Make notifications pluggable

- Defines a plugin interface for what's actually emitted as part
  of designate "notifications".
- The default plugin emits the same thing as notifications did prior
  to this patch.
- The "audit" notification plugin emits recordset data changes and
  zone/recordset names, if they exist, the notifications with this
  plugin look like http://paste.openstack.org/show/545210/
- Adds support for multiple notifications for a single change
- Also adds client IP to the context object, as it's a field that
  may be of interest to some types of notifications
- Many tests

Change-Id: I01118fae8ce6e38ccc61b0ce763fd759affd9a86

8 files changed, 772 insertions, 7 deletions

diff --git a/contrib/consume.py b/contrib/consume.py
new file mode 100644
index 00000000..c3f141d2
--- /dev/null
+++ b/contrib/consume.py
@@ -0,0 +1,39 @@
+# Copyright 2016 Rackspace, Inc.
+#
+# Author: Tim Simmons <tim.simmons@rackspace.com>
+#
+# 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
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+"""
+This dumb script allows you to see what's being dumped onto
+the notifications.info queue
+
+nabbed from:
+https://pika.readthedocs.io/en/latest/examples/blocking_consume.html
+"""
+import pika
+
+
+def on_message(channel, method_frame, header_frame, body):
+    print(method_frame.delivery_tag)
+    print(body)
+    channel.basic_ack(delivery_tag=method_frame.delivery_tag)
+
+
+connection = pika.BlockingConnection()
+channel = connection.channel()
+channel.basic_consume(on_message, 'notifications.info')
+try:
+    channel.start_consuming()
+except KeyboardInterrupt:
+    channel.stop_consuming()
+connection.close()
diff --git a/designate/api/middleware.py b/designate/api/middleware.py
index 49cfc024..0a941de8 100644
--- a/designate/api/middleware.py
+++ b/designate/api/middleware.py
@@ -107,6 +107,10 @@ class ContextMiddleware(base.Middleware):
                 strutils.bool_from_string(
                     request.headers.get('X-Designate-Edit-Managed-Records'))
 
+    def _extract_client_addr(self, ctxt, request):
+        if hasattr(request, 'client_addr'):
+            ctxt.client_addr = request.client_addr
+
     def make_context(self, request, *args, **kwargs):
         req_id = request.environ.get(request_id.ENV_REQUEST_ID)
         kwargs.setdefault('request_id', req_id)
@@ -118,6 +122,7 @@ class ContextMiddleware(base.Middleware):
             self._extract_all_projects(ctxt, request)
             self._extract_edit_managed_records(ctxt, request)
             self._extract_dns_hide_counts(ctxt, request)
+            self._extract_client_addr(ctxt, request)
         finally:
             request.environ['context'] = ctxt
         return ctxt
diff --git a/designate/central/service.py b/designate/central/service.py
index 52852e56..2f512702 100644
--- a/designate/central/service.py
+++ b/designate/central/service.py
@@ -42,6 +42,7 @@ from designate import context as dcontext
 from designate import exceptions
 from designate import dnsutils
 from designate import network_api
+from designate import notifications
 from designate import objects
 from designate import policy
 from designate import quota
@@ -157,11 +158,17 @@ def notification(notification_type):
                 # Call the wrapped function
                 result = f(self, *args, **kwargs)
 
+                # Feed the args/result to a notification plugin
+                # to determine what is emitted
+                payloads = notifications.get_plugin().emit(
+                    notification_type, context, result, args, kwargs)
+
                 # Enqueue the notification
-                LOG.debug('Queueing notification for %(type)s ',
-                          {'type': notification_type})
-                NOTIFICATION_BUFFER.queue.appendleft(
-                    (context, notification_type, result,))
+                for payload in payloads:
+                    LOG.debug('Queueing notification for %(type)s ',
+                              {'type': notification_type})
+                    NOTIFICATION_BUFFER.queue.appendleft(
+                        (context, notification_type, payload,))
 
                 return result
 
diff --git a/designate/context.py b/designate/context.py
index 4c2a695b..72a632c8 100644
--- a/designate/context.py
+++ b/designate/context.py
@@ -32,10 +32,12 @@ class DesignateContext(context.RequestContext):
     _abandon = None
     original_tenant = None
     _edit_managed_records = False
+    _client_addr = None
 
     def __init__(self, service_catalog=None, all_tenants=False, abandon=None,
                  tsigkey_id=None, user_identity=None, original_tenant=None,
-                 edit_managed_records=False, hide_counts=False, **kwargs):
+                 edit_managed_records=False, hide_counts=False,
+                 client_addr=None, **kwargs):
 
