def _call(addr, context, msg_id, topic, msg, timeout=None):
# timeout_response is how long we wait for a response
timeout = timeout or CONF.rpc_response_timeout
# The msg_id is used to track replies.
msg_id = uuid.uuid4().hex
# Replies always come into the reply service.
reply_topic = "zmq_replies.%s" % CONF.rpc_zmq_host
LOG.debug(_("Creating payload"))
# Curry the original request into a reply method.
mcontext = RpcContext.marshal(context)
payload = {
'method': '-reply',
'args': {
'msg_id': msg_id,
'context': mcontext,
'topic': reply_topic,
'msg': [mcontext, msg]
}
}
LOG.debug(_("Creating queue socket for reply waiter"))
# Messages arriving async.
# TODO(ewindisch): have reply consumer with dynamic subscription mgmt
with Timeout(timeout, exception=rpc_common.Timeout):
try:
msg_waiter = ZmqSocket(
"ipc://%s/zmq_topic_zmq_replies" % CONF.rpc_zmq_ipc_dir,
zmq.SUB, subscribe=msg_id, bind=False
)
LOG.debug(_("Sending cast"))
_cast(addr, context, msg_id, topic, payload)
LOG.debug(_("Cast sent; Waiting reply"))
# Blocks until receives reply
msg = msg_waiter.recv()
LOG.debug(_("Received message: %s"), msg)
LOG.debug(_("Unpacking response"))
responses = rpc_common.deserialize_msg(msg[-1])
# ZMQError trumps the Timeout error.
except zmq.ZMQError:
raise RPCException("ZMQ Socket Error")
finally:
if 'msg_waiter' in vars():
msg_waiter.close()
# It seems we don't need to do all of the following,
# but perhaps it would be useful for multicall?
# One effect of this is that we're checking all
# responses for Exceptions.
for resp in responses:
if isinstance(resp, types.DictType) and 'exc' in resp:
raise rpc_common.deserialize_remote_exception(CONF, resp['exc'])
return responses[-1]
def __call__(self, data):
"""The consume() callback will call this. Store the result."""
if data['failure']:
failure = data['failure']
self._result = rpc_common.deserialize_remote_exception(self._conf,
failure)
elif data.get('ending', False):
self._got_ending = True
else:
self._result = data['result']