Merge pull request #7732 from heyitsanthony/lease-err-ka

clientv3: don't halt lease client if there is a lease error

clientv3/concurrency/session.go

@@ -51,12 +51,9 @@ func NewSession(client *v3.Client, opts ...SessionOption) (*Session, error) {
 	}
 
 	ctx, cancel := context.WithCancel(ops.ctx)
-	keepAlive, err := client.KeepAlive(ctx, id)
-	if err != nil || keepAlive == nil {
-		return nil, err
-	}
-
+	keepAlive := client.KeepAlive(ctx, id)
 	donec := make(chan struct{})
+
 	s := &Session{client: client, opts: ops, id: id, cancel: cancel, donec: donec}
 
 	// keep the lease alive until client error or cancelled context

clientv3/example_lease_test.go

@@ -100,12 +100,13 @@ func ExampleLease_keepAlive() {
 	}
 
 	// the key 'foo' will be kept forever
-	ch, kaerr := cli.KeepAlive(context.TODO(), resp.ID)
-	if kaerr != nil {
-		log.Fatal(kaerr)
-	}
+	ch := cli.KeepAlive(context.TODO(), resp.ID)
 
 	ka := <-ch
+	if ka.Err != nil {
+		log.Fatal(ka.Err)
+	}
+
 	fmt.Println("ttl:", ka.TTL)
 	// Output: ttl: 5
 }
@@ -131,9 +132,9 @@ func ExampleLease_keepAliveOnce() {
 	}
 
 	// to renew the lease only once
-	ka, kaerr := cli.KeepAliveOnce(context.TODO(), resp.ID)
-	if kaerr != nil {
-		log.Fatal(kaerr)
+	ka := cli.KeepAliveOnce(context.TODO(), resp.ID)
+	if ka.Err != nil {
+		log.Fatal(ka.Err)
 	}
 
 	fmt.Println("ttl:", ka.TTL)

clientv3/integration/lease_test.go

@@ -104,14 +104,14 @@ func TestLeaseKeepAliveOnce(t *testing.T) {
 		t.Errorf("failed to create lease %v", err)
 	}
 
-	_, err = lapi.KeepAliveOnce(context.Background(), resp.ID)
-	if err != nil {
-		t.Errorf("failed to keepalive lease %v", err)
+	ka := lapi.KeepAliveOnce(context.Background(), resp.ID)
+	if ka.Err != nil {
+		t.Errorf("failed to keepalive lease %v", ka.Err)
 	}
 
-	_, err = lapi.KeepAliveOnce(context.Background(), clientv3.LeaseID(0))
-	if err != rpctypes.ErrLeaseNotFound {
-		t.Errorf("expected %v, got %v", rpctypes.ErrLeaseNotFound, err)
+	ka = lapi.KeepAliveOnce(context.Background(), clientv3.LeaseID(0))
+	if ka.Err != rpctypes.ErrLeaseNotFound {
+		t.Errorf("expected %v, got %v", rpctypes.ErrLeaseNotFound, ka.Err)
 	}
 }
 
@@ -129,10 +129,7 @@ func TestLeaseKeepAlive(t *testing.T) {
 		t.Errorf("failed to create lease %v", err)
 	}
 
-	rc, kerr := lapi.KeepAlive(context.Background(), resp.ID)
-	if kerr != nil {
-		t.Errorf("failed to keepalive lease %v", kerr)
-	}
+	rc := lapi.KeepAlive(context.Background(), resp.ID)
 
 	kresp, ok := <-rc
 	if !ok {
@@ -163,11 +160,7 @@ func TestLeaseKeepAliveOneSecond(t *testing.T) {
 	if err != nil {
 		t.Errorf("failed to create lease %v", err)
 	}
-	rc, kerr := cli.KeepAlive(context.Background(), resp.ID)
-	if kerr != nil {
-		t.Errorf("failed to keepalive lease %v", kerr)
-	}
-
+	rc := cli.KeepAlive(context.Background(), resp.ID)
 	for i := 0; i < 3; i++ {
 		if _, ok := <-rc; !ok {
 			t.Errorf("chan is closed, want not closed")
@@ -193,10 +186,7 @@ func TestLeaseKeepAliveHandleFailure(t *testing.T) {
 		t.Errorf("failed to create lease %v", err)
 	}
 
