cppzmq ROUTER DEALER & pyzmq DEALER

client.cc

#include "client.hpp"

void Sock::bind(size_t port) {
  sock = zmq::socket_t(ctx, zmq::socket_type::router);
  sock.set(zmq::sockopt::linger, 0);
  sock.bind("tcp://*:" + std::to_string(port));
}

void Sock::close() {
  sock.close();
  ctx.close();
}

void Sock::send_multipart(const std::string &m0, const std::string &m1) {
  zmq::send_multipart(sock,
                      std::initializer_list<zmq::const_buffer>{zmq::buffer(m0), zmq::buffer(m1)});
}

#include <iostream>

int main() {
  int port = 5566;
  Sock sock;
  sock.bind(port);
  std::array<std::string, 3> msgs;
  sock.recv_multipart_n<3>(msgs);
  auto &identity = msgs[0];
  std::cout << msgs[1] << ' ' << msgs[2] << '\n';
  sock.send_multipart(identity, "pong");
  sock.close();
}

client.hpp

#pragma once
#include "zmq_addon.hpp"
#include <array>
#include <string>

class Sock {
  zmq::context_t ctx;
  zmq::socket_t sock;

public:
  void bind(size_t);
  void close();
  void send_multipart(const std::string &, const std::string &);
  template <size_t N> void recv_multipart_n(std::array<std::string, N> &ret) {
    std::array<zmq::message_t, N> msgs;
    try {
      (void)zmq::recv_multipart_n(sock, msgs.data(), msgs.size());
      for (size_t i = 0; i < N; ++i) {
        ret[i] = msgs[i].to_string();
      }
    } catch (...) {
      throw;
    }
  }
};

send.py

import zmq

remote = "127.0.0.1:5566"
ctx = zmq.Context()
zsock = ctx.socket(zmq.DEALER)
zsock.setsockopt(zmq.LINGER, 0)
zsock.setsockopt(zmq.ROUTING_ID, b"0")
zsock.connect(f"tcp://{remote}")
zsock.send_multipart([b"ping", b"data"])

server.cc

#include "server.hpp"

void Sock::connect(const std::string &remote, const std::string &id) {
  sock = zmq::socket_t(ctx, zmq::socket_type::dealer);
  sock.set(zmq::sockopt::linger, 0);
  sock.set(zmq::sockopt::routing_id, id);
  sock.connect(remote);
}

void Sock::close() {
  sock.close();
  ctx.close();
}

void Sock::send_multipart(const std::string &m0, const std::string &m1) {
  zmq::send_multipart(sock,
                      std::initializer_list<zmq::const_buffer>{zmq::buffer(m0), zmq::buffer(m1)});
}

void Sock::recv(std::string &ret) {
  zmq::message_t msg;
  try {
    (void)sock.recv(msg);
    ret = msg.to_string();
  } catch (...) {
    throw;
  }
}

#include <iostream>

int main() {
  std::string remote{"127.0.0.1:5566"};
  int rank = 0;
  Sock sock;
  sock.connect("tcp://" + remote, std::to_string(rank));
  sock.send_multipart("ping", "data");
  {
    std::string msg;
    try {
      sock.recv(msg);
    } catch (...) {
      return;
    }
    std::cout << msg << '\n';
  }
  sock.close();
}

server.hpp

#pragma once
#include "zmq_addon.hpp"
#include <string>

class Sock {
  zmq::context_t ctx;
  zmq::socket_t sock;

public:
  void connect(const std::string &, const std::string &);
  void close();
  void send_multipart(const std::string &, const std::string &);
  void recv(std::string &);
};