         # NOTE: user_identity may be passed in, but will be silently dropped as
         #       it is a generated field based on several others.
@@ -50,6 +52,7 @@ class DesignateContext(context.RequestContext):
         self.abandon = abandon
         self.edit_managed_records = edit_managed_records
         self.hide_counts = hide_counts
+        self.client_addr = client_addr
 
     def deepcopy(self):
         d = self.to_dict()
@@ -83,7 +86,8 @@ class DesignateContext(context.RequestContext):
             'abandon': self.abandon,
             'edit_managed_records': self.edit_managed_records,
             'tsigkey_id': self.tsigkey_id,
-            'hide_counts': self.hide_counts
+            'hide_counts': self.hide_counts,
+            'client_addr': self.client_addr,
         })
 
         return copy.deepcopy(d)
@@ -184,6 +188,14 @@ class DesignateContext(context.RequestContext):
             policy.check('edit_managed_records', self)
         self._edit_managed_records = value
 
+    @property
+    def client_addr(self):
+        return self._client_addr
+
+    @client_addr.setter
+    def client_addr(self, value):
+        self._client_addr = value
+
 
 def get_current():
     return context.get_current()
diff --git a/designate/notifications.py b/designate/notifications.py
index 817c30e1..e9c6dd81 100644
--- a/designate/notifications.py
+++ b/designate/notifications.py
@@ -15,21 +15,28 @@
 # under the License.
 #
 # Copied: nova.notifications
+import abc
 
 from oslo_config import cfg
 from oslo_log import log as logging
 
+from designate.i18n import _LW
+from designate.plugin import DriverPlugin
+from designate import objects
 from designate import rpc
 
 LOG = logging.getLogger(__name__)
 
 notify_opts = [
     cfg.BoolOpt('notify_api_faults', default=False,
-                help='Send notifications if there\'s a failure in the API.')
+                help='Send notifications if there\'s a failure in the API.'),
+    cfg.StrOpt('notification-plugin', default='default',
+               help='The notification plugin to use'),
 ]
 
 CONF = cfg.CONF
 CONF.register_opts(notify_opts)
+NOTIFICATION_PLUGIN = None
 
 
 def send_api_fault(context, url, status, exception):
@@ -41,3 +48,176 @@ def send_api_fault(context, url, status, exception):
     payload = {'url': url, 'exception': str(exception), 'status': status}
 
