python 3 logging code example

Example 1: python logging to file

import logging
import sys

logger = logging.getLogger()
logger.setLevel(logging.INFO)
formatter = logging.Formatter('%(asctime)s | %(levelname)s | %(message)s', 
                              '%m-%d-%Y %H:%M:%S')

stdout_handler = logging.StreamHandler(sys.stdout)
stdout_handler.setLevel(logging.DEBUG)
stdout_handler.setFormatter(formatter)

file_handler = logging.FileHandler('logs.log')
file_handler.setLevel(logging.DEBUG)
file_handler.setFormatter(formatter)

logger.addHandler(file_handler)
logger.addHandler(stdout_handler)

Example 2: logging.logger

import logging

logging.basicConfig(level=logging.WARNING)
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
  
logger.debug("some debugging...")
logger.error("some error...")

Example 3: python logging basiclogging rotatingfilehandler

import logging

rfh = logging.handlers.RotatingFileHandler(
 	filename='foo.log', 
  	mode='a',
  	maxBytes=20*1024*1024,
  	backupCount=2,
  	encoding=None,
  	delay=0
)

logging.basicConfig(
  	level=logging.DEBUG,
  	format="%(asctime)s %(name)-25s %(levelname)-8s %(message)s",
    datefmt="%y-%m-%d %H:%M:%S",
    handlers=[
    	rfh
    ]
)

logger = logging.getLogger('main')

logger.debug("test")