-	rc, kerr := lapi.KeepAlive(context.Background(), resp.ID)
-	if kerr != nil {
-		t.Errorf("failed to keepalive lease %v", kerr)
-	}
+	rc := lapi.KeepAlive(context.Background(), resp.ID)
 
 	kresp := <-rc
 	if kresp.ID != resp.ID {
@@ -230,7 +220,7 @@ func TestLeaseKeepAliveHandleFailure(t *testing.T) {
 
 type leaseCh struct {
 	lid clientv3.LeaseID
-	ch  <-chan *clientv3.LeaseKeepAliveResponse
+	ch  clientv3.LeaseKeepAliveChan
 }
 
 // TestLeaseKeepAliveNotFound ensures a revoked lease won't stop other keep alives
@@ -247,10 +237,7 @@ func TestLeaseKeepAliveNotFound(t *testing.T) {
 		if rerr != nil {
 			t.Fatal(rerr)
 		}
-		kach, kaerr := cli.KeepAlive(context.Background(), resp.ID)
-		if kaerr != nil {
-			t.Fatal(kaerr)
-		}
+		kach := cli.KeepAlive(context.Background(), resp.ID)
 		lchs = append(lchs, leaseCh{resp.ID, kach})
 	}
 
@@ -375,10 +362,7 @@ func TestLeaseKeepAliveCloseAfterDisconnectRevoke(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	rc, kerr := cli.KeepAlive(context.Background(), resp.ID)
-	if kerr != nil {
-		t.Fatal(kerr)
-	}
+	rc := cli.KeepAlive(context.Background(), resp.ID)
 	kresp := <-rc
 	if kresp.ID != resp.ID {
 		t.Fatalf("ID = %x, want %x", kresp.ID, resp.ID)
@@ -397,9 +381,10 @@ func TestLeaseKeepAliveCloseAfterDisconnectRevoke(t *testing.T) {
 
 	// some keep-alives may still be buffered; drain until close
 	timer := time.After(time.Duration(kresp.TTL) * time.Second)
-	for kresp != nil {
+	loop := true
+	for loop {
 		select {
-		case kresp = <-rc:
+		case _, loop = <-rc:
 		case <-timer:
 			t.Fatalf("keepalive channel did not close")
 		}
@@ -423,10 +408,7 @@ func TestLeaseKeepAliveInitTimeout(t *testing.T) {
 	}
 	// keep client disconnected
 	clus.Members[0].Stop(t)
-	rc, kerr := cli.KeepAlive(context.Background(), resp.ID)
-	if kerr != nil {
-		t.Fatal(kerr)
-	}
+	rc := cli.KeepAlive(context.Background(), resp.ID)
 	select {
 	case ka, ok := <-rc:
 		if ok {
@@ -454,10 +436,7 @@ func TestLeaseKeepAliveTTLTimeout(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	rc, kerr := cli.KeepAlive(context.Background(), resp.ID)
-	if kerr != nil {
-		t.Fatal(kerr)
-	}
+	rc := cli.KeepAlive(context.Background(), resp.ID)
 	if kresp := <-rc; kresp.ID != resp.ID {
 		t.Fatalf("ID = %x, want %x", kresp.ID, resp.ID)
 	}
@@ -580,10 +559,7 @@ func TestLeaseRenewLostQuorum(t *testing.T) {
 
 	kctx, kcancel := context.WithCancel(context.Background())
 	defer kcancel()
-	ka, err := cli.KeepAlive(kctx, r.ID)
-	if err != nil {
-		t.Fatal(err)
-	}
+	ka := cli.KeepAlive(kctx, r.ID)
 	// consume first keepalive so next message sends when cluster is down
 	<-ka
 	lastKa := time.Now()
@@ -630,9 +606,9 @@ func TestLeaseKeepAliveLoopExit(t *testing.T) {
 	}
 	cli.Close()
 
-	_, err = cli.KeepAlive(ctx, resp.ID)
-	if _, ok := err.(clientv3.ErrKeepAliveHalted); !ok {
-		t.Fatalf("expected %T, got %v(%T)", clientv3.ErrKeepAliveHalted{}, err, err)
+	ka := cli.KeepAlive(ctx, resp.ID)
+	if resp, ok := <-ka; ok {
+		t.Fatalf("expected closed channel, got response %+v", resp)
 	}
 }
 
