Question

我正在尝试软件中的一些极端情况。因此，我创建了一个非常简单的测试环境：

在CentOS 7上运行的RabbitMQ服务器
在CentOS 7下运行的C＃中针对.NETCore 2.1编写的消息使用者。
在CentOS 7下运行的C＃中针对.NETCore 2.1编写的消息发件人

我每5秒发送一条简单的短信。发送者和接收者在同一UNIX机器上运行，而RabbitMQ服务器在网络中的另一台机器上运行。到目前为止，一切都很好。现在，我用systemctl stop rabbitmq-server停止RabbitMQ服务器。

我在预期的发送方和接收方上收到错误。

我使用systemctl start rabbitmq-server重新启动RabbitMQ服务器。

现在好玩了！发件人可以恢复并继续发送消息，但发信人无法恢复，并且不接收消息。它们累积在RabbitMQ服务器上！

这是我发件人的日志条目（按预期工作）：

2019-01-22 21:18:25.628 +01:00 [ERR] [EasyNetQ.PersistentConnection] [ThreadId 10] Failed to connect to broker infraserver-tbws2, port 5672, vhost testvh
RabbitMQ.Client.Exceptions.BrokerUnreachableException: None of the specified endpoints were reachable ---> System.AggregateException: One or more errors occurred. (Connection failed) ---> RabbitMQ.Client.Exceptions.ConnectFailureException: Connection failed ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException: Connection refused 172.16.63.239:5672
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__272_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at RabbitMQ.Client.TcpClientAdapter.ConnectAsync(String host, Int32 port)
   at RabbitMQ.Client.Impl.TaskExtensions.TimeoutAfter(Task task, Int32 millisecondsTimeout)
   at RabbitMQ.Client.Impl.SocketFrameHandler.ConnectOrFail(ITcpClient socket, AmqpTcpEndpoint endpoint, Int32 timeout)
   --- End of inner exception stack trace ---
   at RabbitMQ.Client.Impl.SocketFrameHandler.ConnectUsingAddressFamily(AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 timeout, AddressFamily family)
   at RabbitMQ.Client.Impl.SocketFrameHandler.ConnectUsingIPv4(AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 timeout)
   at RabbitMQ.Client.Impl.SocketFrameHandler..ctor(AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 connectionTimeout, Int32 readTimeout, Int32 writeTimeout)
   at RabbitMQ.Client.Framing.Impl.IProtocolExtensions.CreateFrameHandler(IProtocol protocol, AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 connectionTimeout, Int32 readTimeout, Int32 writeTimeout)
   at RabbitMQ.Client.ConnectionFactory.CreateFrameHandler(AmqpTcpEndpoint endpoint)
   at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func`2 selector)
   --- End of inner exception stack trace ---
   at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func`2 selector)
   at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName)
   --- End of inner exception stack trace ---
   at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName)
   at RabbitMQ.Client.ConnectionFactory.CreateConnection(String clientProvidedName)
   at EasyNetQ.ConnectionFactoryWrapper.CreateConnection()
   at EasyNetQ.PersistentConnection.TryToConnect()
2019-01-22 21:18:25.632 +01:00 [ERR] [EasyNetQ.PersistentConnection] [ThreadId 10] Failed to connect to any Broker. Retrying in 00:00:05
2019-01-22 21:18:35.444 +01:00 [INF] [] [ThreadId 1] Sucessfully sent Message 'Message: 'This is test message number 7.' | Num: 7 | Guid: 5345c7e4-61e6-4c79-8179-d4bef7864420'.
2019-01-22 21:18:40.452 +01:00 [INF] [] [ThreadId 1] Sucessfully sent Message 'Message: 'This is test message number 8.' | Num: 8 | Guid: 3cd8635c-cdfa-45f3-8495-2acb0713d47b'.
2019-01-22 21:18:45.457 +01:00 [INF] [] [ThreadId 1] Sucessfully sent Message 'Message: 'This is test message number 9.' | Num: 9 | Guid: 099462b8-cd66-40b9-ac10-89c3246819ec'.
2019-01-22 21:18:50.470 +01:00 [INF] [] [ThreadId 1] Sucessfully sent Message 'Message: 'This is test message number 10.' | Num: 10 | Guid: c25139b2-8e45-4771-9544-830014382e0c'.
2019-01-22 21:18:55.515 +01:00 [INF] [] [ThreadId 1] Sucessfully sent Message 'Message: 'This is test message number 11.' | Num: 11 | Guid: 90049d91-3805-4aaa-ac18-b61c09164afd'.
2019-01-22 21:19:00.526 +01:00 [INF] [] [ThreadId 1] Sucessfully sent Message 'Message: 'This is test message number 12.' | Num: 12 | Guid: 108ff318-6a34-4e64-94bd-dafa67aa6717'.

