kv/client: fix the error handling for io.EOF may miss region reconnect (#1641)

cdc/kv/client.go

@@ -1109,16 +1109,14 @@ func (s *eventFeedSession) receiveFromStream(
 	for {
 		cevent, err := stream.Recv()
 
-		failpoint.Inject("kvClientStreamRecvError", func() {
-			err = errors.New("injected stream recv error")
-		})
-		// TODO: Should we have better way to handle the errors?
-		if err == io.EOF {
-			for _, state := range regionStates {
-				close(state.regionEventCh)
+		failpoint.Inject("kvClientStreamRecvError", func(msg failpoint.Value) {
+			errStr := msg.(string)
+			if errStr == io.EOF.Error() {
+				err = io.EOF
+			} else {
+				err = errors.New(errStr)
 			}
-			return nil
-		}
+		})
 		if err != nil {
 			if status.Code(errors.Cause(err)) == codes.Canceled {
 				log.Debug(
@@ -1406,12 +1404,8 @@ func (s *eventFeedSession) singleEventFeed(
 			continue
 		case event, ok = <-receiverCh:
 		}
-		if !ok {
-			log.Debug("singleEventFeed receiver closed")
-			return lastResolvedTs, nil
-		}
 
-		if event == nil {
+		if !ok || event == nil {
 			log.Debug("singleEventFeed closed by error")
 			return lastResolvedTs, cerror.ErrEventFeedAborted.GenWithStackByArgs()
 		}

cdc/kv/client_test.go

@@ -1193,11 +1193,7 @@ func (s *etcdSuite) TestStreamSendWithError(c *check.C) {
 	cancel()
 }
 
-// TestStreamSendWithError mainly tests the scenario that the `Recv` call of a gPRC
-// stream in kv client meets error, and kv client logs the error and re-establish
-// new request
-func (s *etcdSuite) TestStreamRecvWithError(c *check.C) {
-	defer testleak.AfterTest(c)()
+func (s *etcdSuite) testStreamRecvWithError(c *check.C, failpointStr string) {
 	defer s.TearDownTest(c)
 	ctx, cancel := context.WithCancel(context.Background())
 	wg := &sync.WaitGroup{}
@@ -1226,7 +1222,7 @@ func (s *etcdSuite) TestStreamRecvWithError(c *check.C) {
 	cluster.AddStore(1, addr1)
 	cluster.Bootstrap(regionID, []uint64{1}, []uint64{4}, 4)
 
-	err = failpoint.Enable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvError", "1*return(true)")
+	err = failpoint.Enable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvError", failpointStr)
 	c.Assert(err, check.IsNil)
 	defer func() {
 		_ = failpoint.Disable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvError")
@@ -1316,6 +1312,42 @@ func (s *etcdSuite) TestStreamRecvWithError(c *check.C) {
 	cancel()
 }
 
+// TestStreamSendWithErrorNormal mainly tests the scenario that the `Recv` call
+// of a gPRC stream in kv client meets a **logical related** error, and kv client
+// logs the error and re-establish new request.
+func (s *etcdSuite) TestStreamRecvWithErrorNormal(c *check.C) {
+	defer testleak.AfterTest(c)()
+
+	// test client v2
+	s.testStreamRecvWithError(c, "1*return(\"injected stream recv error\")")
+
+	// test client v1
+	clientv2 := enableKVClientV2
+	enableKVClientV2 = false
+	defer func() {
+		enableKVClientV2 = clientv2
+	}()
+	s.testStreamRecvWithError(c, "1*return(\"injected stream recv error\")")
+}
+
+// TestStreamSendWithErrorIOEOF mainly tests the scenario that the `Recv` call
+// of a gPRC stream in kv client meets error io.EOF, and kv client logs the error
+// and re-establish new request
+func (s *etcdSuite) TestStreamRecvWithErrorIOEOF(c *check.C) {
+	defer testleak.AfterTest(c)()
+
+	// test client v2
+	s.testStreamRecvWithError(c, "1*return(\"EOF\")")
+
+	// test client v1
+	clientv2 := enableKVClientV2
+	enableKVClientV2 = false
+	defer func() {
+		enableKVClientV2 = clientv2
+	}()
+	s.testStreamRecvWithError(c, "1*return(\"EOF\")")
+}
+
 // TestIncompatibleTiKV tests TiCDC new request to TiKV meets `ErrVersionIncompatible`
 // error (in fact this error is raised before EventFeed API is really called),
 // TiCDC will wait 20s and then retry. This is a common scenario when rolling
@@ -2351,8 +2383,8 @@ func (s *etcdSuite) TestFailRegionReentrant(c *check.C) {
 	err = failpoint.Enable("github.com/pingcap/ticdc/cdc/kv/kvClientRegionReentrantErrorDelay", "sleep(500)")
 	c.Assert(err, check.IsNil)
 	defer func() {
-		_ = failpoint.Disable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvError")
-		_ = failpoint.Disable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvErrorDelay")
+		_ = failpoint.Disable("github.com/pingcap/ticdc/cdc/kv/kvClientRegionReentrantError")
+		_ = failpoint.Disable("github.com/pingcap/ticdc/cdc/kv/kvClientRegionReentrantErrorDelay")
 	}()
 	baseAllocatedID := currentRequestID()
 	lockresolver := txnutil.NewLockerResolver(kvStorage.(tikv.Storage))
@@ -2434,7 +2466,7 @@ func (s *etcdSuite) TestClientV1UnlockRangeReentrant(c *check.C) {
 	cluster.Bootstrap(regionID3, []uint64{1}, []uint64{4}, 4)
 	cluster.SplitRaw(regionID3, regionID4, []byte("b"), []uint64{5}, 5)
 
-	err = failpoint.Enable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvError", "1*return(true)")
+	err = failpoint.Enable("github.com/pingcap/ticdc/cdc/kv/kvClientStreamRecvError", "1*return(\"injected stream recv error\")")
 	c.Assert(err, check.IsNil)
 	err = failpoint.Enable("github.com/pingcap/ticdc/cdc/kv/kvClientPendingRegionDelay", "1*sleep(0)->1*sleep(2000)")
 	c.Assert(err, check.IsNil)

cdc/kv/client_v2.go

@@ -210,13 +210,14 @@ func (s *eventFeedSession) receiveFromStreamV2(
 				worker.inputCh <- nil
 			}
 		})
-		failpoint.Inject("kvClientStreamRecvError", func() {
-			err = errors.New("injected stream recv error")
+		failpoint.Inject("kvClientStreamRecvError", func(msg failpoint.Value) {
+			errStr := msg.(string)
+			if errStr == io.EOF.Error() {
+				err = io.EOF
+			} else {
+				err = errors.New(errStr)
+			}
 		})
-		if err == io.EOF {
-			close(worker.inputCh)
-			return nil
-		}
 		if err != nil {
 			if status.Code(errors.Cause(err)) == codes.Canceled {
 				log.Debug(

cdc/kv/region_worker.go

@@ -267,13 +267,9 @@ func (w *regionWorker) eventHandler(ctx context.Context) error {
 		case <-ctx.Done():
 			return errors.Trace(ctx.Err())
 		case event, ok := <-w.inputCh:
-			if !ok {
-				log.Debug("region worker receiver closed")
-				return nil
-			}
 			// event == nil means the region worker should exit and re-establish
 			// all existing regions.
-			if event == nil {
+			if !ok || event == nil {
 				log.Info("region worker closed by error")
 				return w.evictAllRegions(ctx)
 			}