generalize helper for loading module from source (#2862)

api/core/extension/extensible.py

@@ -1,5 +1,4 @@
 import enum
-import importlib.util
 import json
 import logging
 import os
@@ -7,6 +6,7 @@ from typing import Any, Optional
 
 from pydantic import BaseModel
 
+from core.utils.module_import_helper import load_single_subclass_from_source
 from core.utils.position_helper import sort_to_dict_by_position_map
 
 
@@ -73,17 +73,9 @@ class Extensible:
 
                 # Dynamic loading {subdir_name}.py file and find the subclass of Extensible
                 py_path = os.path.join(subdir_path, extension_name + '.py')
-                spec = importlib.util.spec_from_file_location(extension_name, py_path)
-                mod = importlib.util.module_from_spec(spec)
-                spec.loader.exec_module(mod)
-
-                extension_class = None
-                for name, obj in vars(mod).items():
-                    if isinstance(obj, type) and issubclass(obj, cls) and obj != cls:
-                        extension_class = obj
-                        break
-
-                if not extension_class:
+                try:
+                    extension_class = load_single_subclass_from_source(extension_name, py_path, cls)
+                except Exception:
                     logging.warning(f"Missing subclass of {cls.__name__} in {py_path}, Skip.")
                     continue