How to Create a Logger
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#!/usr/bin/env python
import logging
import logging.handlers
'''
Log both to a file and to console: use 2 different handlers
Logging:
http://docs.python.org/2/library/logging.html
Formatter:
http://docs.python.org/2/library/logging.html#logrecord-attributes
'''
def create_logger(logger_name, log_level=logging.WARNING, filename=None, format_str=None):
'''
Create a logger that log to the console, if a filename is supplied, log to that file
as well.
'''
logger = logging.getLogger(logger_name)
logger.setLevel(log_level)
# create console handler and set appropriate level
ch = logging.StreamHandler()
ch.setLevel(log_level)
formatter = logging.Formatter(format_str or "%(asctime)s %(name)s %(levelname)-8s %(message)s")
ch.setFormatter(formatter)
logger.addHandler(ch)
# Create a file handler and set appropriate level
if filename:
fh = logging.FileHandler(filename=filename, mode='w')
fh.setLevel(log_level)
fformatter = logging.Formatter(
'%(asctime)s;%(filename)s;%(lineno)d;%(levelname)s;%(message)s',
"%Y-%m-%d %H:%M:%S")
fh.setFormatter(fformatter)
logger.addHandler(fh)
return logger
def main():
log_filename = 'out.log'
logger = create_logger('demo', logging.DEBUG, log_filename)
logger.debug("debug message")
logger.info("info message")
logger.warning("warn message")
logger.error("error message")
logger.critical("critical message")
# Show the log file contents
print('---')
print(log_filename)
print('---')
with open(log_filename) as f:
print(f.read())
if __name__ == '__main__':
main()
Python
INFO