Rule -> Policies

passbook/core/policies.py

@@ -0,0 +1,48 @@
+"""passbook core policy engine"""
+from logging import getLogger
+
+from celery import group
+
+from passbook.core.celery import CELERY_APP
+from passbook.core.models import Policy, User
+
+LOGGER = getLogger(__name__)
+
+@CELERY_APP.task()
+def _policy_engine_task(user_pk, policy_pk, **kwargs):
+    """Task wrapper to run policy checking"""
+    policy_obj = Policy.objects.filter(pk=policy_pk).select_subclasses().first()
+    user_obj = User.objects.get(pk=user_pk)
+    for key, value in kwargs.items():
+        setattr(user_obj, key, value)
+    LOGGER.debug("Running policy `%s`#%s for user %s...", policy_obj.name,
+                 policy_obj.pk.hex, user_obj)
+    return policy_obj.passes(user_obj)
+
+class PolicyEngine:
+    """Orchestrate policy checking, launch tasks and return result"""
+
+    policies = None
+    _group = None
+
+    def __init__(self, policies):
+        self.policies = policies
+
+    def for_user(self, user):
+        """Check policies for user"""
+        signatures = []
+        kwargs = {
+            '__password__': getattr(user, '__password__')
+        }
+        for policy in self.policies:
+            signatures.append(_policy_engine_task.s(user.pk, policy.pk.hex, **kwargs))
+        self._group = group(signatures)()
+        return self
+
+    @property
+    def result(self):
+        """Get policy-checking result"""
+        for policy_result in self._group.get():
+            if policy_result is False:
+                return False
+        return True