Merge pull request #10 from actioncy/proxy-enforcer-improvements

Proxy enforcer improvements

README.md

@@ -64,6 +64,32 @@ def hello(request):
         pass
 ```
 
+## Configuration
+
+### `CASBIN_MODEL`
+A string containing the file location of your casbin model.
+
+### `CASBIN_LOG_ENABLED`
+If `True`, enables logging. `False` by default.
+
+### `CASBIN_ADAPTER`
+A string containing the adapter import path. Defaults 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
+in `CASBIN_ADAPTER`. Refer to adapters to see available arguments. 
+
+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_WATCHER`
+Watcher instance to be set as the watcher on the enforcer instance.
+
+### `CASBIN_ROLE_MANAGER`
+Role manager instance to be set as the role manager on the enforcer instance.
+
+
 ### Getting Help
 
 - [PyCasbin](https://github.com/casbin/pycasbin)

casbin_adapter/enforcer.py

@@ -1,10 +1,15 @@
+import logging
 from django.conf import settings
 from django.db import connection
 from django.db.utils import OperationalError, ProgrammingError
 
 from casbin import Enforcer
 
 from .adapter import Adapter
+from .utils import import_class
+
+logger = logging.getLogger(__name__)
+
 
 
 class ProxyEnforcer(Enforcer):
@@ -13,15 +18,22 @@ class ProxyEnforcer(Enforcer):
     def __init__(self, *args, **kwargs):
         if self._initialized:
             super().__init__(*args, **kwargs)
+        else:
+            logger.info('Deferring casbin enforcer initialisation until django is ready')
 
     def _load(self):
         if self._initialized == False:
+            logger.info('Performing deferred casbin enforcer initialisation')
             self._initialized = True
             model = getattr(settings, 'CASBIN_MODEL')
             enable_log = getattr(settings, 'CASBIN_LOG_ENABLED', False)
-            adapter = Adapter()
+            adapter_loc = getattr(settings, 'CASBIN_ADAPTER', 'casbin_adapter.adapter.Adapter')
+            adapter_args = getattr(settings, 'CASBIN_ADAPTER_ARGS', tuple())
+            Adapter = import_class(adapter_loc)
+            adapter = Adapter(*adapter_args)
 
             super().__init__(model, adapter, enable_log)
+            logger.debug('Casbin enforcer initialised')
 
             watcher = getattr(settings, 'CASBIN_WATCHER', None)
             if watcher:

casbin_adapter/utils.py

@@ -0,0 +1,11 @@
+import importlib
+
+def import_class(name):
+    """Import class from string
+    e.g. `package.module.ClassToImport` returns the `ClasToImport` class"""
+    components = name.split('.')
+    module_name = '.'.join(components[:-1])
+    class_name = components[-1]
+    module = importlib.import_module(module_name)
+    class_ = getattr(module, class_name)
+    return class_