     rpc.get_notifier('api').error(context, 'dns.api.fault', payload)
+
+
+def init_notification_plugin():
+    LOG.debug("Loading notification plugin: %s" % cfg.CONF.notification_plugin)
+    cls = NotificationPlugin.get_driver(cfg.CONF.notification_plugin)
+
+    global NOTIFICATION_PLUGIN
+    NOTIFICATION_PLUGIN = cls()
+
+
+def get_plugin():
+    if NOTIFICATION_PLUGIN is None:
+        init_notification_plugin()
+    return NOTIFICATION_PLUGIN
+
+
+class NotificationPlugin(DriverPlugin):
+    """Base class for Notification Driver implementations"""
+    __plugin_type__ = 'notification'
+    __plugin_ns__ = 'designate.notification.plugin'
+
+    def __init__(self):
+        super(NotificationPlugin, self).__init__()
+
+    @abc.abstractmethod
+    def emit(self, notification_type, context, result, *args, **kwargs):
+        """Return a payload to emit as part of the notification"""
+
+
+class Default(NotificationPlugin):
+    """Returns the result, as implemented in the base class"""
+    __plugin_name__ = 'default'
+
+    def emit(self, notification_type, context, result, *args, **kwargs):
+        """Return the result of the function called"""
+        return [result]
+
+
+class Audit(NotificationPlugin):
+    """Grabs Zone/Recordset names and RRData changes"""
+    __plugin_name__ = 'audit'
+
+    def zone_name(self, arglist, result):
+        for arg in arglist + [result]:
+            if isinstance(arg, objects.Zone):
+                if arg.name is not None:
+                    return arg.name
+            if hasattr(arg, 'zone_name'):
+                if arg.zone_name is not None:
+                    return arg.zone_name
+
+        return None
+
+    def zone_id(self, arglist, result):
+        for arg in arglist + [result]:
+            if isinstance(arg, objects.Zone):
+                if arg.id is not None:
+                    return arg.id
+            if hasattr(arg, 'zone_id'):
+                if arg.zone_id is not None:
+                    return arg.zone_id
+
+        return None
+
+    def recordset_name(self, arglist, result):
+        for arg in arglist + [result]:
+            if isinstance(arg, objects.RecordSet):
+                if arg.name is not None:
+                    return arg.name
+
+        return None
+
+    def recordset_data(self, arglist, result):
+        if not isinstance(result, objects.RecordSet):
+            return []
+
+        for arg in arglist:
+            if isinstance(arg, objects.RecordSet):
+                if 'records' not in arg.obj_what_changed():
+                    return []
+                original_rrs = arg.obj_get_original_value('records')
+
+                old_value = ' '.join(
+                    [obj['data'] for obj in original_rrs])
+
+                new_value = ' '.join(
+                    [rr.data for rr in result.records])
+
+                if old_value == new_value:
+                    return []
+
+                return [{
+                    'change': 'records',
+                    'old_value': old_value,
+                    'new_value': new_value,
+                }]
+
+        return []
+
+    def other_data(self, arglist, result):
+        changes = []
+
+        for arg in arglist:
+            if isinstance(arg, objects.DesignateObject):
+                for change in arg.obj_what_changed():
+                    if change != 'records':
+                        old_value = arg.obj_get_original_value(change)
+                        new_value = getattr(arg, change)
+
+                        # Just in case something odd makes it here
+                        if any(type(val) not in
+                               (int, float, bool, str, type(None))
+                               for val in (old_value, new_value)):
+                            old_value, new_value = None, None
+                            msg = _LW("Nulling notification values after "
+                                      "unexpected values %s")
+                            LOG.warning(msg, (old_value, new_value))
+
+                        if old_value == new_value:
+                            continue
+
+                        changes.append({
+                            'change': change,
+                            'old_value': str(old_value),
+                            'new_value': str(new_value),
+                        })
+
+        return changes
+
+    def blank_event(self):
+        return [{
+            'change': None,
+            'old_value': None,
+            'new_value': None,
+        }]
+
+    def gather_changes(self, arglist, result, notification_type):
+        changes = []
+
+        if 'update' in notification_type:
+            changes.extend(self.other_data(arglist, result))
+            if notification_type == 'dns.recordset.update':
+                changes.extend(self.recordset_data(arglist, result))
+        elif 'create' in notification_type:
+            if notification_type == 'dns.recordset.create':
+                changes.extend(self.recordset_data(arglist, result))
+            else:
+                changes.extend(self.blank_event())
+        else:
+            changes.extend(self.blank_event())
+
+        return changes
+
+    def emit(self, notification_type, context, result, *args, **kwargs):
+        arglist = []
+        for item in args:
+            if isinstance(item, tuple) or isinstance(item, list):
+                arglist.extend(item)
+            if isinstance(item, dict):
+                arglist.extend(list(item.values()))
+
+        payloads = []
+        for change in self.gather_changes(arglist, result, notification_type):
+            payloads.append({
+                'zone_name': self.zone_name(arglist, result),
+                'zone_id': self.zone_id(arglist, result),
