auto updating software on cloud

I know wordpress,joomla,drupal etc ( most of php_mysql stack ) can auto detect update in software itself or/and plugin and either ask for user permission to update or auto update it.

How to do similar thing on google app engine like cloud computing ?

I am creating an open source software which is targeted towards non-computer people. who can not clone my code and upd开发者_开发知识库ate their application easily.

what is the easier way to do this ?

While it's technically possible for an app to re-deploy itself, implementing this functionality would be difficult, and may be contrary to the Terms of Service, too.

If you want non-technical users to use your app, your best option is to provide it as a Software-as-a-Service app - eg, a single instance that users pay for access to, and which supports multi-tenancy - and update it yourself.