[zeromq-dev] Malamute broker project

Kenneth Adam Miller kennethadammiller at gmail.com
Mon Mar 2 18:56:11 CET 2015


I can help you with writing an article :)

I was literally discovery what you were telling me, since sometimes, about
1/4 of the time, it would succeed. What you say rationalizes my
considerations since I was literally writing you an email about what I was
witnessing.

Let me try to work out what you're saying, then I can post what I
established to a public github repo :)

On Mon, Mar 2, 2015 at 12:50 PM, Pieter Hintjens <ph at imatix.com> wrote:

> The problem with streams is there's no persistence yet, so both peers
> have to be present at the same time.  A name registration/lookup
> service is probably better.
>
> Yes, the set_worker call offers a service. I'd do this:
>
> - offer a service "ADDRESS" using set_worker
> - two messages: SET and GET, each taking a name/value (use frames or
> any other encoding you like)
> - use the sendfor method to send the request
> - use the sendto method to send the replies, which end in a client's
> mailbox
> - read the replies using the recv method
>
> For this to work, peers need to specify a mailbox address in the connect
> method.
>
> If you like I'll write an article and make examples.
>
> -Pieter
>
> On Mon, Mar 2, 2015 at 6:45 PM, Kenneth Adam Miller
> <kennethadammiller at gmail.com> wrote:
> > I got it to work by setting the subscribed topic to "inproc*" on
> > mlm_client_set_worker call.
> >
> > On Mon, Mar 2, 2015 at 12:07 PM, Kenneth Adam Miller
> > <kennethadammiller at gmail.com> wrote:
> >>
> >> Ok after looking at mlm_client.c, I have the following:
> >>
> >> Two concurrent calls to exchange addresses with the following
> parameters:
> >>
> >> //thread 1
> >>   char * servrAddr = exchange_addresses("backendEndpoints",
> >> "frontendEndpoints", "inproc://frontend");
> >> //thread 2
> >>   char * servrAddr = exchange_addresses("frontendEndpoints",
> >> "backendEndpoints", "inproc://backend");
> >>
> >> Where exchange addresses is implemented as:
> >>
> >> char * exchange_addresses(std::string consumer_topic, std::string
> >> production_topic, std::string toSend) {
> >>   mlm_client_t *client_reader = mlm_client_new();
> >>   assert(client_reader);
> >>   mlm_client_t *client_writer = mlm_client_new();
> >>   assert(client_writer);
> >>
> >>   int rc=mlm_client_connect (client_reader,  "tcp://127.0.0.1:9999" ,
> >> 3000, "");
> >>   assert(rc==0);
> >>   rc=mlm_client_connect (client_writer,  "tcp://127.0.0.1:9999" ,
> 3000,
> >> "");
> >>   assert(rc==0);
> >>
> >>   std::cout << "producing to topic: " << production_topic << std::endl;
> >>   std::cout << "consuming from topic: " << consumer_topic << std::endl;
> >>   mlm_client_set_worker(client_reader, consumer_topic.c_str(), "*");
> >>   if (!mlm_client_sendforx (client_writer, production_topic.c_str(),
> >> toSend.c_str(), "", NULL))
> >>     std::cout << "client sent message" << std::endl;
> >>   else
> >>     std::cerr << "error sending message" << std::endl;
> >>
> >>
> >>   char *subject, *content, *attach;
> >>   mlm_client_recvx (client_reader, &subject, &content, NULL);  //<--
> >> blocking here
> >>   mlm_client_destroy(&client_writer);
> >>   mlm_client_destroy(&client_reader);
> >>   std::cout << "received: " << subject << " " << content << std::endl;
> >>   return content;
> >> }
> >>
> >>
> >> Problem is, both threads block at mlm_client_recvx... As per example, it
> >> looks correct.
> >>
> >> On Mon, Mar 2, 2015 at 11:30 AM, Kenneth Adam Miller
> >> <kennethadammiller at gmail.com> wrote:
> >>>
> >>> Oh you mean with mlm_client_set_worker! Do I do set_worker on each side
> >>> with different service names? How does a client get a specific service?
> >>>
> >>> On Mon, Mar 2, 2015 at 11:26 AM, Kenneth Adam Miller
> >>> <kennethadammiller at gmail.com> wrote:
> >>>>
> >>>> Service semantics? I don't know what those are...
> >>>> I read what tutorials I think that there are. I have some questions
> >>>> about the how things are forwarded-I want only one to one pairing...
> I'm not
> >>>> sure if what I'm doing is setting up for publishing and
> subscriptions. There
> >>>> was a lot of talk about some of the other features in the malamute
> >>>> manual/whitepaper, and it's kind of confusing. Basically, I just want
> FCFS
> >>>> exchange of information for mutually requiring parties.
> >>>>
> >>>> On Mon, Mar 2, 2015 at 4:13 AM, Pieter Hintjens <ph at imatix.com>
> wrote:
> >>>>>
> >>>>> The simplest way to make a lookup service is using the service
> >>>>> semantics, and the lookup service can talk to the broker over inproc
> >>>>> or tcp as it wants (it could be a thread in the same process, or a
> >>>>> separate process).
> >>>>>
> >>>>> On Sun, Mar 1, 2015 at 9:00 PM, Kenneth Adam Miller
> >>>>> <kennethadammiller at gmail.com> wrote:
> >>>>> > So, in order to manage a mutual exchange of address between two
> >>>>> > concurrent
> >>>>> > parties, I thought that on each side I would have a producer
> produce
> >>>>> > to a
> >>>>> > topic that the opposite side was subscribed to. That means that
> each
> >>>>> > side is
> >>>>> > both a producer and a consumer.
> >>>>> >
> >>>>> > I have the two entities running in parallel. The front end client
> >>>>> > connects
> >>>>> > to the malamute broker, and subscribes to the backendEndpoints
> topic,
> >>>>> > and
> >>>>> > then producing it's endpoint to the frontendEndpoints topic.
> >>>>> >
> >>>>> > The opposite side does the same thing, with the back end
> subscribing
> >>>>> > to the
> >>>>> > frontendEndpoints and producing to backendEndpoints.
> >>>>> >
> >>>>> >
> >>>>> > The problem is that if the front end and back end are in their own
> >>>>> > threads
> >>>>> > then only the thread that completes the mlm_set_producer and
> >>>>> > mlm_set_consumer call proceed. The one that didn't make it that far
> >>>>> > will
> >>>>> > hang at that mlm_set_x pair point...
> >>>>> >
> >>>>> > code:
> >>>>> >
> >>>>> >   std::cout << "connectToFrontEnd" << std::endl;
> >>>>> >   mlm_client_t *frontend_reader = mlm_client_new();
> >>>>> >   assert(frontend_reader);
> >>>>> >   mlm_client_t *frontend_writer = mlm_client_new();
> >>>>> >   assert(frontend_writer);
> >>>>> >   int rc=mlm_client_connect (frontend_reader,  "tcp://
> 127.0.0.1:9999"
> >>>>> > ,
> >>>>> > 1000, "reader/secret");
> >>>>> >   assert(rc==0);
> >>>>> >   rc=mlm_client_connect (frontend_writer,  "tcp://127.0.0.1:9999"
> ,
> >>>>> > 1000,
> >>>>> > "writer/secret");
> >>>>> >   assert(rc==0);
> >>>>> >   std::cout << "frontend mlm clients connected" << std::endl;
> >>>>> >
> >>>>> >   mlm_client_set_consumer(frontend_reader, "backendEndpoints",
> "*");
> >>>>> >   mlm_client_set_producer(frontend_writer, "frontendEndpoints");
> >>>>> >   std::cout << "frontend client producers and consumers set" <<
> >>>>> > std::endl;
> >>>>> >
> >>>>> >
> >>>>> > The code looks exactly* the same for the backend, but with some
> >>>>> > variable and
> >>>>> > other changes.
> >>>>> >
> >>>>> >   std::cout << "connectToBackEnd" << std::endl;
> >>>>> >   mlm_client_t *backend_reader = mlm_client_new();
> >>>>> >   assert(backend_reader);
> >>>>> >   mlm_client_t *backend_writer = mlm_client_new();
> >>>>> >   assert(backend_writer);
