From 984042084f92844147ba70dc6be0f3cb8f4a7494 Mon Sep 17 00:00:00 2001
From: Julien Danjou <julien@danjou.info>
Date: Tue, 10 May 2016 18:26:07 +0200
Subject: [PATCH] collector: use an intermediate proxy class for event
 dispatcher

This makes sure that the base class EventDispatcherBase does not owns
any code itself. This makes external plugin easier to implement as they
don't _have_ to inherit from EventDispatcherBase, they just need to
implement a `record_events(events)' method and that's it.

This will allow Panko to provide the database dispatcher without having
a hard dependency on Ceilometer.

Change-Id: I094aed1e7e081fe1de130d987035a6c9d977d25e
---
 ceilometer/collector.py                     | 22 +++++++++++++++++++--
 ceilometer/dispatcher/__init__.py           | 13 ------------
 ceilometer/tests/unit/dispatcher/test_db.py | 22 ---------------------
 3 files changed, 20 insertions(+), 37 deletions(-)

diff --git a/ceilometer/collector.py b/ceilometer/collector.py
index baa9ea83..4ec3bd99 100644
--- a/ceilometer/collector.py
+++ b/ceilometer/collector.py
@@ -24,7 +24,7 @@ from oslo_utils import netutils
 from oslo_utils import units
 
 from ceilometer import dispatcher
-from ceilometer.i18n import _, _LE
+from ceilometer.i18n import _, _LE, _LW
 from ceilometer import messaging
 from ceilometer import service_base
 from ceilometer import utils
@@ -94,7 +94,8 @@ class CollectorService(service_base.ServiceBase):
                 self.event_listener = (
                     messaging.get_batch_notification_listener(
                         transport, [event_target],
-                        [EventEndpoint(self.event_manager)],
+                        [EventEndpoint(
+                            EventDispatcherVerificator(self.event_manager))],
                         allow_requeue=True,
                         batch_size=cfg.CONF.collector.batch_size,
                         batch_timeout=cfg.CONF.collector.batch_timeout))
@@ -161,6 +162,23 @@ class SampleEndpoint(CollectorEndpoint):
     ep_type = 'sample'
 
 
+class EventDispatcherVerificator(object):
+    def __init__(self, dispatcher):
+        self.dispatcher = dispatcher
+
+    def verify_and_record_events(self, events):
+        """Verify event signature and record them."""
+        goods = []
+        for event in events:
+            if utils.verify_signature(
+                    event, self.conf.publisher.telemetry_secret):
+                goods.append(event)
+            else:
+                LOG.warning(_LW(
+                    'event signature invalid, discarding event: %s'), event)
+        return self.dispatcher.record_events(goods)
+
+
 class EventEndpoint(CollectorEndpoint):
     method = 'verify_and_record_events'
     ep_type = 'event'
diff --git a/ceilometer/dispatcher/__init__.py b/ceilometer/dispatcher/__init__.py
index d8fcc93c..bd8e42b8 100644
--- a/ceilometer/dispatcher/__init__.py
+++ b/ceilometer/dispatcher/__init__.py
@@ -21,7 +21,6 @@ import six
 from stevedore import named
 
 from ceilometer.i18n import _LW
-from ceilometer.publisher import utils
 
 
 LOG = log.getLogger(__name__)
@@ -108,15 +107,3 @@ class EventDispatcherBase(Base):
     @abc.abstractmethod
     def record_events(self, events):
         """Record events."""
-
-    def verify_and_record_events(self, events):
-        """Verify event signature and record them."""
-        goods = []
-        for event in events:
-            if utils.verify_signature(
-                    event, self.conf.publisher.telemetry_secret):
-                goods.append(event)
-            else:
-                LOG.warning(_LW(
-                    'event signature invalid, discarding event: %s'), event)
-        return self.record_events(goods)
diff --git a/ceilometer/tests/unit/dispatcher/test_db.py b/ceilometer/tests/unit/dispatcher/test_db.py
index 2173ad19..a10c4c3e 100644
--- a/ceilometer/tests/unit/dispatcher/test_db.py
+++ b/ceilometer/tests/unit/dispatcher/test_db.py
@@ -44,28 +44,6 @@ class TestDispatcherDB(base.BaseTestCase):
             self.dispatcher.record_events(event)
         self.assertEqual(1, len(record_events.call_args_list[0][0][0]))
 
-    @mock.patch('ceilometer.publisher.utils.verify_signature')
-    def test_event_with_bad_signature(self, mocked_verify):
-        event = event_models.Event(uuid.uuid4(), 'test',
-                                   datetime.datetime(2012, 7, 2, 13, 53, 40),
-                                   [], {}).serialize()
-
-        def _fake_verify(ev, secret):
-            if ev.get('message_signature') == 'bad_signature':
-                return False
-            return True
-        mocked_verify.side_effect = _fake_verify
-        with mock.patch.object(self.dispatcher.event_conn,
-                               'record_events') as record_events:
-            event['message_signature'] = 'bad_signature'
-            self.dispatcher.verify_and_record_events([event])
-            self.assertEqual([], record_events.call_args_list[0][0][0])
-            del event['message_signature']
-            event['message_signature'] = utils.compute_signature(
-                event, self.CONF.publisher.telemetry_secret)
-            self.dispatcher.verify_and_record_events([event])
-            self.assertEqual(1, len(record_events.call_args_list[1][0][0]))
-
     def test_valid_message(self):
         msg = {'counter_name': 'test',
                'resource_id': self.id(),