client: support create with context (#1995)

Signed-off-by: disksing <i@disksing.com>

client/client.go

@@ -141,23 +141,30 @@ type SecurityOption struct {
 
 // NewClient creates a PD client.
 func NewClient(pdAddrs []string, security SecurityOption) (Client, error) {
+	return NewClientWithContext(context.Background(), pdAddrs, security)
+}
+
+// NewClientWithContext creates a PD client with context.
+func NewClientWithContext(ctx context.Context, pdAddrs []string, security SecurityOption) (Client, error) {
 	log.Info("[pd] create pd client with endpoints", zap.Strings("pd-address", pdAddrs))
-	ctx, cancel := context.WithCancel(context.Background())
+	ctx1, cancel := context.WithCancel(ctx)
 	c := &client{
 		urls:          addrsToUrls(pdAddrs),
 		tsoRequests:   make(chan *tsoRequest, maxMergeTSORequests),
 		tsDeadlineCh:  make(chan deadline, 1),
 		checkLeaderCh: make(chan struct{}, 1),
-		ctx:           ctx,
+		ctx:           ctx1,
 		cancel:        cancel,
 		security:      security,
 	}
 	c.connMu.clientConns = make(map[string]*grpc.ClientConn)
 
 	if err := c.initRetry(c.initClusterID); err != nil {
+		cancel()
 		return nil, err
 	}
 	if err := c.initRetry(c.updateLeader); err != nil {
+		cancel()
 		return nil, err
 	}
 	log.Info("[pd] init cluster id", zap.Uint64("cluster-id", c.clusterID))
@@ -184,7 +191,11 @@ func (c *client) initRetry(f func() error) error {
 		if err = f(); err == nil {
 			return nil
 		}
-		time.Sleep(time.Second)
+		select {
+		case <-c.ctx.Done():
+			return err
+		case <-time.After(time.Second):
+		}
 	}
 	return errors.WithStack(err)
 }

client/client_test.go

@@ -470,3 +470,16 @@ func (s *testClientSuite) TestScatterRegion(c *C) {
 	})
 	c.Succeed()
 }
+
+var _ = Suite(&testClientCtxSuite{})
+
+type testClientCtxSuite struct{}
+
+func (s *testClientCtxSuite) TestClientCtx(c *C) {
+	start := time.Now()
+	ctx, cancel := context.WithTimeout(context.TODO(), time.Second*3)
+	defer cancel()
+	_, err := NewClientWithContext(ctx, []string{"localhost:8080"}, SecurityOption{})
+	c.Assert(err, NotNil)
+	c.Assert(time.Since(start), Less, time.Second*4)
+}