[zeromq-dev] odd zmqstream.py behavior

[Steve Huffman]

Hi Guys,

I've updated stack_context.py and zmqstream.py to incorporate recent
changes from Tornado.

http://github.com/zeromq/pyzmq/pull/38

In addition to fixing some other bugs we found in Tornado, this
appears to fix the issue where close() was hanging. I didn't undo the
DelayedCallback logic you added, but if you try reverting that change,
hopefully you don't see the bug anymore as well.

Cheers,

Steve

On Thu, Oct 7, 2010 at 11:19 AM, Steve Huffman <steve at hipmunk.com> wrote:
>> Interesting, if weird:
>> With current pyzmq trunk and zeromq 2.0.9, your script behaves exactly as
>> it should on my laptop (system Python 2.6.1, OSX 10.6.4), but hangs on Linux
>> (Ubuntu 10.04 x86_64, system Python 2.6.5). As far as I know, everything
>> else is the same version for both; certainly zmq and pyzmq.
>>
>> Any ideas?
>
> My only suspicion was that there was something amiss with the handler
> pointer sent to zmq_close in socket.pyx/_zmq.pyx, but I didn't investigate
> further.
>
>
>>
>> I changed the zmqstream behavior such that it still calls socket.close(),
>> but as a DelayedCallback.  This is now the only difference between the
>> zmqstream.close() behavior and the tornado iostream.close() behavior.  This
>> way, even if socket.close() blocks and mucks tornado up, at least the
>> *first* error will be reported and logged. However, I find that
>> socket.close() does not block when I do this, though that is likely just due
>> to the fact that the send has completed by the time the close callback
>> fires.
>>
>> -MinRK
>> On Wed, Oct 6, 2010 at 14:27, Steve Huffman <steve at hipmunk.com> wrote:
>>>>
>>>> I can't actually reproduce the issue at the head of this topic with
>>>> master, though.  I see the loop properly logging the error and marching
>>>> right along, having closed and detached the socket. Can you post a sample of
>>>> where it hangs, and check against my zmqstream branch on github
>>>> (http://github.com/minrk/pyzmq/tree/zmqstream) to see if that behaves any
>>>> better?
>>>
>>> Attached is a script that demonstrates the error. I run ./zmqtest.py
>>> "server" to start a listener, and ./zmqtest.py to send a test message. There
>>> is an error in the on_send callback for the client, which causes the
>>> hanging.
>>> It works on your branch, but that isn't a huge surprise because the
>>> close() that causes the hanging is commented out. Uncommenting that close()
>>> causes it to hang as does on the current master.
>>> I haven't been able to reproduce this error using vanilla pyzmq without
>>> ioloop/zmqstream, but my zmq experience is limited.
>>> Steve
>>>
>>>
>>>
>>>>
>>>> I'm using zmq 2.0.9.
>>>> -MinRK
>>>>
>>>> On Mon, Oct 4, 2010 at 20:20, Brian Granger <ellisonbg at gmail.com> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> Min and I looked at this today and this is a bug in pyzmq.  When a
>>>>> callback in the eventloop raises, we are currently closing the socket,
>>>>> which we should not do.  We are still figuring out the error handling
>>>>> symantics, but we should have a fix in place soon in pyzmq master.
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Brian
>>>>>
>>>>> On Fri, Oct 1, 2010 at 7:08 PM, Pieter Hintjens <ph at imatix.com> wrote:
>>>>> > On Sat, Oct 2, 2010 at 3:58 AM, Steve Huffman <steve at hipmunk.com>
>>>>> > wrote:
>>>>> >
>>>>> >> I don't think so. I'll try the new version, but what the behavior
>>>>> >> I'm seeing
>>>>> >> is zmq_close() doesn't return when an exception is thrown in the
>>>>> >> callback.
>>>>> >
>>>>> > I didn't read your email properly, sorry... zmq_close() should not
>>>>> > block.
>>>>> >
>>>>> > If you can follow what zmqstream is doing, and get a straight pyzmq
>>>>> > example that has the same behavior, that'll make it easier to debug.
>>>>> >
>>>>> > -Pieter
>>>>> > _______________________________________________
>>>>> > zeromq-dev mailing list
>>>>> > zeromq-dev at lists.zeromq.org
>>>>> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>>>> >
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Brian E. Granger, Ph.D.
>>>>> Assistant Professor of Physics
>>>>> Cal Poly State University, San Luis Obispo
>>>>> bgranger at calpoly.edu
>>>>> ellisonbg at gmail.com
>>>>> _______________________________________________
>>>>> zeromq-dev mailing list
>>>>> zeromq-dev at lists.zeromq.org
>>>>> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>>>
>>>>
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>>>
>>>
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>>
>
>