text: #   Copyright 2013 IBM Corp.
  #
  #   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.
  
  from cinder.api import extensions
  from cinder.api.openstack import wsgi
  
  authorize = extensions.soft_extension_authorizer('volume',
                                                   'volume_mig_status_attribute')
  
  
  class VolumeMigStatusAttributeController(wsgi.Controller):
      def _add_volume_mig_status_attribute(self, req, resp_volume):
          db_volume = req.get_db_volume(resp_volume['id'])
          key = "%s:migstat" % Volume_mig_status_attribute.alias
          resp_volume[key] = db_volume['migration_status']
          key = "%s:name_id" % Volume_mig_status_attribute.alias
          resp_volume[key] = db_volume['_name_id']
  
      @wsgi.extends
      def show(self, req, resp_obj, id):
          context = req.environ['cinder.context']
          if authorize(context):
              self._add_volume_mig_status_attribute(req, resp_obj.obj['volume'])
  
      @wsgi.extends
      def detail(self, req, resp_obj):
          context = req.environ['cinder.context']
          if authorize(context):
              for vol in list(resp_obj.obj['volumes']):
                  self._add_volume_mig_status_attribute(req, vol)
  
  
  class Volume_mig_status_attribute(extensions.ExtensionDescriptor):
      """Expose migration_status as an attribute of a volume."""
  
      name = "VolumeMigStatusAttribute"
      alias = "os-vol-mig-status-attr"
      updated = "2013-08-08T00:00:00+00:00"
  
      def get_controller_extensions(self):
          controller = VolumeMigStatusAttributeController()
          extension = extensions.ControllerExtension(self, 'volumes', controller)
          return [extension]
  