a985eaf359
Change-Id: I04e47ffc2eed86483e0c902532f20ef02d1d0641 Signed-off-by: Julien Danjou <julien@danjou.info>
76 lines
2.9 KiB
Python
76 lines
2.9 KiB
Python
# -*- encoding: utf-8 -*-
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#
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# Copyright © 2012 New Dream Network, LLC (DreamHost)
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#
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# Author: Doug Hellmann <doug.hellmann@dreamhost.com>
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Given an incoming message, process it through the registered converters
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and publish the results.
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"""
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import pkg_resources
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from ceilometer.openstack.common import log
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LOG = log.getLogger(__name__)
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class NotificationDispatcher(object):
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"""Manages invoking plugins to convert notification messages to counters.
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"""
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def __init__(self, plugin_namespace, publish_func):
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self.plugin_namespace = plugin_namespace
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self.publish_func = publish_func
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self.handlers = {}
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self._load_plugins()
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def _load_plugins(self):
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# Listen for notifications from nova
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for ep in pkg_resources.iter_entry_points(self.plugin_namespace):
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LOG.info('attempting to load notification handler for %s:%s',
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self.plugin_namespace, ep.name)
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try:
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plugin_class = ep.load()
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plugin = plugin_class()
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# FIXME(dhellmann): Currently assumes all plugins are
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# enabled when they are discovered and
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# importable. Need to add check against global
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# configuration flag and check that asks the plugin if
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# it should be enabled.
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for event_type in plugin.get_event_types():
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LOG.info('subscribing %s handler to %s events',
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ep.name, event_type)
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self.handlers.setdefault(event_type, []).append(plugin)
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except Exception as err:
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LOG.warning('Failed to load notification handler %s: %s',
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ep.name, err)
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LOG.exception(err)
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if not self.handlers:
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LOG.warning('Failed to load any notification handlers for %s',
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self.plugin_namespace)
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def notify(self, body):
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"""Dispatch the notification to the appropriate handler
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and publish the counters returned.
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"""
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event_type = body.get('event_type')
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LOG.info('NOTIFICATION: %s', event_type)
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for handler in self.handlers.get(event_type, []):
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for c in handler.process_notification(body):
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LOG.info('COUNTER: %s', c)
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# FIXME(dhellmann): Spawn green thread?
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self.publish_func(c)
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return
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