Sorry for confusion. When I said out-of-control -- I meant they do have ZMQ but they may have different release cycle and QoS. It's just a service on ZMQ, on a ROUTER.
Our application is aimed to take a message, get its headers, decide on what service ROUTER to send and that's it. W/o waiting for reply. Essentially we are a DEALER. Replies are important, but as long as they coming back. If they not. Not a problem. Client application (iPhone game) by itself checking replies and correlation, and keep watching: "ahha, I didn't receive ack for betting. hmmm. Let's try again". Now it's more clear? I really don't need PUB/SUB. I need DEALER/ROUTER. Here, in my company, the only biggest concern so far with ZMQ -- misleading behaviour: when .send() returns "true" that should mean that message "sent", whatever that means: left our PID, left our NIC and so on, we have to guarantee that message is not on us. I know what's PUB/SUB. And again, telling you that it's not suitable. The problem statement is simple: - don't use HWM for DEALER/ROUTER (prohibit message queueing). - raise immediately if you can't .send() (don't collect in internal queue) Is it possible? BR -artemv 2013/12/6 Justin Cook <[email protected]> > Ok, this is confusing. If you are sending a message to a service that is > out of your control, either they use 0MQ or not. I assume they do not. If > that’s the case, it should not be a part of the use case. > > You say you need to know if a message has been received. But, then you say > no ACKs or timeouts. I’m even more confused. If you are making a request to > a foreign service over — I assume — HTTP which uses TCP, you are very well > getting HTTP return codes with the TCP session doing all the hard work. You > already have what you are looking for there. > > As far as your system — going out to mobile devices — using PUB/SUB and > ACKing messages, this is something you will have to do in another channel > with 0MQ. Multicast uses UDP; because, it is not feasible to send TCP ACKs > from every single subscriber. It’s simply not scalable. > > You very well may need to develop your own application protocol to send > ACKs or the publisher retransmits. I highly suggest you have a look at this: > > > http://stackoverflow.com/questions/12956685/what-are-the-retransmission-rules-for-tcp > > It may be something you will want to mimic in your implementation. Someone > else has already suggested a timeout for resending unacknowledged messages. > As you can see, this is one of the ways TCP retransmissions work. You also > may have corrupt data that fail a CRC or hash. > > I will finish by saying that if you do have a PUB/SUB design using another > channel for unicast communication, you will need to be very aware of > scalability issues. You may need to use a lockstep pattern such as REQ/REP > if you need guarantee of communication. > > -- > Justin Cook > > > On Friday, 6 December 2013 at 09:46, artemv zmq wrote: > > > Thanks for heads up. > > > > 2crocket: > > No acks. No timeouts. Nothing should be kept. Messages should just > flowing back and forth. But for every message we have to answer a question: > "has message left NIC on sending process or not". Let me give example with > betting: game on iPhone sending us a message "make-a-bet", then we send > this to BettingService which isn't in our control, > > so all we have to guarantee -- "make-a-bet" message has left our NIC and > been "sent" to BettingService. If "make-a-bet" has been droped on a network > - ok, if BettingService itself drops it - ok. > > > > Back to HWM. Let's consider that we send to unavaliable peer. > > hwm=1. It means you can send 1 message "blindly" and .send() function > returns success. Of course sending second time will fail. But... the trick > is -- we need answer first time. > > hwm=0. It means you can send any number of messages and .send() function > _always_ returns success :(( Again, isn't this a bug? > > > > > > So let me re-phrase the original question -- how to fail at .send() > function in ZMQ? > > > > > > BR > > -artemv > > > > > > > > 2013/12/6 crocket <[email protected] (mailto: > [email protected])> > > > Why don't you set a timeout for asynchronous ACKs? > > > You receive ACKs asynchronously and keep associated messages until > ACKs come or a timeout occurs. > > > A timeout of 20 seconds is a reasonable estimate. > > > After a timeout, if a message doesn't have a corresponding ACK, it is > determined that the message wasn't delievered, and the message is sent > again or discarded. > > > > > > > > > > > > On Fri, Dec 6, 2013 at 3:19 AM, artemv zmq <[email protected](mailto: > [email protected])> wrote: > > > > Hi, > > > > > > > > My name is Artem. I stay with ZMQ (on java) a year or so. Got a cool > question for you, ppl! > > > > > > > > Here's my story. Recently I entered a new company (gambling games), > after working few weeks, after getting accustomed with a code, I found that > they are building very-unnecessarly-complex-distibuted-application ... I > was unhappy few days, because couldn't even imagine how to support ALL THAT > CRAP in an upcoming future. So I suggested ZMQ hoping that ZMQ will "open > eyes" to others. But, as a feedback I got one big fundamental concern (from > chief architects): > > > > > > > > - we have to know only one thing about every message: it has been > delivered onto remote peer or not > > > > > > > > And few additional comments: > > > > -we don't care if message will get lost on a network > > > > - we don't need guarantee deliveri > > > > - no RPC / everything is asynchronous > > > > - we don't need HWM > > > > > > > > > > > > So I'm here, because I really can't address this question: "for > every single message how to know : whether it was delivered or not" . > > > > > > > > Thanks in advance. And appreciate for your help. > > > > _______________________________________________ > > > > zeromq-dev mailing list > > > > [email protected] (mailto:[email protected]) > > > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > > > > > > > > > _______________________________________________ > > > zeromq-dev mailing list > > > [email protected] (mailto:[email protected]) > > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > > > _______________________________________________ > > zeromq-dev mailing list > > [email protected] (mailto:[email protected]) > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > _______________________________________________ > zeromq-dev mailing list > [email protected] > http://lists.zeromq.org/mailman/listinfo/zeromq-dev >
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