b6e1c7e5dc
Currently, not all the central agent pollsters use discoveries. In order to enable horizontal scaling, all pollsters must use discoveries so the resources can be partitioned across the pool of running central agents. For pollsters that don't poll specific resources, but only poll general info from services, we treat the service endpoints as resources. So in the case of Glance, there will be only one resource available for all the pollsters (a Glance endpoint). If there are multiple agents running, only one will be assigned that endpoint and only one will poll Glance API. DocImpact Co-Authored-By: Dina Belova <dbelova@mirantis.com> Closes-Bug: #1364352 Change-Id: I8f3b228db9aacf3a7cc4b719c50013cc30d5aa79
61 lines
1.9 KiB
Python
61 lines
1.9 KiB
Python
#
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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 used by the compute agent.
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"""
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import abc
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from oslo.utils import timeutils
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import six
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from ceilometer import plugin
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@six.add_metaclass(abc.ABCMeta)
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class ComputePollster(plugin.PollsterBase):
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"""Base class for plugins.
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It supports the polling API on the compute node.
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"""
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@property
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def default_discovery(self):
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# get resources from agent-default discovery
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return None
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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 invoking the plugin
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:param cache: A dictionary for passing data between plugins
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:param resources: The resources to examine (expected to be instances)
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"""
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def _record_poll_time(self):
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"""Method records current time as the poll time.
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:return: time in seconds since the last poll time was recorded
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"""
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current_time = timeutils.utcnow()
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duration = None
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if hasattr(self, '_last_poll_time'):
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duration = timeutils.delta_seconds(self._last_poll_time,
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current_time)
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self._last_poll_time = current_time
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return duration
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