feat: add db alias (#21)

* feat: add db alias

* feat: add db alias

* docs: add CASBIN_DB_ALIAS argument to readme

README.md

@@ -70,7 +70,7 @@ def hello(request):
 A string containing the file location of your casbin model.
 
 ### `CASBIN_ADAPTER`
-A string containing the adapter import path. Defaults to the django adapter shipped with this package: `casbin_adapter.adapter.Adapter`
+A string containing the adapter import path. Default to the django adapter shipped with this package: `casbin_adapter.adapter.Adapter`
 
 ### `CASBIN_ADAPTER_ARGS`
 A tuple of arguments to be passed into the constructor of the adapter specified
@@ -80,6 +80,9 @@ E.g. if you wish to use the file adapter
 set the adapter to `casbin.persist.adapters.FileAdapter` and use
 `CASBIN_ADAPTER_ARGS = ('path/to/policy_file.csv',)`
 
+### `CASBIN_DB_ALIAS`
+The database the adapter uses. Default to "default".
+
 ### `CASBIN_WATCHER`
 Watcher instance to be set as the watcher on the enforcer instance.
 

casbin_adapter/adapter.py

@@ -11,10 +11,13 @@
 class Adapter(persist.Adapter):
     """the interface for Casbin adapters."""
 
+    def __init__(self, db_alias="default"):
+        self.db_alias = db_alias
+
     def load_policy(self, model):
         """loads all policy rules from the storage."""
         try:
-            lines = CasbinRule.objects.all()
+            lines = CasbinRule.objects.using(self.db_alias).all()
 
             for line in lines:
                 persist.load_policy_line(str(line), model)
@@ -41,7 +44,7 @@ def save_policy(self, model):
         """saves all policy rules to the storage."""
         # See https://casbin.org/docs/en/adapters#autosave
         # for why this is deleting all rules
-        CasbinRule.objects.all().delete()
+        CasbinRule.objects.using(self.db_alias).all().delete()
 
         lines = []
         for sec in ["p", "g"]:
@@ -50,7 +53,7 @@ def save_policy(self, model):
             for ptype, ast in model.model[sec].items():
                 for rule in ast.policy:
                     lines.append(self._create_policy_line(ptype, rule))
-        CasbinRule.objects.bulk_create(lines)
+        CasbinRule.objects.using(self.db_alias).bulk_create(lines)
         return True
 
     def add_policy(self, sec, ptype, rule):
@@ -63,7 +66,7 @@ def remove_policy(self, sec, ptype, rule):
         query_params = {"ptype": ptype}
         for i, v in enumerate(rule):
             query_params["v{}".format(i)] = v
-        rows_deleted, _ = CasbinRule.objects.filter(**query_params).delete()
+        rows_deleted, _ = CasbinRule.objects.using(self.db_alias).filter(**query_params).delete()
         return True if rows_deleted > 0 else False
 
     def remove_filtered_policy(self, sec, ptype, field_index, *field_values):
@@ -77,5 +80,5 @@ def remove_filtered_policy(self, sec, ptype, field_index, *field_values):
             return False
         for i, v in enumerate(field_values):
             query_params["v{}".format(i + field_index)] = v
-        rows_deleted, _ = CasbinRule.objects.filter(**query_params).delete()
+        rows_deleted, _ = CasbinRule.objects.using(self.db_alias).filter(**query_params).delete()
         return True if rows_deleted > 0 else False

casbin_adapter/apps.py

@@ -1,6 +1,4 @@
 from django.apps import AppConfig
-from django.db import connection
-from django.db.utils import OperationalError, ProgrammingError
 
 
 class CasbinAdapterConfig(AppConfig):

casbin_adapter/enforcer.py

@@ -5,14 +5,14 @@
 
 from casbin import Enforcer
 
-from .adapter import Adapter
 from .utils import import_class
 
 logger = logging.getLogger(__name__)
 
 
 class ProxyEnforcer(Enforcer):
     _initialized = False
+    db_alias = "default"
 
     def __init__(self, *args, **kwargs):
         if self._initialized:
@@ -27,8 +27,9 @@ def _load(self):
             model = getattr(settings, "CASBIN_MODEL")
             adapter_loc = getattr(settings, "CASBIN_ADAPTER", "casbin_adapter.adapter.Adapter")
             adapter_args = getattr(settings, "CASBIN_ADAPTER_ARGS", tuple())
+            self.db_alias = getattr(settings, "CASBIN_DB_ALIAS", "default")
             Adapter = import_class(adapter_loc)
-            adapter = Adapter(*adapter_args)
+            adapter = Adapter(self.db_alias, *adapter_args)
 
             super().__init__(model, adapter)
             logger.debug("Casbin enforcer initialised")
@@ -44,7 +45,7 @@ def _load(self):
     def __getattribute__(self, name):
         safe_methods = ["__init__", "_load", "_initialized"]
         if not super().__getattribute__("_initialized") and name not in safe_methods:
-            initialize_enforcer()
+            initialize_enforcer(self.db_alias)
             if not super().__getattribute__("_initialized"):
                 raise Exception(
                     (
@@ -59,17 +60,29 @@ def __getattribute__(self, name):
 enforcer = ProxyEnforcer()
 
 
-def initialize_enforcer():
+def initialize_enforcer(db_alias=None):
     try:
-        with connection.cursor() as cursor:
-            cursor.execute(
-                """
-                SELECT app, name applied FROM django_migrations
-                WHERE app = 'casbin_adapter' AND name = '0001_initial';
-                """
-            )
-            row = cursor.fetchone()
-            if row:
-                enforcer._load()
+        row = None
+        if db_alias:
+            with connection[db_alias].cursor() as cursor:
+                cursor.execute(
+                    """
+                    SELECT app, name applied FROM django_migrations
+                    WHERE app = 'casbin_adapter' AND name = '0001_initial';
+                    """
+                )
+                row = cursor.fetchone()
+        else:
+            with connection.cursor() as cursor:
+                cursor.execute(
+                    """
+                    SELECT app, name applied FROM django_migrations
+                    WHERE app = 'casbin_adapter' AND name = '0001_initial';
+                    """
+                )
+                row = cursor.fetchone()
+
+        if row:
+            enforcer._load()
     except (OperationalError, ProgrammingError):
         pass

requirements.txt

@@ -1,3 +1,3 @@
-casbin==1.16.10
+casbin>=1.16.10
 Django
 

requirements_dev.txt

@@ -1,3 +1,2 @@
 -r requirements.txt
-setuptools==60.2.0
-simpleeval==0.9.12
+setuptools==60.2.0

tests/test_adapter.py

@@ -1,7 +1,6 @@
 import os
 import casbin
 import simpleeval
-from unittest import TestCase
 
 from django.test import TestCase
 from casbin_adapter.models import CasbinRule