Login hook on Google Appengine
I'm using Python on GAE (so it may be different for Java) but have seen no documentation about such a hook for a user logging in. If you used one of the session management frameworks you'd probably get some indication for that, but otherwise I do this kind of house keeping on my opening page itself which requires login. (What do you want to do about an already logged in user returning to your site a few days later... that is, do you really want to record logins or the start time of a visit/session??)
If I wanted to do this but with multiple landing pages, and without using a session framework, 
I'd use memcache to do a quick check on every page request and then only write to the datastore when a new visit starts.
Every time a user logs in to the application, I want to perform a certain task, say, record the time of login. So I wanted to know if a hook is fired on login by default? If yes, how can I make my module respond to it.
Edit - Assume there are multiple entry points in the application to login.