[zeromq-dev] state of publishers and subscribers via ZMQ_PUB and ZMQ_SUB

[Doron Somech]

Just to clarify, zeromq doesn't recognize disconnection (yet), operating
system is, however it cannot recognize disconnection when it is not
graceful. This why we need the heart beat. The reason the publisher need to
be the client, the one doing connect is responsible to do reconnections and
only send operation can recognize disconnection when it is ungraceful (recv
will block forever or until send operation happen on the same socket).
Because in pub/sub only publisher is doing send operation publisher need to
be the client for reconnection to happen automatically.
On Oct 24, 2015 6:54 AM, "Justin Karneges" <justin at affinix.com> wrote:

> Sockets automatically reconnect. You don't have to think about
> connections, just messages.
>
>
> On Fri, Oct 23, 2015, at 08:01 PM, Aravind Sethuraman wrote:
>
> sorry i guess the answer to my question is in Zoron's email ...subscribe
> to ping heartbeat....ok i will give this a shot...
>
> thanks everyone
>
> On Fri, Oct 23, 2015 at 10:47 PM, Aravind Sethuraman <arvinj1 at gmail.com>
> wrote:
>
> interesting point...so if sockets do not connect or are in midst of
> connecting or were connected and a system comes down, upon restart, do
> systems implicitly reconnect?
>
> On Fri, Oct 23, 2015 at 9:54 PM, Justin Karneges <justin at affinix.com>
> wrote:
>
>
> With ZeroMQ, any socket type can bind or connect. Who binds and who
> connects is matter of which entities should have stable or dynamic
> existence, not who is acting as a "server" in some kind of traditional
> sense. So yeah, you can have a PUB socket connect to a SUB socket and vice
> versa. Similarly you can have a REP socket connect to a REQ socket.
> Realizing that these combinations are possible is one of those "ah-hah"
> moments of enjoying ZeroMQ. :)
>
> As for knowing when subscribers are connecting/reconnecting, in general
> you should not need to care about this.
>
> On Fri, Oct 23, 2015, at 06:21 PM, Aravind Sethuraman wrote:
>
> hello doron,
> i am actually interested in making the publisher a client and subscriber a
> server. Correct me if i am wrong but is it not a departure from the usual
> understanding of publisher being a server and subscriber clients? is it
> even possible to do that (i am guessing since you mentioned it; it must be
> ) . also how do i know which subscribers are connected and are reconnecting
> etc?
>
> On Fri, Oct 23, 2015 at 5:55 PM, Justin Karneges <justin at affinix.com>
> wrote:
>
>
> If you make the subscriber the client, reconnections should still work. I
> tested this myself again just now to be sure.
>
> On Fri, Oct 23, 2015, at 02:07 PM, Doron Somech wrote:
>
> make the publisher the client (connect) and the subscriber the server
> (bind), this is important, it will not work the other way, send heartbeat
> from publisher every X seconds (don't forget to make sure subscriber
> subscribe to the heartbeat). If you do it that way reconnection will happen
> automatically. Alternatively you can just enable TCP keep alive.
> On Oct 23, 2015 11:53 PM, "Aravind Sethuraman" <arvinj1 at gmail.com> wrote:
>
> I am building a full mesh of publishers and subscribers (no brokers) and
> as i would like to implement re-connecting when there is a reboot of a
> node. How can i get a list of current state of subscribers to a publisher
> node?
>
> thanks
> aRavind
>
>
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
> *_______________________________________________*
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
> *_______________________________________________*
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
> *_______________________________________________*
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20151024/2b659c02/attachment.htm>