代碼筆記 | zeromq 的 router學習分析

 
// lbbroker_cpp.cpp : 定義控制檯應用程序的入口點。
//
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#include "stdafx.h"
#include "zhelpers.hpp"
#include <thread>
#include <queue>
  
void client_thread(void* arg) {
    zmq::context_t context(1);
    zmq::socket_t client(context, ZMQ_REQ);
  
    s_set_id(client, (intptr_t)1);
    client.connect("tcp://localhost:5672");
  
    s_send(client, "HELLO");
    std::string reply = s_recv(client);
    std::cout << "Client: " << reply << std::endl;
    return;
}
  
  
void worker_thread(void* arg){
    zmq::context_t context(1);
    zmq::socket_t worker(context, ZMQ_REQ);
  
    s_set_id(worker, (intptr_t)9);
    worker.connect("tcp://localhost:5673");
  
    s_send(worker, "READY");
    while (1) {
        std::string address = s_recv(worker);
        {
            std::string empty = s_recv(worker);
            assert(empty.size() == 0);
        }
        std::string request = s_recv(worker);
        std::cout << "Worker: " << request << std::endl;
      
        s_sendmore(worker, address);
        s_sendmore(worker, "");
        s_send(worker, "OK");
    }
    return;
}
  
  
int main()
{
    zmq::context_t context(1);
    zmq::socket_t frontend(context, ZMQ_ROUTER);
    zmq::socket_t backend(context, ZMQ_ROUTER);
  
    frontend.bind("tcp://*:5672");
    backend.bind("tcp://*:5673");
  
    int client_nbr;
    std::thread client[1];
    for (client_nbr = 0; client_nbr < 1; client_nbr++)
    {
        client[client_nbr] = std::thread(client_thread,(void *)(intptr_t)client_nbr);
    }
  
    int worker_nbr;
    std::thread worker[1];
    for (worker_nbr = 0; worker_nbr < 1; worker_nbr++)
    {
        worker[worker_nbr] = std::thread(worker_thread, (void *)(intptr_t)worker_nbr);
    }
  
    std::queue<std::string> worker_queue;
  
    while (1)
    {
        zmq::pollitem_t items[] = {
            {backend,0,ZMQ_POLLIN,0},
            {frontend,0,ZMQ_POLLIN,0}
        };
        if (worker_queue.size())
            zmq::poll(&items[0], 2, -1);
        else
            zmq::poll(&items[0], 1, -1);
  
        if (items[0].revents & ZMQ_POLLIN) {
  
            //  Queue worker address for LRU routing
            worker_queue.push(s_recv(backend));
  
            {
                //  Second frame is empty
                std::string empty = s_recv(backend);
                assert(empty.size() == 0);
            }
  
            //  Third frame is READY or else a client reply address
            std::string client_addr = s_recv(backend);
  
            //  If client reply, send rest back to frontend
            if (client_addr.compare("READY") != 0) {
  
                {
                    std::string empty = s_recv(backend);
                    assert(empty.size() == 0);
                }
  
                std::string reply = s_recv(backend);
                s_sendmore(frontend, client_addr);
                s_sendmore(frontend, "");
                s_send(frontend, reply);
  
                if (--client_nbr == 0)
                    break;
            }
        }
        if (items[1].revents & ZMQ_POLLIN) {
  
            //  Now get next client request, route to LRU worker
            //  Client request is [address][empty][request]
            std::string client_addr = s_recv(frontend);
  
            {
                std::string empty = s_recv(frontend);
                assert(empty.size() == 0);
            }
  
            std::string request = s_recv(frontend);
  
            std::string worker_addr = worker_queue.front();//worker_queue [0];
            worker_queue.pop();
  
            s_sendmore(backend, worker_addr);
            s_sendmore(backend, "");
            s_sendmore(backend, client_addr);
            s_sendmore(backend, "");
            s_send(backend, request);
        }
    }
  
    for (client_nbr = 0; client_nbr < 1; client_nbr++)
    {
        client[client_nbr].join();
    }
  
  
    for (worker_nbr = 0; worker_nbr < 1; worker_nbr++)
    {
        worker[worker_nbr].join();
    }
  
    return 0;
}