Flask is not reacting to the FLASK_ENV variable setting

Question

I am trying to activate debug mode in Flask.

What I have tried so far:

set FLASK_ENV=development directly in Windows cmd
pip installed python-dotenv successfully and set FLASKENV=development in .env file
ensured that there is no dotenv package globally and within virtual env
pip force uninstall/reinstall python-dotenv a few times
with python-dotenv, tried load_dotenv() and os.getenv('FLASK_ENV') and it shows that the value of FLASK_ENV is development

None of the above enabled the debug mode of Flask. FLASK_APP variable is correctly set and read though. Only by running Flask --debug run activates the debug mode.

Why is the FLASK_ENV variable not recognized by Flask?

Looks like it was removed: https://flask.palletsprojects.com/en/2.3.x/changes/#version-2-3-0 — ivvija, Sep 01 '23 at 12:13
Use `FLASK_DEBUG` instead: https://flask.palletsprojects.com/en/2.3.x/config/#DEBUG — ivvija, Sep 01 '23 at 12:15
Indeed. `FLASK_DEBUG` fixed it. You might like to make your comment an answer. — JeffP, Sep 01 '23 at 12:18

Undesirable · Accepted Answer · 2023-09-01T19:33:26.690

1

As pointed out by ivvija: In Flask version 2.3.0, the FLASK_ENV environment variable (including the ENV config key and app.env property) has been removed.

You should instead set FLASK_DEBUG=1, or set debug=True in your app.run() method or use the --debug option when running the flask run command to enable debug mode - any of these will work.

edited Sep 01 '23 at 19:33

answered Sep 01 '23 at 14:53

Undesirable

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This is hard to catch as most tutorials out there are outdated. – JeffP Sep 02 '23 at 01:00

Flask is not reacting to the FLASK_ENV variable setting

1 Answers1