text: # Copyright (c) 2013-2014 Mirantis Inc. 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 __future__ import absolute_import
  
  from zake import fake_client
  from zake import fake_storage
  
  from tooz import coordination
  from tooz.drivers import zookeeper
  
  
  class ZakeDriver(zookeeper.KazooDriver):
      """This driver uses the `zake`_ client to mimic real `zookeeper`_ servers.
  
      It **should** be mainly used (and **is** really only intended to be used in
      this manner) for testing and integration (where real `zookeeper`_ servers
      are typically not available).
  
      .. _zake: https://pypi.org/project/zake
      .. _zookeeper: http://zookeeper.apache.org/
      """
  
      CHARACTERISTICS = (
          coordination.Characteristics.NON_TIMEOUT_BASED,
          coordination.Characteristics.DISTRIBUTED_ACROSS_THREADS,
      )
      """
      Tuple of :py:class:`~tooz.coordination.Characteristics` introspectable
      enum member(s) that can be used to interogate how this driver works.
      """
  
      # NOTE(harlowja): this creates a shared backend 'storage' layer that
      # would typically exist inside a zookeeper server, but since zake has
      # no concept of a 'real' zookeeper server we create a fake one and share
      # it among active clients to simulate zookeeper's consistent storage in
      # a thread-safe manner.
      fake_storage = fake_storage.FakeStorage(
          fake_client.k_threading.SequentialThreadingHandler())
  
      @classmethod
      def _make_client(cls, parsed_url, options):
          if 'storage' in options:
              storage = options['storage']
          else:
              storage = cls.fake_storage
          return fake_client.FakeClient(storage=storage)
  