python - Formatting Flask app logs in json -

i'm working python/flask application , trying logs formatted (by line) in json.

using python-json-logger package, i've modified formatter app.logger follows:

from pythonjsonlogger import jsonlogger formatter = jsonlogger.jsonformatter(     '%(asctime) %(levelname) %(module) %(funcname) %(lineno) %(message)') app.logger.handlers[0].setformatter(formatter) 

this works expected. messages passed app.logger correctly formatted in json.

however application automatically logging requests. information shows in stdout follows:

127.0.0.1 - - [19/jun/2015 12:22:03] "get /portal/ http/1.1" 200 - 

i want information formatted in json well. i've been looking logger/code responsible creating output no success.

where output generated? mechanisms change formatting of logged information?

when use app.logger attribute first time, flask sets log handlers:

• a debug logger set log level debug , filters on app.debug being true.
• a production logger set error.

you can remove handlers again yourself, running:

app.logger.handlers[:] = [] 

however, log line see not logged flask, wsgi server. both built-in werkzeug server (used when use app.run()) , various other wsgi servers this. gunicorn example uses default python logger record access.

the built-in wsgi server should never used in production (it won't scale well, , not battle-hardened against malicious attackers).

for gunicorn, can disable log propagation keep logging separate:

logging.getlogger('gunicorn').propagate = false