How to deploy one app engine app to multiple projects

Question

My problem is that I want to create dev, stage, prod environments by using different GCP projects.

Basically they are running

Answer 1

For Python applications, you can set application in the app.yaml file. This allows you to use different data for each project. This is when you deploy using the appcfg.py command.

application: myproject
version: alpha-001
runtime: python27
api_version: 1
threadsafe: true

handlers:
- url: /
  script: home.app

If you don't want to change the application value in this file for each project, you can run the following:

appcfg.py -A  -V v1 update myapp/

https://cloud.google.com/appengine/docs/python/config/appref

If you do not specify the application in the file, use the --application option in the appcfg command when you deploy. This element is ignored when you deploy using the gcloud app deploy command.