Workflow Delete: remove workflow before artifacts

Otherwise the cancel/delete and cleanup work can fail.

Signed-off-by: Matt Lord <mattalord@gmail.com>

go/vt/vtctl/workflow/server.go

@@ -1970,11 +1970,24 @@ func (s *Server) WorkflowDelete(ctx context.Context, req *vtctldatapb.WorkflowDe
 	span.Annotate("keep_routing_rules", req.KeepRoutingRules)
 	span.Annotate("shards", req.Shards)
 
-	// Cleanup related data and artifacts.
-	if _, err := s.DropTargets(ctx, req.Keyspace, req.Workflow, req.KeepData, req.KeepRoutingRules, false); err != nil {
-		if topo.IsErrType(err, topo.NoNode) {
-			return nil, vterrors.Wrapf(err, "%s keyspace does not exist", req.Keyspace)
-		}
+	ts, state, err := s.getWorkflowState(ctx, req.GetKeyspace(), req.GetWorkflow())
+	if err != nil {
+		log.Errorf("Failed to get VReplication workflow state for %s.%s: %v", req.GetKeyspace(), req.GetWorkflow(), err)
+		return nil, err
+	}
+
+	// There is nothing to drop for a LookupVindex workflow.
+	if ts.workflowType == binlogdatapb.VReplicationWorkflowType_CreateLookupIndex {
+		return nil, nil
+	}
+
+	// Return an error if the workflow traffic is partially switched.
+	if state.WritesSwitched || len(state.ReplicaCellsSwitched) > 0 || len(state.RdonlyCellsSwitched) > 0 {
+		return nil, ErrWorkflowPartiallySwitched
+	}
+
+	if state.WorkflowType == TypeMigrate {
+		_, err := s.finalizeMigrateWorkflow(ctx, req.GetKeyspace(), req.GetWorkflow(), "", true, req.GetKeepData(), req.GetKeepRoutingRules(), false)
 		return nil, err
 	}
 
@@ -2002,6 +2015,14 @@ func (s *Server) WorkflowDelete(ctx context.Context, req *vtctldatapb.WorkflowDe
 		return nil, vterrors.Errorf(vtrpcpb.Code_FAILED_PRECONDITION, "the %s workflow does not exist in the %s keyspace", req.Workflow, req.Keyspace)
 	}
 
+	// Cleanup related data and artifacts.
+	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.Keyspace)
+		}
+		return nil, err
+	}
+
 	response := &vtctldatapb.WorkflowDeleteResponse{}
 	response.Summary = fmt.Sprintf("Successfully cancelled the %s workflow in the %s keyspace", req.Workflow, req.Keyspace)
 	details := make([]*vtctldatapb.WorkflowDeleteResponse_TabletInfo, 0, len(res))
@@ -2497,28 +2518,8 @@ func (s *Server) optimizeCopyStateTable(tablet *topodatapb.Tablet) {
 
 // DropTargets cleans up target tables, shards and denied tables if a MoveTables/Reshard
 // is cancelled.
-func (s *Server) DropTargets(ctx context.Context, targetKeyspace, workflow string, keepData, keepRoutingRules, dryRun bool) (*[]string, error) {
-	ts, state, err := s.getWorkflowState(ctx, targetKeyspace, workflow)
-	if err != nil {
-		log.Errorf("Failed to get VReplication workflow state for %s.%s: %v", targetKeyspace, workflow, err)
-		return nil, err
-	}
-
-	// There is nothing to drop for a LookupVindex workflow.
-	if ts.workflowType == binlogdatapb.VReplicationWorkflowType_CreateLookupIndex {
-		return nil, nil
-	}
-
-	// Return an error if the workflow traffic is partially switched.
-	if state.WritesSwitched || len(state.ReplicaCellsSwitched) > 0 || len(state.RdonlyCellsSwitched) > 0 {
-		return nil, ErrWorkflowPartiallySwitched
-	}
-
-	if state.WorkflowType == TypeMigrate {
-		_, err := s.finalizeMigrateWorkflow(ctx, targetKeyspace, workflow, "", true, keepData, keepRoutingRules, dryRun)
-		return nil, err
-	}
-
+func (s *Server) DropTargets(ctx context.Context, ts *trafficSwitcher, keepData, keepRoutingRules, dryRun bool) (*[]string, error) {
+	var err error
 	ts.keepRoutingRules = keepRoutingRules
 	var sw iswitcher
 	if dryRun {