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每当部署我们的组件时，我们都会收到以下异常。有时组件本身不会启动，有时服务控制台可能会说已启动但服务不会处理任何消息。错误非常简单。还有一个 HttpListener 仍在监听前缀。

NServiceBus.Hosting.GenericHost System.Exception: Failed to start listener for http://localhost/products/ make sure that you have admin priviliges ---> System.Net.HttpListenerException: Failed to listen on prefix 'http://localhost:80/products/' because it conflicts with an existing registration on the machine.
   at System.Net.HttpListener.AddAllPrefixes()
   at System.Net.HttpListener.Start()
   at NServiceBus.Gateway.Channels.Http.HttpChannelReceiver.Start(String address, Int32 numWorkerThreads) in c:\BuildAgent\work\nsb.master_6\src\gateway\NServiceBus.Gateway\Channels\Http\HttpChannelReceiver.cs:line 30
   --- End of inner exception stack trace ---
   at NServiceBus.Gateway.Channels.Http.HttpChannelReceiver.Start(String address, Int32 numWorkerThreads) in c:\BuildAgent\work\nsb.master_6\src\gateway\NServiceBus.Gateway\Channels\Http\HttpChannelReceiver.cs:line 37
   at NServiceBus.Gateway.Receiving.GatewayReceiver.Start(Address localAddress) in c:\BuildAgent\work\nsb.master_6\src\gateway\NServiceBus.Gateway\Receiving\GatewayReceiver.cs:line 38
   at System.Collections.Generic.List`1.ForEach(Action`1 action)
   at NServiceBus.Unicast.UnicastBus.NServiceBus.IStartableBus.Start(Action startupAction) in c:\BuildAgent\work\nsb.master_6\src\unicast\NServiceBus.Unicast\UnicastBus.cs:line 867
   at NServiceBus.Hosting.GenericHost.Start() in c:\BuildAgent\work\nsb.master_6\src\hosting\NServiceBus.Hosting\GenericHost.cs:line 34

当我们进行深度分析时。

  1. 此问题仅在您运行 NServiceBus.Master 配置文件时发生
  2. 仅当您从服务控制台执行服务重新启动时才会发生此问题
  3. 无论你运行多少个 WorkerThread

让我们困惑的是，当我们更深入地阅读 NSB 代码时，我们发现在对象 Dispose 期间 HttpListener 是关闭的。除此之外，当您停止服务时，整个进程本身都会被杀死，因此机器上不会有任何对象来监听给定的 URL 前缀。但是，我们错了。当我们分析很多闭包时，我们发现即使在 Service-Console 认为该服务已停止之后， NServinceBus.Host 进程仍在运行。每当我们在服务控制台上停止服务时，该进程在机器上仍然处于活动状态，并且需要更长的时间才能完全关闭。因此，当我们执行重新启动时，有可能存在多个当前服务的进程实例——一个正在尝试启动，另一个仍在尝试停止。我们确认重启过程会抛出上述异常。

我们对正在关闭的进程进行了转储。我们发现，尽管服务控制台显示状态为已停止，但进程中仍有后台线程处于活动状态。Dispose 期间有很多锁/ObjWait。确保停止的服务尚未关闭 HttpListener 对象。

