Do not register notification objects

Only registering the notification objects during unit test.
Notification objects are never used in the Nova RPC interface
and shall not be mixed with such objects.

Change-Id: Iba9079bb204e6ef1302529ac159199ab9fa6272b

doc/ext/versioned_notifications.py

@@ -41,6 +41,7 @@ class VersionedNotificationDirective(Directive):
         return self._build_markup(notifications)
 
     def _collect_notifications(self):
+        base.NovaObjectRegistry.register_notification_objects()
         notifications = []
         ovos = base.NovaObjectRegistry.obj_classes()
         for name, cls in ovos.items():

doc/source/notifications.rst

@@ -106,20 +106,25 @@ How to add a new versioned notification
 
 To support the above contract from the Nova code every versioned notification
 is modeled with oslo versionedobjects. Every versioned notification class
-shall inherit from the `nova.objects.notification.NotificationBase` which
+shall inherit from the `nova.notifications.objects.base.NotificationBase` which
 already defines three mandatory fields of the notification `event_type`,
 `publisher_id` and `priority`. The new notification class shall add a new field
 `payload` with an appropriate payload type. The payload object of the
 notifications shall inherit from the
-`nova.objects.notification.NotificationPayloadBase` class and shall define the
-fields of the payload as versionedobject fields. The base classes are described
-in [3]_.
+`nova.objects.notifications.base.NotificationPayloadBase` class and shall
+define the fields of the payload as versionedobject fields. The base classes
+are described in [3]_.
+
+Please note that the notification objects shall not be registered to the
+NovaObjectRegistry to avoid mixing nova internal objects with the notification
+objects. Instead of that use the register_notification decorator on every
+concrete notification object.
 
 The following code example defines the necessary model classes for a new
 notification `myobject.update`::
 
     @notification.notification_sample('myobject-update.json')
-    @base.NovaObjectRegistry.register
+    @object_base.NovaObjectRegistry.register.register_notification
     class MyObjectNotification(notification.NotificationBase):
         # Version 1.0: Initial version
         VERSION = '1.0'
@@ -129,7 +134,7 @@ notification `myobject.update`::
         }
 
 
-    @base.NovaObjectRegistry.register
+    @object_base.NovaObjectRegistry.register.register_notification
     class MyObjectUpdatePayload(notification.NotificationPayloadBase):
         # Version 1.0: Initial version
         VERSION = '1.0'
@@ -177,7 +182,7 @@ object. For example the service.status notification reuses the existing
 `nova.objects.service.Service` object when defines the notification's payload::
 
     @notification.notification_sample('service-update.json')
-    @base.NovaObjectRegistry.register
+    @object_base.NovaObjectRegistry.register.register_notification
     class ServiceStatusNotification(notification.NotificationBase):
         # Version 1.0: Initial version
         VERSION = '1.0'
@@ -186,7 +191,7 @@ object. For example the service.status notification reuses the existing
             'payload': fields.ObjectField('ServiceStatusPayload')
         }
 
-    @base.NovaObjectRegistry.register
+    @object_base.NovaObjectRegistry.register.register_notification
     class ServiceStatusPayload(notification.NotificationPayloadBase):
         SCHEMA = {
             'host': ('service', 'host'),

nova/notifications/objects/base.py

@@ -12,14 +12,20 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-
 from nova.objects import base
 from nova.objects import fields
 from nova import rpc
 
 
-@base.NovaObjectRegistry.register
-class EventType(base.NovaObject):
+@base.NovaObjectRegistry.register_if(False)
+class NotificationObject(base.NovaObject):
+    """Base class for every notification related versioned object."""
+    # Version 1.0: Initial version
+    VERSION = '1.0'
+
+
+@base.NovaObjectRegistry.register_notification
+class EventType(NotificationObject):
     # Version 1.0: Initial version
     VERSION = '1.0'
 
