[zeromq-dev] odd zmqstream.py behavior

[Steve Huffman]

>
> Brian,
>
> I added to my zmqstream branch, which updates the zmqstream object to have
> the rest of the socket interface (now everything except recv*).  It also no
> longer closes the socket on an error in a callback, it merely unregisters
> the callback.
>

While not closing the socket on an error prevents sockets from silently
dying, it also potentially leaves file descriptors hanging around. That
said, the sockets silently closing has bitten me a couple of times, both in
zmqstream and in Tornado's iostream. I feel like the correct solution would
be to print the exception so the developer can at least see an explanation
and possibly wrap the callback call in a NullContext. Either way, I think
it's important to match the logic of Tornado when possible since Tornado has
a lot more production users, so things are the way they are for a reason.
I'm also chatting with Ben from Tornado, who added the StackContext stuff in
the first place, to see if this makes sense.


> Steve,
>
> 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?
>
> I'm using zmq 2.0.9.
>

Yep, will let you know.



>
> -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
>> > _______________________________________________
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>> > 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
>> _______________________________________________
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>> zeromq-dev at lists.zeromq.org
>> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>
>
>
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