I have an application that manages the heavy processing for my project, and need to convert it to a "Windows Service." I need to allow running multiple versions instances of the application processing, which seems to be a fairly normal requirement.
I can see at least three approaches to do this:
My intention was approach #1, but I kept tripping over the limitations, both in design and especially documentation for Services:
So, the questions:
NOTE: I've side-stepped the problem by using approach #3, so I can't justify much time figuring this out. But I thought someone might have information on how to implement #1 -- or good reasons why it isn't a good idea.
[Edit] I originally had a 4th option (install multiple copies of the application on the hard drive) but I removed it because it just feels, um, hackish. That's why I said "at least three approaches".
However, unless the app is recompiled, it must dynamically set its ServiceName, hence that has the solution to the third bullet/problem above. So, unless an instance needed to alter it's install files, #1 should work fine with N config files in the directory and a registry entry indicating which the instance should use.
In order to add additional instance of a service to the Windows Service dialog box, each service must have a unique name. In order to achieve this you will need to use the Windows SC utility. The SC utility communicates with the Service Controller and installed services.
You need to copy your service executable to a separate directory and use InstallUtil.exe to give it a different service name. From a command prompt, you'll need to use InstallUtil to install both instances of your service. For instructions on how to use InstallUtil, see Installer Tool (InstallUtil.exe).
To open a second window of certain open apps, just hold Shift and click on the icon in your taskbar. For programs like Word, Notepad, File Explorer, and Chrome, this will open a second window with a blank document. You can work in that instance of the app separately from whatever else you already have open.
Answer. No, you should not have 2 services with the same name. It is mentioned in the Service Configuration Guide that service names should be unique. It it may be possible to create 2 services with the same name, but this can lead to problems in the future and is not a supported configuration.
Though I can't answer your questions specific to option #1, I can tell you that option #2 worked very well for us. We wanted to create an app domain for each 'child' service to run under and for each of them to use a different configuration file. In our service's config file we stored the app domains to start and the configuration file to use. So for each entry we simply created the app domain, set the configuration file etc and off we went. This separation of configuration allowed us to easily specify the ports and log file locations uniquely for each instance. Of additional benefit to us was that we wrote our 'child service' as a command-line exe and simply called the AppDomain's ExecuteAssembly() on a new thread for each 'child' service. The only 'clunk' in the solution was shutdown, we didn't bother to create a 'good' solution for it.
Update Feb, 2012
Some time ago we started using 'named' services (like SQL Server). I detailed the entire process on my blog in a series "Building a Windows Service – Part 1 through Part 7". They take you through creating a command-line/windows service hybrid complete with self-installation. The following goals where met:
A complete Visual Studio project template is available in the last article of the series Building a Windows Service – Part 7: Finishing touches.
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