I am newbie in Google App Engine. While I was going through the tutorial, I found several things that we do in php-mysql is not available in GAE. For example in dataStore auto i
Django is your best bet -- with the version I pointed you to, auth and sessions should both "just work" as per the Django docs. this article gives simple instructions and example of how to proceed from there.
For Django sessions, see here; for Django auth, here.