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# Python modules
import time
import hashlib
# 3rd party modules
import sysv_ipc
# Utils for this demo
import utils
utils.say("Oooo 'ello, I'm Mrs. Premise!")
params = utils.read_params()
# Create the message queue.
mq = sysv_ipc.MessageQueue(params["KEY"], sysv_ipc.IPC_CREX)
# The first message is a random string (the current time).
s = time.asctime()
utils.say("Sending %s" % s)
mq.send(s)
what_i_sent = s
for i in range(0, params["ITERATIONS"]):
utils.say("iteration %d" % i)
s, _ = mq.receive()
s = s.decode()
utils.say("Received %s" % s)
# If the message is what I wrote, put it back on the queue.
while s == what_i_sent:
# Nothing new; give Mrs. Conclusion another chance to respond.
mq.send(s)
s, _ = mq.receive()
s = s.decode()
utils.say("Received %s" % s)
# What I read must be the md5 of what I wrote or something's
# gone wrong.
what_i_sent = what_i_sent.encode()
try:
assert(s == hashlib.md5(what_i_sent).hexdigest())
except AssertionError:
raise AssertionError("Message corruption after %d iterations." % i)
# MD5 the reply and write back to Mrs. Conclusion.
s = hashlib.md5(s.encode()).hexdigest()
utils.say("Sending %s" % s)
mq.send(s)
what_i_sent = s
utils.say("")
utils.say("%d iterations complete" % (i + 1))
utils.say("Destroying the message queue.")
mq.remove()
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