lease: fix lease init race

clientv3/lease.go

@@ -57,8 +57,10 @@ type Lease interface {
 type lessor struct {
 	c *Client
 
-	mu     sync.Mutex       // guards all fields
-	conn   *grpc.ClientConn // conn in-use
+	mu      sync.Mutex       // guards all fields
+	conn    *grpc.ClientConn // conn in-use
+	initedc chan bool
+
 	remote pb.LeaseClient
 
 	stream       pb.Lease_LeaseKeepAliveClient
@@ -76,12 +78,17 @@ func NewLease(c *Client) Lease {
 		c:    c,
 		conn: c.ActiveConnection(),
 
+		initedc: make(chan bool, 1),
+
 		keepAlives: make(map[lease.LeaseID]chan *LeaseKeepAliveResponse),
 		deadlines:  make(map[lease.LeaseID]time.Time),
 	}
 
 	l.remote = pb.NewLeaseClient(l.conn)
 	l.stopCtx, l.stopCancel = context.WithCancel(context.Background())
+
+	l.initedc <- false
+
 	go l.recvKeepAliveLoop()
 	go l.sendKeepAliveLoop()
 
@@ -103,7 +110,6 @@ func (l *lessor) Create(ctx context.Context, ttl int64) (*LeaseCreateResponse, e
 		if isRPCError(err) {
 			return nil, err
 		}
-
 		if nerr := l.switchRemoteAndStream(err); nerr != nil {
 			return nil, nerr
 		}
@@ -354,14 +360,17 @@ func (l *lessor) newStream() error {
 }
 
 func (l *lessor) initStream() bool {
-	if l.getKeepAliveStream() != nil {
+	ok := <-l.initedc
+	if ok {
 		return true
 	}
 
 	err := l.switchRemoteAndStream(nil)
 	if err == nil {
+		l.initedc <- true
 		return true
 	}
+	l.initedc <- false
 	return false
 }