,10 +32,7 @@ func ExampleWatcher_watch() {
 	}
 	defer cli.Close()
 
-	wc := clientv3.NewWatcher(cli)
-	defer wc.Close()
-
-	rch := wc.Watch(context.Background(), "foo")
+	rch := cli.Watch(context.Background(), "foo")
 	for wresp := range rch {
 		for _, ev := range wresp.Events {
 			fmt.Printf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
@@ -54,10 +51,7 @@ func ExampleWatcher_watchPrefix() {
 	}
 	defer cli.Close()
 
-	wc := clientv3.NewWatcher(cli)
-	defer wc.Close()
-
-	rch := wc.Watch(context.Background(), "foo", clientv3.WithPrefix())
+	rch := cli.Watch(context.Background(), "foo", clientv3.WithPrefix())
 	for wresp := range rch {
 		for _, ev := range wresp.Events {
 			fmt.Printf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)

clientv3/mirror/syncer.go

@@ -106,21 +106,5 @@ func (s *syncer) SyncUpdates(ctx context.Context) clientv3.WatchChan {
 	if s.rev == 0 {
 		panic("unexpected revision = 0. Calling SyncUpdates before SyncBase finishes?")
 	}
-
-	respchan := make(chan clientv3.WatchResponse, 1024)
-
-	go func() {
-		wapi := clientv3.NewWatcher(s.c)
-		defer wapi.Close()
-		defer close(respchan)
-
-		// get all events since revision (or get non-compacted revision, if
-		// rev is too far behind)
-		wch := wapi.Watch(ctx, s.prefix, clientv3.WithPrefix(), clientv3.WithRev(s.rev))
-		for wr := range wch {
-			respchan <- wr
-		}
-	}()
-
-	return respchan
+	return s.c.Watch(ctx, s.prefix, clientv3.WithPrefix(), clientv3.WithRev(s.rev))
 }

contrib/recipes/watch.go

@@ -22,23 +22,19 @@ import (
 
 // WaitEvents waits on a key until it observes the given events and returns the final one.
 func WaitEvents(c *clientv3.Client, key string, rev int64, evs []storagepb.Event_EventType) (*storagepb.Event, error) {
-	w := clientv3.NewWatcher(c)
-	wc := w.Watch(context.Background(), key, clientv3.WithRev(rev))
+	wc := c.Watch(context.Background(), key, clientv3.WithRev(rev))
 	if wc == nil {
-		w.Close()
 		return nil, ErrNoWatcher
 	}
-	return waitEvents(wc, evs), w.Close()
+	return waitEvents(wc, evs), nil
 }
 
 func WaitPrefixEvents(c *clientv3.Client, prefix string, rev int64, evs []storagepb.Event_EventType) (*storagepb.Event, error) {
-	w := clientv3.NewWatcher(c)
-	wc := w.Watch(context.Background(), prefix, clientv3.WithPrefix(), clientv3.WithRev(rev))
+	wc := c.Watch(context.Background(), prefix, clientv3.WithPrefix(), clientv3.WithRev(rev))
 	if wc == nil {
-		w.Close()
 		return nil, ErrNoWatcher
 	}
-	return waitEvents(wc, evs), w.Close()
+	return waitEvents(wc, evs), nil
 }
 
 func waitEvents(wc clientv3.WatchChan, evs []storagepb.Event_EventType) *storagepb.Event {

etcdctlv3/command/snapshot_command.go

@@ -52,9 +52,7 @@ func snapshotCommandFunc(cmd *cobra.Command, args []string) {
 // snapshotToStdout streams a snapshot over stdout
 func snapshotToStdout(c *clientv3.Client) {
 	// must explicitly fetch first revision since no retry on stdout
-	wapi := clientv3.NewWatcher(c)
-	defer wapi.Close()
-	wr := <-wapi.Watch(context.TODO(), "", clientv3.WithPrefix(), clientv3.WithRev(1))
+	wr := <-c.Watch(context.TODO(), "", clientv3.WithPrefix(), clientv3.WithRev(1))
 	if len(wr.Events) > 0 {
 		wr.CompactRevision = 1
 	}

etcdctlv3/command/watch_command.go

@@ -57,16 +57,14 @@ func watchCommandFunc(cmd *cobra.Command, args []string) {
 		ExitWithError(ExitBadArgs, fmt.Errorf("watch in non-interactive mode requires an argument as key or prefix"))
 	}
 
-	c := mustClientFromCmd(cmd)
-	w := clientv3.NewWatcher(c)
-
 	opts := []clientv3.OpOption{clientv3.WithRev(watchRev)}
 	if watchPrefix {
 		opts = append(opts, clientv3.WithPrefix())
 	}
-	wc := w.Watch(context.TODO(), args[0], opts...)
+	c := mustClientFromCmd(cmd)
+	wc := c.Watch(context.TODO(), args[0], opts...)
 	printWatchCh(wc)
-	err := w.Close()
+	err := c.Close()
 	if err == nil {
 		ExitWithError(ExitInterrupted, fmt.Errorf("watch is canceled by the server"))
 	}
@@ -75,7 +73,6 @@ func watchCommandFunc(cmd *cobra.Command, args []string) {
 
 func watchInteractiveFunc(cmd *cobra.Command, args []string) {
 	c := mustClientFromCmd(cmd)
-	w := clientv3.NewWatcher(c)
 
 	reader := bufio.NewReader(os.Stdin)
 
@@ -117,7 +114,7 @@ func watchInteractiveFunc(cmd *cobra.Command, args []string) {
 		if watchPrefix {
 			opts = append(opts, clientv3.WithPrefix())
 		}
-		ch := w.Watch(context.TODO(), key, opts...)
+		ch := c.Watch(context.TODO(), key, opts...)
 		go printWatchCh(ch)
 	}
 }