Timer in WCF service host

Question

Is it a good idea to initialize a timer to do a periodic task in a WCF service host or will that mess with the lifecycle or performance of the service being hosted?

I have a custom service host that announces it's availability (with the goal of creating a registry for clients) upon starting and stopping. I want to create a timer to do this periodically but my concern is that this will cause problems (I haven't ran into any yet but maybe I haven't stressed it enough or something) or maybe it will eat resources and kill the performance of the service. The idea is to hookup the timer on the OnOpened and OnClosing events, of course.

For what is worth, this service is hosted in IIS so it is IIS the one instantiating and managing the service host.

Answer 1

Is it a good idea to initialize a timer to do a periodic task in a WCF service host or will that mess with the lifecycle or performance of the service being hosted?

That will depend on where your WCF service is hosted. If it is hosted inside IIS it might be problematic. The reason for this is because IIS can decide to recycle the ASP.NET application pool at any time and your timer will simply stop working. It is not something you can rely upon. If on the other hand you have hosted your WCF service inside a Windows Service self host, it is fine to use a timer. You may take a look at the following blog post about the dangers of implementing recurring background tasks in ASP.NET hosts.