56 lines
1.8 KiB
Python
56 lines
1.8 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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@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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