VReplication: Relax restrictions on Cancel and ReverseTraffic when writes not involved

go/test/endtoend/vreplication/multi_tenant_test.go

@@ -214,6 +214,18 @@ func TestMultiTenantSimple(t *testing.T) {
 		require.Zero(t, rowCount)
 	})
 
+	t.Run("cancel after switching reads", func(t *testing.T) {
+		// First let's test canceling the workflow after only switching reads
+		// to ensure that it properly cleans up all of the state.
+		createFunc()
+		mt.SwitchReads()
+		confirmOnlyReadsSwitched(t)
+		mt.Cancel()
+		confirmNoRoutingRules(t)
+		rowCount := getRowCount(t, vtgateConn, fmt.Sprintf("%s.%s", targetKeyspace, "t1"))
+		require.Zero(t, rowCount)
+	})
+
 	// Create again and run it to completion.
 	createFunc()
 

go/test/endtoend/vreplication/vreplication_vtctldclient_cli_test.go

@@ -304,6 +304,22 @@ func testMoveTablesFlags3(t *testing.T, sourceKeyspace, targetKeyspace string, t
 	// Confirm that the source tables were renamed.
 	require.True(t, checkTablesExist(t, "zone1-100", []string{"_customer2_old"}))
 	require.False(t, checkTablesExist(t, "zone1-100", []string{"customer2"}))
+
+	// Confirm that we can cancel a workflow after ONLY switching read traffic.
+	mt = createMoveTables(t, sourceKeyspace, targetKeyspace, workflowName, "customer", createFlags, nil, nil)
+	mt.Start() // Need to start because we set stop-after-copy to true.
+	waitForWorkflowState(t, vc, ksWorkflow, binlogdatapb.VReplicationWorkflowState_Running.String())
+	for _, tab := range targetTabs {
+		catchup(t, tab, workflowName, "MoveTables")
+	}
+	mt.SwitchReads()
+	wf := mt.(iWorkflow)
+	validateReadsRouteToTarget(t, "replica")
+	validateTableRoutingRule(t, "customer", "replica", sourceKs, targetKs)
+	validateTableRoutingRule(t, "customer", "", targetKs, sourceKs)
+	confirmStates(t, &wf, wrangler.WorkflowStateNotSwitched, wrangler.WorkflowStateReadsSwitched)
+	mt.Cancel()
+	confirmNoRoutingRules(t)
 }
 
 // Create two workflows in order to confirm that listing all workflows works.
@@ -450,6 +466,7 @@ func splitShard(t *testing.T, keyspace, workflowName, sourceShards, targetShards
 		"--all-cells", "--format=json",
 		"--config-overrides", mapToCSV(overrides),
 	}
+
 	rs := newReshard(vc, &reshardWorkflow{
 		workflowInfo: &workflowInfo{
 			vc:             vc,
@@ -460,7 +477,6 @@ func splitShard(t *testing.T, keyspace, workflowName, sourceShards, targetShards
 		targetShards: targetShards,
 		createFlags:  createFlags,
 	}, workflowFlavorVtctld)
-
 	ksWorkflow := fmt.Sprintf("%s.%s", keyspace, workflowName)
 	wf := rs.(iWorkflow)
 	rs.Create()
@@ -769,8 +785,10 @@ func getRoutingRules(t *testing.T) *vschemapb.RoutingRules {
 }
 
 func confirmNoRoutingRules(t *testing.T) {
-	routingRulesResponse := getRoutingRules(t)
-	require.Zero(t, len(routingRulesResponse.Rules))
+	rrRes := getRoutingRules(t)
+	require.Zero(t, len(rrRes.Rules))
+	krrRes := getKeyspaceRoutingRules(t, vc)
+	require.Zero(t, len(krrRes.Rules))
 }
 
 func confirmRoutingRulesExist(t *testing.T) {

go/vt/vtctl/workflow/server.go

@@ -148,9 +148,9 @@ var (
 	// ErrMultipleTargetKeyspaces occurs when a workflow somehow has multiple
 	// target keyspaces across different shard primaries. This should be
 	// impossible.
-	ErrMultipleTargetKeyspaces   = errors.New("multiple target keyspaces for a single workflow")
-	ErrWorkflowNotFullySwitched  = errors.New("cannot complete workflow because you have not yet switched all read and write traffic")
-	ErrWorkflowPartiallySwitched = errors.New("cannot cancel workflow because you have already switched some or all read and write traffic")
+	ErrMultipleTargetKeyspaces          = errors.New("multiple target keyspaces for a single workflow")
+	ErrWorkflowCompleteNotFullySwitched = errors.New("cannot complete workflow because you have not yet switched all read and write traffic")
+	ErrWorkflowDeleteWritesSwitched     = errors.New("cannot delete workflow because you have already switched write traffic")
 )
 
