modify: mqtt 插件返回问题

example/__init__.py

@@ -33,22 +33,36 @@ auto_bind_models("example")
 # 详见 src/chongming/app/__init__.py 的 lifespan。
 
 
+# 幂等标记：防止 create_workers 被重复调用时重复初始化数据库等资源
+_initialized = False
+
+
 async def create_workers(session, config, count=1, worker_manager=None):
     """插件入口 — 委托给 chongming_worker 运行时创建 Worker 协程"""
+    global _initialized
+    if _initialized:
+        print("[example] create_workers 重复调用，跳过重复初始化")
+        return _create_workers(session, config, count, worker_manager)
+
     from .global_var import set_global_var
     from chongming_database import Database
-    
+
     db_path = Path(config.get("data_dir", "./data")) / "example.db"
 
     db = Database(db_path)
     await db.initialize()
     set_global_var("db", db)
 
+    _initialized = True
     return _create_workers(session, config, count, worker_manager)
 
+
 async def cleanup(worker_item: str):
-    from .global_var import db
+    global _initialized
+    from .global_var import db, set_global_var
 
     if db is not None:
         await db.dispose()
+        set_global_var("db", None)
+    _initialized = False
     print(f"{worker_item} 清理完毕")