Add global lock for migrations to make upgrade more safe with multiple replications (#33706)

services/doctor/dbversion.go

@@ -9,6 +9,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/migrations"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/services/versioned_migration"
 )
 
 func checkDBVersion(ctx context.Context, logger log.Logger, autofix bool) error {
@@ -21,7 +22,7 @@ func checkDBVersion(ctx context.Context, logger log.Logger, autofix bool) error
 		logger.Warn("Got Error: %v during ensure up to date", err)
 		logger.Warn("Attempting to migrate to the latest DB version to fix this.")
 
-		err = db.InitEngineWithMigration(ctx, migrations.Migrate)
+		err = db.InitEngineWithMigration(ctx, versioned_migration.Migrate)
 		if err != nil {
 			logger.Critical("Error: %v during migration", err)
 		}

services/versioned_migration/migration.go

@@ -0,0 +1,24 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package versioned_migration //nolint
+
+import (
+	"context"
+
+	"code.gitea.io/gitea/models/migrations"
+	"code.gitea.io/gitea/modules/globallock"
+
+	"xorm.io/xorm"
+)
+
+func Migrate(ctx context.Context, x *xorm.Engine) error {
+	// only one instance can do the migration at the same time if there are multiple instances
+	release, err := globallock.Lock(ctx, "gitea_versioned_migration")
+	if err != nil {
+		return err
+	}
+	defer release()
+
+	return migrations.Migrate(x)
+}