feat: wire native leaudit upload flow

fastapi_common/fastapi_common_sqlalchemy/database.py

@@ -4,18 +4,36 @@ from __future__ import annotations
 
 from contextlib import asynccontextmanager
 
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
 
 from fastapi_admin.config import ASYNCPG_DATABASE_URL
 
-_engine = create_async_engine(ASYNCPG_DATABASE_URL, echo=False, pool_size=20, max_overflow=10)
+_engine: AsyncEngine | None = None
+_AsyncSessionFactory: async_sessionmaker[AsyncSession] | None = None
 
-_AsyncSessionFactory = async_sessionmaker(_engine, class_=AsyncSession, expire_on_commit=False)
+
+def _get_session_factory() -> async_sessionmaker[AsyncSession]:
+    """按需创建 session factory，避免 reload/多事件循环复用旧连接池。"""
+    global _engine, _AsyncSessionFactory
+    if _AsyncSessionFactory is None:
+        _engine = create_async_engine(
+            ASYNCPG_DATABASE_URL,
+            echo=False,
+            poolclass=NullPool,
+        )
+        _AsyncSessionFactory = async_sessionmaker(
+            _engine,
+            class_=AsyncSession,
+            expire_on_commit=False,
+        )
+    return _AsyncSessionFactory
 
 
 @asynccontextmanager
 async def GetAsyncSession():
     """获取异步数据库 session（上下文管理器）。"""
-    async with _AsyncSessionFactory() as session:
+    SessionFactory = _get_session_factory()
+    async with SessionFactory() as session:
         yield session
         await session.commit()