.*: fix bug that after execute pause-task the task may still running

_utils/terror_gen/errors_release.txt

@@ -390,8 +390,8 @@ ErrWorkerStartService,[code=40048:class=dm-worker:scope=internal:level=high],"st
 ErrWorkerNoStart,[code=40070:class=dm-worker:scope=internal:level=high],"worker has not started"
 ErrWorkerAlreadyClosed,[code=40049:class=dm-worker:scope=internal:level=high],"worker already closed"
 ErrWorkerAlreadyStart,[code=40071:class=dm-worker:scope=internal:level=high],"worker already started"
-ErrWorkerNotRunningStage,[code=40050:class=dm-worker:scope=internal:level=high],"current stage is not running not valid"
-ErrWorkerNotPausedStage,[code=40051:class=dm-worker:scope=internal:level=high],"current stage is not paused not valid"
+ErrWorkerNotRunningStage,[code=40050:class=dm-worker:scope=internal:level=high],"current stage is %s but not running, invalid"
+ErrWorkerNotPausedStage,[code=40051:class=dm-worker:scope=internal:level=high],"current stage is %s but not paused, invalid"
 ErrWorkerUpdateTaskStage,[code=40052:class=dm-worker:scope=internal:level=high],"can only update task on Paused stage, but current stage is %s"
 ErrWorkerMigrateStopRelay,[code=40053:class=dm-worker:scope=internal:level=high],"relay unit has stopped, can not be migrated"
 ErrWorkerSubTaskNotFound,[code=40054:class=dm-worker:scope=internal:level=high],"sub task with name %s not found"

dm/proto/dmworker.proto

@@ -145,6 +145,9 @@ enum Stage {
     Paused = 3;
     Stopped = 4;
     Finished = 5;
+
+    Pausing = 6;
+    Resuming = 7;
 }
 
 // CheckStatus represents status for check unit

dm/unit/unit.go

@@ -15,6 +15,7 @@ package unit
 
 import (
 	"context"
+	"strings"
 	"time"
 
 	"github.com/pingcap/dm/dm/config"
@@ -77,3 +78,11 @@ func NewProcessError(err error) *pb.ProcessError {
 	}
 	return result
 }
+
+// IsCtxCanceledProcessErr returns true if the err's context canceled
+func IsCtxCanceledProcessErr(err *pb.ProcessError) bool {
+	if strings.Contains(err.Msg, "context canceled") {
+		return true
+	}
+	return false
+}

dm/unit/unit_test.go

@@ -0,0 +1,33 @@
+// Copyright 2020 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package unit
+
+import (
+	"context"
+
+	"github.com/pingcap/check"
+	"github.com/pingcap/errors"
+)
+
+var _ = check.Suite(&testUnitSuite{})
+
+type testUnitSuite struct{}
+
+func (t *testUnitSuite) TestIsCtxCanceledProcessErr(c *check.C) {
+	err := NewProcessError(context.Canceled)
+	c.Assert(IsCtxCanceledProcessErr(err), check.IsTrue)
+
+	err = NewProcessError(errors.New("123"))
+	c.Assert(IsCtxCanceledProcessErr(err), check.IsFalse)
+}

dm/worker/subtask.go

@@ -236,18 +236,25 @@ func (st *SubTask) callCurrCancel() {
 func (st *SubTask) fetchResult(pr chan pb.ProcessResult) {
 	defer st.wg.Done()
 
-	st.RLock()
-	ctx := st.currCtx
-	st.RUnlock()
-
 	select {
-	case <-ctx.Done():
+	case <-st.ctx.Done():
+		// should not use st.currCtx, because will do st.currCancel when Pause task,
+		// and this function will return, and the unit's Process maybe still running.
 		return
 	case result := <-pr:
+		// filter the context canceled error
+		errs := make([]*pb.ProcessError, 0, 2)
+		for _, err := range result.Errors {
+			if !unit.IsCtxCanceledProcessErr(err) {
+				errs = append(errs, err)
+			}
+		}
+		result.Errors = errs
+
 		st.setResult(&result) // save result
 		st.callCurrCancel()   // dm-unit finished, canceled or error occurred, always cancel processing
 
-		if len(result.Errors) == 0 && st.Stage() == pb.Stage_Paused {
+		if len(result.Errors) == 0 && st.Stage() == pb.Stage_Pausing {
 			return // paused by external request
 		}
 
@@ -371,6 +378,7 @@ func (st *SubTask) setStage(stage pb.Stage) {
 func (st *SubTask) stageCAS(oldStage, newStage pb.Stage) bool {
 	st.Lock()
 	defer st.Unlock()
+
 	if st.stage == oldStage {
 		st.stage = newStage
 		taskState.WithLabelValues(st.cfg.Name).Set(float64(st.stage))
@@ -428,8 +436,8 @@ func (st *SubTask) Close() {
 
 // Pause pauses the running sub task
 func (st *SubTask) Pause() error {
-	if !st.stageCAS(pb.Stage_Running, pb.Stage_Paused) {
-		return terror.ErrWorkerNotRunningStage.Generate()
+	if !st.stageCAS(pb.Stage_Running, pb.Stage_Pausing) {
+		return terror.ErrWorkerNotRunningStage.Generate(st.Stage().String())
 	}
 
 	st.callCurrCancel()
@@ -439,6 +447,7 @@ func (st *SubTask) Pause() error {
 	cu.Pause()
 
 	st.l.Info("paused", zap.Stringer("unit", cu.Type()))
+	st.setStage(pb.Stage_Paused)
 	return nil
 }
 
