Easier way to debug a Windows service

Question

Is there an easier way to step through the code than to start the service through the Windows Service Control Manager and then attaching the debugger to the thread  It s kind of cumbersome and I m wondering if there is a more straightforward approach

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static class Program       static void Main                  if DEBUG             TODO  Add code to start application here                  If the mode is in debugging                 create a new service instance         Service1 myService   new Service1                     call the start method - this will start the Timer          myService Start                     Set the Thread to sleep         Thread Sleep 300000                    Call the Stop method-this will stop the Timer          myService Stop               else         ServiceBase   ServicesToRun          ServicesToRun   new ServiceBase                           new Service1                        ServiceBase Run ServicesToRun             endif

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What I usually do is encapsulate the logic of the service in a separate class and start that from a  runner  class  This runner class can be the actual service or just a console application  So your solution has  atleast  3 projects    ConsoleRunner           ServiceRunner           ApplicationLogic

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Use Windows Service Template C  project to create a new service app https   github com HarpyWar windows-service-template  There are console service mode automatically detected  auto installer deinstaller of your service and several most used features are included

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Just paste  Debugger Break      any where in you code   For Example     internal static class Program                    lt summary gt              The main entry point for the application               lt  summary gt          private static void Main                         Debugger Break                ServiceBase   ServicesToRun              ServicesToRun   new ServiceBase                                 new Service1                              ServiceBase Run ServicesToRun                     It will hit Debugger Break    when you run your program

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Just put your debugger lunch anywhere and attach Visualstudio on startup   if DEBUG     Debugger Launch     endif   Also you need to start VS as Administatrator and you need to allow  that a process can automatically be debugged by a diffrent user  as explained here    reg add  HKCR AppID E62A7A31-6025-408E-87F6-81AEB0DC9347    v AppIDFlags  t REG DWORD  d 8  f

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if DEBUG     System Diagnostics Debugger Break     endif

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I use a variation on JOP s answer  Using command line parameters you can set the debugging mode in the IDE with project properties or through the Windows service manager   protected override void OnStart string   args      if  args Contains lt string gt   DEBUG SERVICE            Debugger Break

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I also think having a separate  version  for normal execution and as a service is the way to go  but is it really required to dedicate a separate command line switch for that purpose   Couldn t you just do   public static int Main string   args      if   Environment UserInteractive             Startup as service        else            Startup as application         That would have the  benefit   that you can just start your app via doubleclick  OK  if you really need that  and that you can just hit F5 in Visual Studio  without the need to modify the project settings to include that  console Option    Technically  the Environment UserInteractive checks if the WSF VISIBLE Flag is set for the current window station  but is there any other reason where it would return false  apart from being run as a  non-interactive  service

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This YouTube video by Fabio Scopel explains how to debug a Windows service quite nicely    the actual method of doing it starts at 4 45 in the video     Here is the code explained in the video    in your Program cs file  add the stuff for the Debug section      namespace YourNamespace       static class Program                    lt summary gt              The main entry point for the application               lt  summary gt          static void Main              if DEBUG             Service1 myService   new Service1                myService OnDebug                System Threading Thread Sleep System Threading Timeout Infinite    else             ServiceBase   ServicesToRun              ServicesToRun   new ServiceBase                                 new Service1                              ServiceBase Run ServicesToRun    endif                      In your Service1 cs file  add the OnDebug   method         public Service1                 InitializeComponent               public void OnDebug                 OnStart null              protected override void OnStart string   args                   your code to do something            protected override void OnStop                    How it works   Basically you have to create a public void OnDebug   that calls the OnStart string   args  as it s protected and not accessible outside  The void Main   program is added with  if preprocessor with  DEBUG    Visual Studio defines DEBUG if project is compiled in Debug mode This will allow the debug section below  to execute when the condition is true  Service1 myService   new Service1    myService OnDebug    System Threading Thread Sleep System Threading Timeout Infinite     And it will run just like a console application  once things go OK you can change the mode Release and the regular else section will trigger the logic

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For trouble-shooting on existing Windows Service program  use  Debugger Break    as other guys suggested   For new Windows Service program  I would suggest using James Michael Hare s method http   geekswithblogs net BlackRabbitCoder archive 2011 03 01 c-toolbox-debug-able-self-installable-windows-service-template-redux aspx

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How about Debugger Break   in the first line

