On 6/8/07, David Mitchell firstname.lastname@example.org wrote:
I've got what I think is a potential application for Twisted, but I'm having trouble figuring out whether Twisted is going to be the best path or not. I've worked through the Twisted Finger tutorial and read through the "Ball of snakes" O'Reilly book, but I'm not sure I've got my head around Twisted sufficiently.
I have to simulate a server that reads messages off IBM's MQ queues, and posts responses back to different MQ queues. I've used both pymqi and Python/COM (on Windows only) to perform this sort of task in the past, but now I need something that's going to be able to respond to incoming MQ messages at a very high rate.
I suspect I'm going to have to use reactor.callInThread to spawn off threads within Twisted in order to handle IO with the MQ queues, as I'm not aware of any event-based interface to MQ and therefore any reads/writes from queues are potentially going to block for a while.
Is Twisted suited for this sort of application? Better yet, is anyone aware of info I can access regarding this sort of application with Twisted? - Google hasn't been much help...
Thanks in advance
I haven't written any real code that does this, but I was just investigating it for feasability myself a couple days ago. I wrote a thread that looked basically like this: (pseudocode, as I don't have any of the code in front of me)
while True: try: res = mq.get() #blocking call, with a fairly long timeout - 5-10 seconds reactor.callFromThead(someCallbackFunc, res) except Timeout: #pymqi will translate the timeout to an exception pass if self.exit.is_set(): #threading.Event to check for termination. self.terminate()
This just spins happily along, and dispatches processing into the Twisted event loop. I didn't really test it for performance or latency. Used reactor.callInThread to dispatch the writes.