Ensure microserivices communication using ZeroMQ sockets

[smaillns]

Have you any comment or idea about how to implement such sample https://github.com/smaillns/ZMQ_Samples/blob/master/capture.png
Thanks so much

Originally posted by @smaillns in #3583 (comment)

[ljluestc]

#include <zmq.hpp>
#include <string>
#include <iostream>

void service_function() {
    zmq::context_t context(1);
    zmq::socket_t socket(context, ZMQ_REP);
    socket.bind("tcp://*:5555");

    while (true) {
        zmq::message_t request;

        // Wait for next request from client
        socket.recv(request);
        std::string request_str(static_cast<char*>(request.data()), request.size());
        std::cout << "Received Request: " << request_str << std::endl;

        // Do some 'work'
        std::string response = "Service Response to '" + request_str + "'";

        // Send reply back to client
        zmq::message_t reply(response.size());
        memcpy(reply.data(), response.data(), response.size());
        socket.send(reply, zmq::send_flags::none);
    }
}

void client_function() {
    zmq::context_t context(1);
    zmq::socket_t socket(context, ZMQ_REQ);
    socket.connect("tcp://localhost:5555");

    // Create a request
    std::string request_str = "Hello";
    zmq::message_t request(request_str.size());
    memcpy(request.data(), request_str.data(), request_str.size());

    // Send the request
    std::cout << "Sending request: " << request_str << std::endl;
    socket.send(request, zmq::send_flags::none);

    // Get the reply
    zmq::message_t reply;
    socket.recv(reply);
    std::string reply_str(static_cast<char*>(reply.data()), reply.size());
    std::cout << "Received reply: " << reply_str << std::endl;
}

int main() {
    // Run the service in a separate thread or process
    std::thread service_thread(service_function);

    // Simulate client requests
    client_function();

    service_thread.join();
    return 0;
}