> >>>>> >   int rc=mlm_client_connect(backend_reader,"tcp://127.0.0.1:9999",
> >>>>> > 1000,
> >>>>> > "reader/secret");
> >>>>> >   assert(rc==0);
> >>>>> >   rc=mlm_client_connect(backend_writer,"tcp://127.0.0.1:9999",
> 1000,
> >>>>> > "writer/secret");
> >>>>> >   assert(rc==0);
> >>>>> >   std::cout << "backend mlm clients connected" << std::endl;
> >>>>> >
> >>>>> >   mlm_client_set_consumer(backend_reader, "frontendEndpoints",
> "*");
> >>>>> >   mlm_client_set_producer(backend_writer, "backendEndpoints");
> >>>>> >   std::cout << "backend client producers and consumers set" <<
> >>>>> > std::endl;
> >>>>> >
> >>>>> > I only ever will see either "frontend client produces and consumers
> >>>>> > set" or
> >>>>> > "backend client producers and consumers set".
> >>>>> >
> >>>>> > On Sun, Mar 1, 2015 at 2:00 PM, Pieter Hintjens <ph at imatix.com>
> >>>>> > wrote:
> >>>>> >>
> >>>>> >> My assumption is that a broker that's doing a lot of service
> >>>>> >> requests
> >>>>> >> won't be showing costs of regular expression matching, compared to
> >>>>> >> the
> >>>>> >> workload.
> >>>>> >>
> >>>>> >>
> >>>>> >> On Sun, Mar 1, 2015 at 7:49 PM, Doron Somech <somdoron at gmail.com>
> >>>>> >> wrote:
> >>>>> >> >> I did it in actors and then moved it back into the main server
> as
> >>>>> >> >> it
> >>>>> >> >> was complexity for nothing (at that stage). I'd rather design
> >>>>> >> >> against
> >>>>> >> >> real use than against theory.
> >>>>> >> >
> >>>>> >> > Don't you worry about the matching performance which will happen
> >>>>> >> > on the
> >>>>> >> > main
> >>>>> >> > thread? Also a usage I can see is to use exact matching (string
> >>>>> >> > comparison)
> >>>>> >> > over regular expression (I usually use exact matching), this is
> >>>>> >> > way I
> >>>>> >> > think
> >>>>> >> > the plugin model fits the service as well.
> >>>>> >> >
> >>>>> >> > On Sun, Mar 1, 2015 at 8:09 PM, Pieter Hintjens <ph at imatix.com>
> >>>>> >> > wrote:
> >>>>> >> >>
> >>>>> >> >> On Sun, Mar 1, 2015 at 5:52 PM, Doron Somech <
> somdoron at gmail.com>
> >>>>> >> >> wrote:
> >>>>> >> >>
> >>>>> >> >> > So I went over the code, really liked it. Very simple.
> >>>>> >> >>
> >>>>> >> >> Thanks. I like the plugin model, especially neat using CZMQ
> >>>>> >> >> actors.
> >>>>> >> >>
> >>>>> >> >> > I have a question regarding services, for each stream you are
> >>>>> >> >> > using a
> >>>>> >> >> > dedicate thread (actors) and one thread for managing
> mailboxes.
> >>>>> >> >> > However
> >>>>> >> >> > (if
> >>>>> >> >> > I understood correctly) for services you are doing the
> >>>>> >> >> > processing
> >>>>> >> >> > inside
> >>>>> >> >> > the
> >>>>> >> >> > server thread, why didn't you use an actor for each service
> or
> >>>>> >> >> > actor
> >>>>> >> >> > to
> >>>>> >> >> > manage all services? I think the matching of services can be
> >>>>> >> >> > expensive
> >>>>> >> >> > and
> >>>>> >> >> > block the main thread.
> >>>>> >> >>
> >>>>> >> >> I did it in actors and then moved it back into the main server
> as
> >>>>> >> >> it
> >>>>> >> >> was complexity for nothing (at that stage). I'd rather design
> >>>>> >> >> against
> >>>>> >> >> real use than against theory.
> >>>>> >> >>
> >>>>> >> >> -Pieter
> >>>>> >> >> _______________________________________________
> >>>>> >> >> 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
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> >>>>> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> >>>>
> >>>>
> >>>
> >>
> >
> >
> > _______________________________________________
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> >
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