cerr cerr - 8 months ago 26
Python Question

logger configuration to log to file and print to stdout

I'm using Python's logging module to log some debug strings to a file which works pretty well. Now in addition, I'd like to use this module to also print the strings out to stdout. How do I do this? In order to log my strings to a file I use following code:

import logging
import logging.handlers
logger = logging.getLogger("")
handler = logging.handlers.RotatingFileHandler(
LOGFILE, maxBytes=(1048576*5), backupCount=7
formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")

and then call a logger function like

logger.debug("I am written to the file")

Thank you for some help here!


Just get a handle to the root logger and add the StreamHandler. The StreamHandler writes to stderr. Not sure if you really need stdout over stderr, but this is what I use when I setup the Python logger and I also add the FileHandler as well. Then all my logs go to both places (which is what it sounds like you want).

import logging

You could also add a Formatter to it so all your log lines have a common header.


import logging
logFormatter = logging.Formatter("%(asctime)s [%(threadName)-12.12s] [%(levelname)-5.5s]  %(message)s")
rootLogger = logging.getLogger()

fileHandler = logging.FileHandler("{0}/{1}.log".format(logPath, fileName))

consoleHandler = logging.StreamHandler()

Prints to the format of:

2012-12-05 16:58:26,618 [MainThread  ] [INFO ]  my message