Add priority based queues to notifications.

Remove duplicate json encoding in notifier (rpc.cast does encoding... ) 
make no_op_notifier  match rabbit one for signature on notify()

nova/notifier/__init__.py

@@ -14,14 +14,13 @@
 #    under the License.
 
 import datetime
-import json
 
 from nova import flags
 from nova import utils
 
 FLAGS = flags.FLAGS
 
-flags.DEFINE_string('default_notification_level', 'info',
+flags.DEFINE_string('default_notification_level', 'INFO',
                     'Default notification level for outgoing notifications')
 
 WARN = 'WARN'
@@ -69,4 +68,4 @@ def notify(event_name, publisher_id, event_type, priority, payload):
                    priority=priority,
                    payload=payload,
                    time=str(datetime.datetime.utcnow()))
-    driver.notify(json.dumps(message))
+    driver.notify(message)

nova/notifier/no_op_notifier.py

@@ -14,6 +14,6 @@
 #    under the License.
 
 class NoopNotifier(object):
-    def notify(self, event_name, model):
+    def notify(self, payload):
         """Notifies the recipient of the desired event given the model"""
         pass

nova/notifier/rabbit_notifier.py

@@ -13,7 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import json
 
 import nova.context
 
@@ -28,10 +27,12 @@ flags.DEFINE_string('notification_topic', 'notifications',
 
 class RabbitNotifier(object):
     """Sends notifications to a specific RabbitMQ server and topic"""
-    pass
 
     def notify(self, payload):
         """Sends a notification to the RabbitMQ"""
         context = nova.context.get_admin_context()
-        topic = FLAGS.notification_topic
+        priority = payload.get('priority',
+                               FLAGS.default_notification_level)
+        priority = priority.lower()
+        topic = '%s.%s' % (FLAGS.notification_topic, priority)
         rpc.cast(context, topic, payload)