Debugging and windows services

Hey everybody, this is driving me nuts.

I'm trying to write a windows service that just starts a timer and then does its magic evertime the timer ticks. I had everything written, but then I ran into a bunch of problems trying to get it installed. So I reduced it down to a very simple service that just writes info to an event log.

The problem is when I try to start the service, it starts and stops right away, and never gets into the OnStart method (I put a message box in the OnStart and it never appears). I can't for the life of me figure out how to debug a process that isn't running. Is it possible to attach the debugger to a stoped service and have the debugger enter it when the service is attempted to be started?

Or does anybody know of some stupid thing I'm missing in my program thats causing this error when I try to start the service:

Quote:

---

The <service name> on the local computer started and then stoped. Som services stop automatically if they have no work to do, for example the performance logs and alert service.

---

My OnStart has work to do, so I dont know why it just quits. Below is the code for my service:

VB Code:

Imports System.ServiceProcess
 
Public Class SnapshotService
    Inherits System.ServiceProcess.ServiceBase
 
#Region " Component Designer generated code "
 
    Public Sub New()
        MyBase.New()
 
        ' This call is required by the Component Designer.
        InitializeComponent()
 
        ' Add any initialization after the InitializeComponent() call
 
    End Sub
 
    'UserService overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
 
    ' The main entry point for the process
    <MTAThread()> _
    Shared Sub Main()
        Dim ServicesToRun() As System.ServiceProcess.ServiceBase
 
        ' More than one NT Service may run within the same process. To add
        ' another service to this process, change the following line to
        ' create a second service object. For example,
        '
        '   ServicesToRun = New System.ServiceProcess.ServiceBase () {New Service1, New MySecondUserService}
        '
        ServicesToRun = New System.ServiceProcess.ServiceBase() {New SnapshotService()}
 
        System.ServiceProcess.ServiceBase.Run(ServicesToRun)
    End Sub
 
    'Required by the Component Designer
    Private components As System.ComponentModel.IContainer
 
    ' NOTE: The following procedure is required by the Component Designer
    ' It can be modified using the Component Designer.  
    ' Do not modify it using the code editor.
    Friend WithEvents LocalEventLog As System.Diagnostics.EventLog
    Public WithEvents LocalTimer As System.Timers.Timer
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.LocalTimer = New System.Timers.Timer()
        Me.LocalEventLog = New System.Diagnostics.EventLog()
        CType(Me.LocalTimer, System.ComponentModel.ISupportInitialize).BeginInit()
        CType(Me.LocalEventLog, System.ComponentModel.ISupportInitialize).BeginInit()
        '
        'LocalTimer
        '
        Me.LocalTimer.Interval = 100000000000
        '
        'SnapshotService
        '
        Me.ServiceName = "Snapshot Service"
        CType(Me.LocalTimer, System.ComponentModel.ISupportInitialize).EndInit()
        CType(Me.LocalEventLog, System.ComponentModel.ISupportInitialize).EndInit()
 
    End Sub
 
#End Region
 
    Public Verbose As Boolean
    Private DataFile As String
    Private DataSchema As String
 
    Protected Overrides Sub OnStart(ByVal args() As String)
        Windows.Forms.MessageBox.Show("Entered OnStart")
        ' Add code here to start your service. This method should set things
        ' in motion so your service can do its work.
 
        ' Create the event log if it doesn't exist, and set the local
        ' event log to point to it
        If Not EventLog.SourceExists("Snapshot") Then
            EventLog.CreateEventSource("Snapshot", "Snapshot Log")
        End If
        LocalEventLog.Source = "Snapshot Service"
        LocalEventLog.Log = "Snapshot"
 
        LocalEventLog.WriteEntry("The Snapshot service is starting")
 
        ' Get the bits from the registry so we know where to start looking
        DataFile = GetSetting("Snapshot", "", "DataFile", Nothing)
        DataFile = GetSetting("Snapshot", "", "DataSchema", Nothing)
 
        ' Check that all the required bits and pieces are about
        If DataFile = Nothing Then _
            Message_Die("There is no service data. You must create a DataFile before Snapshot can run.")
        If Not (System.IO.File.Exists(DataFile)) Then _
            Message_Die("'" & DataFile & "' does not exist, you must create the file before snapshot can run.")
 
        If DataSchema = Nothing Then Message_Die("There is no service data. You must create a DataSchema before Snapshot can run.")
        If Not (System.IO.File.Exists(DataSchema)) Then _  
            Message_Die("'" & DataSchema & "' does not exist, you must create the file before snapshot can run.")
 
        ' Set the timer to fire on the next hour
        Dim TimeTillHour As Integer = (60 - Minute(Now())) * 60000
        LocalTimer.Interval = TimeTillHour
        LocalTimer.Enabled = True
 
        LocalEventLog.WriteEntry("The Snapshot service started successfully")
        Windows.Forms.MessageBox.Show("Exiting OnStart")
    End Sub
 
    Protected Overrides Sub OnStop()
        Windows.Forms.MessageBox.Show("Entered OnStop")
        ' Add code here to perform any tear-down necessary to stop your service.
        LocalEventLog.WriteEntry("The Snapshot service was stoped")
        Windows.Forms.MessageBox.Show("Exiting OnStop")
    End Sub
 
    Private Sub Message_Die(ByVal Message As String)
        LocalEventLog.WriteEntry(Message, EventLogEntryType.Error)
        Me.Dispose()
    End Sub
End Class

Bump.

I've only made one service, but maybe something will help. Check the event log for any exceptions you haven't caught. Unless you tell the service to interact with the desktop (I *think*), you can't use message boxes - services are meant to run in the background.

There is some help available on debugging a service - you have to attach the debugger to your app. I never got around to doing this, instead, I just log a bunch of stuff to a text file - where I am in the code, exceptions etc.

I had some errors when I started working on installing the service, but I think I traced them back to a conflict of services, I had the service trying to load with windows and with FireDamon at the same time. After un-installing FireDamon the errors went away. But to cover all bases, the errors I was getting in that situation was that the process could not be killed because no active threads could be found, I got an error like every second (or less).

As far as debugging, I know how to attach the debugger to a running process, thats really handy and works great for debugging a running process. But I can't get my service to run... it starts and stops imediatly.

As far as the messageboxes, I know they will cause an error when I try to call them as a service, I didn't realize it when I made them, but I left them hoping even for the error they would cause (which would allow me a chance to attach the debugger). But it would appear that my service never even enters OnStart(), or any of the other methods.

Have you tried catching exceptions? If something happens as soon as you enter OnStart and it's not caught, I think the thread ends, then so does your service.

I've had my service end right away also, so that's what I did.

I got it working... after your thoughts I took a deep look into the application log, and I had a couple errors (one is still unresloved, but adding the try...catch to the OnStart block allowed the service to start anyway). I hadn't looked closely in the application log, I thought I had everything going to my custom EventLog.

I have an error in my decleration of the custom event log, thats currently what kills my process. I'll work on it more but its probably something simple. I just get an error saying "The source 'Snapshot Service' is not registered in log 'Snapshot'. (It is registered in log 'Application'.) The Source and Log properties must be matched, or you may set Log to the empty string, and it will automatically be matched to the Source property."

And like you suggested the MessageBox lines were also causing an error (which got loged, and the process shutdown). I was expecting the JIT Debugger to pop up on such an error, but maybe with AutoLogging enabled these errors just get logged and the process killed.

Thanks for your help, I may still need help with the EventLog, but its likely a simple error.