调试模式下的 Flask 应用程序不会显示信息或调试日志消息

Question

I'm starting a flask application like this:

from idapi.wsgi import app
app.run(port=8080, debug=True)

Where app is an object of a subclass of flask.Flask . Within the application, I'm only ever calling app.logger.<level> (or self.logger.<level> within the class itself). I'm never importing the Python logging module itself.

My understanding was that when startring a flask app with debug=True , I should see see messages from app.logger.debug(...) and app.logger.info(...) , but I'm not.

I can solve this problem by explicitly configuring the root logger:

import logging
from idapi.wsgi import app

logging.basicConfig(level='DEBUG')

app.run(port=8080, debug=True)

Or I can use app.logger.warning(...) instead. What could be going on here...am I incorrect in my understanding of how logging is configured by Flask when running in debug mode?

Answer 1

I'm not sure, but in the documentation of Flask I've seen that you need to set variable FLASK_ENV to development if you want to see debug messages:

To enable all development features (including debug mode) you can export the FLASK_ENV environment variable and set it to development before running the server:

$ export FLASK_ENV=development

$ flask run