[zeromq-dev] NetMQ: Poller usage

[Doron Somech]

Almost, you just need to wait for the first subscription (socket.Receive)
on the publisher side...

If you have more then one subscriber the story is a little different...


On Fri, Jun 28, 2013 at 11:30 AM, Giacomo Tesio <giacomo at tesio.it> wrote:

> Hi Doron, thanks for your kind help!
>
> So with an XPUB/SUB connection over an inproc transport no hand-made
> syncronization is needed? Have I understand correctly?
>
>
> Giacomo
>
>
> On Fri, Jun 28, 2013 at 9:19 AM, Doron Somech <somdoron at gmail.com> wrote:
>
>> Hi Giacomo,
>>
>> The poller is actually a copy of the zloop from czmq, actually I'm not
>> big fun of the event pattern but I want to make it as close as possible to
>> CLRZMQ.
>>
>> 1. The start method is blocking, you should call if from a dedicated
>> thread.
>> 2. Stop(false) just signal the dedicated thread to stop but don't
>> actually wait the thread is stopped, this is good when you want to close
>> the poller but continue doing something else with your code, but if for
>> example you closing the application and want to wait until the poller is
>> completely stopped call it with true.
>> 3. Actually you cannot call Stop(true) from the dedicated thread, you can
>> call Stop(false) from the dedicated thread, but I don't have to implement
>> this kind of socket, you can just call Stop
>> 4. Just call the stop method
>>
>> Regarding the bonus question, you have to do some synchronization magic
>> to make it work, for the example let's call the socket which bind server
>> and the sockets which connect clients. So when the server binds no client
>> is connected yet (with inproc you have to bind before you can connect), now
>> if you will start send messages now the client will miss them.
>>
>> After the client connected the client should send a signal message to the
>> server, after the server bind we wait for message from client, after this
>> the server can start publish messages.
>>
>> If we are talking about pub-sub pattern you should have a sub socket as
>> the client, xpub socket as server, now the client immediately send
>> subscribe message and the server wait for the first message...
>>
>>   Doron
>>
>>
>> On Fri, Jun 28, 2013 at 3:23 AM, Giacomo Tesio <giacomo at tesio.it> wrote:
>>
>>> Hi, I'm having an hard time understanding the NetMQ.Poller usage (here:
>>> https://github.com/zeromq/netmq/blob/master/src/NetMQ/Poller.cs).
>>>
>>> The fact is, it doesn't expose any Poll method.
>>>
>>> I guess that this is done in the aim of OOP desing.
>>>
>>> But I'm not sure about its correct usage.
>>>
>>> My insight is that after adding the sockets to the Poller, I should
>>> simply observe the sockets' events ReceiveReady and SendReady, but if so:
>>>
>>>
>>>    1. does the Start method block? If not, this should mean that I
>>>    don't have to use it in a dedicated thread, right?
>>>    2. what are the pro/cons of Stop(false)?
>>>    3. one of the socket I added to the poller is a "control" one that
>>>    send a "STOP" command when required. In the event handler can I stop the
>>>    poller and remove the sockets?
>>>    4. what should I do to cleanup things (before context disposition)?
>>>
>>> Moreover I'd like to know if the socket events will ever be fired from
>>> sockets that aren't in a Poller, or not.
>>>
>>>
>>> Finally a bonus question (be patient, I'm a newbie here): I've read that
>>> with ZeroMQ I can loose a few messages at connection startup (even if I
>>> start the receiver before the sender): does this apply to inproc sockets
>>> too?
>>>
>>>
>>> Thanks a lot.
>>>
>>>
>>> Giacomo
>>>
>>> _______________________________________________
>>> 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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