async def async_request(self,
command,
args=None,
timeout=None,
req_meta=None):
"""Send an asynchronous request using asyncio.
Has the same arguments and return values as ``serial_request``.
"""
timeout = (float(timeout) * 1000 if timeout else None) or self.timeout
if not args:
args = {}
# Note: we are using CurveZMQ to secure the messages (see
# self.curve_auth, self.socket.curve_...key etc.). We have set up
# public-key cryptography on the ZMQ messaging and sockets, so
# there is no need to encrypt messages ourselves before sending.
# send message
msg = {'command': command, 'args': args}
msg.update(self.header)
# add the request metadata
if req_meta:
msg['meta'].update(req_meta)
LOG.debug('zmq:send %s', msg)
message = encode_(msg)
self.socket.send_string(message)
# receive response
if self.poller.poll(timeout):
res = await self.socket.recv()
else:
if callable(self.timeout_handler):
self.timeout_handler()
raise ClientTimeout(
'Timeout waiting for server response.'
' This could be due to network or server issues.'
' Check the workflow log.')
if msg['command'] in PB_METHOD_MAP:
response = {'data': res}
else:
response = decode_(res.decode())
LOG.debug('zmq:recv %s', response)
try:
return response['data']
except KeyError:
error = response['error']
raise ClientError(error['message'], error.get('traceback'))
def _listener(self):
"""The server main loop, listen for and serve requests."""
while True:
# process any commands passed to the listener by its parent process
if self.queue.qsize():
command = self.queue.get()
if command == 'STOP':
break
raise ValueError('Unknown command "%s"' % command)
try:
# wait RECV_TIMEOUT for a message
msg = self.socket.recv_string()
except zmq.error.Again:
# timeout, continue with the loop, this allows the listener
# thread to stop
continue
except zmq.error.ZMQError as exc:
LOG.exception('unexpected error: %s', exc)
continue
# attempt to decode the message, authenticating the user in the
# process
try:
message = decode_(msg)
except Exception as exc: # purposefully catch generic exception
# failed to decode message, possibly resulting from failed
# authentication
LOG.exception('failed to decode message: "%s"', exc)
else:
# success case - serve the request
res = self._receiver(message)
if message['command'] in PB_METHOD_MAP:
response = res['data']
else:
response = encode_(res).encode()
# send back the string to bytes response
self.socket.send(response)
# Note: we are using CurveZMQ to secure the messages (see
# self.curve_auth, self.socket.curve_...key etc.). We have set up
# public-key cryptography on the ZMQ messaging and sockets, so
# there is no need to encrypt messages ourselves before sending.
sleep(0) # yield control to other threads