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Use the TopShelf library   Create a console application then configure setup in your Main  class Program               static void Main string   args                        HostFactory Run x   gt                                    setup service start and stop                  x Service lt Controller gt  s   gt                                        s ConstructUsing name   gt  new Controller                         s WhenStarted controller   gt  controller Start                         s WhenStopped controller   gt  controller Stop                                             setup recovery here                 x EnableServiceRecovery rc   gt                                        rc RestartService delayInMinutes  0                       rc SetResetPeriod days  0                                        x RunAsLocalSystem                                 public class Controller               public void Start                                 public void Stop                                To debug your service  just hit F5 in visual studio   To install service  type in cmd  console exe install   You can then start and stop service in the windows service manager

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What I used to do was to have a command line switch which would start the program either as a service or as a regular application  Then  in my IDE I would set the switch so that I could step through my code   With some languages you can actually detect if it s running in an IDE  and perform this switch automatically   What language are you using

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Sometimes it is important to analyze what s going on during the start up of the service  Attaching to the process does not help here  because you are not quick enough to attach the debugger while the service is starting up   The short answer is  I am using the following 4 lines of code to do this    if DEBUG     base RequestAdditionalTime 600000      600 1000ms   10 minutes timeout     Debugger Launch       launch and attach debugger  endif   These are inserted into the OnStart method of the service as follows   protected override void OnStart string   args         if DEBUG        base RequestAdditionalTime 600000      10 minutes timeout for startup        Debugger Launch       launch and attach debugger      endif     MyInitOnstart       my individual initialization code for the service        allow the base class to perform any work it needs to do     base OnStart args       For those who haven t done it before  I have included detailed hints below  because you can easily get stuck  The following hints refer to Windows 7x64 and Visual Studio 2010 Team Edition  but should be valid for other environments  too      Important  Deploy the service in  manual  mode  using either the InstallUtil utility from the VS command prompt or run a service installer project you have prepared   Open Visual Studio before you start the service and load the solution containing the service s source code - set up additional breakpoints as you require them in Visual Studio - then start the service via the Service Control Panel   Because of the Debugger Launch code  this will cause a dialog  An unhandled Microsoft  NET Framework exception occured in Servicename exe   to appear  Click  Yes  debug Servicename exe as shown in the screenshot     Afterwards  escpecially in Windows 7 UAC might prompt you to enter admin credentials  Enter them and proceed with Yes     After that  the well known Visual Studio Just-In-Time Debugger window appears  It asks you if you want to debug using the delected debugger  Before you click Yes  select that you don t want to open a new instance  2nd option  - a new instance would not be helpful here  because the source code wouldn t be displayed  So you select the Visual Studio instance you ve opened earlier instead    After you have clicked Yes  after a while Visual Studio will show the yellow arrow right in the line where the Debugger Launch statement is and you are able to debug your code  method MyInitOnStart  which contains your initialization      Pressing F5 continues execution immediately  until the next breakpoint you have prepared is reached   Hint  To keep the service running  select Debug -  Detach all  This allows you to run a client communicating with the service after it started up correctly and you re finished debugging the startup code  If you press Shift F5  stop debugging   this will terminate the service  Instead of doing this  you should use the Service Control Panel to stop it   Note that    If you build a Release  then the debug code is automatically removed and the service runs normally  I am using Debugger Launch    which starts and attaches a debugger  I have tested Debugger Break   as well  which did not work  because there is no debugger attached on start up of the service yet  causing the  Error 1067  The process terminated unexpectedly     RequestAdditionalTime sets a longer timeout for the startup of the service  it is not delaying the code itself  but will immediately continue with the Debugger Launch statement   Otherwise the default timeout for starting the service is too short and starting the service fails if you don t call base Onstart args  quickly enough from the debugger  Practically  a timeout of 10 minutes avoids that you see the message  the service did not respond     immediately after the debugger is started  Once you get used to it  this method is very easy because it just requires you to add 4 lines to an existing service code  allowing you quickly to gain control and debug

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If I want to quickly debug the service  I just drop in a Debugger Break   in there  When that line is reached  it will drop me back to VS  Don t forget to remove that line when you are done  UPDATE  As an alternative to  if DEBUG pragmas  you can also use Conditional  quot DEBUG SERVICE quot   attribute   Conditional  quot DEBUG SERVICE quot    private static void DebugMode         Debugger Break       On your OnStart  just call this method  public override void OnStart          DebugMode                do the rest       There  the code will only be enabled during Debug builds  While you re at it  it might be useful to create a separate Build Configuration for service debugging

