I have a situation where an existing GAE App (let's call it app A) is running, but for non-technical reasons can't be modified. As users migrates to a new client version, we need to migrate their data from app A to a new GAE app (which I'll call app B).
Is there a way that I can grant app B access to app A's live datastore without modifying app A? My not modifying I mean not having to deploy new code. Changing setting or permissions in the Cloud Console is fine.
In case it matters, both apps that I'm referring to are written in Go.