Disable console messages in Flask server

Question

I have a Flask server running in standalone mode (using app.run()). But, I don\'t want any messages in the console, like

127.0.0.1 - - [15/Feb/2         


        

Answer 1

A brute force way to do it if you really don't want anything to log into the console beside print() statements is to logging.basicConfig(level=logging.FATAL). This would disable all logs that are of status under fatal. It would not disable printing but yeah, just a thought :/

EDIT: I realized it would be selfish of me not to put a link to the documentation I used :) https://docs.python.org/3/howto/logging.html#logging-basic-tutorial

Answer 2

You can set level of the Werkzeug logger to ERROR, in that case only errors are logged:

import logging
log = logging.getLogger('werkzeug')
log.setLevel(logging.ERROR)

Here is a fully working example tested on OSX, Python 2.7.5, Flask 0.10.0:

from flask import Flask
app = Flask(__name__)

import logging
log = logging.getLogger('werkzeug')
log.setLevel(logging.ERROR)

@app.route("/")
def hello():
    return "Hello World!"

if __name__ == "__main__":
    app.run()

Answer 3

Another reason you may want to change the logging output is for tests, and redirect the server logs to a log file.

I couldn't get the suggestion above to work either, it looks like loggers are setup as part of the app starting. I was able to get it working by changing the log levels after starting the app:

... (in setUpClass)
server = Thread(target=lambda: app.run(host=hostname, port=port, threaded=True))
server.daemon = True
server.start()
wait_for_boot(hostname, port)  # curls a health check endpoint

log_names = ['werkzeug']
app_logs = map(lambda logname: logging.getLogger(logname), log_names)
file_handler = logging.FileHandler('log/app.test.log', 'w')

for app_log in app_logs:
    for hdlr in app_log.handlers[:]:  # remove all old handlers
        app_log.removeHandler(hdlr)

    app_log.addHandler(file_handler)

Unfortunately the * Running on localhost:9151 and the first health check is still printed to standard out, but when running lots of tests it cleans up the output a ton.

"So why log_names?", you ask. In my case there were some extra logs I needed to get rid of. I was able to find which loggers to add to log_names via:

from flask import Flask
app = Flask(__name__)

import logging
print(logging.Logger.manager.loggerDict)

Side note: It would be nice if there was a flaskapp.getLogger() or something so this was more robust across versions. Any ideas?

Some more key words: flask test log remove stdout output

thanks to:

• http://code.activestate.com/lists/python-list/621740/ and
• How to change filehandle with Python logging on the fly with different classes and imports

Answer 4

The first point: In according to official Flask documentation, you shouldn't run Flask application using app.run(). The best solution is using uwsgi, so you can disable default flask logs using command "--disable-logging"

For example:

uwsgi --socket 0.0.0.0:8001 --disable-logging --protocol=http -w app:app