@@ -37,10 +43,8 @@ class EventType(base.NovaObject):
         return s
 
 
-# Note(gibi): It is explicitly not registered as this class shall not be used
-# directly, it is just a base class for notification payloads.
 @base.NovaObjectRegistry.register_if(False)
-class NotificationPayloadBase(base.NovaObject):
+class NotificationPayloadBase(NotificationObject):
     """Base class for the payload of versioned notifications."""
     # SCHEMA defines how to populate the payload fields. It is a dictionary
     # where every key value pair has the following format:
@@ -81,8 +85,8 @@ class NotificationPayloadBase(base.NovaObject):
         self.populated = True
 
 
-@base.NovaObjectRegistry.register
-class NotificationPublisher(base.NovaObject):
+@base.NovaObjectRegistry.register_notification
+class NotificationPublisher(NotificationObject):
     # Version 1.0: Initial version
     VERSION = '1.0'
 
@@ -96,10 +100,8 @@ class NotificationPublisher(base.NovaObject):
         return cls(host=service.host, binary=service.binary)
 
 
-# Note(gibi): It is explicitly not registered as this class shall not be used
-# directly, it is just a base class for notification.
 @base.NovaObjectRegistry.register_if(False)
-class NotificationBase(base.NovaObject):
+class NotificationBase(NotificationObject):
     """Base class for versioned notifications.
 
     Every subclass shall define a 'payload' field.

nova/notifications/objects/service.py

@@ -14,12 +14,12 @@
 #    under the License.
 
 from nova.notifications.objects import base
-from nova.objects import base as object_base
+from nova.objects import base as nova_base
 from nova.objects import fields
 
 
 @base.notification_sample('service-update.json')
-@object_base.NovaObjectRegistry.register
+@nova_base.NovaObjectRegistry.register_notification
 class ServiceStatusNotification(base.NotificationBase):
     # Version 1.0: Initial version
     VERSION = '1.0'
@@ -29,7 +29,7 @@ class ServiceStatusNotification(base.NotificationBase):
     }
 
 
-@object_base.NovaObjectRegistry.register
+@nova_base.NovaObjectRegistry.register_notification
 class ServiceStatusPayload(base.NotificationPayloadBase):
     SCHEMA = {
         'host': ('service', 'host'),

nova/objects/base.py

@@ -40,6 +40,8 @@ def get_attrname(name):
 
 
 class NovaObjectRegistry(ovoo_base.VersionedObjectRegistry):
+    notification_classes = []
+
     def registration_hook(self, cls, index):
         # NOTE(danms): This is called when an object is registered,
         # and is responsible for maintaining nova.objects.$OBJECT
@@ -53,6 +55,25 @@ class NovaObjectRegistry(ovoo_base.VersionedObjectRegistry):
             if version >= cur_version:
                 setattr(objects, cls.obj_name(), cls)
 
+    @classmethod
+    def register_notification(cls, notification_cls):
+        """Register a class as notification.
+        Use only to register concrete notification or payload classes,
+        do not register base classes intended for inheritance only.
+        """
+        cls.register_if(False)(notification_cls)
+        cls.notification_classes.append(notification_cls)
+        return notification_cls
+
+    @classmethod
+    def register_notification_objects(cls):
+        """Register previously decorated notification as normal ovos.
+        This is not intended for production use but only for testing and
+        document generation purposes.
+        """
+        for notification_cls in cls.notification_classes:
+            cls.register(notification_cls)
+
 
 remotable_classmethod = ovoo_base.remotable_classmethod
 remotable = ovoo_base.remotable

nova/tests/unit/objects/test_objects.py

@@ -1209,6 +1209,11 @@ object_data = {
 
 
 class TestObjectVersions(test.NoDBTestCase):
+
+    def setUp(self):
+        super(test.NoDBTestCase, self).setUp()
+        base.NovaObjectRegistry.register_notification_objects()
+
     def test_versions(self):
         checker = fixture.ObjectVersionChecker(
             base.NovaObjectRegistry.obj_classes())