feat: nested session causes deadlock (#67)

Author: yenchenLiu

casbin_sqlalchemy_adapter/adapter.py

@@ -127,12 +127,15 @@ def filter_query(self, querydb, filter):
                 )
         return querydb.order_by(self._db_class.id)
 
-    def _save_policy_line(self, ptype, rule):
-        with self._session_scope() as session:
-            line = self._db_class(ptype=ptype)
-            for i, v in enumerate(rule):
-                setattr(line, "v{}".format(i), v)
+    def _save_policy_line(self, ptype, rule, session=None):
+        line = self._db_class(ptype=ptype)
+        for i, v in enumerate(rule):
+            setattr(line, "v{}".format(i), v)
+        if session:
             session.add(line)
+        else:
+            with self._session_scope() as session:
+                session.add(line)
 
     def save_policy(self, model):
         """saves all policy rules to the storage."""
@@ -144,7 +147,7 @@ def save_policy(self, model):
                     continue
                 for ptype, ast in model.model[sec].items():
                     for rule in ast.policy:
-                        self._save_policy_line(ptype, rule)
+                        self._save_policy_line(ptype, rule, session=session)
         return True
 
     def add_policy(self, sec, ptype, rule):