@@ -707,15 +683,9 @@ func TestLeaseWithRequireLeader(t *testing.T) {
 		t.Fatal(err2)
 	}
 	// kaReqLeader close if the leader is lost
-	kaReqLeader, kerr1 := c.KeepAlive(clientv3.WithRequireLeader(context.TODO()), lid1.ID)
-	if kerr1 != nil {
-		t.Fatal(kerr1)
-	}
+	kaReqLeader := c.KeepAlive(clientv3.WithRequireLeader(context.TODO()), lid1.ID)
 	// kaWait will wait even if the leader is lost
-	kaWait, kerr2 := c.KeepAlive(context.TODO(), lid2.ID)
-	if kerr2 != nil {
-		t.Fatal(kerr2)
-	}
+	kaWait := c.KeepAlive(context.TODO(), lid2.ID)
 
 	select {
 	case <-kaReqLeader:

clientv3/lease.go

@@ -41,8 +41,10 @@ type LeaseGrantResponse struct {
 // LeaseKeepAliveResponse is used to convert the protobuf keepalive response.
 type LeaseKeepAliveResponse struct {
 	*pb.ResponseHeader
-	ID  LeaseID
-	TTL int64
+	ID       LeaseID
+	TTL      int64
+	Err      error
+	Deadline time.Time
 }
 
 // LeaseTimeToLiveResponse is used to convert the protobuf lease timetolive response.
@@ -70,23 +72,11 @@ const (
 	NoLease LeaseID = 0
 
 	// retryConnWait is how long to wait before retrying on a lost leader
+	// or keep alive loop failure.
 	retryConnWait = 500 * time.Millisecond
 )
 
-// ErrKeepAliveHalted is returned if client keep alive loop halts with an unexpected error.
-//
-// This usually means that automatic lease renewal via KeepAlive is broken, but KeepAliveOnce will still work as expected.
-type ErrKeepAliveHalted struct {
-	Reason error
-}
-
-func (e ErrKeepAliveHalted) Error() string {
-	s := "etcdclient: leases keep alive halted"
-	if e.Reason != nil {
-		s += ": " + e.Reason.Error()
-	}
-	return s
-}
+type LeaseKeepAliveChan <-chan LeaseKeepAliveResponse
 
 type Lease interface {
 	// Grant creates a new lease.
@@ -98,12 +88,24 @@ type Lease interface {
 	// TimeToLive retrieves the lease information of the given lease ID.
 	TimeToLive(ctx context.Context, id LeaseID, opts ...LeaseOption) (*LeaseTimeToLiveResponse, error)
 
-	// KeepAlive keeps the given lease alive forever.
-	KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAliveResponse, error)
-
-	// KeepAliveOnce renews the lease once. In most of the cases, Keepalive
-	// should be used instead of KeepAliveOnce.
-	KeepAliveOnce(ctx context.Context, id LeaseID) (*LeaseKeepAliveResponse, error)
+	// KeepAlive keeps the given lease alive forever. If the keepalive response posted to
+	// the channel is not consumed immediately, the lease client will continue sending keep alive requests
+	// to the etcd server at least every second until latest response is consumed.
+	//
+	// The KeepAlive channel closes if the underlying keep alive stream is interrupted in some
+	// way the client cannot handle itself; the error will be posted in the last keep
+	// alive message before closing. If there is no keepalive response within the
+	// lease's time-out, the channel will close with no error. In most cases calling
+	// KeepAlive again will re-establish keepalives with the target lease if it has not
+	// expired.
+	KeepAlive(ctx context.Context, id LeaseID) LeaseKeepAliveChan
+
+	// KeepAliveOnce renews the lease once. The response corresponds to the
+	// first message from calling KeepAlive. If the response has a recoverable
+	// error, KeepAliveOnce will retry the RPC with a new keep alive message.
+	//
+	// In most of the cases, Keepalive should be used instead of KeepAliveOnce.
+	KeepAliveOnce(ctx context.Context, id LeaseID) LeaseKeepAliveResponse
 
 	// Close releases all resources Lease keeps for efficient communication
 	// with the etcd server.
@@ -113,9 +115,8 @@ type Lease interface {
 type lessor struct {
 	mu sync.Mutex // guards all fields
 
-	// donec is closed and loopErr is set when recvKeepAliveLoop stops
-	donec   chan struct{}
-	loopErr error
+	// donec is closed when all goroutines are torn down from Close()
+	donec chan struct{}
 
 	remote pb.LeaseClient
 
@@ -137,7 +138,7 @@ type lessor struct {
 
 // keepAlive multiplexes a keepalive for a lease over multiple channels
 type keepAlive struct {
-	chs  []chan<- *LeaseKeepAliveResponse
+	chs  []chan<- LeaseKeepAliveResponse
 	ctxs []context.Context
 	// deadline is the time the keep alive channels close if no response
 	deadline time.Time
@@ -219,24 +220,22 @@ func (l *lessor) TimeToLive(ctx context.Context, id LeaseID, opts ...LeaseOption
 	}
 }
 
