PythonでloggerにFormatterをセットして改行を潰すサンプル

logger-formatter.py

#!/usr/bin/env python

import logging

logger1 = logging.getLogger('test1')

logger1.warn(' foo1 \n bar1')

logger2 = logging.getLogger('test2')

handler = logging.StreamHandler()
formatter = logging.Formatter('dummy')

def my_formatter(record):
    return record.msg.replace('\n', '<NEWLINE>')

formatter.format = my_formatter

handler.setFormatter(formatter)
logger2.addHandler(handler)

logger2.warn(' foo2 \n bar2')

output

$ python logger-formatter.py
 foo1
 bar1
 foo2 <NEWLINE> bar2