+                'recordset_name': self.recordset_name(arglist, result),
+                'old_data': change['old_value'],
+                'new_data': change['new_value'],
+                'changed_field': change['change'],
+            })
+
+        return payloads
diff --git a/designate/tests/unit/test_central/test_notifications.py b/designate/tests/unit/test_central/test_notifications.py
new file mode 100644
index 00000000..8e874927
--- /dev/null
+++ b/designate/tests/unit/test_central/test_notifications.py
@@ -0,0 +1,498 @@
+# Copyright 2016 Rackspace
+#
+# Author: Tim Simmons <tim.simmons@rackspace.com>
+#
+# 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
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+import unittest
+
+import mock
+from oslo_log import log as logging
+
+from designate import objects
+from designate import notifications
+
+LOG = logging.getLogger(__name__)
+
+
+class DefaultNotificationTest(unittest.TestCase):
+
+    def setUp(self):
+        self.driver = notifications.Default()
+
+        self.context = mock.Mock()
+
+    def test_default_notifications(self):
+        result = 'result'
+        event = 'dns.zone.create'
+        args = ('foo', 'bar',)
+        kwargs = {'wumbo': 'mumbo'}
+
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, ['result'])
+
+
+class AuditNotificationTest(unittest.TestCase):
+
+    def setUp(self):
+        self.driver = notifications.Audit()
+
+        self.context = mock.Mock()
+        self.maxDiff = None
+
+    #
+    # Zone changes
+    #
+
+    def test_audit_zone_name(self):
+        zone = objects.Zone(
+                name='example.com.',
+                type='PRIMARY',
+        )
+
+        result = zone
+        event = 'dns.zone.create'
+        args = (zone,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': None,
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_zone_id(self):
+        zone = objects.Zone(
+                id='123',
+                name='example.com.',
+                type='PRIMARY',
+        )
+
+        result = zone
+        event = 'dns.zone.create'
+        args = (zone,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_zone_update(self):
+        zone = objects.Zone(
+                id='123',
+                name='example.com.',
+                type='PRIMARY',
+                ttl=1
+        )
+        zone.ttl = 300
+
+        result = zone
+        event = 'dns.zone.update'
+        args = (zone,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': 'ttl',
+            'new_data': '300',
+            'old_data': '1',
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_zone_delete(self):
+        zone = objects.Zone(
+                id='123',
+                name='example.com.',
+                type='PRIMARY',
+                ttl=1
+        )
+
+        result = zone
+        event = 'dns.zone.delete'
+        args = ('123',)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    #
+    # Recordset Changes
+    #
+
+    def test_audit_rrset_name(self):
+        rrset = objects.RecordSet(
+                name='foo.example.com.',
+                type='PRIMARY',
+                records=objects.RecordList.from_list([])
+        )
+
+        rrset.records = objects.RecordList.from_list(
+            [{'data': '192.168.1.1'}])
+
+        result = rrset
+        event = 'dns.recordset.create'
+        args = (rrset,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': 'records',
+            'new_data': '192.168.1.1',
+            'old_data': '',
+            'recordset_name': 'foo.example.com.',
+            'zone_id': None,
+            'zone_name': None
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_rrset_create(self):
+        rrset = objects.RecordSet(
+                name='foo.example.com.',
+                type='PRIMARY',
+                records=[],
+                zone_id='123',
+                zone_name='example.com.'
+        )
+
+        rrset.records = objects.RecordList.from_list(
+            [{'data': '192.168.1.1'}])
+
+        result = rrset
+        event = 'dns.recordset.create'
+        args = (rrset,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': 'records',
+            'new_data': '192.168.1.1',
+            'old_data': '',
+            'recordset_name': 'foo.example.com.',
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_rrset_update_records(self):
+        rrset = objects.RecordSet(
+                name='foo.example.com.',
+                type='PRIMARY',
+                records=objects.RecordList.from_list(
+                    [{'data': '192.168.1.1'}]),
+                zone_id='123',
+                zone_name='example.com.'
+        )
+
+        rrset.records = objects.RecordList.from_list(
+            [{'data': '192.168.1.2'}])
+
+        result = rrset
+        event = 'dns.recordset.update'
+        args = (rrset,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': 'records',
+            'new_data': '192.168.1.2',
+            'old_data': '192.168.1.1',
+            'recordset_name': 'foo.example.com.',
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_rrset_update_other(self):
+        rrset = objects.RecordSet(
+                name='foo.example.com.',
+                type='PRIMARY',
+                records=objects.RecordList.from_list(
+                    [{'data': '192.168.1.1'}]),
+                zone_id='123',
+                zone_name='example.com.',
+                ttl=300
+        )
+
+        rrset.ttl = 400
+
+        result = rrset
+        event = 'dns.recordset.update'
+        args = (rrset,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': 'ttl',
+            'new_data': '400',
+            'old_data': '300',
+            'recordset_name': 'foo.example.com.',
