Refactor database initialization and connection handling

src/backend/langflow/alembic/env.py

@@ -62,12 +62,26 @@ def run_migrations_online() -> None:
     and associate a connection with the context.
 
     """
-    from langflow.services.deps import get_db_service
 
     try:
+        from langflow.services.database.factory import DatabaseServiceFactory
+        from langflow.services.deps import get_db_service
+        from langflow.services.manager import (
+            initialize_settings_service,
+            service_manager,
+        )
+        from langflow.services.schema import ServiceType
+
+        initialize_settings_service()
+        service_manager.register_factory(
+            DatabaseServiceFactory(), [ServiceType.SETTINGS_SERVICE]
+        )
         connectable = get_db_service().engine
     except Exception as e:
         logger.error(f"Error getting database engine: {e}")
+        url = os.getenv("LANGFLOW_DATABASE_URL")
+        url = url or config.get_main_option("sqlalchemy.url")
+        config.set_main_option("sqlalchemy.url", url)
         connectable = engine_from_config(
             config.get_section(config.config_ini_section, {}),
             prefix="sqlalchemy.",

src/backend/langflow/alembic/script.py.mako

@@ -23,10 +23,12 @@ depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
 def upgrade() -> None:
     conn = op.get_bind()
     inspector = Inspector.from_engine(conn)  # type: ignore
+    table_names = inspector.get_table_names()
     ${upgrades if upgrades else "pass"}
 
 
 def downgrade() -> None:
     conn = op.get_bind()
     inspector = Inspector.from_engine(conn)  # type: ignore
+    table_names = inspector.get_table_names()
     ${downgrades if downgrades else "pass"}