old_contents: from oslo import messaging
  from oslo.config import cfg
  import logging
  
  LOG = logging.getLogger(__name__)
  
  class BaseAPIClient(messaging.RPCClient):
      def __init__(self, transport):
          target = messaging.Target(topic='default_topic')
          super(BaseAPIClient, self).__init__(transport, target)
  
      def ping(self, context, topic, args=None):
          print 'Launch ping topic=%s' % topic
          cctxt = self.prepare(topic=topic)
          #return cctxt.call(context,'ping', args=args)
          return cctxt.cast(context,'ping', args=args)
  
      def poller_msg(self, context, topic, args=None):
          LOG.info('Send message %s context %s' % (topic, context))
          cctxt = self.prepare(topic=topic)
          return cctxt.cast(context,'poller_msg', args=args)
  
  def get_rpc_client(hosts=[]):
      conf = cfg.CONF
      conf.transport_url = 'rabbit://'
      conf.rabbit_max_retries = 1
      conf.rabbit_hosts = hosts
      transport = messaging.get_transport(conf)
      return BaseAPIClient(transport)
  
new_contents: from oslo import messaging
  from oslo.config import cfg
  import logging
  
  LOG = logging.getLogger(__name__)
  
  class BaseAPIClient(messaging.RPCClient):
      def __init__(self, transport):
          target = messaging.Target(topic='default_topic')
          super(BaseAPIClient, self).__init__(transport, target)
  
      def ping(self, context, topic, args=None):
          print 'Launch ping topic=%s' % topic
          cctxt = self.prepare(topic=topic)
          #return cctxt.call(context,'ping', args=args)
          return cctxt.cast(context,'ping', args=args)
  
      def poller_msg(self, context, topic, args=None):
          LOG.info('Send message %s context %s' % (topic, context))
          args['topic'] = topic
          return self.cast(context,'poller_msg', args=args)
  
  def get_rpc_client(hosts=[]):
      conf = cfg.CONF
      conf.transport_url = 'rabbit://'
      conf.rabbit_max_retries = 1
      conf.rabbit_hosts = hosts
      transport = messaging.get_transport(conf)
      return BaseAPIClient(transport)
  
subject: Change oslo client send prepare