Merge pull request #16 from Nekotoxin/add_err_handler

fix: add error handler when initial django app

casbin_adapter/adapter.py

@@ -1,18 +1,25 @@
-from django.conf import settings
+import logging
+
 from casbin import persist
+from django.db.utils import OperationalError, ProgrammingError
 
 from .models import CasbinRule
 
+logger = logging.getLogger(__name__)
+
 
 class Adapter(persist.Adapter):
     """the interface for Casbin adapters."""
 
     def load_policy(self, model):
         """loads all policy rules from the storage."""
-        lines = CasbinRule.objects.all()
+        try:
+            lines = CasbinRule.objects.all()
 
-        for line in lines:
-            persist.load_policy_line(str(line), model)
+            for line in lines:
+                persist.load_policy_line(str(line), model)
+        except (OperationalError, ProgrammingError) as error:
+            logger.warning("Could not load policy from database: {}".format(error))
 
     def _create_policy_line(self, ptype, rule):
         line = CasbinRule(ptype=ptype)