-func (l *lessor) KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAliveResponse, error) {
-	ch := make(chan *LeaseKeepAliveResponse, leaseResponseChSize)
+func (l *lessor) KeepAlive(ctx context.Context, id LeaseID) LeaseKeepAliveChan {
+	ch := make(chan LeaseKeepAliveResponse, leaseResponseChSize)
 
 	l.mu.Lock()
 	// ensure that recvKeepAliveLoop is still running
 	select {
 	case <-l.donec:
-		err := l.loopErr
-		l.mu.Unlock()
 		close(ch)
-		return ch, ErrKeepAliveHalted{Reason: err}
+		return ch
 	default:
 	}
 	ka, ok := l.keepAlives[id]
 	if !ok {
 		// create fresh keep alive
 		ka = &keepAlive{
-			chs:           []chan<- *LeaseKeepAliveResponse{ch},
+			chs:           []chan<- LeaseKeepAliveResponse{ch},
 			ctxs:          []context.Context{ctx},
 			deadline:      time.Now().Add(l.firstKeepAliveTimeout),
 			nextKeepAlive: time.Now(),
@@ -252,24 +251,51 @@ func (l *lessor) KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAl
 
 	go l.keepAliveCtxCloser(id, ctx, ka.donec)
 	l.firstKeepAliveOnce.Do(func() {
-		go l.recvKeepAliveLoop()
+		go func() {
+			defer func() {
+				l.mu.Lock()
+				for _, ka := range l.keepAlives {
+					ka.Close(nil)
+				}
+				close(l.donec)
+				l.mu.Unlock()
+			}()
+
+			for l.stopCtx.Err() == nil {
+				err := l.recvKeepAliveLoop()
+				if err == context.Canceled {
+					// canceled by user; no error like WatchChan
+					err = nil
+				}
+				l.mu.Lock()
+				for _, ka := range l.keepAlives {
+					ka.Close(err)
+				}
+				l.keepAlives = make(map[LeaseID]*keepAlive)
+				l.mu.Unlock()
+				select {
+				case <-l.stopCtx.Done():
+				case <-time.After(retryConnWait):
+				}
+			}
+		}()
 		go l.deadlineLoop()
 	})
 
-	return ch, nil
+	return ch
 }
 
-func (l *lessor) KeepAliveOnce(ctx context.Context, id LeaseID) (*LeaseKeepAliveResponse, error) {
+func (l *lessor) KeepAliveOnce(ctx context.Context, id LeaseID) LeaseKeepAliveResponse {
 	for {
-		resp, err := l.keepAliveOnce(ctx, id)
-		if err == nil {
+		resp := l.keepAliveOnce(ctx, id)
+		if resp.Err == nil {
 			if resp.TTL <= 0 {
-				err = rpctypes.ErrLeaseNotFound
+				resp.Err = rpctypes.ErrLeaseNotFound
 			}
-			return resp, err
+			return resp
 		}
-		if isHaltErr(ctx, err) {
-			return nil, toErr(ctx, err)
+		if isHaltErr(ctx, resp.Err) {
+			return resp
 		}
 	}
 }
@@ -339,7 +365,7 @@ func (l *lessor) closeRequireLeader() {
 			continue
 		}
 		// remove all channels that required a leader from keepalive
-		newChs := make([]chan<- *LeaseKeepAliveResponse, len(ka.chs)-reqIdxs)
+		newChs := make([]chan<- LeaseKeepAliveResponse, len(ka.chs)-reqIdxs)
 		newCtxs := make([]context.Context, len(newChs))
 		newIdx := 0
 		for i := range ka.chs {
@@ -353,45 +379,34 @@ func (l *lessor) closeRequireLeader() {
 	}
 }
 