这显示了最后一条错误消息，然后您可以看到EasyNetQ已恢复并可以再次发送消息。

消息使用者不起作用！这是我的日志条目：

2019-01-22 21:18:25.623 +01:00 [ERR] [EasyNetQ.PersistentConnection] [ThreadId 12] Failed to connect to broker infraserver-tbws2, port 5672, vhost testvh
RabbitMQ.Client.Exceptions.BrokerUnreachableException: None of the specified endpoints were reachable ---> System.AggregateException: One or more errors occurred. (Connection failed) ---> RabbitMQ.Client.Exceptions.ConnectFailureException: Connection failed ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException: Connection refused 172.16.63.239:5672
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.<>c.<ConnectAsync>b__272_0(IAsyncResult iar)
--- End of stack trace from previous location where exception was thrown ---
   at RabbitMQ.Client.TcpClientAdapter.ConnectAsync(String host, Int32 port)
   at RabbitMQ.Client.Impl.TaskExtensions.TimeoutAfter(Task task, Int32 millisecondsTimeout)
   at RabbitMQ.Client.Impl.SocketFrameHandler.ConnectOrFail(ITcpClient socket, AmqpTcpEndpoint endpoint, Int32 timeout)
   --- End of inner exception stack trace ---
   at RabbitMQ.Client.Impl.SocketFrameHandler.ConnectUsingAddressFamily(AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 timeout, AddressFamily family)
   at RabbitMQ.Client.Impl.SocketFrameHandler.ConnectUsingIPv4(AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 timeout)
   at RabbitMQ.Client.Impl.SocketFrameHandler..ctor(AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 connectionTimeout, Int32 readTimeout, Int32 writeTimeout)
   at RabbitMQ.Client.Framing.Impl.IProtocolExtensions.CreateFrameHandler(IProtocol protocol, AmqpTcpEndpoint endpoint, Func`2 socketFactory, Int32 connectionTimeout, Int32 readTimeout, Int32 writeTimeout)
   at RabbitMQ.Client.ConnectionFactory.CreateFrameHandler(AmqpTcpEndpoint endpoint)
   at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func`2 selector)
   --- End of inner exception stack trace ---
   at RabbitMQ.Client.EndpointResolverExtensions.SelectOne[T](IEndpointResolver resolver, Func`2 selector)
   at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName)
   --- End of inner exception stack trace ---
   at RabbitMQ.Client.ConnectionFactory.CreateConnection(IEndpointResolver endpointResolver, String clientProvidedName)
   at RabbitMQ.Client.ConnectionFactory.CreateConnection(String clientProvidedName)
   at EasyNetQ.ConnectionFactoryWrapper.CreateConnection()
   at EasyNetQ.PersistentConnection.TryToConnect()
2019-01-22 21:18:25.625 +01:00 [ERR] [EasyNetQ.PersistentConnection] [ThreadId 12] Failed to connect to any Broker. Retrying in 00:00:05

这里坐着，永远等待！看起来是已死锁，而消息在RabbitMQ服务器上累积的方式是这样的：

当我停止我的消费者应用程序并重新启动它时，将拾取消息。

我使用以下代码在两个应用程序（发送者和使用者）中进行连接：

private static IBus SetupRabbitMqConnection(string rabbitServer, string rabbitVHost, ushort rabbitPort, string rabbitUser, string rabbitPwd)
{
    Log.Logger.Debug($"Creating a connection to RabbitMQ server '{rabbitServer}' on port {rabbitPort.ToString()} " +
                     $"using the EasyNetQ library....");

    try
    {
        var connStr = $"host={rabbitServer}:{rabbitPort.ToString()};virtualHost={rabbitVHost};username={rabbitUser};" +
            $"password={rabbitPwd};publisherConfirms=true;timeout=30;prefetchcount=1;requestedHeartbeat=30";
        var msgBus = RabbitHutch.CreateBus(connStr, x => { });
        if (!msgBus.IsConnected)
        {
            var errMsg = $"Currently not connected to RabbitMQ server '{rabbitServer}'.";
            Log.Logger.Error(errMsg);
        }
        Log.Logger.Debug("Successfully connected to RabbitMQ server.");
        return msgBus;
    }
    catch (Exception ex)
    {
        Log.Logger.Error($"Error to establish a connection to RabbitMQ server '{rabbitServer}'. Error: {ex}");
        throw;
    }
}

使用者程序按以下方式注册侦听器：

var msgBus = SetupRabbitMqConnection(rabbitServer, vhost, rabbitPort, rabbitUser, rabbitPwd);
RegisterMsgSubscriptions(msgBus);

private static void RegisterMsgSubscriptions(IBus msgBus)
{
    Log.Logger.Debug("Starting to register RabbitMQ message subscriptions...");
    try
    {
        #region Queue declarations

        var advancedBus = msgBus.Advanced;
        var testQueueOne = new EasyNetQ.Topology.Queue(TestQueueOneName, true);

        Log.Logger.Debug("Finished declaring queues.");

        #endregion

        #region Message Queue Handler registrations

        advancedBus.Consume(testQueueOne, registration => registration
            .Add<RabbitMessage<TestTextMessageDto>>(MessageProcessor.ProcessRabbitTestMessage));

        Log.Logger.Debug("Finished registration of message handlers for several queues.");

        #endregion
    }
    catch (Exception ex)
    {
        Log.Logger.Error($"Error registering message handler. Error: {ex}");
    }
}

任何想法在这里可能出什么问题吗？在生产中，我们有超过100台使用消息的服务器。这些服务器在本地分布在全国各地。 RabbitMQ服务器在数据中心中。因此，如果连接丢失，使用服务器必须恢复，否则将无法使用！

Answer 1

只需在连接事件上添加订阅逻辑（将在每个代理连接事件上触发）。

advancedBus.Connected += (sender, args) => { 
   // subscribe logic
};

当然，您应该避免在任何连接等情况下都不要两次调用订阅逻辑。

RabbitMQ服务器无法访问后，EasyNetQ无法重新连接

1 个答案: