Question

每当部署我们的组件时，我们都会收到以下异常。有时组件本身无法启动，有时服务控制台可能会说启动但服务不会处理任何消息。错误非常简单。还有另一个HttpListener仍然在监听前缀。

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。

只有在运行NServiceBus.Master时才会出现此问题简介
只有从服务控制台
无论您运行多少个WorkerThreads

令我们困惑的是，当我们更深入地阅读NSB代码时，我们发现HttpListener在对象Dispose期间被关闭。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侦听给定的URL前缀。但是，我们错了。当我们分析很多关闭时，我们发现即使在服务控制台认为服务已停止之后，NServinceBus.Host进程仍在运行。每当我们停止服务控制台上的服务时，该过程仍然在机器上处于活动状态。完全关闭需要很长时间。因此，当我们执行重启时，有可能存在多个当前服务的进程实例 - 一个尝试启动另一个实例仍在尝试停止。我们确认重启过程会抛出上述异常。

我们接管了正在关闭的流程。我们发现，虽然服务控制台将状态显示为已停止，但仍有活动后台线程。在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是活跃的＆amp;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该服务，您可能需要更多尝试才能解决此问题。

更新

当我读取NSB代码时，在HttpChannelReceiver.Start（）上，它在新线程上启动监听器。

此侦听器线程是Foreground线程。（所有其他工作线程都是BG线程）
没有停止信号进入此Foreground线程
没有变量/字段保存此线程的引用 - 无法中止。

只有在ServiceHost杀死当前进程的内存时才会回收此侦听器线程，直到ServicHost收集它，此线程将被阻止退出当前进程。

Answer 1

这应该已在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

System.Net.HttpListenerException：无法侦听前缀'xxxx'，因为它与计算机上的现有注册冲突

1 个答案: