We need to migrate from one app engine project to another (due to the constraints put in place for changing region).
The ideal solution would just be to proxy all requests through to the new server however we are using Google Cloud Endpoints which are intercepted by the server and delivered as POST requests.
We can't redirect as we have mobile apps relying on the API.
Does anyone have a solution (rather than proxying every API method we have) to proxy to a new server?
I would write a ServletFilter on the old app that intercepts /_ah/spi/* and forwards it to the new app, also on /_ah/spi/*. Keep in mind that you'll have to keep the existing Endpoints code in place, or the proxy will delete your configuration and not forward anything.