Implement a basic alarm notification service

Change-Id: I74b28a8754a9541981ed8e8f27cd05ceb43c3776
Blueprint: alarm-notifier

ceilometer/alarm/notifier/__init__.py

@@ -0,0 +1,35 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2013 eNovance <licensing@enovance.com>
+#
+# Author: Julien Danjou <julien@danjou.info>
+#
+# 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 abc
+
+
+class AlarmNotifier(object):
+    """Base class for alarm notifier plugins."""
+
+    __metaclass__ = abc.ABCMeta
+
+    @abc.abstractmethod
+    def notify(self, action, alarm, state, reason):
+        """Notify that an alarm has been triggered.
+
+        :param action: The action that is being attended, as a parsed URL.
+        :param alarm: The triggered alarm.
+        :param state: The state the alarm is now in.
+        :param reason: The reason the alarm changed its state.
+        """

ceilometer/alarm/notifier/log.py

@@ -0,0 +1,31 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2013 eNovance
+#
+# Author: Julien Danjou <julien@danjou.info>
+#
+# 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.
+"""Log alarm notifier."""
+
+from ceilometer.alarm import notifier
+from ceilometer.openstack.common import log
+
+LOG = log.getLogger(__name__)
+
+
+class LogAlarmNotifier(notifier.AlarmNotifier):
+    "Log alarm notifier."""
+
+    def notify(action, alarm, state, reason):
+        LOG.info("Notifying alarm %s in state %s with action %s because %s",
+                 alarm, state, action, reason)

ceilometer/alarm/notifier/test.py

@@ -0,0 +1,30 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2013 eNovance
+#
+# Author: Julien Danjou <julien@danjou.info>
+#
+# 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.
+"""Test alarm notifier."""
+
+from ceilometer.alarm import notifier
+
+
+class TestAlarmNotifier(notifier.AlarmNotifier):
+    "Test alarm notifier."""
+
+    def __init__(self):
+        self.notifications = []
+
+    def notify(self, action, alarm, state, reason):
+        self.notifications.append((action, alarm, state, reason))

ceilometer/alarm/service.py

@@ -1,8 +1,10 @@
 # -*- encoding: utf-8 -*-
 #
 # Copyright © 2013 Red Hat, Inc
+# Copyright © 2013 eNovance <licensing@enovance.com>
 #
-# Author: Eoghan Glynn <eglynn@redhat.com>
+# Authors: Eoghan Glynn <eglynn@redhat.com>
+#          Julien Danjou <julien@danjou.info>
 #
 # 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
@@ -21,9 +23,13 @@ from stevedore import extension
 
 from ceilometer.service import prepare_service
 from ceilometer.openstack.common import log
+from ceilometer.openstack.common import network_utils
 from ceilometer.openstack.common import service as os_service
+from ceilometer.openstack.common.gettextutils import _
+from ceilometer.openstack.common.rpc import service as rpc_service
 from ceilometerclient import client as ceiloclient
 
+
 OPTS = [
     cfg.IntOpt('threshold_evaluation_interval',
                default=60,
@@ -88,3 +94,78 @@ class SingletonAlarmService(os_service.Service):
 def singleton_alarm():
     prepare_service()
     os_service.launch(SingletonAlarmService()).wait()
+
+
+cfg.CONF.import_opt('host', 'ceilometer.service')
+
+
+class AlarmNotifierService(rpc_service.Service):
+
+    EXTENSIONS_NAMESPACE = "ceilometer.alarm.notifier"
+
+    def __init__(self, host, topic):
+        super(AlarmNotifierService, self).__init__(host, topic, self)
+        self.notifiers = extension.ExtensionManager(self.EXTENSIONS_NAMESPACE,
+                                                    invoke_on_load=True)
+
+    def start(self):
+        super(AlarmNotifierService, self).start()
+        # Add a dummy thread to have wait() working
+        self.tg.add_timer(604800, lambda: None)
+
+    def _handle_action(self, action, alarm, state, reason):
+        try:
+            action = network_utils.urlsplit(action)
+        except Exception:
+            LOG.error(
+                _("Unable to parse action %(action)s for alarm %(alarm)s"),
+                locals())
+            return
+
+        try:
+            notifier = self.notifiers[action.scheme].obj
+        except KeyError:
+            scheme = action.scheme
+            LOG.error(
+                _("Action %(scheme)s for alarm %(alarm)s is unknown, "
+                  "cannot notify"),
+                locals())
+            return
+
+        try:
+            LOG.debug("Notifying alarm %s with action %s",
+                      alarm, action)
+            notifier.notify(action, alarm, state, reason)
+        except Exception:
+            LOG.exception(_("Unable to notify alarm %s"), alarm)
+            return
+
+    def notify_alarm(self, context, data):
+        """Notify that alarm has been triggered.
+
+        data should be a dict with the following keys:
+        - actions, the URL of the action to run;
+          this is a mapped to extensions automatically
+        - alarm, the alarm that has been triggered
+        - state, the new state the alarm transitionned to
+        - reason, the reason the alarm changed its state
+
+        :param context: Request context.
+        :param data: A dict as described above.
+        """
+        actions = data.get('actions')
+        if not actions:
+            LOG.error(_("Unable to notify for an alarm with no action"))
+            return
+
+        for action in actions:
+            self._handle_action(action,
+                                data.get('alarm'),
+                                data.get('state'),
+                                data.get('reason'))
+
+
+def alarm_notifier():
+    prepare_service()
+    os_service.launch(AlarmNotifierService(
+        cfg.CONF.host, 'ceilometer.alarm')).wait()

