# # Copyright 2012 New Dream Network, LLC (DreamHost) # # Author: Doug Hellmann # # 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 used by the compute agent. """ import abc import six from ceilometer.openstack.common import timeutils from ceilometer import plugin @six.add_metaclass(abc.ABCMeta) class ComputePollster(plugin.PollsterBase): """Base class for plugins that support the polling API on the compute node. """ @abc.abstractmethod def get_samples(self, manager, cache, resources): """Return a sequence of Counter instances from polling the resources. :param manager: The service manager invoking the plugin :param cache: A dictionary for passing data between plugins :param resources: The resources to examine (expected to be instances) """ def _record_poll_time(self): """Method records current time as the poll time. :return: time in seconds since the last poll time was recorded """ current_time = timeutils.utcnow() duration = None if hasattr(self, '_last_poll_time'): duration = timeutils.delta_seconds(self._last_poll_time, current_time) self._last_poll_time = current_time return duration