python - PyZMQ Subscriber doesn't receive messages when working with request socket -

i working pyzmq , have seems rather peculiar issue. have 2 classes wrapping sockets communication, mzlsubscriber , mzlrequester. there class contains both of them, mzllink. each of these, have tests mzlsubscribertest, mzlrequestertest, , mzlinktest. tests subscriber , requester work should, mzlinktest not receive subscriber messages.

below seems relative code, constructors 3 classes run() mzlsubscriber , tests mzlink , mzlsubscriber.

mzlink constructor:

    # host information     self.host = host     self.requestport = requestport     self.subscriberport = subscriberport      # set zmq context     self.zmq_context = zmq.context()      # set subscriber , replier     self.subscriber = mzlsubscriber(self.zmq_context, self.host, self.subscriberport)     self.requester = mzlrequester(self.zmq_context, self.host, self.requestport)      # start subscriber     self.subscriber.start() 

mzlink test:

# constants host = "localhost" req_port = 5555 sub_port = 5556  # create link link = midaszmqlink(host, req_port, sub_port)  link.close() 

mzlrequester constructor:

    # initialize class member variables     self.zmq_context = zmq_context     self.host = host     self.port = port      # set reply socket     self.socket = self.zmq_context.socket(zmq.req)      # connect socket     self.socket.connect("tcp://{0}:{1}".format(self.host, self.port)) 

mzlsubscriber constructor:

   # initialize parent process     process.__init__(self)      # store zmq context , connection host/port     self.zmq_context = zmq_context     self.host = host     self.port = port      # sockets. don't set them here because sockets not thread safe     self.socket = none      # queue store data in     # todo: make queue not overflow if events come in     self.queue = queue() 

mzlsubscriber.run():

    # parent call     process.run(self)      # set subscriber socket in thread     self.socket = self.zmq_context.socket(zmq.sub)     self.socket.setsockopt_string(zmq.subscribe, unicode())      # connect socket     self.socket.connect("tcp://{0}:{1}".format(self.host, self.port))      # while thread alive, poll data put queue     # calling mzlsubscriber.stop() automatically change     while self.is_alive():         datum = self.socket.recv()         self.queue.put(datum)      # disconnect , close socket.     #fixme: doesn't here because terminate() stops process     self.socket.disconnect("tcp://{0}:{1}".format(self.host, self.port))     self.socket.close() 

mzlsubscriber test:

# host information host = "localhost" subscriber_port = "5556"  # set zmq context zmq_context = zmq.context()  # set subscriber subscriber = mzlsubscriber(zmq_context, host, subscriber_port)  # start subscriber subscriber.start()  # stop , join subscriber subscriber.close() subscriber.join() 

the subscriber thread seems block @ datum = self.socket.recv(), makes me think issue socket creation. however, seem work when working subscriber. requester seems work in both cases. in addition, goes smoothly commenting out 2 lines dealing requester.

i apologize wall of code, can't narrow code issue coming @ point. when do, i'll remove irrelevant code. test code deals incoming data has been removed.

as bit of clarification, using python 2.7 pyzmq 14.3.1.

update: seems running mzlsubscriber in main thread rather creating process results in expected result, seems sort of thread safety. knowledge, zmq contexts thread-safe, sockets not. thought wouldn't cause issue because i'm explicitly making sure there socket each thread.

update 2: if calls setting socket in mzlsubscriber moved run() __init__, socket seems receive small portion of published message, have error:

process mzlsubscriber-1: traceback (most recent call last):   file "/system/library/frameworks/python.framework/versions/2.7/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap     self.run()   file "/users/user/repos/midas-client/client/midasclient/mzlsubscriber.py", line 45, in run     datum = self.socket.recv()   file "socket.pyx", line 628, in zmq.backend.cython.socket.socket.recv (zmq/backend/cython/socket.c:5616)   file "socket.pyx", line 662, in zmq.backend.cython.socket.socket.recv (zmq/backend/cython/socket.c:5436)   file "socket.pyx", line 139, in zmq.backend.cython.socket._recv_copy (zmq/backend/cython/socket.c:1771)   file "checkrc.pxd", line 21, in zmq.backend.cython.checkrc._check_rc (zmq/backend/cython/socket.c:6032) zmqerror: interrupted system call 

i have gotten workaround creating new zmq.context in mzlsubscriber.run(), although feel shouldn't necessary if zmq contexts thread-safe.

it seems issue using multiple zmq contexts on different processes. while pyzmq documentation states zmq context thread-safe, can assume meant python threads rather processes. quite confusing in c, zmq contexts thread safe despite running in way similar python multiprocessing.process.

the issue solved creating zmq context each process.