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  # Copyright (c) 2012 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 oslo_config import cfg
  import oslo_messaging
  from oslo_messaging import serializer as om_serializer
  
  from tacker.common import exceptions
  from tacker import context
  from tacker.openstack.common import log as logging
  
  
  LOG = logging.getLogger(__name__)
  
  
  TRANSPORT = None
  NOTIFIER = None
  
  ALLOWED_EXMODS = [
      exceptions.__name__,
  ]
  EXTRA_EXMODS = []
  
  
  TRANSPORT_ALIASES = {
      'tacker.openstack.common.rpc.impl_fake': 'fake',
      'tacker.openstack.common.rpc.impl_qpid': 'qpid',
      'tacker.openstack.common.rpc.impl_kombu': 'rabbit',
      'tacker.openstack.common.rpc.impl_zmq': 'zmq',
      'tacker.rpc.impl_fake': 'fake',
      'tacker.rpc.impl_qpid': 'qpid',
      'tacker.rpc.impl_kombu': 'rabbit',
      'tacker.rpc.impl_zmq': 'zmq',
  }
  
  
  def init(conf):
      global TRANSPORT, NOTIFIER
      exmods = get_allowed_exmods()
      TRANSPORT = oslo_messaging.get_transport(conf,
                                          allowed_remote_exmods=exmods,
                                          aliases=TRANSPORT_ALIASES)
      NOTIFIER = oslo_messaging.Notifier(TRANSPORT)
  
  
  def cleanup():
      global TRANSPORT, NOTIFIER
      assert TRANSPORT is not None
      assert NOTIFIER is not None
      TRANSPORT.cleanup()
      TRANSPORT = NOTIFIER = None
  
  
  def add_extra_exmods(*args):
      EXTRA_EXMODS.extend(args)
  
  
  def clear_extra_exmods():
      del EXTRA_EXMODS[:]
  
  
  def get_allowed_exmods():
      return ALLOWED_EXMODS + EXTRA_EXMODS
  
  
  def get_notifier(service=None, host=None, publisher_id=None):
      assert NOTIFIER is not None
      if not publisher_id:
          publisher_id = "%s.%s" % (service, host or cfg.CONF.host)
      return NOTIFIER.prepare(publisher_id=publisher_id)
  
  
  class PluginRpcSerializer(om_serializer.Serializer):
      """Serializer.
  
      This serializer is used to convert RPC common context into
      Tacker Context.
      """
      def __init__(self, base):
          super(PluginRpcSerializer, self).__init__()
          self._base = base
  
      def serialize_entity(self, ctxt, entity):
          if not self._base:
              return entity
          return self._base.serialize_entity(ctxt, entity)
  
      def deserialize_entity(self, ctxt, entity):
          if not self._base:
              return entity
          return self._base.deserialize_entity(ctxt, entity)
  
      def serialize_context(self, ctxt):
          return ctxt.to_dict()
  
      def deserialize_context(self, ctxt):
          rpc_ctxt_dict = ctxt.copy()
          user_id = rpc_ctxt_dict.pop('user_id', None)
          if not user_id:
              user_id = rpc_ctxt_dict.pop('user', None)
          tenant_id = rpc_ctxt_dict.pop('tenant_id', None)
          if not tenant_id:
              tenant_id = rpc_ctxt_dict.pop('project_id', None)
          return context.Context(user_id, tenant_id,
                                 load_admin_roles=False, **rpc_ctxt_dict)
  