[zeromq-dev] PAIR pattern doesn't reconnects when client restarted

[Pieter Hintjens]

The zmq_socket man page says,

ZMQ_PAIR sockets are designed for inter-thread communication across
the zmq_inproc(7) transport and do not implement functionality such as
auto-reconnection. ZMQ_PAIR sockets are considered experimental and
may have other missing or broken aspects.

Though it's documented, it really is a broken implementation.

-Pieter

On Mon, Jul 8, 2013 at 11:27 AM, Sergey Gavruk <svgavruk at gmail.com> wrote:
> Hi, Pieter.
>
> Thanks for your answer, I am just leaning zmq and trying different patterns.
>
> I'm reading your book and later after my question I found that:
>
> "Principally, nodes come and go whereas threads are usually static. PAIR
> sockets do not automatically reconnect if the remote node goes away and
> comes back." (http://zguide.zeromq.org/page:all#Node-Coordination)
>
> It is a documented feature. And for thread sync that works okay. But I
> haven't found this info anywhere except your book.
>
>
> On Mon, Jul 8, 2013 at 11:52 AM, Pieter Hintjens <ph at imatix.com> wrote:
>>
>> Hi Sergey,
>>
>> This is a fault in the implementation of PAIR sockets, something I
>> wanted to fix at some stage. As a workaround you can replace PAIR with
>> DEALER and it will work as intended.
>>
>> -Pieter
>>
>> On Sun, Jul 7, 2013 at 4:38 PM, Sergey Gavruk <svgavruk at gmail.com> wrote:
>> > Hello.
>> >
>> > If I disconnect my client in zmq (pub/sub, req/rep) and then connect
>> > again,
>> > it will continue to receive messages. But with PAIR pattern i faced a
>> > problem:
>> > I am using this example
>> >
>> > https://learning-0mq-with-pyzmq.readthedocs.org/en/latest/pyzmq/patterns/pair.html
>> > and I found that if I have both client and server running, then I
>> > stop-start
>> > server, 2 sockets will continue send and receive messages. But if I
>> > stop-start client - nothing will be printed to the terminal. Messages
>> > will
>> > not be sent and received.
>> >
>> > Here is my code:
>> > server.py
>> > http://pastebin.com/3bU93vSc
>> > client.py
>> > http://pastebin.com/2zdGXPCG
>> >
>> > So, I wonder: this is a bug or I am doing this wrong?
>> > pyzmq==13.1.0
>> > zeromq==3.2.3
>> >
>> > Thanks.
>> > --
>> > Best regards,
>> > Sergey Gavruk
>> >
>> > _______________________________________________
>> > zeromq-dev mailing list
>> > zeromq-dev at lists.zeromq.org
>> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> >
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>
>
>
>
> --
> Best regards,
> Sergey Gavruk
>
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