Question

我已经用NetMQ实现创建了一个Gist，因为我觉得要粘贴到这里有点多了：https://gist.github.com/gthvidsten/e626d7e6c51012b1ba152d22e034d93d

如果我在.Net Core控制台应用程序中执行以下操作，则一切正常，并且我收到MessageReceived事件：

static void Main(string[] args)
{
    _transportWithHost = new NetMqTransport(
        "tcp://localhost:9990",
        "tcp://localhost:9991",
        true);
    _transportWithHost.Start();

    Console.WriteLine("Press [Enter] to publish");
    Console.ReadLine();

    _transportWithHost.MessageReceived += (sender, e) =>
    {
        ; // Breakpoints here are hit
    };
    _transportWithHost.Publish(new byte[] { 1, 2, 3, 4 });

    Console.WriteLine("Press [Enter] to exit");
    Console.ReadLine();
}

但是，如果我尝试在NUnit测试环境中执行相同的操作，则不会触发MessageReceived事件！

class NetMqTransportTests
{
    private NetMqTransport _transportWithHost;

    [OneTimeSetUp]
    public void Setup()
    {
        _transportWithHost = new NetMqTransport(
            "tcp://localhost:9990",
            "tcp://localhost:9991",
            true);
        _transportWithHost.Start();
    }

    [Test]
    public void PublishTest()
    {
        ManualResetEvent mre = new ManualResetEvent(false);

        _transportWithHost.MessageReceived += (sender, e) =>
        {
            mre.Set();
            // Breakpoints here are never hit as MessageReceived is never called
        };

        _transportWithHost.Publish(new byte[] { 1, 2, 3, 4 });

        bool eventFired = mre.WaitOne(new TimeSpan(0, 0, 5));
        Assert.True(eventFired);
    }
}

为什么几乎相同的代码在控制台应用程序中却不能在NUnit环境中工作？

Answer 1

我能够重现它，并发现了该线程https://github.com/zeromq/netmq/issues/482，这表明它在启动发布服务器和订阅服务器接收消息的时间之间存在计时问题。

using NetMQ;
using NetMQ.Sockets;
using NUnit.Framework;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace Tests
{
    class NetMqTransportTests
    {
        [Test]
        public void TestMulticastNetMQ()
        {
            bool wasCalled = false;

            var coreEventbus = "tcp://localhost:12345";

            Task.Run(() =>
            {
                using (var subSocket = new SubscriberSocket())
                {
                    subSocket.Connect(coreEventbus);
                    subSocket.Subscribe("account");

                    while (true)
                    {
                        string messageTopicReceived = subSocket.ReceiveFrameString();
                        string messageReceived = subSocket.ReceiveFrameString();

                        Assert.IsTrue(messageReceived == "testing");
                        wasCalled = true;
                        break;
                    }
                }

            });

            Thread.Sleep(TimeSpan.FromSeconds(1));

            using (var pubSocket = new PublisherSocket())
            {
                pubSocket.Bind(coreEventbus);

                Thread.Sleep(500);
                pubSocket.SendMoreFrame("account").SendFrame("testing");
            }

            Thread.Sleep(TimeSpan.FromSeconds(5));

            Assert.IsTrue(wasCalled);
        }
    }
}

更新：

以下是NetMQ库随附的单元测试：https://github.com/zeromq/netmq/blob/master/src/NetMQ.Tests/XPubSubTests.cs

看看他们如何分解实例化NetMqTransport以同时使用XPublisherSocket和XPublisherSocket ...

还请注意，根据问题482，他们在接收消息之前做了500毫秒的延迟，以使订户连接，就像他们在问题中所讨论的一样：

[Fact]
public void TopicPubSub()
{
    using (var pub = new XPublisherSocket())
    using (var sub = new XPublisherSocket())
    {
        var port = pub.BindRandomPort("tcp://127.0.0.1");
        sub.Connect("tcp://127.0.0.1:" + port);
        sub.SendFrame(new byte[] { 1, (byte)'A' });

        // let the subscriber connect to the publisher before sending a message
        Thread.Sleep(500);

        var msg = pub.ReceiveFrameBytes();

为什么NetMQ在NUnit环境中不起作用

1 个答案: