Question

返回后，以下（Web）角色入口点会导致抛出以下异常。

public class WebRole : RoleEntryPoint
{
    public override bool OnStart()
    {
        Task.Run(() =>
            {
                // Anything can be here, but the lamdbda can be empty too...
            }).Wait();

        return true;
    }
}

例外：

类型的第一次机会异常   ＆＃39; System.Threading.WaitHandleCannotBeOpenedException＆＃39;发生在   mscorlib.dll中

附加信息：不存在给定名称的句柄。

很明显，这是从框架中抛出的。这个例外似乎是无害的，我没有遇到任何问题。

我还好奇，为什么会这样？有没有办法在角色启动方法中运行异步代码而不会导致此类异常？

修改

这是例外的调用堆栈：

>   mscorlib.dll!System.Threading.EventWaitHandle.OpenExisting(string name, System.Security.AccessControl.EventWaitHandleRights rights) Unknown
    Microsoft.WindowsAzure.ServiceRuntime.dll!Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment.StartRoleInternal() Unknown
    Microsoft.WindowsAzure.ServiceRuntime.dll!Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment.StartRole() Unknown
    Microsoft.WindowsAzure.ServiceRuntime.dll!Microsoft.WindowsAzure.ServiceRuntime.Implementation.Loader.RoleRuntimeBridge.StartRole.AnonymousMethod__2()  Unknown
    mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx)   Unknown
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
    mscorlib.dll!System.Threading.ThreadHelper.ThreadStart()    Unknown
    [Native to Managed Transition]

编辑2：

这是有问题的Azure运行时源：

private void StartRoleInternal()
{
    string environmentVariable = Environment.GetEnvironmentVariable("RdRoleId");
    string name = RoleEnvironment.NormalizeEventName("Global\\started_{0}", environmentVariable);
    try
    {
        using (EventWaitHandle eventWaitHandle = EventWaitHandle.OpenExisting(name, EventWaitHandleRights.Modify))
        {
            eventWaitHandle.Set();
        }
    }
    catch (WaitHandleCannotBeOpenedException)
    {
    }
    RoleEnvironment.TraceSource.TraceEvent(TraceEventType.Information, 203, "Role entrypoint . CALLING   Run(): " + this.role);
    SystemEvents.LogEventToSystemEvents("Windows Azure Runtime 2.3.0.0", RuntimeEventType.OnRoleRunBegin, "Role is running: OnRun(): " + this.role);
    this.role.Run();
    RoleEnvironment.TraceSource.TraceEvent(TraceEventType.Warning, 204, "Role entrypoint . COMPLETED Run() ==> ROLE RECYCLING INITIATED: " + this.role);
    SystemEvents.LogEventToSystemEvents("Windows Azure Runtime 2.3.0.0", RuntimeEventType.OnRoleRunEnd, "Role will recyle: OnRun(): " + this.role);
    RoleEnvironment.RequestRecycle();
}

Azure Web角色上的WaitHandleCannotBeOpenedException以Task.Wait（）开头

0 个答案: