Avoid unnecessary API dependency on tooz & ceilometerclient

Previously, importing the alarm.service in the v2 API layer
created an unnecessary transitive dependency on python-tooz
and python-ceilometerclient.

We avoid these dependencies simply by moving the relevant code.

Change-Id: I1b936bf4dc2ad28afb7a45f61bfcd111adb20e1c
Closes-Bug: #1413237

ceilometer/alarm/__init__.py

@@ -0,0 +1,26 @@
+#
+# Copyright 2015 Red Hat, Inc
+#
+# Authors: Eoghan Glynn <eglynn@redhat.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.
+
+from stevedore import extension
+
+
+EVALUATOR_EXTENSIONS_NAMESPACE = "ceilometer.alarm.evaluator"
+NOTIFIER_EXTENSIONS_NAMESPACE = "ceilometer.alarm.notifier"
+
+NOTIFIERS = extension.ExtensionManager(NOTIFIER_EXTENSIONS_NAMESPACE,
+                                       invoke_on_load=True)
+NOTIFIER_SCHEMAS = NOTIFIERS.map(lambda x: x.name)

ceilometer/alarm/service.py

@@ -25,6 +25,7 @@ from oslo_utils import netutils
 import six
 from stevedore import extension
 
+from ceilometer import alarm as ceilometer_alarm
 from ceilometer.alarm.partition import coordination as alarm_coordination
 from ceilometer.alarm import rpc as rpc_alarm
 from ceilometer import coordination as coordination
@@ -54,8 +55,6 @@ LOG = log.getLogger(__name__)
 @six.add_metaclass(abc.ABCMeta)
 class AlarmService(object):
 
-    EXTENSIONS_NAMESPACE = "ceilometer.alarm.evaluator"
-
     def __init__(self):
         super(AlarmService, self).__init__()
         self._load_evaluators()
@@ -63,7 +62,7 @@ class AlarmService(object):
 
     def _load_evaluators(self):
         self.evaluators = extension.ExtensionManager(
-            namespace=self.EXTENSIONS_NAMESPACE,
+            namespace=ceilometer_alarm.EVALUATOR_EXTENSIONS_NAMESPACE,
             invoke_on_load=True,
             invoke_args=(rpc_alarm.RPCAlarmNotifier(),)
         )
@@ -228,12 +227,6 @@ class PartitionedAlarmService(AlarmService, os_service.Service):
 
 class AlarmNotifierService(os_service.Service):
 
-    EXTENSIONS_NAMESPACE = "ceilometer.alarm.notifier"
-
-    notifiers = extension.ExtensionManager(EXTENSIONS_NAMESPACE,
-                                           invoke_on_load=True)
-    notifiers_schemas = notifiers.map(lambda x: x.name)
-
     def __init__(self):
         super(AlarmNotifierService, self).__init__()
         transport = messaging.get_transport()
@@ -261,7 +254,7 @@ class AlarmNotifierService(os_service.Service):
             return
 
         try:
-            notifier = self.notifiers[action.scheme].obj
+            notifier = ceilometer_alarm.NOTIFIERS[action.scheme].obj
         except KeyError:
             scheme = action.scheme
             LOG.error(

ceilometer/api/controllers/v2.py

@@ -51,7 +51,7 @@ from wsme import types as wtypes
 import wsmeext.pecan as wsme_pecan
 
 import ceilometer
-from ceilometer.alarm import service as alarm_service
+from ceilometer import alarm as ceilometer_alarm
 from ceilometer.alarm.storage import models as alarm_models
 from ceilometer.api import rbac
 from ceilometer.event.storage import models as event_models
@@ -1889,7 +1889,7 @@ class Alarm(_Base):
 
     @staticmethod
     def check_alarm_actions(alarm):
-        actions_schema = alarm_service.AlarmNotifierService.notifiers_schemas
+        actions_schema = ceilometer_alarm.NOTIFIER_SCHEMAS
         for state in state_kind:
             actions_name = state.replace(" ", "_") + '_actions'
             actions = getattr(alarm, actions_name)

ceilometer/tests/alarm/test_notifier.py

@@ -23,6 +23,7 @@ from oslotest import mockpatch
 import requests
 import six.moves.urllib.parse as urlparse
 
+from ceilometer import alarm as ceilometer_alarm
 from ceilometer.alarm import service
 from ceilometer.tests import base as tests_base
 
@@ -71,7 +72,7 @@ class TestAlarmNotifier(tests_base.BaseTestCase):
             'reason_data': {'fire': 'everywhere'}
         }
         self.service.notify_alarm(context.get_admin_context(), data)
-        notifications = self.service.notifiers['test'].obj.notifications
+        notifications = ceilometer_alarm.NOTIFIERS['test'].obj.notifications
         self.assertEqual(1, len(notifications))
         self.assertEqual((urlparse.urlsplit(data['actions'][0]),
                           data['alarm_id'],