setup.cfg

@@ -86,6 +86,10 @@ ceilometer.publisher =
 ceilometer.alarm =
     threshold_eval = ceilometer.alarm.threshold_evaluation:Evaluator
 
+ceilometer.alarm.notifier =
+    log = ceilometer.alarm.notifier.log:LogAlarmNotifier
+    test = ceilometer.alarm.notifier.test:TestAlarmNotifier
+
 paste.filter_factory =
     swift = ceilometer.objectstore.swift_middleware:filter_factory
 
@@ -97,6 +101,7 @@ console_scripts =
     ceilometer-collector = ceilometer.collector.service:collector
     ceilometer-collector-udp = ceilometer.collector.service:udp_collector
     ceilometer-alarm-singleton = ceilometer.alarm.service:singleton_alarm
+    ceilometer-alarm-notifier = ceilometer.alarm.notifier:alarm_notifier
 
 [build_sphinx]
 all_files = 1

tests/alarm/test_notifier.py

@@ -0,0 +1,87 @@
+# -*- encoding: utf-8 -*-
+#
+# Copyright © 2013 eNovance
+#
+# Author: Julien Danjou <julien@danjou.info>
+#
+# 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 urlparse
+import mock
+
+from ceilometer.alarm import service
+from ceilometer.openstack.common import context
+from ceilometer.tests import base
+
+
+class TestAlarmNotifier(base.TestCase):
+
+    def setUp(self):
+        super(TestAlarmNotifier, self).setUp()
+        self.service = service.AlarmNotifierService('somehost', 'sometopic')
+
+    def test_notify_alarm(self):
+        data = {
+            'actions': ['test://'],
+            'alarm': {'name': 'foobar'},
+            'state': 'ALARM',
+            'reason': 'Everything is on fire',
+        }
+        self.service.notify_alarm(context.get_admin_context(), data)
+        notifications = self.service.notifiers['test'].obj.notifications
+        self.assertEqual(len(notifications), 1)
+        self.assertEqual(notifications[0], (
+            urlparse.urlsplit(data['actions'][0]),
+            data['alarm'],
+            data['state'],
+            data['reason']))
+
+    def test_notify_alarm_no_action(self):
+        self.service.notify_alarm(context.get_admin_context(), {})
+
+    def test_notify_alarm_log_action(self):
+        self.service.notify_alarm(context.get_admin_context(),
+                                  {
+                                      'actions': ['log://'],
+                                      'alarm': {'name': 'foobar'},
+                                      'condition': {'threshold': 42},
+                                  })
+
+    @staticmethod
+    def _fake_urlsplit(*args, **kwargs):
+        raise Exception("Evil urlsplit!")
+
+    def test_notify_alarm_invalid_url(self):
+        with mock.patch('ceilometer.openstack.common.network_utils.urlsplit',
+                        self._fake_urlsplit):
+            LOG = mock.MagicMock()
+            with mock.patch('ceilometer.alarm.service.LOG', LOG):
+                self.service.notify_alarm(
+                    context.get_admin_context(),
+                    {
+                        'actions': ['no-such-action-i-am-sure'],
+                        'alarm': {'name': 'foobar'},
+                        'condition': {'threshold': 42},
+                    })
+                self.assertTrue(LOG.error.called)
+
+    def test_notify_alarm_invalid_action(self):
+        LOG = mock.MagicMock()
+        with mock.patch('ceilometer.alarm.service.LOG', LOG):
+            self.service.notify_alarm(
+                context.get_admin_context(),
+                {
+                    'actions': ['no-such-action-i-am-sure://'],
+                    'alarm': {'name': 'foobar'},
+                    'condition': {'threshold': 42},
+                })
+            self.assertTrue(LOG.error.called)