-func (l *lessor) keepAliveOnce(ctx context.Context, id LeaseID) (*LeaseKeepAliveResponse, error) {
+func (l *lessor) keepAliveOnce(ctx context.Context, id LeaseID) LeaseKeepAliveResponse {
 	cctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
 	stream, err := l.remote.LeaseKeepAlive(cctx, grpc.FailFast(false))
 	if err != nil {
-		return nil, toErr(ctx, err)
+		return LeaseKeepAliveResponse{Err: toErr(ctx, err)}
 	}
 
 	err = stream.Send(&pb.LeaseKeepAliveRequest{ID: int64(id)})
 	if err != nil {
-		return nil, toErr(ctx, err)
+		return LeaseKeepAliveResponse{Err: toErr(ctx, err)}
 	}
 
 	resp, rerr := stream.Recv()
 	if rerr != nil {
-		return nil, toErr(ctx, rerr)
+		return LeaseKeepAliveResponse{Err: toErr(ctx, rerr)}
 	}
 
-	karesp := &LeaseKeepAliveResponse{
+	return LeaseKeepAliveResponse{
 		ResponseHeader: resp.GetHeader(),
 		ID:             LeaseID(resp.ID),
 		TTL:            resp.TTL,
+		Deadline:       time.Now().Add(time.Duration(resp.TTL) * time.Second),
 	}
-	return karesp, nil
 }
 
 func (l *lessor) recvKeepAliveLoop() (gerr error) {
-	defer func() {
-		l.mu.Lock()
-		close(l.donec)
-		l.loopErr = gerr
-		for _, ka := range l.keepAlives {
-			ka.Close()
-		}
-		l.keepAlives = make(map[LeaseID]*keepAlive)
-		l.mu.Unlock()
-	}()
-
 	stream, serr := l.resetRecv()
 	for serr == nil {
 		resp, err := stream.Recv()
@@ -443,6 +458,7 @@ func (l *lessor) recvKeepAlive(resp *pb.LeaseKeepAliveResponse) {
 		ResponseHeader: resp.GetHeader(),
 		ID:             LeaseID(resp.ID),
 		TTL:            resp.TTL,
+		Deadline:       time.Now().Add(time.Duration(resp.TTL) * time.Second),
 	}
 
 	l.mu.Lock()
@@ -456,7 +472,7 @@ func (l *lessor) recvKeepAlive(resp *pb.LeaseKeepAliveResponse) {
 	if karesp.TTL <= 0 {
 		// lease expired; close all keep alive channels
 		delete(l.keepAlives, karesp.ID)
-		ka.Close()
+		ka.Close(nil)
 		return
 	}
 
@@ -465,7 +481,7 @@ func (l *lessor) recvKeepAlive(resp *pb.LeaseKeepAliveResponse) {
 	ka.deadline = time.Now().Add(time.Duration(karesp.TTL) * time.Second)
 	for _, ch := range ka.chs {
 		select {
-		case ch <- karesp:
+		case ch <- *karesp:
 			ka.nextKeepAlive = nextKeepAlive
 		default:
 		}
@@ -486,7 +502,7 @@ func (l *lessor) deadlineLoop() {
 		for id, ka := range l.keepAlives {
 			if ka.deadline.Before(now) {
 				// waited too long for response; lease may be expired
-				ka.Close()
+				ka.Close(nil)
 				delete(l.keepAlives, id)
 			}
 		}
@@ -528,9 +544,18 @@ func (l *lessor) sendKeepAliveLoop(stream pb.Lease_LeaseKeepAliveClient) {
 	}
 }
 
-func (ka *keepAlive) Close() {
+func (ka *keepAlive) Close(err error) {
 	close(ka.donec)
 	for _, ch := range ka.chs {
+		if err != nil {
+			// try to post error if buffer space available
+			select {
+			case ch <- LeaseKeepAliveResponse{Err: err}:
+			default:
+			}
+		}
 		close(ch)
 	}
+	// so keepAliveCtxClose doesn't double-close ka.chs
+	ka.chs, ka.ctxs = nil, nil
 }

etcdctl/ctlv3/command/lease_command.go

@@ -148,13 +148,12 @@ func leaseKeepAliveCommandFunc(cmd *cobra.Command, args []string) {
 	}
 
 	id := leaseFromArgs(args[0])
-	respc, kerr := mustClientFromCmd(cmd).KeepAlive(context.TODO(), id)
-	if kerr != nil {
-		ExitWithError(ExitBadConnection, kerr)
-	}
-
+	respc := mustClientFromCmd(cmd).KeepAlive(context.TODO(), id)
 	for resp := range respc {
-		display.KeepAlive(*resp)
+		if resp.Err != nil {
+			ExitWithError(ExitError, resp.Err)
+		}
+		display.KeepAlive(resp)
 	}
 
 	if _, ok := (display).(*simplePrinter); ok {

integration/cluster_proxy.go

@@ -75,6 +75,7 @@ type proxyCloser struct {
 	clientv3.Watcher
 	wdonec  <-chan struct{}
 	kvdonec <-chan struct{}
+	lclose  func()
 	lpdonec <-chan struct{}
 }
 
