OperationCanceledException应力测试

Question

我刚刚制作了一个WebApi (C#，.net 4.5.2)，并将它发布到了网上。为了确保它正常工作，我开始测试它。

其余的网络服务没有通过“压力”测试。我每秒钟发送服务30+- http请求，并得到以下典型的错误消息：

System.OperationCanceledException: The operation was canceled.
   at System.Threading.CancellationToken.ThrowOperationCanceledException()
   at System.Net.Http.HttpContentExtensions.<ReadAsAsyncCore>d__0`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.ModelBinding.FormatterParameterBinding.<ExecuteBindingAsyncCore>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Controllers.HttpActionBinding.<ExecuteBindingAsyncCore>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext()

日志中也发生了多次相同的错误。

当我进入特定的机器时，我看到CPU是100%，RAM是80%。这意味着，机器给她最好的处理负荷。

问题

1. 根据我上面提供的StackTrace，我无法理解代码中的问题到底在哪里？
2. 我的代码是自动扩展的(托管在云中)。但是，新机器只在5分钟后创建(取决于平均CPU > 50%)。我应该如何处理突然出现的大量HTTP请求？也许服务器应该说：“嘿，30秒后试试阿吉安”之类的？什么是正确的解决办法？

Answer 1

System.OperationCanceledException: The operation was canceled.

这通常表示连接到服务的客户端在服务发送响应之前关闭了连接。就api层而言，这通常意味着您在建立http连接时指定了超时，或者您使用的用于进行http调用的库具有默认超时。

您可能需要检查iis请求日志，以了解出了什么问题。因为这是在压力测试中发生的，我猜您的服务缺少线程(更多细节请阅读这 )。您可能需要考虑请求处理程序的异步模型，以提高可伸缩性并更好地利用线程。(阅读这)