Port to oslo.messaging.Notifier API

Add a temporary nova.notifier.Notifier helper class which translates
oslo.messaging.Notifier compatible calls into openstack.common.notifier
compatible calls.

This allows us to port the notifier code over to the oslo.messaging API
before actually switching over oslo.messaging fully.

This patch contains no functional changes at all, except that all
notifications go through this temporary helper class.

Some notes on the new API:

  * The notifier API is changed so that what was previously global state
    is now encapsulated in a Notifier object. This object also includes
    the publisher_id and has error()/info()/etc. methods rather than
    just notify().

  * The notify_decorator() helper wasn't carried across to the new API
    because its semantics are a bit weird. Something along these lines
    could be added in future, though.

  * We use a fake Notifier implementation for tests because there's no
    API in oslo.messaging to actually get the notifications queued
    up in the fake notification driver, which is a bit dumb. However,
    this feels like the right thing to do anyway. We're not wanting
    to test oslo.messaging.Notifier itself, but rather we want to test
    how we call it.

blueprint: oslo-messaging
Change-Id: I262163c7e05e6a6fb79265e904ce761fc3ac5806

1 files changed, 40 insertions, 9 deletions

diff --git a/nova/notifications.py b/nova/notifications.py
index aefd1fa82a..fe0dd73904 100644
--- a/nova/notifications.py
+++ b/nova/notifications.py
@@ -2,6 +2,7 @@
 
 # Copyright (c) 2012 OpenStack Foundation
 # All Rights Reserved.
+# Copyright 2013 Red Hat, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -29,10 +30,11 @@ from nova import db
 from nova.image import glance
 from nova import network
 from nova.network import model as network_model
+from nova import notifier as notify
+from nova.openstack.common import context as common_context
 from nova.openstack.common import excutils
 from nova.openstack.common.gettextutils import _
 from nova.openstack.common import log
-from nova.openstack.common.notifier import api as notifier_api
 from nova.openstack.common import timeutils
 from nova import utils
 
@@ -53,6 +55,40 @@ notify_opts = [
 
 CONF = cfg.CONF
 CONF.register_opts(notify_opts)
+CONF.import_opt('default_notification_level',
+                'nova.openstack.common.notifier.api')
+CONF.import_opt('default_publisher_id',
+                'nova.openstack.common.notifier.api')
+
+
+def notify_decorator(name, fn):
+    """Decorator for notify which is used from utils.monkey_patch().
+
+        :param name: name of the function
+        :param function: - object of the function
+        :returns: function -- decorated function
+
+    """
+    def wrapped_func(*args, **kwarg):
+        body = {}
+        body['args'] = []
+        body['kwarg'] = {}
+        for arg in args:
+            body['args'].append(arg)
+        for key in kwarg:
+            body['kwarg'][key] = kwarg[key]
+
+        ctxt = common_context.get_context_from_function_and_args(
+            fn, args, kwarg)
+
+        notifier = notify.get_notifier(publisher_id=(CONF.default_publisher_id
+                                                     or CONF.host))
+        method = notifier.getattr(CONF.default_notification_level.lower(),
+                                  'info')
+        method(ctxt, name, body)
+
+        return fn(*args, **kwarg)
+    return wrapped_func
 
 
 def send_api_fault(url, status, exception):
@@ -63,10 +99,7 @@ def send_api_fault(url, status, exception):
 
     payload = {'url': url, 'exception': str(exception), 'status': status}
 
-    publisher_id = notifier_api.publisher_id("api")
-
-    notifier_api.notify(None, publisher_id, 'api.fault', notifier_api.ERROR,
-                        payload)
+    notify.get_notifier('api').error(None, 'api.fault', payload)
 
 
 def send_update(context, old_instance, new_instance, service=None, host=None):
@@ -192,10 +225,8 @@ def _send_instance_update_notification(context, instance, old_vm_state=None,
     if old_display_name:
         payload["old_display_name"] = old_display_name
 
-    publisher_id = notifier_api.publisher_id(service, host)
-
-    notifier_api.notify(context, publisher_id, 'compute.instance.update',
-            notifier_api.INFO, payload)
+    notify.get_notifier(service, host).info(context,
+                                            'compute.instance.update', payload)
 
 
 def audit_period_bounds(current_period=False):