aodh/ceilometer/plugin.py
Julien Danjou e49c949f39 Handle more Nova and Neutron events
This introduces a simpler matching system for event types that supports
wildcard. We use this to grab all Nova instances notifications and a bit
more Neutron events.

We also change the get_event_types to a property to simplify the code a
bit.

Change-Id: Ica133ff2e9348a5d2640f068251d034bbd8a4f43
2013-08-07 10:55:27 +02:00

111 lines
3.4 KiB
Python

# -*- encoding: utf-8 -*-
#
# Copyright © 2012 New Dream Network, LLC (DreamHost)
#
# Author: Doug Hellmann <doug.hellmann@dreamhost.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.
"""Base class for plugins.
"""
import abc
import collections
import fnmatch
from oslo.config import cfg
# Import this option so every Notification plugin can use it freely.
cfg.CONF.import_opt('notification_topics',
'ceilometer.openstack.common.notifier.rpc_notifier')
ExchangeTopics = collections.namedtuple('ExchangeTopics',
['exchange', 'topics'])
class PluginBase(object):
"""Base class for all plugins.
"""
@staticmethod
def is_enabled():
"""Return boolean indicating whether this plugin should
be enabled and used by the caller.
"""
return True
class NotificationBase(PluginBase):
"""Base class for plugins that support the notification API."""
__metaclass__ = abc.ABCMeta
@abc.abstractproperty
def event_types(self):
"""Return a sequence of strings defining the event types to be
given to this plugin.
"""
@abc.abstractmethod
def get_exchange_topics(self, conf):
"""Return a sequence of ExchangeTopics defining the exchange and
topics to be connected for this plugin.
:param conf: Configuration.
"""
@abc.abstractmethod
def process_notification(self, message):
"""Return a sequence of Counter instances for the given message.
:param message: Message to process.
"""
@staticmethod
def _handle_event_type(event_type, event_type_to_handle):
"""Check whether event_type should be handled according to
event_type_to_handle.
"""
return any(map(lambda e: fnmatch.fnmatch(event_type, e),
event_type_to_handle))
def to_samples(self, notification):
"""Return samples produced by *process_notification* for the given
notification, if it's handled by this notification handler.
:param notification: The notification to process.
"""
if self._handle_event_type(notification['event_type'],
self.event_types):
return self.process_notification(notification)
return []
class PollsterBase(PluginBase):
"""Base class for plugins that support the polling API."""
__metaclass__ = abc.ABCMeta
@abc.abstractmethod
def get_samples(self, manager, cache):
"""Return a sequence of Counter instances from polling the resources.
:param manager: The service manager class invoking the plugin.
:param cache: A dictionary to allow pollsters to pass data
between themselves when recomputing it would be
expensive (e.g., asking another service for a
list of objects).
"""