Neil's News

App Engine Python 3

31 January 2020

App Engine is a great platform for creating minimal cloud-hosted applications without fuss and bother. Here's a simple Python 2.7 application that takes two numbers as URL parameters, adds them, and prints them back out:

Thus when you visit / the result is 3.

Unfortunately App Engine's 'upgrade' from Python 2 to Python 3 appears to have made such lightweight applications impossible. First, app.yaml no longer provides routing of different URLs, so that logic needs to be moved into a singular Python program named Furthermore, the documentation states:

In the Python 3 runtime, your app needs to use a web framework such as Flask or Django
A quick glance at Flask (which describes itself as a "micro framework") reveals 300 kb of code. No.

Fortunately the documentation is a lie, it is perfectly possible to use Python 3 on App Engine without a framework:

Hope this helps anyone else who is struggling to retain the simplicity of their Python 2 App Engine services during the forced upgrade to Python 3.

Update in 2024: The 'cgi' module is being removed from Python 3.13 with no replacement. Below is a solution for GET parameters.

For an example which handles POST data, see Glockenspiel's

< Previous | Next >

Legal yada yada: My views do not necessarily represent those of my employer or my goldfish.