@@ -450,9 +459,10 @@ func (st *SubTask) Resume() error {
 		return nil
 	}
 
-	if !st.stageCAS(pb.Stage_Paused, pb.Stage_Running) {
-		return terror.ErrWorkerNotPausedStage.Generate()
+	if !st.stageCAS(pb.Stage_Paused, pb.Stage_Resuming) {
+		return terror.ErrWorkerNotPausedStage.Generate(st.Stage().String())
 	}
+
 	ctx, cancel := context.WithCancel(st.ctx)
 	st.setCurrCtx(ctx, cancel)
 	// NOTE: this may block if user resume a task
@@ -462,6 +472,7 @@ func (st *SubTask) Resume() error {
 		st.setStage(pb.Stage_Paused)
 		return err
 	} else if ctx.Err() != nil {
+		st.setStage(pb.Stage_Paused)
 		return nil
 	}
 
@@ -473,6 +484,8 @@ func (st *SubTask) Resume() error {
 	st.wg.Add(1)
 	go st.fetchResult(pr)
 	go cu.Resume(ctx, pr)
+
+	st.setStage(pb.Stage_Running)
 	return nil
 }
 

loader/loader.go

@@ -505,13 +505,13 @@ func (l *Loader) Process(ctx context.Context, pr chan pb.ProcessResult) {
 	}
 
 	isCanceled := false
-	if len(errs) == 0 {
-		select {
-		case <-ctx.Done():
-			isCanceled = true
-		default:
-		}
-	} else {
+	select {
+	case <-ctx.Done():
+		isCanceled = true
+	default:
+	}
+
+	if len(errs) != 0 {
 		// pause because of error occurred
 		l.Pause()
 	}

pkg/terror/error_list.go

@@ -981,8 +981,8 @@ var (
 	ErrWorkerNoStart                 = New(codeWorkerNoStart, ClassDMWorker, ScopeInternal, LevelHigh, "worker has not started")
 	ErrWorkerAlreadyClosed           = New(codeWorkerAlreadyClosed, ClassDMWorker, ScopeInternal, LevelHigh, "worker already closed")
 	ErrWorkerAlreadyStart            = New(codeWorkerAlreadyStarted, ClassDMWorker, ScopeInternal, LevelHigh, "worker already started")
-	ErrWorkerNotRunningStage         = New(codeWorkerNotRunningStage, ClassDMWorker, ScopeInternal, LevelHigh, "current stage is not running not valid")
-	ErrWorkerNotPausedStage          = New(codeWorkerNotPausedStage, ClassDMWorker, ScopeInternal, LevelHigh, "current stage is not paused not valid")
+	ErrWorkerNotRunningStage         = New(codeWorkerNotRunningStage, ClassDMWorker, ScopeInternal, LevelHigh, "current stage is %s but not running, invalid")
+	ErrWorkerNotPausedStage          = New(codeWorkerNotPausedStage, ClassDMWorker, ScopeInternal, LevelHigh, "current stage is %s but not paused, invalid")
 	ErrWorkerUpdateTaskStage         = New(codeWorkerUpdateTaskStage, ClassDMWorker, ScopeInternal, LevelHigh, "can only update task on Paused stage, but current stage is %s")
 	ErrWorkerMigrateStopRelay        = New(codeWorkerMigrateStopRelay, ClassDMWorker, ScopeInternal, LevelHigh, "relay unit has stopped, can not be migrated")
 	ErrWorkerSubTaskNotFound         = New(codeWorkerSubTaskNotFound, ClassDMWorker, ScopeInternal, LevelHigh, "sub task with name %s not found")

syncer/syncer.go

@@ -551,13 +551,13 @@ func (s *Syncer) Process(ctx context.Context, pr chan pb.ProcessResult) {
 	}
 
 	isCanceled := false
-	if len(errs) == 0 {
-		select {
-		case <-ctx.Done():
-			isCanceled = true
-		default:
-		}
-	} else {
+	select {
+	case <-ctx.Done():
+		isCanceled = true
+	default:
+	}
+
+	if len(errs) != 0 {
 		// pause because of error occurred
 		s.Pause()
 	}

tests/sharding/run.sh

@@ -90,12 +90,21 @@ function run() {
     # `FIXME: the following case is not supported automatically now, try to support it later`
     # so we try to do this `pause-task` and `resume-task` in the case now.
     sleep 3
+    run_dm_ctl_with_retry $WORK_DIR "127.0.0.1:$MASTER_PORT" \
+        "pause-task test"\
+        "\"result\": true" 3
+    # pause twice
     run_dm_ctl_with_retry $WORK_DIR "127.0.0.1:$MASTER_PORT" \
         "pause-task test"\
         "\"result\": true" 3
     # wait really paused
-    # FIXME: `if !st.stageCAS(pb.Stage_Running, pb.Stage_Paused)` in `subtask.go` is not enough to indicate the real stage.
-    sleep 2
+    run_dm_ctl_with_retry $WORK_DIR "127.0.0.1:$MASTER_PORT" \
+        "query-status test" \
+        "Paused" 2
+    run_dm_ctl_with_retry $WORK_DIR "127.0.0.1:$MASTER_PORT" \
+        "resume-task test"\
+        "\"result\": true" 3
+    # resume twice
     run_dm_ctl_with_retry $WORK_DIR "127.0.0.1:$MASTER_PORT" \
         "resume-task test"\
         "\"result\": true" 3