Adding dynamic string to logger format

Question

I am trying to add a dynamic string to a formatter but unable to do so.

Here is the code.

import logging

logger = logging.getLogger('simple_example')
logger.setLevel(logging.DEBUG)
fh = logging.FileHandler('spam.log')

var = 'some vaue'
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s %s' % var)
fh.setFormatter(formatter)
logger.addHandler(fh)
logger.error('error message')

Output:

Traceback (most recent call last):
  File "try.py", line 8, in <module>
    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s %s' % var)
TypeError: format requires a mapping

here

formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s %s' % var)

is what causing the error, i really need to add a varible var to this format.

formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s simple_example')

works fine.

DevC · Accepted Answer · 2013-10-22 06:58:50Z

1

This will work

formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s {0}'.format(var))

You can learn more here http://docs.python.org/2/library/string.html#format-examples

edited Oct 22, 2013 at 6:58

answered Oct 22, 2013 at 6:44

DevC

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1 Comment

duck Over a year ago

Thanks it work. Please remove 'simple_example' from your answer

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