Moving WCF service from IIS to a Windows service

Question

We have an existing WCF service that makes use of wsDualHttpBinding to enable callbacks to the client. I am considering moving it to netTcpBinding for better performance, but I'm quite wary of moving away from the IIS-hosted service (a "comfort zone" we currently enjoy) into having our own Windows service to host it. I was hoping we could still host this on IIS 7 but Win2K8 won't be reality for us for some time.

What things should I watch out for when creating our own Windows service to host our WCF service? Things like lifetime management and request throttling are features that come free with IIS hosting so I'd also like to know how we can effectively host our service on our own without the convenience of having IIS do the hard work for us. Thanks! :)

Answer 1

Hosting in a Windows Service Application (http://msdn.microsoft.com/en-us/library/ms734781.aspx) is a good start.

If you can host your service on Vista, you can also benefit from Windows Process Activation Service (WAS). WAS is a generalization of the IIS process activation, which can be used to activate processes over non-HTTP endpoints (TCP, Named Pipe, MSMQ). To learn more about WCF hosted in WAS, read http://msdn.microsoft.com/en-us/library/ms733109.aspx. To learn how to install and configure WAS, read http://msdn.microsoft.com/en-us/library/ms731053.aspx.

Answer 2

So as you cannot host using WAS there are a couple of things to realise.

• If the service crashes it doesn't restart by default (although you can change this in service properties)
• IIS will recycle the application pool if it hangs or grows too big; you must do this yourself if you want the same sort of reliability.
• You must create an account for the service to run under, or use one of the default services. Resit the temptation to run the service as SYSTEM or under an administrator account; if you want to use a built in account use NETWORK SERVICE.
• It becomes harder to debug in situ.
• Consider using a error logger such as log4net

Having said that I deployed a WCF/Windows service combination for a customer 9 months ago; it's heavily used and hasn't died once.

You can request throttle in a Windows service, it's part of the WCF configuration. Note the defaults are very low, it is likely you will have to increase these.