 // Server provides an API to work with Vitess workflows, like vreplication
@@ -1736,7 +1736,7 @@ func (s *Server) MoveTablesComplete(ctx context.Context, req *vtctldatapb.MoveTa
 	}
 
 	if !state.WritesSwitched || len(state.ReplicaCellsNotSwitched) > 0 || len(state.RdonlyCellsNotSwitched) > 0 {
-		return nil, ErrWorkflowNotFullySwitched
+		return nil, ErrWorkflowCompleteNotFullySwitched
 	}
 	var renameTable TableRemovalType
 	if req.RenameTables {
@@ -2111,10 +2111,12 @@ func (s *Server) WorkflowDelete(ctx context.Context, req *vtctldatapb.WorkflowDe
 	}
 
 	if ts.workflowType != binlogdatapb.VReplicationWorkflowType_CreateLookupIndex {
-		// Return an error if the workflow traffic is partially switched.
-		if state.WritesSwitched || len(state.ReplicaCellsSwitched) > 0 || len(state.RdonlyCellsSwitched) > 0 {
-			return nil, ErrWorkflowPartiallySwitched
+		// Return an error if the write workflow traffic is switched.
+		if state.WritesSwitched {
+			return nil, ErrWorkflowDeleteWritesSwitched
 		}
+		// If only reads have been switched, then we can delete the
+		// workflow and its related artifacts.
 	}
 
 	// Lock the workflow for deletion.
@@ -2158,22 +2160,21 @@ func (s *Server) WorkflowDelete(ctx context.Context, req *vtctldatapb.WorkflowDe
 				ts.workflowType)
 		}
 		// We need to delete the rows that the target tables would have for the tenant.
-		// We don't cleanup other related artifacts since they are not tied to the tenant.
 		if !req.GetKeepData() {
 			if err := s.deleteTenantData(ctx, ts, req.DeleteBatchSize); err != nil {
 				return nil, vterrors.Wrapf(err, "failed to fully delete all migrated data for tenant %s, please retry the operation",
 					ts.options.TenantId)
 			}
 		}
-	} else {
-		// Cleanup related data and artifacts. There are none for a LookupVindex workflow.
-		if ts.workflowType != binlogdatapb.VReplicationWorkflowType_CreateLookupIndex {
-			if _, err := s.dropTargets(ctx, ts, req.GetKeepData(), req.GetKeepRoutingRules(), false); err != nil {
-				if topo.IsErrType(err, topo.NoNode) {
-					return nil, vterrors.Wrapf(err, "%s keyspace does not exist", req.GetKeyspace())
-				}
-				return nil, err
+	}
+
+	// Cleanup related data and artifacts. There are none for a LookupVindex workflow.
+	if ts.workflowType != binlogdatapb.VReplicationWorkflowType_CreateLookupIndex {
+		if _, err := s.dropTargets(ctx, ts, req.GetKeepData(), req.GetKeepRoutingRules(), false); err != nil {
+			if topo.IsErrType(err, topo.NoNode) {
+				return nil, vterrors.Wrapf(err, "%s keyspace does not exist", req.GetKeyspace())
 			}
+			return nil, err
 		}
 	}
 
@@ -2697,8 +2698,10 @@ func (s *Server) dropTargets(ctx context.Context, ts *trafficSwitcher, keepData,
 	if !keepData {
 		switch ts.MigrationType() {
 		case binlogdatapb.MigrationType_TABLES:
-			if err := sw.removeTargetTables(ctx); err != nil {
-				return nil, err
+			if !ts.IsMultiTenantMigration() {
+				if err := sw.removeTargetTables(ctx); err != nil {
+					return nil, err
+				}
 			}
 			if err := sw.dropSourceDeniedTables(ctx); err != nil {
 				return nil, err
@@ -3239,12 +3242,13 @@ func (s *Server) WorkflowSwitchTraffic(ctx context.Context, req *vtctldatapb.Wor
 		return nil, vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "invalid action for Migrate workflow: SwitchTraffic")
 	}
 
