import zmq
import json
import logging
from common.struct import Struct
SEND_TIMEOUT = 2 * 1000 # in milliseconds
RECV_TIMEOUT = 3 * 1000 # in milliseconds
class GaragePiClient(object):
"""
Client that connects with GaragePi backend to perform tasks
"""
def __init__(self, logger: logging.Logger, connect_port='5550'):
assert logger is not None
self.__logger = logger
self.__connect_addr = "tcp://localhost:%s" % connect_port
self.__logger.debug("Connect address: " + self.__connect_addr)
self.__context = zmq.Context()
self.__context.setsockopt(zmq.RCVTIMEO, RECV_TIMEOUT)
self.__poller = zmq.Poller()
self.__socket = None # type: zmq.sugar.Socket
self.__create_socket()
def __create_socket(self):
if self.__socket is not None:
self.close()
self.__logger.debug("Creating new socket")
self.__socket = self.__context.socket(zmq.DEALER)
self.__socket.connect(self.__connect_addr)
self.__poller.register(self.__socket, zmq.POLLIN)
def close(self):
self.__logger.debug("Closing out existing socket")
self.__socket.setsockopt(zmq.LINGER, 0)
self.__socket.close()
self.__poller.unregister(self.__socket)
self.__socket = None
def __send_recv_msg(self, msg):
# Make sure we're sending bytes instead of strings
msg = list(map(lambda s: str.encode(s) if type(s) is str else s, msg))
self.__socket.send_multipart(msg)
events = dict(self.__poller.poll(SEND_TIMEOUT))
if events.get(self.__socket) == zmq.POLLIN:
try:
# Receive response and make sure the return is converted to string if necessary
ret_msg = self.__socket.recv_multipart()[0]
return bytes.decode(ret_msg) if type(ret_msg) is bytes else ret_msg
except zmq.error.Again:
# If the receive timed out then return None
self.__logger.warning("Receive operation timed out!")
self.__create_socket()
return None
else:
self.__logger.warning("Send operation timed out!")
self.__create_socket()
return None
def echo(self, message):
self.__logger.debug("Requesting 'echo' with message: {0}".format(message))
msg_json = json.dumps({'message': message})
msg = ['echo', msg_json]
reply_json = self.__send_recv_msg(msg)
if reply_json is None: return None
return json.loads(reply_json)['message']
def get_status(self):
self.__logger.debug("Requesting 'get_status'")
msg = ['get_status', '{}']
reply_json = self.__send_recv_msg(msg)
if reply_json is None: return None
return json.loads(reply_json)
def trigger_relay(self, user_agent: str, login: str):
self.__logger.debug("Requesting 'trigger_relay'")
data = Struct(user_agent=user_agent, login=login)
msg_json = data.to_json_bytes()
msg = ['trigger_relay', msg_json]
reply_json = self.__send_recv_msg(msg)
if reply_json is None: return None
return json.loads(reply_json)
