Can I pre-attach a debugger to a service?

Question

I have a Windows Service and I would like to see what it's doing when it starts up. Normally to accomplish something like that, I'd hard-code a Thread.Sleep for like 10 seconds to give me enough time to attach the debugger. This is effective, but annoying, as I need to re-compile once to put the pause in and again when I (hopefully remember to) take the pause out. I know I could alternatively hard-code a break command in, but that also requires me to re-compile my solution.

I know I can also separate my service's logic into a separate project that can be run in Visual Studio, which I can use most of the time, but sometimes I want to see exactly what my service is doing when it's running as a service.

Is there a way that I can get my debugger attached to my service so that I can see the things it's doing on startup, without hard-coding and re-compiling anything?

Answer 1

Take a look at Attach to a process on the Tools menu in Visual Studio. You can put a break point in your code and then start the process and debug the service. You may have to put a thread.sleep() to give you enough time to react.

You have to start the service than attach to the process in Visual Studio. The thread.sleep() will give you the time to perform the attaching without blowing by your start up code.

Answer 2

Here is Microsoft's advice on how to accomplish this: http://msdn.microsoft.com/en-us/library/7a50syb3%28VS.80%29.aspx

Answer 3

There is a registry key which gives you a chance to attach a debugger to the process as soon as it is created.

Save the following snippet as a *.reg file and import to your registry:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\services.exe]
"Debugger"="c:\\Program Files\\Debugging Tool For Windows\\windbg.exe"

remember to change 'services.exe' to the actual services executable file name.

You can also use the gflag tool to facilitate the work. For detailed information please check KB 824344: How to debug Windows services