Chore: [Nested Folder] Add db migration at service start time (#58590)

* add db migration at service start time

* make changes for the 3 db

* revert migrator

* fix feature toggle check

Co-authored-by: Serge Zaitsev <serge.zaitsev@grafana.com>

pkg/services/folder/folderimpl/folder.go

@@ -15,6 +15,8 @@ import (
 	"github.com/grafana/grafana/pkg/services/dashboards"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/folder"
+	"github.com/grafana/grafana/pkg/services/sqlstore"
+	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
 	"github.com/grafana/grafana/pkg/util"
 
 	"github.com/grafana/grafana/pkg/services/guardian"
@@ -54,7 +56,7 @@ func ProvideService(
 	ac.RegisterScopeAttributeResolver(dashboards.NewFolderNameScopeResolver(dashboardStore))
 	ac.RegisterScopeAttributeResolver(dashboards.NewFolderIDScopeResolver(dashboardStore))
 	store := ProvideStore(db, cfg, features)
-	return &Service{
+	svr := &Service{
 		cfg:              cfg,
 		log:              log.New("folder-service"),
 		dashboardService: dashboardService,
@@ -66,6 +68,28 @@ func ProvideService(
 		accessControl:    ac,
 		bus:              bus,
 	}
+	if features.IsEnabled(featuremgmt.FlagNestedFolders) {
+		svr.DBMigration(db)
+	}
+	return svr
+}
+
+func (s *Service) DBMigration(db db.DB) {
+	ctx := context.Background()
+	err := db.WithDbSession(ctx, func(sess *sqlstore.DBSession) error {
+		var err error
+		if db.GetDialect().DriverName() == migrator.SQLite {
+			_, err = sess.Exec("INSERT OR REPLACE INTO folder (id, uid, org_id, title, created, updated) SELECT id, uid, org_id, title, created, updated FROM dashboard WHERE is_folder = 1")
+		} else if db.GetDialect().DriverName() == migrator.Postgres {
+			_, err = sess.Exec("INSERT INTO folder (id, uid, org_id, title, created, updated) SELECT id, uid, org_id, title, created, updated FROM dashboard WHERE is_folder = true ON CONFLICT DO NOTHING")
+		} else {
+			_, err = sess.Exec("INSERT IGNORE INTO folder (id, uid, org_id, title, created, updated) SELECT id, uid, org_id, title, created, updated FROM dashboard WHERE is_folder = 1")
+		}
+		return err
+	})
+	if err != nil {
+		s.log.Error("DB migration on folder service start failed.")
+	}
 }
 
 func (s *Service) Get(ctx context.Context, cmd *folder.GetFolderQuery) (*folder.Folder, error) {

pkg/services/sqlstore/migrations/folder_mig.go

@@ -1,9 +1,6 @@
 package migrations
 
 import (
-	"fmt"
-
-	"github.com/grafana/grafana/pkg/services/folder"
 	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
 )
 
@@ -11,13 +8,6 @@ import (
 func addFolderMigrations(mg *migrator.Migrator) {
 	mg.AddMigration("create folder table", migrator.NewAddTableMigration(folderv1()))
 
-	// copy any existing folders in the dashboard table into the new folder
-	// table. The *legacy* parent folder ID, stored as folder_id  in the
-	// dashboard table, is always going to be "0" so it is safe to convert to a parent UID.
-	mg.AddMigration("copy existing folders from dashboard table", migrator.NewRawSQLMigration(
-		"INSERT INTO folder (id, uid, org_id, title, created, updated) SELECT id, uid, org_id, title, created, updated FROM dashboard WHERE is_folder = 1;",
-	).Postgres("INSERT INTO folder (id, uid, org_id, title, created, updated) SELECT id, uid, org_id, title, created, updated FROM dashboard WHERE is_folder = true;"))
-
 	mg.AddMigration("Add index for parent_uid", migrator.NewAddIndexMigration(folderv1(), &migrator.Index{
 		Cols: []string{"parent_uid", "org_id"},
 	}))
@@ -43,7 +33,7 @@ func folderv1() migrator.Table {
 			{Name: "org_id", Type: migrator.DB_BigInt, Nullable: false},
 			{Name: "title", Type: migrator.DB_NVarchar, Length: 255, Nullable: false},
 			{Name: "description", Type: migrator.DB_NVarchar, Length: 255, Nullable: true},
-			{Name: "parent_uid", Type: migrator.DB_NVarchar, Length: 40, Default: fmt.Sprintf("'%s'", folder.GeneralFolderUID)},
+			{Name: "parent_uid", Type: migrator.DB_NVarchar, Length: 40, Default: ""},
 			{Name: "created", Type: migrator.DB_DateTime, Nullable: false},
 			{Name: "updated", Type: migrator.DB_DateTime, Nullable: false},
 		},