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The best option is to use the  System Diagnostics  namespace   Enclose your code in if else block for debug mode and release mode as shown below to switch between debug and release mode in visual studio    if DEBUG     for debug mode          Debugger Launch         debugger will hit here        foreach  var job in JobFactory GetJobs                                    do something                  else       for release mode         Debugger Launch         debugger will hit here         write code here to do something in Release mode    endif

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if DEBUG     System Diagnostics Debugger Break     endif

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For routine small-stuff programming I ve done a very simple trick to easily debug my service   On start of the service  I check for a command line parameter   debug   If the service is called with this parameter  I don t do the usual service startup  but instead start all the listeners and just display a messagebox  Debug in progress  press ok to end    So if my service is started the usual way  it will start as service  if it is started with the command line parameter  debug it will act like a normal program   In VS I ll just add  debug as debugging parameter and start the service program directly   This way I can easily debug for most small kind problems  Of course  some stuff still will need to be debugged as service  but for 99  this is good enough

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You can also start the service through the command prompt  sc exe    Personally  I d run the code as a stand-alone program in the debugging phase  and when most bugs are ironed out  change to running as service

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When I set up a new service project a few weeks ago I found this post  While there are many great suggestions  I still didn t find the solution I wanted  The possibility to call the service classes  OnStart and OnStop methods without any modification to the service classes   The solution I came up with uses the Environment Interactive the select running mode  as suggested by other answers to this post   static void Main         ServiceBase   servicesToRun      servicesToRun   new ServiceBase                  new MyService              if  Environment UserInteractive                RunInteractive servicesToRun             else               ServiceBase Run servicesToRun             The RunInteractive helper uses reflection to call the protected OnStart and OnStop methods   static void RunInteractive ServiceBase   servicesToRun        Console WriteLine  Services running in interactive mode         Console WriteLine         MethodInfo onStartMethod   typeof ServiceBase  GetMethod  OnStart            BindingFlags Instance   BindingFlags NonPublic       foreach  ServiceBase service in servicesToRun                Console Write  Starting  0       service ServiceName           onStartMethod Invoke service  new object     new string                   Console Write  Started               Console WriteLine        Console WriteLine        Console WriteLine           Press any key to stop the services and end the process           Console ReadKey        Console WriteLine         MethodInfo onStopMethod   typeof ServiceBase  GetMethod  OnStop            BindingFlags Instance   BindingFlags NonPublic       foreach  ServiceBase service in servicesToRun                Console Write  Stopping  0       service ServiceName           onStopMethod Invoke service  null           Console WriteLine  Stopped               Console WriteLine  All services stopped            Keep the console alive for a second to allow the user to see the message      Thread Sleep 1000       This is all the code required  but I also wrote walkthrough with explanations

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To debug Windows Services I combine GFlags and a  reg file created by regedit    Run GFlags  specifying the exe-name and vsjitdebugger Run regedit and go to the location where GFlags sets his options Choose  Export Key  from the file-menu Save that file somewhere with the  reg extension Anytime you want to debug the service  doubleclick on the  reg file If you want to stop debugging  doubleclick on the second  reg file   Or save the following snippets and replace servicename exe with the desired executable name     debugon reg   Windows Registry Editor Version 5 00   HKEY LOCAL MACHINE SOFTWARE Microsoft Windows NT CurrentVersion Image File Execution Options servicename exe   GlobalFlag   0x00000000   Debugger   vsjitdebugger exe     debugoff reg   Windows Registry Editor Version 5 00   HKEY LOCAL MACHINE SOFTWARE Microsoft Windows NT CurrentVersion Image File Execution Options servicename exe   GlobalFlag   0x00000000

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I think it depends on what OS you are using  Vista is much harder to attach to Services  because of the separation between sessions   The two options I ve used in the past are    Use GFlags  in the Debugging Tools for Windows  to setup a permanent debugger for a process   This exists in the  Image File Execution Options  registry key and is incredibly useful   I think you ll need to tweak the Service settings to enable  Interact with Desktop    I use this for all types of debugging  not just services  The other option  is to separate the code a bit  so that the service part is interchangable with a normal app startup   That way  you can use a simple command line flag  and launch as a process  rather than a Service   which makes it much easier to debug    Hope this helps

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When I write a service I put all the service logic in a dll project and create two  hosts  that call into this dll  one is a Windows service and the other is a command line application   I use the command line application for debugging and attach the debugger to the real service only for bugs I can t reproduce in the command line application   I you use this approach just remember that you have to test all the code while running in a real service  while the command line tool is a nice debugging aid it s a different environment and it doesn t behave exactly like a real service

