ETW非预期跟踪事件254？

Question

我正在设置一个托管在Windows服务中的WCF服务，该服务使用Windows事件跟踪（ETW）进行日志记录。目前我只专注于使用ETW设置虚拟Windows服务，我看到一些意外事件被记录。特别是，每当我启动或停止服务时，我都会看到一个带有Opcode 254且没有消息的事件。

我试过在网上四处看看但到目前为止我还没有找到任何关于这是什么的参考。

如果您想尝试一下，这是服务代码：

Imports System.Threading

Public Class MyTestService

    Private _cts As CancellationTokenSource
    Private _workTask As Task = Nothing

    Private Class WorkState
        Public Property CancellationToken As CancellationToken
        Public Sub New(ByVal cancelToken As CancellationToken)
            Me.CancellationToken = cancelToken
        End Sub

    End Class

    Protected Overrides Sub OnStart(ByVal args() As String)
        ' Add code here to start your service. This method should set things
        ' in motion so your service can do its work.

        Debugger.Launch()

        _cts = New CancellationTokenSource()
        _workTask = Task.Factory.StartNew(AddressOf DoWork, New WorkState(_cts.Token), _cts.Token)
        _workTask.ContinueWith(AddressOf OnWorkDone)

        MyTestServiceEventSource.Log.OnServiceStarted()
    End Sub

    Private Sub OnWorkDone(parent As Task)
        If Not IsNothing(parent.Exception) Then
            MyTestServiceEventSource.Log.OnError(parent.Exception)
        End If
    End Sub

    Private Sub DoWork(ByVal obj As Object)
        Dim state = CType(obj, WorkState)

        While Not state.CancellationToken.IsCancellationRequested
            Threading.Thread.Sleep(5000)
            MyTestServiceEventSource.Log.OnTick()
        End While

    End Sub

    Protected Overrides Sub OnStop()
        ' Add code here to perform any tear-down necessary to stop your service.

        Try
            _cts.Cancel()
            _workTask.Wait(1500)
        Catch ex As Exception
            MyTestServiceEventSource.Log.OnError(ex)
        Finally
            _cts = Nothing
            _workTask = Nothing
        End Try

        MyTestServiceEventSource.Log.OnServiceStopped()
    End Sub

End Class

这是Event Source类：

Imports System.Diagnostics.Tracing
Imports Newtonsoft

<EventSource(Name:="Company-MyTestService")>
Public Class MyTestServiceEventSource
    Inherits EventSource

#Region "Singleton Pattern"
    Private Shared _inst As New Lazy(Of MyTestServiceEventSource)(Function() New MyTestServiceEventSource())
    Public Shared ReadOnly Property Log As MyTestServiceEventSource
        Get
            Return _inst.Value
        End Get
    End Property

    Private Sub New()
        MyBase.New()
    End Sub
#End Region

    Public Class EventIds
        Public Const SERVICE_STARTED As Integer = 1
        Public Const SERVICE_STOPPPED As Integer = 2
        Public Const TICK_EVENT As Integer = 3
        Public Const ERROR_EVENT As Integer = 4
    End Class

    <[Event](EventIds.SERVICE_STARTED, Opcode:=EventOpcode.Start, Message:="MyTestService Started", Level:=EventLevel.Informational)>
    Public Sub OnServiceStarted()
        If IsEnabled() Then
            Me.WriteEvent(EventIds.SERVICE_STARTED)
        End If
    End Sub


    <[Event](EventIds.TICK_EVENT, Message:="MyTestService Tick", Level:=EventLevel.Verbose)>
    Public Sub OnTick()
        If IsEnabled() Then
            Me.WriteEvent(EventIds.TICK_EVENT)
        End If
    End Sub

    <[Event](EventIds.ERROR_EVENT, Message:="{0}", Level:=EventLevel.Error)>
    Public Sub OnError(ByVal errMsg As String, ByVal details As String)
        If IsEnabled() Then
            Me.WriteEvent(EventIds.ERROR_EVENT, errMsg, details)
        End If
    End Sub

    <NonEvent>
    Public Sub OnError(ByVal ex As Exception)
        Try
            Dim details = Json.JsonConvert.SerializeObject(ex)
            OnError(ex.Message, details)
        Catch ex2 As Exception
            Debugger.Break()
        End Try
    End Sub

    <[Event](EventIds.SERVICE_STOPPPED, Opcode:=EventOpcode.Stop, Message:="MyTestService Stopped", Level:=EventLevel.Informational)>
    Public Sub OnServiceStopped()
        If IsEnabled() Then
            Me.WriteEvent(EventIds.SERVICE_STOPPPED)
        End If
    End Sub



End Class

Answer 1

所有ETW提供商必须具有显示提供者事件的清单。这是由EventSource通过您看到的ManifestData事件完成的。

事件MSec =“16059,4211”PID =“3444”PName =“foo”TID =“1776”ActivityID =“ffd679657c475d357c32b8dbe608b3ff”EventName =“ManifestData”ProviderName =“FooEventSource”ProviderGuid =“GUID”ClassicProvider =“False”ProcessorNumber = “1”Opcode =“254”>