text: # -*- encoding: utf-8 -*-
  #
  # Copyright © 2012 New Dream Network, LLC (DreamHost)
  #
  # Author: Doug Hellmann <doug.hellmann@dreamhost.com>
  #
  # 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
  
  from ceilometer import plugin
  
  
  class ComputePollster(plugin.PollsterBase):
      """Base class for plugins that support the polling API on the compute node.
      """
  
      __metaclass__ = abc.ABCMeta
  
      @abc.abstractmethod
      def get_samples(self, manager, cache, instance):
          """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 instance: The instance to examine
          """
  