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UPDATE  This approach is by far the easiest   http   www codeproject com KB dotnet DebugWinServices aspx  I leave my original answer below for posterity     My services tend to have a class that encapsulates a Timer as I want the service to check at regular intervals whether there is any work for it to do   We new up the class and call StartEventLoop   during the service start-up   This class could easily be used from a console app too    The nice side-effect of this design is that the arguments with which you set up the Timer can be used to have a delay before the service actually starts working  so that you have time to attach a debugger manually      p s  How to attach the debugger manually to a running process       using System  using System Threading  using System Configuration       public class ServiceEventHandler       Timer  timer      public ServiceEventHandler                    get configuration etc           timer   new Timer              new TimerCallback EventTimerCallback                null               Timeout Infinite               Timeout Infinite              private void EventTimerCallback object state                   do something            public void StartEventLoop                    wait a minute  then run every 30 minutes          timer Change TimeSpan Parse  00 01 00    TimeSpan Parse  00 30 00              Also I used to do the following  already mentioned in previous answers but with the conditional compiler   if  flags to help avoid it firing in a Release build    I stopped doing it this way because sometimes we d forget to build in Release and have a debugger break in an app running on a client demo  embarrasing      if DEBUG if   System Diagnostics Debugger IsAttached        System Diagnostics Debugger Break       endif

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Here is the simple method which I used to test the service  without any additional  Debug  methods and with integrated VS Unit Tests    TestMethod  public void TestMyService         MyService fs   new MyService         var OnStart   fs GetType   BaseType GetMethod  OnStart   BindingFlags NonPublic   BindingFlags Public   BindingFlags Instance   BindingFlags Static        OnStart Invoke fs  new object     null           As an extension method public static void Start this ServiceBase service  List lt string gt  parameters         string   par   parameters    null   null   parameters ToArray          var OnStart   service GetType   GetMethod  OnStart   BindingFlags NonPublic   BindingFlags Public   BindingFlags Instance   BindingFlags Static         OnStart Invoke service  new object     par

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static void Main      if DEBUG                    Run as interactive exe in debug mode to allow easy                    debugging                   var service   new MyService                    service OnStart null                       Sleep the main thread indefinitely while the service code                    runs in  OnStart                  Thread Sleep Timeout Infinite    else                    Run normally as service in release mode                   ServiceBase   ServicesToRun                  ServicesToRun   new ServiceBase    new MyService                      ServiceBase Run ServicesToRun    endif

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When developing and debugging a Windows service I typically run it as a console application by adding a  console startup parameter and checking this  Makes life much easier   static void Main string   args        if  Console In    StreamReader Null            if  args Length  gt  0  amp  amp  args 0       console                    Start your service work

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You have two options to do the debugging    create a log file   Personally i prefer a separate log file like text file rather using the application log or event log But this will cost you a lot on behalf of time  because its still hard to figure our where the exact error location is Convert the application to console application   this will enable you  all the debugging tools which we can use in VS    Please refer THIS blog post that i created for the topic

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I like to be able to debug every aspect of my service  including any initialization in OnStart    while still executing it with full service behavior within the framework of the SCM    no  console  or  app  mode    I do this by creating a second service  in the same project  to use for debugging  The debug service  when started as usual  i e  in the services MMC plugin   creates the service host process  This gives you a process to attach the debugger to even though you haven t started your real service yet  After attaching the debugger to the process  start your real service and you can break into it anywhere in the service lifecycle  including OnStart     Because it requires very minimal code intrusion  the debug service can easily be included in your service setup project  and is easily removed from your production release by commenting out a single line of code and deleting a single project installer   Details   1  Assuming you are implementing MyService  also create MyServiceDebug  Add both to the ServiceBase array in Program cs like so            lt summary gt          The main entry point for the application           lt  summary gt      static void Main                 ServiceBase   ServicesToRun          ServicesToRun   new ServiceBase                           new MyService                new MyServiceDebug                      ServiceBase Run ServicesToRun           2  Add the real service AND the debug service to the project installer for the service project     Both services  real and debug  get included when you add the service project output to the setup project for the service  After installation  both services will appear in the service msc MMC plugin   3  Start the debug service in MMC   4  In Visual Studio  attach the debugger to the process started by the debug service   5  Start the real service and enjoy debugging

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