b54e97e300
Precursor-to: BP decoupled-source-sink-discoverable-resources Add the concept of per-AgentManager resource discovery extensions loaded via stevedore entry points. The extensions are loaded from a single namespace: ceilometer.discover shared by all agents. An agent may have a list of per-agent default discovery extensions associated with it on creation. This is used by the compute agent, which currently uses a single discovery extension for all matching pipelines. The per-pipeline statically configured resources remain in place to potentially override the per-agent discovered resources - these will be augmented by per-pipeline discovery in a subsequent patch. Recast the compute agent's interrogation of the nova servers API in the form of a discovery extension. Unify the pollster abstraction used by the central and compute agents (which had previously diverged along with the introduction of per-pipeline resources). Unify the polling task logic used by the central and compute agents (so that the compute agent now iterates over each pollster for all local instances, as opposed to interating over all pollsters for each local instance). Change-Id: I625df47231a1dbf7ef721c297701799b224ce67e
116 lines
3.6 KiB
Python
116 lines
3.6 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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"""Base class for plugins.
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"""
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import abc
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import collections
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import fnmatch
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from oslo.config import cfg
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import six
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# Import this option so every Notification plugin can use it freely.
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cfg.CONF.import_opt('notification_topics',
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'ceilometer.openstack.common.notifier.rpc_notifier')
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ExchangeTopics = collections.namedtuple('ExchangeTopics',
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['exchange', 'topics'])
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class PluginBase(object):
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"""Base class for all plugins.
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"""
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@six.add_metaclass(abc.ABCMeta)
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class NotificationBase(PluginBase):
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"""Base class for plugins that support the notification API."""
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@abc.abstractproperty
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def event_types(self):
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"""Return a sequence of strings defining the event types to be
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given to this plugin.
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"""
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@abc.abstractmethod
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def get_exchange_topics(self, conf):
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"""Return a sequence of ExchangeTopics defining the exchange and
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topics to be connected for this plugin.
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:param conf: Configuration.
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"""
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@abc.abstractmethod
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def process_notification(self, message):
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"""Return a sequence of Counter instances for the given message.
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:param message: Message to process.
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"""
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@staticmethod
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def _handle_event_type(event_type, event_type_to_handle):
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"""Check whether event_type should be handled according to
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event_type_to_handle.
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"""
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return any(map(lambda e: fnmatch.fnmatch(event_type, e),
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event_type_to_handle))
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def to_samples(self, notification):
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"""Return samples produced by *process_notification* for the given
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notification, if it's handled by this notification handler.
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:param notification: The notification to process.
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"""
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if self._handle_event_type(notification['event_type'],
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self.event_types):
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return self.process_notification(notification)
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return []
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@six.add_metaclass(abc.ABCMeta)
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class PollsterBase(PluginBase):
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"""Base class for plugins that support the polling API."""
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@abc.abstractmethod
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def get_samples(self, manager, cache, resources=[]):
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"""Return a sequence of Counter instances from polling the resources.
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:param manager: The service manager class invoking the plugin.
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:param cache: A dictionary to allow pollsters to pass data
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between themselves when recomputing it would be
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expensive (e.g., asking another service for a
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list of objects).
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:param resources: A list of the endpoints the pollster will get data
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from. It's up to the specific pollster to decide
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how to use it.
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"""
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@six.add_metaclass(abc.ABCMeta)
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class DiscoveryBase(object):
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@abc.abstractmethod
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def discover(self, param=None):
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"""Discover resources to monitor.
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:param param: an optional parameter to guide the discovery
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"""
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