text: #
  # Copyright 2014 ZHAW SoE
  #
  # Authors: Lucas Graf <graflu0@students.zhaw.ch>
  #          Toni Zehnder <zehndton@students.zhaw.ch>
  #
  # 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.
  """Inspector abstraction for read-only access to hardware components"""
  
  import abc
  
  import six
  
  
  @six.add_metaclass(abc.ABCMeta)
  class Inspector(object):
      @abc.abstractmethod
      def inspect_generic(self, host, cache, extra_metadata, param):
          """A generic inspect function.
  
          :param host: the target host
          :param cache: cache passed from the pollster
          :param extra_metadata: extra dict to be used as metadata
          :param param: a dict of inspector specific param
          :return: an iterator of (value, metadata, extra)
          :return value: the sample value
          :return metadata: dict to construct sample's metadata
          :return extra: dict of extra metadata to help constructing sample
          """
  
      def prepare_params(self, param):
          """Parse the params to a format which the inspector itself recognizes.
  
          :param param: inspector params from meter definition file
          :return: a dict of param which the inspector recognized
          """
          return {}
  