-	if direction == DirectionBackward && ts.IsMultiTenantMigration() {
-		// In a multi-tenant migration, multiple migrations would be writing to the same
-		// table, so we can't stop writes like we do with MoveTables, using denied tables,
-		// since it would block all other migrations as well as traffic for tenants which
-		// have already been migrated.
-		return nil, vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "cannot reverse traffic for multi-tenant migrations")
+	if ts.IsMultiTenantMigration() {
+		// Multi-tenant migrations use keyspace routing rules, so we need to update the state
+		// using them.
+		err = updateKeyspaceRoutingState(ctx, ts.TopoServer(), ts.sourceKeyspace, ts.targetKeyspace, startState)
+		if err != nil {
+			return nil, vterrors.Wrap(err, "failed to update multi-tenant workflow state using keyspace routing rules")
+		}
 	}
 
 	// We need this to know when there isn't a (non-FROZEN) reverse workflow to use.
@@ -3255,6 +3259,13 @@ func (s *Server) WorkflowSwitchTraffic(ctx context.Context, req *vtctldatapb.Wor
 		(direction == DirectionBackward && !startState.WritesSwitched)
 
 	if direction == DirectionBackward && !onlySwitchingReads {
+		if ts.IsMultiTenantMigration() {
+			// In a multi-tenant migration, multiple migrations would be writing to the same
+			// table, so we can't stop writes like we do with MoveTables, using denied tables,
+			// since it would block all other migrations as well as traffic for tenants which
+			// have already been migrated.
+			return nil, vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "cannot reverse write traffic for multi-tenant migrations")
+		}
 		// This means that the main workflow is FROZEN and the reverse workflow
 		// exists. So we update the starting state so that we're using the reverse
 		// workflow and we can move forward with a normal traffic switch forward
@@ -3336,6 +3347,15 @@ func (s *Server) WorkflowSwitchTraffic(ctx context.Context, req *vtctldatapb.Wor
 		resp.StartState = startState.String()
 		s.Logger().Infof("Before reloading workflow state after switching traffic: %+v\n", resp.StartState)
 		_, currentState, err := s.getWorkflowState(ctx, ts.targetKeyspace, ts.workflow)
+		if ts.IsMultiTenantMigration() {
+			// Multi-tenant migrations use keyspace routing rules, so we need to update the state
+			// using them.
+			sourceKs, targetKs := ts.sourceKeyspace, ts.targetKeyspace
+			if TrafficSwitchDirection(req.Direction) == DirectionBackward {
+				sourceKs, targetKs = targetKs, sourceKs
+			}
+			err = updateKeyspaceRoutingState(ctx, ts.TopoServer(), sourceKs, targetKs, currentState)
+		}
 		if err != nil {
 			resp.CurrentState = fmt.Sprintf("Error reloading workflow state after switching traffic: %v", err)
 		} else {
@@ -3387,11 +3407,7 @@ func (s *Server) switchReads(ctx context.Context, req *vtctldatapb.WorkflowSwitc
 		// shard level traffic switching is all or nothing
 		trafficSwitchingIsAllOrNothing = true
 	case ts.MigrationType() == binlogdatapb.MigrationType_TABLES && ts.IsMultiTenantMigration():
-		if direction == DirectionBackward {
-			return defaultErrorHandler(ts.Logger(), "invalid request", vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT,
-				"requesting reversal of read traffic for multi-tenant migrations is not supported"))
-		}
-		// For multi-tenant migrations, we only support switching traffic to all cells at once
+		// For multi-tenant migrations, we only support switching traffic to all cells at once.
 		allCells, err := ts.TopoServer().GetCellInfoNames(ctx)
 		if err != nil {
 			return nil, err
@@ -3415,7 +3431,7 @@ func (s *Server) switchReads(ctx context.Context, req *vtctldatapb.WorkflowSwitc
 		}
 		if direction == DirectionBackward && switchRdonly && len(state.RdonlyCellsSwitched) == 0 {
 			return defaultErrorHandler(ts.Logger(), "invalid request", vterrors.Errorf(vtrpcpb.Code_FAILED_PRECONDITION,
-				"requesting reversal of SwitchReads for RDONLYs but RDONLY reads have not been switched"))
+				"requesting reversal of read traffic for RDONLYs but RDONLY reads have not been switched"))
 		}
 	}