Ahoy, Folks!
I've been looking all over for this, but I just can't seem to shake any
documentation out of the MSDN or from Google. I've reviewed every .NET
article on developing Windows Services in the MSDN I've located.
I'm developing a Windows Service application. This service reads its
configuration data from the system registry (HKLM) where it was deposited by
another "manager" application. No problems there.
The service uses a worker thread to do its work. The thread is created in
the OnStart() and signaled/joined/disposed in the OnStop(). Again, no
problems.
Everything works beautifully when:
1. The system administrator has set up everything properly, and
2. the foreign network resources are all reachable.
But of course, we as developers simply can't rely on:
1. The system administrator having set up everything properly, or
2. the foreign network resources being reachable.
Really, what we need is for the service application to have some way of
dying on its own. If a network resource goes down, we need the service to
stop. But more to the point, we need the SCM to know it has stopped on its
own accord. SCM needs to know that the service has "failed"...and hasn't
just been shut down by someone.
Calling "return" or throwing an exception in the "OnStart()" method isn't
even helpful for services still in the start-up process.. The SCM goes
merrily on and the process keeps running in the Task Manager--though it's
not actually doing anything since the worker thread was never created and
started.
Using a ServiceController instance doesn't do it, either. That appears to
the SCM as a normal shutdown--not a service failure. So none of the
recovery actions or restarts happen. (Also, there is MSDNful documentation
warning about the perils of a ServiceBase descendant using a
ServiceController to make things happen with itself.)
I've read articles where people were messing about with PInvoking calls to
the native code just to set the "Stopped" status flag in the SCM. But that
doesn't shut down the process the service is running within.
I'd really like to know the Intended Way of:
1. Shutting down a service from within the service, where
2. The SCM is appropriatedly notified that the service has "Stopped",
and
3. The process disappears from the Task Manager.
Solutions involving ServiceControllers don't seem to be appropriate, if only
because 2 is not satisfied. (That the Framework documentation specifically
contraindicates doing that carries a good deal of weight, incidentally.)
I'd appreciate any recommendations, pointers to documentation, or even
well-reasoned conjecture. :-) Oh! And I'm perfectly happy to entertain
that I've missed the point.
Most cordially,
Ross Bennett
Solution Developer <-- This does not mean I will develop your
photographs. That would be "Developer Solution"
Optical Image Technology, Inc.
