Disable console messages in Flask server

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()

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

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.

To suppress Serving Flask app ...:

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