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Allow to execute "flask shell" in the portal container without setting env variables

Recommended skills:

  • Rough understanding of Docker, or
  • Will to read some documentation and fiddle around.

Flask applications allow access to a Python shell with which Python code can be executed in the running application using the command flask shell.

For this to work, the environment variable FLASK_APP needs to be set to contain the name of the application to spawn a shell into.

As we run the Flask app inside docker, we first need to get inside the Docker container using:

sudo docker exec -it portal-app-1 bash

Then, we need to set the environment variable and launch the shell:

export FLASK_APP=portal
flask shell

This is annoying. It would be cooler to just execute:

sudo docker exec -it portal-app-1 flask shell

But that yields to the following error, because the environment variable FLASK_APP is not set:

Usage: flask shell [OPTIONS]
Try 'flask shell --help' for help.

Error: Could not locate a Flask application. Use the 'flask --app' option, 'FLASK_APP' environment variable, or a 'wsgi.py' or 'app.py' file in the current directory.

It would be great if that could be fixed, preferably by editing the Dockerfile somehow.

Maybe helpful resources

Edited by Jakob Moser