java - ZeroMQ 两个 PUB-SUB 代理

Question

我想为我们的分布式系统实现一个发布-订阅基础设施。您可以在图中看到，网络背后的想法是，我想用 java 实现发布者和订阅者。但在JZmq中尚不支持曲线加密。所以我想在 C(++) 可用的地方实现代理。(目前我只在 java 中实现)

这是我的代码

订阅者.java:

import java.nio.charset.Charset;

import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Context;
import org.zeromq.ZMQ.Socket;

public class Subscriber {
    public static void main(String[] args) {
        String address = args[0];
        String topic = args[1];

        Context context = ZMQ.context(1);
        Socket subscriber = context.socket(ZMQ.SUB);
        subscriber.connect(address);
        subscriber.subscribe(topic.getBytes());

        while (!Thread.currentThread().isInterrupted()) {
            String top = subscriber.recvStr(Charset.defaultCharset());
            String contents = subscriber.recvStr(Charset.defaultCharset());

            System.out.println(top + ": " + contents);
        }
        subscriber.close();
        context.term();
    }    
}

Publisher.java:

import java.util.Random;

import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Context;
import org.zeromq.ZMQ.Socket;

public class Publisher {
    public static void main(String[] args) {
        String url = args[0];
        String topic = args[1];
        int intervall = Integer.valueOf(args[2]);

        Context context = ZMQ.context(1);
        Socket publisher = context.socket(ZMQ.PUB);

        Random rand = new Random();
        publisher.connect(url);
        while (!Thread.currentThread().isInterrupted()) {
            try {
                Thread.sleep(intervall);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            int value = rand.nextInt(20) * (rand.nextBoolean() ? (-1) : 1);
            publisher.sendMore(topic);
            publisher.send(String.valueOf(value));
            System.out.println("PUB: " + topic + ":" + value);
        }

        publisher.close();
        context.term();
    }
}

PubSubProxy.java:

import java.io.PrintStream;

import org.zeromq.ZContext;
import org.zeromq.ZFrame;
import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Context;
import org.zeromq.ZMQ.Socket;
import org.zeromq.ZThread;
import org.zeromq.ZThread.IAttachedRunnable;

public class PubSubProxy {
    static Socket frontend;
    static Socket backend;

    public static void main(String[] args) {
        String addressSubscriber = args[0];
        String modeSubscriber = args[1];
        String addressPublisher = args[2];
        String modePublisher = args[3];

        // Prepare our context and sockets
        // ZContext context = ZMQ.context(1);
        ZContext context = new ZContext();

        // This is where the weather server sits
        frontend = context.createSocket(ZMQ.XSUB);
        if (modeSubscriber.equals("client")) {
            System.out.println("Subscriber connecting to: " + addressSubscriber);
            frontend.connect(addressSubscriber);
        } else if (modeSubscriber.equalsIgnoreCase("server")) {
            System.out.println("Subscriber binding to: " + addressSubscriber);
            frontend.bind(addressSubscriber);
        }
        // This is our public endpoint for subscribers
        backend = context.createSocket(ZMQ.XPUB);

        if (modePublisher.equals("client")) {
            System.out.println("Publisher connecting to: " + addressPublisher);
            backend.connect(addressPublisher);
        } else if (modePublisher.equalsIgnoreCase("server")) {
            System.out.println("Publisher binding to: " + addressPublisher);
            backend.bind(addressPublisher);
        }

        // Subscribe on everything
        // frontend.subscribe("".getBytes());

        // Run the proxy until the user interrupts us
        IAttachedRunnable runnable = new Listener();
        Socket listener = ZThread.fork(context, runnable);
        ZMQ.proxy(frontend, backend, listener);

        frontend.close();
        backend.close();
        context.destroy();
    }

    private static class Listener implements IAttachedRunnable {
        @Override
        public void run(Object[] args, ZContext ctx, Socket pipe) {
            // Print everything that arrives on pipe
            while (true) {
                ZFrame frame = ZFrame.recvFrame(pipe);
                if (frame == null)
                    break; // Interrupted
                System.out.println(frame.toString());
                frame.destroy();
            }
        }
    }
}

如您所见，我已向代理添加了一个监听器以查看是否收到消息。在发布者端代理(图中最上面的一个)上，我收到了消息，但在另一个代理上却没有收到任何消息。

这是我执行应用程序的方式

#beaglebone #1
#proxy #1
java -Djava.library.path=/usr/local/lib -jar proxy.jar ipc:///tmp/pub server tcp://*:5555 server 
#pub
java -Djava.library.path=/usr/local/lib -jar publisher.jar ipc:///tmp/pub temperature 10000
java -Djava.library.path=/usr/local/lib -jar publisher.jar ipc:///tmp/pub humidity 1000
java -Djava.library.path=/usr/local/lib -jar publisher.jar ipc:///tmp/pub testvar 5000

#beaglebone #2
#proxy #2
java -Djava.library.path=/usr/local/lib -jar proxy.jar tcp://192.168.0.192:5555 client ipc:///tmp/sub server
#sub
java -Djava.library.path=/usr/local/lib -jar subscriber.jar ipc:///tmp/sub temperature
java -Djava.library.path=/usr/local/lib -jar subscriber.jar ipc:///tmp/sub humidity
java -Djava.library.path=/usr/local/lib -jar subscriber.jar ipc:///tmp/sub testvar

Answer 1

您似乎混淆了客户端/服务器模式与发布/订阅模式的混合。

在发布/订阅模式中，发布者通知其订阅者(如果有)。发布者应使用 bind (监听订阅)，订阅者应使用 connect (请求订阅)。

那么你的交流就变成:

为了做到这一点，您可以:

• 修改 Publisher.java，将 publisher.connect(url); 替换为 publisher.bind(url);
• 修改 PubSubProxy.java 删除无用的客户端/服务器参数

import java.io.PrintStream;

import org.zeromq.ZContext;
import org.zeromq.ZFrame;
import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Context;
import org.zeromq.ZMQ.Socket;
import org.zeromq.ZThread;
import org.zeromq.ZThread.IAttachedRunnable;

public class PubSubProxy {
    static Socket frontend;
    static Socket backend;

    public static void main(String[] args) {
        String addressSubscriber = args[0];
        String addressPublisher = args[1];

        // Prepare our context and sockets
        ZContext context = new ZContext();

        // This is where the weather server sits
        frontend = context.createSocket(ZMQ.XSUB);
        System.out.println("Subscriber connecting to: " + addressSubscriber);
        frontend.connect(addressSubscriber);

        // This is our public endpoint for subscribers
        backend = context.createSocket(ZMQ.XPUB);
        System.out.println("Publisher binding to: " + addressPublisher);
        backend.bind(addressPublisher);

        // Run the proxy until the user interrupts us
        ZMQ.proxy(frontend, backend, null);

        frontend.close();
        backend.close();
        context.destroy();
    }
} 

然后您应该能够使用以下方式从后端接收数据到前端:

#beaglebone #1
#proxy #1
java -Djava.library.path=/usr/local/lib -jar proxy.jar ipc:///tmp/pub tcp://*:5555 
#pub
java -Djava.library.path=/usr/local/lib -jar publisher.jar ipc:///tmp/pub temperature 10000

#beaglebone #2
#proxy #2
java -Djava.library.path=/usr/local/lib -jar proxy.jar tcp://192.168.0.192:5555 ipc:///tmp/sub
#sub
java -Djava.library.path=/usr/local/lib -jar subscriber.jar ipc:///tmp/sub temperature