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/2013 10:52:22] "GET /index.html HTTP/1.1" 200 -
...

How do I disable verbose mode?

Answer 1

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 2

This solution provides you a way to get your own prints and stack traces but without information level logs from flask suck as 127.0.0.1 - - [15/Feb/2013 10:52:22] "GET /index.html HTTP/1.1" 200

from flask import Flask
import logging

app = Flask(__name__)
log = logging.getLogger('werkzeug')
log.disabled = True

Answer 3

None of the other answers worked correctly for me, but I found a solution based off Peter's comment. Flask apparently no longer uses logging for logging, and has switched to the click package. By overriding click.echo and click.secho I eliminated Flask's startup message from app.run().

import logging

import click
from flask import Flask

app = Flask(__name__)

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

def secho(text, file=None, nl=None, err=None, color=None, **styles):
    pass

def echo(text, file=None, nl=None, err=None, color=None, **styles):
    pass

click.echo = echo
click.secho = secho

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

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

Between setting the logging level to ERROR and overriding the click methods with empty functions, all non-error log output should be prevented.

Answer 4

To suppress Serving Flask app ...:

os.environ['WERKZEUG_RUN_MAIN'] = 'true'
app.run()

Answer 5

In case you are using WSGI server , please set the log to None

gevent_server = gevent.pywsgi.WSGIServer(("0.0.0.0", 8080), app, log=None)

Answer 6

@Drewes solution works most of the time, but in some cases, I still tend to get werkzeug logs. If you really don't want to see any of them, I suggest you disabling it like that.

from flask import Flask
import logging

app = Flask(__name__)
log = logging.getLogger('werkzeug')
log.disabled = True
app.logger.disabled = True

For me it failed when abort(500) was raised.

Answer 7

Late answer but I found a way to suppress EACH AND EVERY CONSOLE MESSAGE (including the ones displayed during an abort(...) error).

import os
import logging

logging.getLogger('werkzeug').disabled = True
os.environ['WERKZEUG_RUN_MAIN'] = 'true'

This is basically a combination of the answers given by Slava V and Tom Wojcik

Answer 8

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 9

I spent absolute ages trying to get rid of these response logs with all the different solutions, but as it turns out it wasn't Flask / Werkzeug but Gunicorn access logs dumped on stderr...

The solution was replacing the default access log handler with NullHandler by adding this block in the Gunicorn config file:

logconfig_dict = {
    "version": 1,
    "disable_existing_loggers": False,
    "handlers": {
        "console": {"class": "logging.StreamHandler", "level": "INFO"},
        "null": {"class": "logging.NullHandler"},
    },
    "loggers": {
        "gunicorn.error": {"level": "INFO", "propagate": False, "handlers": ["console"]},
        "gunicorn.access": {"level": "INFO", "propagate": False, "handlers": ["null"]},
    },
}

Answer 10

somehow none of the above options, including .disabled = True, worked for me.

The following did the trick though:

logging.getLogger('werkzeug').setLevel(logging.CRITICAL)

Using the latest versions as of November 2021 under Python 3.7.3:

pip3 list | grep -E "(connexion|Flask|Werkzeug)"
connexion2               2.10.0
Flask                    2.0.2
Werkzeug                 2.0.2

Answer 11

Here's the answer to disable all logging, including on werkzeug version 2.1.0 and newer:

import flask.cli
flask.cli.show_server_banner = lambda *args: None

import logging
logging.getLogger("werkzeug").disabled = True

Answer 12

My current workaround to silence Flask as of 2022-10.

It disables the logging and the startup banner:

class WSServer:

    ...

    @staticmethod
    def _disabled_server_banner(*args, **kwargs):
        """
        Mock for the show_server_banner method to suppress spam to stdout
        """
        pass

    def _run_server(self):
        """
        Winds-up the server.
        """
        # disable general logging
        log = logging.getLogger('werkzeug') 
        log.setLevel(logging.CRITICAL)
        # disable start-up banner
        from flask import cli
        if hasattr(cli, "show_server_banner"):
            cli.show_server_banner = self._disabled_server_banner
        ...

Answer 13

I merged custom logs and flask logs so as to provide same log format.

sample log message

For mote details: https://github.com/senthilkumarimuth/logging_for_python

Answer 14

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 15

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