ZeroMQ -- 四种模型简介

1.  REQ/REP 请求响应模型

 

hwclient.c

//
//  Hello World 客户端
//  连接REQ套接字至 tcp://localhost:5555
//  发送Hello给服务端，并接收World
//
//  Hello World client
#include 
#include 
#include 
#include 
int main (void)
{
    printf ("Connecting to hello world server...\n");
    void *context = zmq_ctx_new ();
    //  连接至服务端的套接字
    void *requester = zmq_socket (context, ZMQ_REQ);
    zmq_connect (requester, "tcp://localhost:5555");

    int request_nbr;
    for (request_nbr = 0; request_nbr != 10; request_nbr++) {
        char buffer [10];
        printf ("正在发送 Hello %d...\n", request_nbr);
        zmq_send (requester, "Hello", 5, 0);
        zmq_recv (requester, buffer, 10, 0);
        printf ("接收到 World %d\n", request_nbr);
    }
    zmq_close (requester);
    zmq_ctx_destroy (context);
    return 0;
}

hwserver.c

//
//  Hello World 服务端
//  绑定一个REP套接字至tcp://*:5555
//  从客户端接收Hello，并应答World
//

#include 
#include 
#include 
#include 
#include 
//gcc -o hwserver hwserver.c -lzmq
int main (void)
{
    //  Socket to talk to clients
    void *context = zmq_ctx_new ();
    //  与客户端通信的套接字
    void *responder = zmq_socket (context, ZMQ_REP);
    int rc = zmq_bind (responder, "tcp://*:5555");
    assert (rc == 0);

    while (1) {
        //  等待客户端请求
        char buffer [10];
        zmq_recv (responder, buffer, 10, 0);
        printf ("收到 Hello\n");
        sleep (1);          //  Do some 'work'
        //  返回应答
        zmq_send (responder, "World", 5, 0);
    }
    return 0;
}

 

2. PUB/SUB发布订阅模型

wuserver.c

//  Weather update server
//  Binds PUB socket to tcp://*:5556
//  Publishes random weather updates

#include "zhelpers.h"

int main (void)
{
    //  Prepare our context and publisher
    void *context = zmq_ctx_new ();
    void *publisher = zmq_socket (context, ZMQ_PUB);
    int rc = zmq_bind (publisher, "tcp://*:5556");
    assert (rc == 0);

    //  Initialize random number generator
    srandom ((unsigned) time (NULL));
    while (1) {
        //  Get values that will fool the boss
        int zipcode, temperature, relhumidity;
        zipcode     = randof (100000);
        temperature = randof (215) - 80;
        relhumidity = randof (50) + 10;

        //  Send message to all subscribers
        char update [20];
        sprintf (update, "%05d %d %d", zipcode, temperature, relhumidity);
        s_send (publisher, update);
    }
    zmq_close (publisher);
    zmq_ctx_destroy (context);
    return 0;
}

wuclient.c

//  Weather update client
//  Connects SUB socket to tcp://localhost:5556
//  Collects weather updates and finds avg temp in zipcode

#include "zhelpers.h"

int main (int argc, char *argv [])
{
    //  Socket to talk to server
    printf ("Collecting updates from weather server...\n");
    void *context = zmq_ctx_new ();
    void *subscriber = zmq_socket (context, ZMQ_SUB);
    int rc = zmq_connect (subscriber, "tcp://localhost:5556");
    assert (rc == 0);

    //  Subscribe to zipcode, default is NYC, 10001
    const char *filter = (argc > 1)? argv [1]: "10001 ";
    rc = zmq_setsockopt (subscriber, ZMQ_SUBSCRIBE,
                         filter, strlen (filter));
    assert (rc == 0);

    //  Process 100 updates
    int update_nbr;
    long total_temp = 0;
    for (update_nbr = 0; update_nbr < 100; update_nbr++) {
        char *string = s_recv (subscriber);

        int zipcode, temperature, relhumidity;
        sscanf (string, "%d %d %d",
            &zipcode, &temperature, &relhumidity);
        total_temp += temperature;
        free (string);
    }
    printf ("Average temperature for zipcode '%s' was %dF\n",
        filter, (int) (total_temp / update_nbr));

    zmq_close (subscriber);
    zmq_ctx_destroy (context);
    return 0;
}

3.  Push/Pull推拉模型

taskevent.c

//  Task ventilator
//  Binds PUSH socket to tcp://localhost:5557
//  Sends batch of tasks to workers via that socket

#include "zhelpers.h"

int main (void) 
{
    void *context = zmq_ctx_new ();

    //  Socket to send messages on
    void *sender = zmq_socket (context, ZMQ_PUSH);
    zmq_bind (sender, "tcp://*:5557");

    //  Socket to send start of batch message on
    void *sink = zmq_socket (context, ZMQ_PUSH);
    zmq_connect (sink, "tcp://localhost:5558");

    printf ("Press Enter when the workers are ready: ");
    getchar ();
    printf ("Sending tasks to workers...\n");

    //  The first message is "0" and signals start of batch
    s_send (sink, "0");

    //  Initialize random number generator
    srandom ((unsigned) time (NULL));

    //  Send 100 tasks
    int task_nbr;
    int total_msec = 0;     //  Total expected cost in msecs
    for (task_nbr = 0; task_nbr < 100; task_nbr++) {
        int workload;
        //  Random workload from 1 to 100msecs
        workload = randof (100) + 1;
        total_msec += workload;
        char string [10];
        sprintf (string, "%d", workload);
        s_send (sender, string);
    }
    printf ("Total expected cost: %d msec\n", total_msec);

    zmq_close (sink);
    zmq_close (sender);
    zmq_ctx_destroy (context);
    return 0;
}

taskwork.c

//  Task worker
//  Connects PULL socket to tcp://localhost:5557
//  Collects workloads from ventilator via that socket
//  Connects PUSH socket to tcp://localhost:5558
//  Sends results to sink via that socket