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_rrset_delete(self):
+        rrset = objects.RecordSet(
+                name='foo.example.com.',
+                type='PRIMARY',
+                records=objects.RecordList.from_list([]),
+                zone_id='123',
+                zone_name='example.com.',
+                id='1',
+        )
+
+        result = rrset
+        event = 'dns.recordset.delete'
+        args = ('123', '1',)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': 'foo.example.com.',
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    #
+    # Zone Imports
+    #
+
+    def test_audit_import_create(self):
+        zimport = objects.ZoneImport(
+                zone_id='123',
+        )
+
+        result = zimport
+        event = 'dns.zone_import.create'
+        args = (zimport,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': None
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_import_delete(self):
+        zimport = objects.ZoneImport(
+                zone_id='123',
+        )
+
+        result = zimport
+        event = 'dns.zone_import.create'
+        args = ('1')
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': None
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    #
+    # Zone Exports
+    #
+
+    def test_audit_export_create(self):
+        zexport = objects.ZoneExport(
+                zone_id='123',
+        )
+
+        result = zexport
+        event = 'dns.zone_export.create'
+        args = (zexport,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': None
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_export_delete(self):
+        zexport = objects.ZoneExport(
+                zone_id='123',
+        )
+
+        result = zexport
+        event = 'dns.zone_export.create'
+        args = ('1')
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': None
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    #
+    # Zone Transfer Requests
+    #
+    def test_audit_transfer_request_create(self):
+        ztransfer_request = objects.ZoneTransferRequest(
+                zone_id='123',
+                zone_name='example.com.',
+                target_tenant_id='tenant_a',
+        )
+
+        result = ztransfer_request
+        event = 'dns.zone_transfer_request.create'
+        args = (ztransfer_request,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_transfer_request_update(self):
+        ztransfer_request = objects.ZoneTransferRequest(
+                zone_id='123',
+                zone_name='example.com.',
+                target_tenant_id='tenant_a',
+        )
+
+        ztransfer_request.target_tenant_id = 'tenant_b'
+
+        result = ztransfer_request
+        event = 'dns.zone_transfer_request.update'
+        args = (ztransfer_request,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': 'target_tenant_id',
+            'new_data': 'tenant_b',
+            'old_data': 'tenant_a',
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    def test_audit_transfer_request_delete(self):
+        ztransfer_request = objects.ZoneTransferRequest(
+                zone_id='123',
+                zone_name='example.com.',
+                target_tenant_id='tenant_a',
+        )
+
+        result = ztransfer_request
+        event = 'dns.zone_transfer_request.create'
+        args = ('1')
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': 'example.com.'
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
+
+    #
+    # Zone Transfer Requests
+    #
+    def test_audit_transfer_accept_create(self):
+        ztransfer_accept = objects.ZoneTransferAccept(
+                zone_id='123',
+        )
+
+        result = ztransfer_accept
+        event = 'dns.zone_transfer_accept.create'
+        args = (ztransfer_accept,)
+        kwargs = {'wumbo': 'mumbo'}
+
+        expected = [{
+            'changed_field': None,
+            'new_data': None,
+            'old_data': None,
+            'recordset_name': None,
+            'zone_id': '123',
+            'zone_name': None
+        }]
+        driver_result = self.driver.emit(
+            event, self.context, result, args, kwargs)
+        self.assertEqual(driver_result, expected)
diff --git a/releasenotes/notes/pluggable-notifications-bd049b755a2ace9c.yaml b/releasenotes/notes/pluggable-notifications-bd049b755a2ace9c.yaml
new file mode 100644
index 00000000..c669d8f7
--- /dev/null
+++ b/releasenotes/notes/pluggable-notifications-bd049b755a2ace9c.yaml
@@ -0,0 +1,21 @@
+---
+features:
+  - Operators now have a choice in the type of notification payload
+    content that Designate can emit via oslo.messaging's Notifier.
+    
+    The default plugin is configured to emit the same information
+    that the notifications previous to this patch emitted. So there
+    is no functional change.
+
+    Operators can write their own notification plugins that exist
+    in designate/notifications.py.
+
+    An "audit" plugin is included. This plugin emits object changes,
+    if they exist, along with zone ids, zone/recordset names.
+
+    A plugin can define multiple payloads from a single notification
+    to be emitted at once, if desirable.
+
+    The selection of a plugin is defined by python entrypoints (for
+    driver availability) and the new "notification_plugin" option
+    in the "DEFAULT" config section.
diff --git a/setup.cfg b/setup.cfg
index cd01e705..3dc1d2a2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -137,6 +137,9 @@ designate.heartbeat_emitter =
   noop = designate.service_status:NoopEmitter
   rpc = designate.service_status:RpcEmitter
 
+designate.notification.plugin =
+  default = designate.notifications:Default
+  audit = designate.notifications:Audit
 
 [build_sphinx]
 all_files = 1