@@ -83,6 +84,7 @@ func (pc *proxyCloser) Close() error {
 	<-pc.kvdonec
 	err := pc.Watcher.Close()
 	<-pc.wdonec
+	pc.lclose()
 	<-pc.lpdonec
 	return err
 }
@@ -95,11 +97,13 @@ func newClientV3(cfg clientv3.Config) (*clientv3.Client, error) {
 	rpc := toGRPC(c)
 	c.KV = clientv3.NewKVFromKVClient(rpc.KV)
 	pmu.Lock()
+	lc := c.Lease
 	c.Lease = clientv3.NewLeaseFromLeaseClient(rpc.Lease, cfg.DialTimeout)
 	c.Watcher = &proxyCloser{
 		Watcher: clientv3.NewWatchFromWatchClient(rpc.Watch),
 		wdonec:  proxies[c].wdonec,
 		kvdonec: proxies[c].kvdonec,
+		lclose:  func() { lc.Close() },
 		lpdonec: proxies[c].lpdonec,
 	}
 	pmu.Unlock()

proxy/grpcproxy/lease.go

@@ -255,10 +255,7 @@ func (lps *leaseProxyStream) recvLoop() error {
 func (lps *leaseProxyStream) keepAliveLoop(leaseID int64, neededResps *atomicCounter) error {
 	cctx, ccancel := context.WithCancel(lps.ctx)
 	defer ccancel()
-	respc, err := lps.lessor.KeepAlive(cctx, clientv3.LeaseID(leaseID))
-	if err != nil {
-		return err
-	}
+	respc := lps.lessor.KeepAlive(cctx, clientv3.LeaseID(leaseID))
 	// ticker expires when loop hasn't received keepalive within TTL
 	var ticker <-chan time.Time
 	for {
@@ -276,7 +273,7 @@ func (lps *leaseProxyStream) keepAliveLoop(leaseID int64, neededResps *atomicCou
 			lps.mu.Unlock()
 			return nil
 		case rp, ok := <-respc:
-			if !ok {
+			if !ok || rp.Err != nil {
 				lps.mu.Lock()
 				delete(lps.keepAliveLeases, leaseID)
 				lps.mu.Unlock()

tools/benchmark/cmd/lease.go

@@ -61,8 +61,8 @@ func leaseKeepaliveFunc(cmd *cobra.Command, args []string) {
 			}
 			for range requests {
 				st := time.Now()
-				_, err := c.KeepAliveOnce(context.TODO(), resp.ID)
-				r.Results() <- report.Result{Err: err, Start: st, End: time.Now()}
+				ka := c.KeepAliveOnce(context.TODO(), resp.ID)
+				r.Results() <- report.Result{Err: ka.Err, Start: st, End: time.Now()}
 				bar.Increment()
 			}
 		}(clients[i])

tools/functional-tester/etcd-runner/command/lease_renewer_command.go

@@ -50,7 +50,6 @@ func runLeaseRenewerFunc(cmd *cobra.Command, args []string) {
 	for {
 		var (
 			l   *clientv3.LeaseGrantResponse
-			lk  *clientv3.LeaseKeepAliveResponse
 			err error
 		)
 		for {
@@ -62,13 +61,14 @@ func runLeaseRenewerFunc(cmd *cobra.Command, args []string) {
 		expire := time.Now().Add(time.Duration(l.TTL-1) * time.Second)
 
 		for {
-			lk, err = c.Lease.KeepAliveOnce(ctx, l.ID)
+			lk := c.Lease.KeepAliveOnce(ctx, l.ID)
+			err = lk.Err
 			if grpc.Code(err) == codes.NotFound {
 				if time.Since(expire) < 0 {
 					log.Printf("bad renew! exceeded: %v", time.Since(expire))
 					for {
-						lk, err = c.Lease.KeepAliveOnce(ctx, l.ID)
-						fmt.Println(lk, err)
+						lk = c.Lease.KeepAliveOnce(ctx, l.ID)
+						fmt.Println(lk)
 						time.Sleep(time.Second)
 					}
 				}