Google App Engine - one datastore for different domains and apps

Question

Is that somehow possible to access one datastore? Or access one app from different domains.

Answer 1

Every version of an app is backed by the same datastore. If you want to limit access for individual requests, you'll need to add a field to your model to enforce that restriction. There are low level hooks in the datastore API for this sort of thing, if you want to go that far.

And yes, you can add a single App Engine app to multiple domains - even in multiple Apps accounts.

Answer 2

Kyle's solution would work, but App Engine was never designed to be used in this way. So if you architect your app(s) to rely on this kind of setup and Google clamps down for whatever reason then you'd be screwed.

Answer 3

You can have multitenancy using the Namespace Java API

Answer 4

Every app has its own datastore and memcache (shared among all versions of that app). It seems not possible to share datastores between applications right now (unless you provide some web service for that), but that would be a nice feature to have, so maybe you should file a feature request with Google vote for it.

As for domains, you can associate your app with domains managed by Google Apps. Multiple domains for the same application should be no problem (except for SSL certificates).

Answer 5

App Engine recently add support for a feature called modules (Docs: go, python, java)

App Engine Modules (or just "Modules" hereafter) is a feature that lets developers factor large applications into logical components that can share stateful services and communicate in a secure fashion. An app that handles customer requests might include separate modules to handle other tasks:

• API requests from mobile devices
• Internal, admin-like requests
• Backend processing such as billing pipelines and data analysis

When you create a new module, App Engine will create a url that corresponds to the module name. If you only have one module then the name will be default. e.g.

• http://default.myapp.appspot.com
• http://mobile‑frontend.myapp.appspot.com
• http://my-module.myapp.appspot.com

Using Domain masking, you could then direct from:

• www.myapp.com => http://default.myapp.appspot.com
• www.myapp-mobile.com => http://mobile‑frontend.myapp.appspot.com
• www.example.com => http://my-module.myapp.appspot.com