Lazypirate server / client test

lazypirateclient.py

#
#  Lazy Pirate client
#  Use zmq_poll to do a safe request-reply
#  To run, start lpserver and then randomly kill/restart it
#
#   Author: Daniel Lundin <dln(at)eintr(dot)org>
#
import itertools
import logging
import sys
import zmq

logging.basicConfig(format="%(levelname)s: %(message)s", level=logging.INFO)

REQUEST_TIMEOUT = 2500
REQUEST_RETRIES = 3
SERVER_ENDPOINT = "tcp://192.168.1.44:5454"

try:
    context = zmq.Context()
    logging.info("Connecting to server…")
    client = context.socket(zmq.REQ)
    client.connect(SERVER_ENDPOINT)

    for sequence in itertools.count():
        request = str(sequence).encode()
        logging.info("Sending (%s)", request)
        client.send(request)

        retries_left = REQUEST_RETRIES
        while True:
            if (client.poll(REQUEST_TIMEOUT) & zmq.POLLIN) != 0:
                reply = client.recv()
                if int(reply) == sequence:
                    logging.info("Server replied OK (%s)", reply)
                    retries_left = REQUEST_RETRIES
                    break
                else:
                    logging.error("Malformed reply from server: %s", reply)
                    continue

            retries_left -= 1
            logging.warning("No response from server")
            # Socket is confused. Close and remove it.
            client.setsockopt(zmq.LINGER, 0)
            client.close()
            if retries_left == 0:
                logging.error("Server seems to be offline, abandoning")
                sys.exit()

            logging.info("Reconnecting to server…")
            # Create new connection
            client = context.socket(zmq.REQ)
            client.connect(SERVER_ENDPOINT)
            logging.info("Resending (%s)", request)
            client.send(request)
except KeyboardInterrupt:
     print('> User forced exit!')
finally:
    context.term()

lazypirateserver.py

#
#  Lazy Pirate server
#  Binds REQ socket to tcp://*:5555
#  Like hwserver except:
#   - echoes request as-is
#   - randomly runs slowly, or exits to simulate a crash.
#
#   Author: Daniel Lundin <dln(at)eintr(dot)org>
#
from random import randint
import itertools
import logging
import time
import zmq

logging.basicConfig(format="%(levelname)s: %(message)s", level=logging.INFO)

try:
    context = zmq.Context()
    server = context.socket(zmq.REP)
    server.bind("tcp://*:5454")
    for cycles in itertools.count():
        request = server.recv()

        # Simulate various problems, after a few cycles
        if cycles > 30 and randint(0, 3) == 0:
            logging.info("Simulating a crash")
            break
        elif cycles > 3 and randint(0, 3) == 0:
            logging.info("Simulating CPU overload")
            time.sleep(2)

        logging.info("Normal request (%s)", request)
        time.sleep(0.25)  # Do some heavy work
        server.send(request)
except KeyboardInterrupt:
     print('> User forced exit!')
finally:
    context.term()