core: add basic rule engine, needs celery debugging

passbook/core/apps.py

@@ -1,4 +1,6 @@
 """passbook core app config"""
+from importlib import import_module
+
 from django.apps import AppConfig
 
 
@@ -8,3 +10,6 @@ class PassbookCoreConfig(AppConfig):
     name = 'passbook.core'
     label = 'passbook_core'
     verbose_name = 'passbook Core'
+
+    def ready(self):
+        import_module('passbook.core.rules')

passbook/core/rules.py

@@ -0,0 +1,41 @@
+"""passbook core rule engine"""
+from celery import group
+
+from passbook.core.celery import CELERY_APP
+from passbook.core.models import Rule, User
+
+
+class RuleEngine:
+    """Orchestrate rule checking, launch tasks and return result"""
+
+    _rule_model = None
+    _group = None
+
+    def __init__(self, rule_model):
+        self._rule_model = rule_model
+
+    @CELERY_APP.task(bind=True)
+    def _rule_engine_task(self, user_pk, rule_pk):
+        """Task wrapper to run rule checking"""
+        rule_obj = Rule.objects.filter(pk=rule_pk).select_subclasses().first()
+        user_obj = User.objects.get(user_pk)
+        return rule_obj.passes(user_obj)
+
+    def for_user(self, user):
+        """Check rules for user"""
+        signatures = []
+        for rule in self._rule_model.rules.all():
+            # pylint: disable=no-member
+            signatures.append(self._rule_engine_task.s(user.pk, rule.pk))
+        self._group = group(signatures).apply_async()
+        return self
+
+    def wait(self):
+        """Wait for result, blocking this request"""
+        # return self._group.wait()
+
+    @property
+    def result(self):
+        """Get rule-checking result"""
+        print(self._group.get())
+        return True