text: # vim: tabstop=4 shiftwidth=4 softtabstop=4
  
  # Copyright (c) 2013 OpenStack Foundation.
  # All rights reserved.
  #
  #    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 abc import abstractmethod
  
  from neutron.api import extensions
  from neutron.api.v2 import base
  from neutron.api.v2 import resource
  from neutron.common import constants
  from neutron.extensions import agent
  from neutron import manager
  from neutron.plugins.common import constants as plugin_const
  from neutron import policy
  from neutron import wsgi
  
  LOADBALANCER_POOL = 'loadbalancer-pool'
  LOADBALANCER_POOLS = LOADBALANCER_POOL + 's'
  LOADBALANCER_AGENT = 'loadbalancer-agent'
  
  
  class PoolSchedulerController(wsgi.Controller):
      def index(self, request, **kwargs):
          lbaas_plugin = manager.NeutronManager.get_service_plugins().get(
              plugin_const.LOADBALANCER)
          if not lbaas_plugin:
              return {'pools': []}
  
          policy.enforce(request.context,
                         "get_%s" % LOADBALANCER_POOLS,
                         {},
                         plugin=lbaas_plugin)
          return lbaas_plugin.list_pools_on_lbaas_agent(
              request.context, kwargs['agent_id'])
  
  
  class LbaasAgentHostingPoolController(wsgi.Controller):
      def index(self, request, **kwargs):
          lbaas_plugin = manager.NeutronManager.get_service_plugins().get(
              plugin_const.LOADBALANCER)
          if not lbaas_plugin:
              return
  
          policy.enforce(request.context,
                         "get_%s" % LOADBALANCER_AGENT,
                         {},
                         plugin=lbaas_plugin)
          return lbaas_plugin.get_lbaas_agent_hosting_pool(
              request.context, kwargs['pool_id'])
  
  
  class Lbaas_agentscheduler(extensions.ExtensionDescriptor):
      """Extension class supporting LBaaS agent scheduler.
      """
  
      @classmethod
      def get_name(cls):
          return "Loadbalancer Agent Scheduler"
  
      @classmethod
      def get_alias(cls):
          return constants.LBAAS_AGENT_SCHEDULER_EXT_ALIAS
  
      @classmethod
      def get_description(cls):
          return "Schedule pools among lbaas agents"
  
      @classmethod
      def get_namespace(cls):
          return "http://docs.openstack.org/ext/lbaas_agent_scheduler/api/v1.0"
  
      @classmethod
      def get_updated(cls):
          return "2013-02-07T10:00:00-00:00"
  
      @classmethod
      def get_resources(cls):
          """Returns Ext Resources."""
          exts = []
          parent = dict(member_name="agent",
                        collection_name="agents")
  
          controller = resource.Resource(PoolSchedulerController(),
                                         base.FAULT_MAP)
          exts.append(extensions.ResourceExtension(
              LOADBALANCER_POOLS, controller, parent))
  
          parent = dict(member_name="pool",
                        collection_name="pools")
  
          controller = resource.Resource(LbaasAgentHostingPoolController(),
                                         base.FAULT_MAP)
          exts.append(extensions.ResourceExtension(
              LOADBALANCER_AGENT, controller, parent,
              path_prefix=plugin_const.
              COMMON_PREFIXES[plugin_const.LOADBALANCER]))
          return exts
  
      def get_extended_resources(self, version):
          return {}
  
  
  class NoEligibleLbaasAgent(agent.AgentNotFound):
      message = _("No eligible loadbalancer agent found "
                  "for pool %(pool_id)s.")
  
  
  class NoActiveLbaasAgent(agent.AgentNotFound):
      message = _("No active loadbalancer agent found "
                  "for pool %(pool_id)s.")
  
  
  class LbaasAgentSchedulerPluginBase(object):
      """REST API to operate the lbaas agent scheduler.
  
      All of method must be in an admin context.
      """
  
      @abstractmethod
      def list_pools_on_lbaas_agent(self, context, id):
          pass
  
      @abstractmethod
      def get_lbaas_agent_hosting_pool(self, context, pool_id):
          pass
  