Change from app.py to main.py when deploying a FLASK app in Google App Engine

Question

I am following the instructions here to deploy an app in Google App Engine. Everything works correctly.

Nevertheless, Google, by default, looks for the main folder (where app = Flask(__name__) is defined) in main.py . How could I redefine this? I would like to define this main folder as app.py .

Answer 1

1. Rename main.py to app.py

2. Add entrypoint: gunicorn -b :$PORT app:app to your app.yaml file. This is where you are telling Google to find the app object in a file called app

3. Add gunicorn to your requirements.txt file

Notes:

i. Because you're changing from main.py to app.py , you need to specify an entrypoint. GAE documentation says

If your app meets the following requirements, App Engine will start your app with the gunicorn web server if you don't specify the entrypoint field:

• The root of your app directory contains a main.py file with a WSGI-compatible object called app.

• Your app does not contain Pipfile or Pipfile.lock files.

ii. If you add an entrypoint, then you need to include gunicorn in your requirements.txt file

iii. I just tested the above configuration (the answer I gave) on a dev environment (Python 3.9 environment on Macbook using dev_appserver.py) and it works