#include "zhelpers.h"

int main (void) 
{
    //  Socket to receive messages on
    void *context = zmq_ctx_new ();
    void *receiver = zmq_socket (context, ZMQ_PULL);
    zmq_connect (receiver, "tcp://localhost:5557");

    //  Socket to send messages to
    void *sender = zmq_socket (context, ZMQ_PUSH);
    zmq_connect (sender, "tcp://localhost:5558");

    //  Process tasks forever
    while (1) {
        char *string = s_recv (receiver);
        printf ("%s.", string);     //  Show progress
        fflush (stdout);
        s_sleep (atoi (string));    //  Do the work
        free (string);
        s_send (sender, "");        //  Send results to sink
    }
    zmq_close (receiver);
    zmq_close (sender);
    zmq_ctx_destroy (context);
    return 0;
}

tasksink.c

//  Task sink
//  Binds PULL socket to tcp://localhost:5558
//  Collects results from workers via that socket

#include "zhelpers.h"

int main (void) 
{
    //  Prepare our context and socket
    void *context = zmq_ctx_new ();
    void *receiver = zmq_socket (context, ZMQ_PULL);
    zmq_bind (receiver, "tcp://*:5558");

    //  Wait for start of batch
    char *string = s_recv (receiver);
    free (string);

    //  Start our clock now
    int64_t start_time = s_clock ();

    //  Process 100 confirmations
    int task_nbr;
    for (task_nbr = 0; task_nbr < 100; task_nbr++) {
        char *string = s_recv (receiver);
        free (string);
        if (task_nbr % 10 == 0)
            printf (":");
        else
            printf (".");
        fflush (stdout);
    }
    //  Calculate and report duration of batch
    printf ("Total elapsed time: %d msec\n", 
        (int) (s_clock () - start_time));

    zmq_close (receiver);
    zmq_ctx_destroy (context);
    return 0;
}

4.  Router/Dealer模型

rrbroker.c

//  Simple request-reply broker

#include "zhelpers.h"

int main (void) 
{
    //  Prepare our context and sockets
    void *context = zmq_ctx_new ();
    void *frontend = zmq_socket (context, ZMQ_ROUTER);
    void *backend  = zmq_socket (context, ZMQ_DEALER);
    zmq_bind (frontend, "tcp://*:5559");
    zmq_bind (backend,  "tcp://*:5560");

    //  Initialize poll set
    zmq_pollitem_t items [] = {
        { frontend, 0, ZMQ_POLLIN, 0 },
        { backend,  0, ZMQ_POLLIN, 0 }
    };
    //  Switch messages between sockets
    while (1) {
        zmq_msg_t message;
        zmq_poll (items, 2, -1);
        if (items [0].revents & ZMQ_POLLIN) {
            while (1) {
                //  Process all parts of the message
                zmq_msg_init (&message);
                zmq_msg_recv (&message, frontend, 0);
                int more = zmq_msg_more (&message);
                zmq_msg_send (&message, backend, more? ZMQ_SNDMORE: 0);
                zmq_msg_close (&message);
                if (!more)
                    break;      //  Last message part
            }
        }
        if (items [1].revents & ZMQ_POLLIN) {
            while (1) {
                //  Process all parts of the message
                zmq_msg_init (&message);
                zmq_msg_recv (&message, backend, 0);
                int more = zmq_msg_more (&message);
                zmq_msg_send (&message, frontend, more? ZMQ_SNDMORE: 0);
                zmq_msg_close (&message);
                if (!more)
                    break;      //  Last message part
            }
        }
    }
    //  We never get here, but clean up anyhow
    zmq_close (frontend);
    zmq_close (backend);
    zmq_ctx_destroy (context);
    return 0;
}

rrwoker.c

//  Hello World worker
//  Connects REP socket to tcp://localhost:5560
//  Expects "Hello" from client, replies with "World"

#include "zhelpers.h"
#include 

int main (void) 
{
    void *context = zmq_ctx_new ();

    //  Socket to talk to clients
    void *responder = zmq_socket (context, ZMQ_REP);
    zmq_connect (responder, "tcp://localhost:5560");

    while (1) {
        //  Wait for next request from client
        char *string = s_recv (responder);
        printf ("Received request: [%s]\n", string);
        free (string);

        //  Do some 'work'
        sleep (1);

        //  Send reply back to client
        s_send (responder, "World");
    }
    //  We never get here, but clean up anyhow
    zmq_close (responder);
    zmq_ctx_destroy (context);
    return 0;
}

rrclient.c

//  Hello World client
//  Connects REQ socket to tcp://localhost:5559
//  Sends "Hello" to server, expects "World" back

#include "zhelpers.h"

int main (void) 
{
    void *context = zmq_ctx_new ();

    //  Socket to talk to server
    void *requester = zmq_socket (context, ZMQ_REQ);
    zmq_connect (requester, "tcp://localhost:5559");

    int request_nbr;
    for (request_nbr = 0; request_nbr != 10; request_nbr++) {
        s_send (requester, "Hello");
        char *string = s_recv (requester);
        printf ("Received reply %d [%s]\n", request_nbr, string);
        free (string);
    }
    zmq_close (requester);
    zmq_ctx_destroy (context);
    return 0;
}

参考资料：

[1] -- www.0voice.com

[2] --