Log the logins to the various applications that identityserver manages

Question

We've got a lot of sites with common authentication by thinktecture identityserver v2.

Now we would like to have a log of the logins to the sites. We've got a custom IUserRepository where we could log a user login in, but how would we goahead and grab the site a user is loggin into?

And when we jump from one site to another - how could that be logged

In case there's no built in support for this, where is the best place to modify the code?

It seems like it could be done in the WSFederationController and in the Issue method I could get the realm based on the uri.

 public ActionResult Issue()
    {
        Tracing.Start("WS-Federation endpoint.");

        if (!ConfigurationRepository.WSFederation.Enabled && ConfigurationRepository.WSFederation.EnableAuthentication)
        {
            return new HttpNotFoundResult();
        }

        var message = WSFederationMessage.CreateFromUri(HttpContext.Request.Url);

        // sign in 
        var signinMessage = message as SignInRequestMessage;
        if (signinMessage != null)
        {
            // Is this a good place to log current user and the application the user is loggin into to db??? 
            // or does Thinktecture have some build in functionaltiy for this?


            return ProcessWSFederationSignIn(signinMessage, ClaimsPrincipal.Current);
        }

Larsi