Refactor notifications

I'm replacing the implementation of notifications with the blinker
library. In order to do this properly I wanted to have a more defined
interface and less coupling in the tests. Test should be unaware of the
implementation of the thing they are testing so that the implementation
can be changed later.

Change-Id: Icdcbf77944187bc9b2b390420862f700baa179c9

keystone/notifications.py

@@ -28,6 +28,7 @@ from pycadf import resource
 from keystone.openstack.common.gettextutils import _
 from keystone.openstack.common import log
 
+
 notifier_opts = [
     cfg.StrOpt('default_publisher_id',
                default=None,
@@ -39,7 +40,7 @@ LOG = log.getLogger(__name__)
 # a new action is supported.
 ACTIONS = frozenset(['created', 'deleted', 'disabled', 'updated'])
 # resource types that can be notified
-SUBSCRIBERS = {}
+_SUBSCRIBERS = {}
 _notifier = None
 
 
@@ -129,8 +130,8 @@ def register_event_callback(event, resource_type, callbacks):
             msg = _('Method not callable: %s') % callback
             LOG.error(msg)
             raise TypeError(msg)
-        SUBSCRIBERS.setdefault(event, {}).setdefault(resource_type, set())
+        _SUBSCRIBERS.setdefault(event, {}).setdefault(resource_type, set())
-        SUBSCRIBERS[event][resource_type].add(callback)
+        _SUBSCRIBERS[event][resource_type].add(callback)
 
         if LOG.logger.getEffectiveLevel() <= logging.INFO:
             # Do this only if its going to appear in the logs.
@@ -144,9 +145,9 @@ def register_event_callback(event, resource_type, callbacks):
 
 def notify_event_callbacks(service, resource_type, operation, payload):
     """Sends a notification to registered extensions."""
-    if operation in SUBSCRIBERS:
+    if operation in _SUBSCRIBERS:
-        if resource_type in SUBSCRIBERS[operation]:
+        if resource_type in _SUBSCRIBERS[operation]:
-            for cb in SUBSCRIBERS[operation][resource_type]:
+            for cb in _SUBSCRIBERS[operation][resource_type]:
                 subst_dict = {'cb_name': cb.__name__,
                               'service': service,
                               'resource_type': resource_type,
@@ -181,7 +182,11 @@ def _get_notifier():
     return _notifier
 
 
-def _reset_notifier():
+def clear_subscribers():
+    _SUBSCRIBERS.clear()
+
+
+def reset_notifier():
     global _notifier
     _notifier = None
 
@@ -199,19 +204,19 @@ def _send_notification(operation, resource_type, resource_id, public=True):
                     if False, the event will only be sent via
                     notify_event_callbacks to in process listeners.
     """
-    context = {}
     payload = {'resource_info': resource_id}
     service = 'identity'
-    event_type = '%(service)s.%(resource_type)s.%(operation)s' % {
-        'service': service,
-        'resource_type': resource_type,
-        'operation': operation}
 
     notify_event_callbacks(service, resource_type, operation, payload)
 
     if public:
         notifier = _get_notifier()
         if notifier:
+            context = {}
+            event_type = '%(service)s.%(resource_type)s.%(operation)s' % {
+                'service': service,
+                'resource_type': resource_type,
+                'operation': operation}
             try:
                 notifier.info(context, event_type, payload)
             except Exception:

keystone/tests/core.py

@@ -412,8 +412,8 @@ class TestCase(BaseTestCase):
         self.addCleanup(kvs.INMEMDB.clear)
 
         # Ensure Notification subscriotions and resource types are empty
-        self.addCleanup(notifications.SUBSCRIBERS.clear)
+        self.addCleanup(notifications.clear_subscribers)
-        self.addCleanup(notifications._reset_notifier)
+        self.addCleanup(notifications.reset_notifier)
 
         # Reset the auth-plugin registry
         self.addCleanup(self.clear_auth_plugin_registry)

keystone/tests/test_notifications.py

@@ -363,7 +363,6 @@ class TestEventCallbacks(test_v3.RestfulTestCase):
 
     def setUp(self):
         super(TestEventCallbacks, self).setUp()
-        notifications.SUBSCRIBERS = {}
         self.has_been_called = False
 
     def _project_deleted_callback(self, service, resource_type, operation,
@@ -382,7 +381,6 @@ class TestEventCallbacks(test_v3.RestfulTestCase):
 
     def test_notification_method_not_callable(self):
         fake_method = None
-        notifications.SUBSCRIBERS = {}
         self.assertRaises(TypeError,
                           notifications.register_event_callback,
                           UPDATED_OPERATION,
@@ -406,11 +404,10 @@ class TestEventCallbacks(test_v3.RestfulTestCase):
         notifications.register_event_callback(DELETED_OPERATION,
                                               resource_type,
                                               self._project_deleted_callback)
-        self.assertIn(DELETED_OPERATION, notifications.SUBSCRIBERS)
-        self.assertIn(resource_type,
-                      notifications.SUBSCRIBERS[DELETED_OPERATION])
 
     def test_provider_event_callbacks_subscription(self):
+        callback_called = []
+
         @dependency.provider('foo_api')
         class Foo:
             def __init__(self):
@@ -419,11 +416,13 @@ class TestEventCallbacks(test_v3.RestfulTestCase):
 
             def foo_callback(self, service, resource_type, operation,
                              payload):
-                pass
+                callback_called.append(True)  # uses callback_called
+                                              # from the closure
 
-        notifications.SUBSCRIBERS = {}
         Foo()
-        self.assertIn(CREATED_OPERATION, notifications.SUBSCRIBERS)
+        project_ref = self.new_project_ref(domain_id=self.domain_id)
+        self.assignment_api.create_project(project_ref['id'], project_ref)
+        self.assertEqual([True], callback_called)
 
     def test_invalid_event_callbacks(self):
         @dependency.provider('foo_api')
@@ -431,7 +430,6 @@ class TestEventCallbacks(test_v3.RestfulTestCase):
             def __init__(self):
                 self.event_callbacks = 'bogus'
 
-        notifications.SUBSCRIBERS = {}
         self.assertRaises(ValueError, Foo)
 
     def test_invalid_event_callbacks_event(self):
@@ -440,7 +438,6 @@ class TestEventCallbacks(test_v3.RestfulTestCase):
             def __init__(self):
                 self.event_callbacks = {CREATED_OPERATION: 'bogus'}
 
-        notifications.SUBSCRIBERS = {}
         self.assertRaises(ValueError, Foo)