Hi Stephen. Thanks for your answering
I am set the identity of each peer/client in their respective ZMQ_DEALER client-side with client.setsockopt(ZMQ_IDENTITY, "PEER1", 5); When this ZMQ_DEALER client send a message to ZMQ_ROUTER Bernardo Augusto García Loaiza Ingeniero de Sistemas Estudiante de Maestría en Ingeniería Informática - Universidad EAFIT http://about.me/bgarcial On Thu, Mar 15, 2018 at 6:59 AM, Stephen Gray <riskybizl...@live.com> wrote: > Hi Bernardo, > > > > The http://zguide.zeromq.org/page:all tells us; > > > > “The ROUTER socket, unlike other sockets, tracks every connection it has, > and tells the caller about these. The way it tells the caller is to stick > the connection *identity* in front of each message received. An identity, > sometimes called an *address*, is just a binary string with no meaning > except "this is a unique handle to the connection". Then, when you send a > message via a ROUTER socket, you first send an identity frame. > > The zmq_socket() <http://api.zeromq.org/3-2:zmq_socket> man page > describes it thus: > > When receiving messages a ZMQ_ROUTER socket shall prepend a message part > containing the identity of the originating peer to the message before > passing it to the application. Messages received are fair-queued from among > all connected peers. When sending messages a ZMQ_ROUTER socket shall remove > the first part of the message and use it to determine the identity of the > peer the message shall be routed to.” > > Though I haven’t run your code I suspect that your ROUTER will bounce back > your test message to the originating DEALER? This would be because the > identity frame was prepended by the ROUTER on receipt and the message is > sent back through the ROUTER; where it strips off the identity and uses the > value to route the message back to the relevant DEALER. > > In order to send it to a different destination it is necessary to have the > ‘identity’ frame of that other DEALER and to prepend that identity when you > send the message; otherwise the ROUTER won’t know where to deliver the > message. > > When receiving off a ROUTER socket the ‘identity’ is the first frame of > the message. You could capture it and store it. Then later prepend it as > the first frame of a message you wish to send to a particular DEALER via > your ROUTER. > > HTH, > > Stephen > > > > > > *From:* zeromq-dev [mailto:zeromq-dev-boun...@lists.zeromq.org] *On > Behalf Of *Bernardo Augusto García Loaiza > *Sent:* 14 March 2018 23:17 > *To:* ZeroMQ development list > *Subject:* [zeromq-dev] ZMQ DEALER - ROUTER Communication > > > > I am currently working on a project that requires some communication over > the network of a different data types from some entities of a distributed > system and I am using ZMQ. > > The main goal of the project is to have a central node which services > clients which can connect at any time. For each client connected, the > central node should manage the message communication between the two. > > Currently, and by the moment, all communication is happening over TCP. > > The clients need to send and receive messages at any time so they are > *ZMQ_DEALER* type sockets and the central node is *ZMQ_ROUTER* > > I have been reading, about of the different patterns communication and I > think the Asynchronous Client/Server pattern > <http://zguide.zeromq.org/page:all#The-Asynchronous-Client-Server-Pattern> > is suited because I am interested in having several clients talking to each > other in a collaborative way, having maybe a server broker or middleware, > which be useful to receive and forward messages between entities related > and because basically, the DEALER - TO - ROUTER > <http://zguide.zeromq.org/php:chapter3#The-DEALER-to-ROUTER-Combination> > combination is that I need. > > > > I have a ZMQ_DEALER socket client which connect to ZMQ_ROUTER socket > server > > #include <zmq.hpp> > > #include "zhelpers.hpp" > > using namespace std; > > > > int main(int argc, char *argv[]) > > { > > > > zmq::context_t context(1); > > zmq::socket_t client(context, ZMQ_DEALER); > > > > const string endpoint = "tcp://localhost:5559"; > > > > client.setsockopt(ZMQ_IDENTITY, "PEER1", 5); > > cout << "Connecting to ZMQ Network Manager " << endpoint << "..." << endl; > > client.connect(endpoint); > > for (int request = 0; request < 10; request++) > > { > > > > s_sendmore(client, ""); > > s_send(client, "Testing sending some data"); > > > > std::string string = s_recv(client); > > > > std::cout << "Received reply " << request > > << " [" << string << "]" << std::endl; > > } > > } > > > On my server code, I have a ZMQ_ROUTER which receive and manage the > messages is, making bind it to a well port. This server is made in Python > > import zmq > > context = zmq.Context() > > frontend = context.socket(zmq.ROUTER) > > frontend.bind("tcp://*:5559") > > > > # Initialize a poll set > > poller = zmq.Poller() > > poller.register(frontend, zmq.POLLIN) > > > > print("Creating Server Network Manager Router") > > > > while True: > > socks = dict(poller.poll()) > > > > if socks.get(frontend) == zmq.POLLIN: > > message = frontend.recv_multipart() > > print(message) > > frontend.send_multipart(message) > > > On my other peer/client I have the following: > > #include <zmq.hpp> > > #include "zhelpers.hpp" > > using namespace std; > > > > int main (int argc, char *argv[]) > > { > > > > zmq::context_t context(1); > > zmq::socket_t peer2(context, ZMQ_DEALER); > > > > const string endpoint = "tcp://localhost:5559"; > > > > peer2.setsockopt(ZMQ_IDENTITY, "PEER2", 5); > > cout << "Connecting to ZMQ Network Manager " << endpoint << "..." << endl; > > peer2.connect(endpoint); > > //s_sendmore(peer2, ""); > > //s_send(peer2, "Probando"); > > > > //std::string string = s_recv(peer2); > > > > //std::cout << "Received reply " << " [" << string << "]" << std::endl; > > > > for (int request = 0; request < 10; request++) > > { > > > > s_sendmore(peer2, ""); > > s_send(peer2, "Probando"); > > > > std::string string = s_recv(peer2); > > > > std::cout << "Received reply " << request > > << " [" << string << "]" << std::endl; > > } > > > > } > > > > But each that I execute some client, their respective messages do not > arrive at another peer client. The messages arrive at ZMQ_ROUTER, but I > haven't clear on my server code how to should I forward this messages to > the respective clients. > > I think so (may be obvious) that in my server code, I am not sending > messages. > > > > > Bernardo Augusto García Loaiza > Ingeniero de Sistemas > Estudiante de Maestría en Ingeniería Informática - Universidad EAFIT > > http://about.me/bgarcial > > > > _______________________________________________ > zeromq-dev mailing list > zeromq-dev@lists.zeromq.org > https://lists.zeromq.org/mailman/listinfo/zeromq-dev > >
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