Prevent IIS from killing a Task before it ends

Question

I\'m building a Logging library that stores everything on an Azure table. Writing to that table obviously takes a lot of time (never more than 1 sec, but it\'s still too muc

Answer 1

Thanks to Damian Schenkelman and that blog post of Phil Haack, I figured out the problem and the solution. The problem is that IIS reuses the threads when it needs to handle new requests. And as it doesn't know that my task is doing some work, it reuses that thread (which makes sense). Then, I just have to notify IIS that I'm using that thread and that it can't be reused (so, it has to either reuse another thread, create a new one, or make it wait). I ended up using my own TaskFactory that handles the task creation, and automatically registers a notifier in IIS. For completeness, to help some other folk with the same issue as me, and to read another suggestions, here's what I've done

public class IISNotifier : IRegisteredObject
{
    public void Stop(bool immediate)
    {
        // do nothing, I only run tasks if I know that they won't
        // take more than a few seconds.
    }

    public void Started()
    {
        HostingEnvironment.RegisterObject(this);
    }

    public void Finished()
    {
        HostingEnvironment.UnregisterObject(this);
    }
}

And then

public class IISTaskFactory
{
    public static Task StartNew(Action act)
    {
        IISNotifier notif = new IISNotifier();
        notif.Started();
        return Task.Factory.StartNew(() => {
            act.Invoke();
            notif.Finished();
        });
    }
}

Now, when I want to start a the log task I just do

return new LogResult(id, IISTaskFactory.StartNew(() => 
    DoLogInAzure(account, id, exception, request))
);

You can see (and download the code) at https://github.com/gmc-dev/IISTask