*: reset config if the input is invalid (#8632)

plugin/scheduler_example/evict_leader.go

@@ -77,13 +77,13 @@ func init() {
 }
 
 // SchedulerType returns the type of the scheduler
-//nolint
+// nolint
 func SchedulerType() string {
 	return EvictLeaderType
 }
 
 // SchedulerArgs returns the args for the scheduler
-//nolint
+// nolint
 func SchedulerArgs() []string {
 	args := []string{"1"}
 	return args
@@ -271,9 +271,21 @@ func (handler *evictLeaderHandler) UpdateConfig(w http.ResponseWriter, r *http.R
 		args = append(args, handler.config.getRanges(id)...)
 	}
 
-	handler.config.BuildWithArgs(args)
-	err := handler.config.Persist()
+	err := handler.config.BuildWithArgs(args)
 	if err != nil {
+		handler.config.mu.Lock()
+		handler.config.cluster.ResumeLeaderTransfer(id)
+		handler.config.mu.Unlock()
+		handler.rd.JSON(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	err = handler.config.Persist()
+	if err != nil {
+		handler.config.mu.Lock()
+		delete(handler.config.StoreIDWitRanges, id)
+		handler.config.cluster.ResumeLeaderTransfer(id)
+		handler.config.mu.Unlock()
 		handler.rd.JSON(w, http.StatusInternalServerError, err.Error())
 	}
 	handler.rd.JSON(w, http.StatusOK, nil)

server/schedulers/evict_leader.go

@@ -96,6 +96,9 @@ func (conf *evictLeaderSchedulerConfig) getStores() []uint64 {
 }
 
 func (conf *evictLeaderSchedulerConfig) BuildWithArgs(args []string) error {
+	failpoint.Inject("buildWithArgsErr", func() {
+		failpoint.Return(errors.New("fail to build with args"))
+	})
 	if len(args) != 1 {
 		return errs.ErrSchedulerConfig.FastGenByArgs("id")
 	}
@@ -367,8 +370,15 @@ func (handler *evictLeaderHandler) UpdateConfig(w http.ResponseWriter, r *http.R
 		args = append(args, handler.config.getRanges(id)...)
 	}
 
-	handler.config.BuildWithArgs(args)
-	err := handler.config.Persist()
+	err := handler.config.BuildWithArgs(args)
+	if err != nil {
+		handler.config.mu.Lock()
+		handler.config.cluster.ResumeLeaderTransfer(id)
+		handler.config.mu.Unlock()
+		handler.rd.JSON(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	err = handler.config.Persist()
 	if err != nil {
 		handler.config.removeStore(id)
 		handler.rd.JSON(w, http.StatusInternalServerError, err.Error())

server/schedulers/grant_leader.go

@@ -286,10 +286,17 @@ func (handler *grantLeaderHandler) UpdateConfig(w http.ResponseWriter, r *http.R
 		args = append(args, handler.config.getRanges(id)...)
 	}
 
-	handler.config.BuildWithArgs(args)
-	err := handler.config.Persist()
+	err := handler.config.BuildWithArgs(args)
 	if err != nil {
-		handler.config.removeStore(id)
+		handler.config.mu.Lock()
+		handler.config.cluster.ResumeLeaderTransfer(id)
+		handler.config.mu.Unlock()
+		handler.rd.JSON(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	err = handler.config.Persist()
+	if err != nil {
+		_, _ = handler.config.removeStore(id)
 		handler.rd.JSON(w, http.StatusInternalServerError, err.Error())
 		return
 	}

tests/pdctl/scheduler/scheduler_test.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	. "github.com/pingcap/check"
+	"github.com/pingcap/failpoint"
 	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/tikv/pd/server"
 	"github.com/tikv/pd/server/config"
@@ -399,3 +400,60 @@ func (s *schedulerTestSuite) TestScheduler(c *C) {
 	c.Assert(err, IsNil)
 	checkSchedulerWithStatusCommand(nil, "disabled", nil)
 }
+
+func (s *schedulerTestSuite) TestEvictLeaderScheduler(c *C) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	cluster, err := tests.NewTestCluster(ctx, 1)
+	c.Assert(err, IsNil)
+	defer cluster.Destroy()
+	err = cluster.RunInitialServers()
+	c.Assert(err, IsNil)
+	cluster.WaitLeader()
+	pdAddr := cluster.GetConfig().GetClientURL()
+	cmd := pdctlCmd.GetRootCmd()
+
+	stores := []*metapb.Store{
+		{
+			Id:            1,
+			State:         metapb.StoreState_Up,
+			LastHeartbeat: time.Now().UnixNano(),
+		},
+		{
+			Id:            2,
+			State:         metapb.StoreState_Up,
+			LastHeartbeat: time.Now().UnixNano(),
+		},
+		{
+			Id:            3,
+			State:         metapb.StoreState_Up,
+			LastHeartbeat: time.Now().UnixNano(),
+		},
+		{
+			Id:            4,
+			State:         metapb.StoreState_Up,
+			LastHeartbeat: time.Now().UnixNano(),
+		},
+	}
+	leaderServer := cluster.GetServer(cluster.GetLeader())
+	c.Assert(leaderServer.BootstrapCluster(), IsNil)
+	for _, store := range stores {
+		pdctl.MustPutStore(c, leaderServer.GetServer(), store)
+	}
+
+	pdctl.MustPutRegion(c, cluster, 1, 1, []byte("a"), []byte("b"))
+	output, err := pdctl.ExecuteCommand(cmd, []string{"-u", pdAddr, "scheduler", "add", "evict-leader-scheduler", "2"}...)
+	c.Assert(err, IsNil)
+	c.Assert(strings.Contains(string(output), "Success!"), IsTrue)
+	failpoint.Enable("github.com/tikv/pd/server/schedulers/buildWithArgsErr", "return(true)")
+	output, err = pdctl.ExecuteCommand(cmd, []string{"-u", pdAddr, "scheduler", "add", "evict-leader-scheduler", "1"}...)
+	c.Assert(err, IsNil)
+	c.Assert(strings.Contains(string(output), "fail to build with args"), IsTrue)
+	failpoint.Disable("github.com/tikv/pd/server/schedulers/buildWithArgsErr")
+	output, err = pdctl.ExecuteCommand(cmd, []string{"-u", pdAddr, "scheduler", "remove", "evict-leader-scheduler"}...)
+	c.Assert(err, IsNil)
+	c.Assert(strings.Contains(string(output), "Success!"), IsTrue)
+	output, err = pdctl.ExecuteCommand(cmd, []string{"-u", pdAddr, "scheduler", "add", "evict-leader-scheduler", "1"}...)
+	c.Assert(err, IsNil)
+	c.Assert(strings.Contains(string(output), "Success!"), IsTrue)
+}