袁聪的第二次提交，项目已完整

app/service/offsite_nl2sql_adapter.py

@@ -1,36 +1,67 @@
-"""场外基金专用 NL2SQL 适配器。
-
-该适配器只隔离调用边界，不改写 `nl2sql_yc.query_dict` 的业务能力。
-"""
+"""场外基金专用 NL2SQL 适配器。"""
 
 from importlib import import_module
 from typing import cast
 
+from sqlalchemy import create_engine
+from sqlalchemy.engine import Engine
+
+from app.core.config import Settings, get_settings
 from app.core.contracts import RequestContext
 
 
 class OffsiteNl2SqlAdapter:
-    """把场外基金上下文转换为 `nl2sql_yc.query_dict` 可接受的稳定参数。"""
+    """把场外基金上下文转换为 query_dict 的稳定参数并执行只读查询。"""
 
     script_path = "nl2sql_yc.py"
 
+    def __init__(
+        self,
+        db_engine: Engine | None = None,
+        settings: Settings | None = None,
+    ) -> None:
+        self._db_engine = db_engine
+        self._settings = settings or get_settings()
+        self._owns_engine = db_engine is None
+
     def query(self, question: str, context: RequestContext) -> dict[str, object]:
         try:
             query_dict = getattr(import_module("nl2sql_yc"), "query_dict", None)
             if not callable(query_dict):
                 return {"status": "error", "message": "NL2SQL入口query_dict不存在"}
+            db_engine = self._get_db_engine()
             result = cast(dict[str, object], query_dict(
                 question,
                 self._auth_context(context),
+                db_engine=db_engine,
                 use_llm=False,
                 persist_audit=False,
             ))
             if isinstance(result, dict):
                 return result
             return {"status": "error", "message": "NL2SQL返回格式不正确"}
-        except Exception as exc:
+        except (OSError, RuntimeError, ValueError) as exc:
             return {"status": "error", "message": f"NL2SQL调用失败：{type(exc).__name__}"}
 
+    def close(self) -> None:
+        """释放适配器自行创建的同步连接池。"""
+        if self._owns_engine and self._db_engine is not None:
+            self._db_engine.dispose()
+            self._db_engine = None
+
+    def _get_db_engine(self) -> Engine:
+        if self._db_engine is not None:
+            return self._db_engine
+        dsn = self._settings.mysql_dsn
+        if dsn.startswith("mysql+asyncmy://"):
+            dsn = dsn.replace("mysql+asyncmy://", "mysql+pymysql://", 1)
+        elif dsn.startswith("mysql://"):
+            dsn = dsn.replace("mysql://", "mysql+pymysql://", 1)
+        if not dsn:
+            raise RuntimeError("未配置数据库连接")
+        self._db_engine = create_engine(dsn, pool_pre_ping=True)
+        return self._db_engine
+
     @staticmethod
     def _auth_context(context: RequestContext) -> dict[str, object]:
         return {