        Child SP               IP Call Site
000000001f19e048 00000000778818ca [GCFrame: 000000001f19e048] 
000000001f19e118 00000000778818ca [HelperMethodFrame_1OBJ: 000000001f19e118] System.Threading.Monitor.ObjWait(Boolean, Int32, System.Object)
000000001f19e230 000007fe99d57ccb System.Transactions.CommittableTransaction.Commit()
000000001f19e2d0 000007fe99d577df System.Transactions.TransactionScope.InternalDispose()
000000001f19e3c0 000007fe99d56f1c System.Transactions.TransactionScope.Dispose()
000000001f19e590 000007fe99c4a3b5 NServiceBus.Utils.TransactionWrapper.RunInTransaction(System.Action, System.Transactions.IsolationLevel, System.TimeSpan)
000000001f19e610 000007fe99c45b2b NServiceBus.Unicast.Transport.Transactional.TransactionalTransport.Process()
000000001f19e680 000007fe99c455cb NServiceBus.Utils.WorkerThread.Loop()
000000001f19e6d0 000007fef6fdf8a5 System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
000000001f19e830 000007fef6fdf609 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
000000001f19e860 000007fef6fdf5c7 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
000000001f19e8b0 000007fef6ff2d21 System.Threading.ThreadHelper.ThreadStart()
000000001f19ebc8 000007fef81cf713 [GCFrame: 000000001f19ebc8] 
000000001f19eef8 000007fef81cf713 [DebuggerU2MCatchHandlerFrame: 000000001f19eef8] 
000000001f19f0d8 000007fef81cf713 [ContextTransitionFrame: 000000001f19f0d8] 
000000001f19f2c8 000007fef81cf713 [DebuggerU2MCatchHandlerFrame: 000000001f19f2c8]

我们发现，HttpListener 处于活动状态并正在侦听。

        Child SP               IP Call Site
000000002038e2f8 000000007788135a [InlinedCallFrame: 000000002038e2f8] System.Net.UnsafeNclNativeMethods+HttpApi.HttpReceiveHttpRequest(System.Runtime.InteropServices.CriticalHandle, UInt64, UInt32, HTTP_REQUEST*, UInt32, UInt32*, System.Threading.NativeOverlapped*)
000000002038e2f8 000007fe99c6a2f8 [InlinedCallFrame: 000000002038e2f8] System.Net.UnsafeNclNativeMethods+HttpApi.HttpReceiveHttpRequest(System.Runtime.InteropServices.CriticalHandle, UInt64, UInt32, HTTP_REQUEST*, UInt32, UInt32*, System.Threading.NativeOverlapped*)
000000002038e2b0 000007fe99c6a2f8 DomainBoundILStubClass.IL_STUB_PInvoke(System.Runtime.InteropServices.CriticalHandle, UInt64, UInt32, HTTP_REQUEST*, UInt32, UInt32*, System.Threading.NativeOverlapped*)
000000002038e3b0 000007fe99c697a4 System.Net.HttpListener.GetContext()
000000002038e4d0 000007fe99c6924f NServiceBus.Gateway.Channels.Http.HttpChannelReceiver.HttpServer()
000000002038e530 000007fef6fdf8a5 System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
000000002038e690 000007fef6fdf609 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
000000002038e6c0 000007fef6fdf5c7 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
000000002038e710 000007fef6ff2d21 System.Threading.ThreadHelper.ThreadStart()
000000002038ea28 000007fef81cf713 [GCFrame: 000000002038ea28] 
000000002038ed58 000007fef81cf713 [DebuggerU2MCatchHandlerFrame: 000000002038ed58] 
000000002038ef38 000007fef81cf713 [ContextTransitionFrame: 000000002038ef38] 
000000002038f128 000007fef81cf713 [DebuggerU2MCatchHandlerFrame: 000000002038f128]

问题：为什么服务控制台报告服务已停止，即使该进程在计算机上仍处于活动状态

注意：要重现此问题，您必须使用 NServiceBus.Master 配置文件将主机安装为 Windows 服务并尝试重新启动服务，您可能需要更多尝试才能解决此问题。

更新：

当我在 HttpChannelReceiver.Start() 上阅读 NSB 代码时，它会在新线程上启动侦听器。

  1. 此侦听器线程是前台线程。（所有其他工作线程都是 BG 线程）
  2. 没有停止信号进入这个前台线程
  3. 没有保存此线程引用的变量/字段 - 中止是不可能的。

这个监听线程只有在ServiceHost杀死当前进程的内存时才回收，直到ServicHost收集到它，这个线程才会被阻止退出当前进程。

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1 回答 1

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这应该已经在 v4 中修复，请参阅https://github.com/NServiceBus/NServiceBus/blob/4.0.0/src/NServiceBus.Core/Gateway/Channels/Http/HttpChannelReceiver.cs#L41

于 2013-04-01T23:23:52.017 回答