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: python logging to file
import logging
"""
DEBUG
INFO
WARNING
ERROR
CRITICAL
"""
# asctime: time of the log was printed out
# levelname: name of the log
# datefmt: format the time of the log
# give DEBUG log
logging.basicConfig(format='%(asctime)s %(levelname)-8s [%(filename)s:%(lineno)d] %(message)s',
datefmt='%d-%m-%Y:%H:%M:%S',
level=logging.DEBUG,
filename='logs.txt')
logger = logging.getLogger('my_app')
logger.debug("This is a debug log")
logger.info("This is an info log")
logger.critical("This is critical")
logger.error("An error occurred")
Example 3: python log to file and console
import logging
logging.basicConfig(
level=logging.INFO,
format="%(asctime)s [%(levelname)s] %(message)s",
handlers=[
logging.FileHandler("debug.log"),
logging.StreamHandler()
]
)
Example 4: 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")
Example 5: from logging import logger
#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
import logging
logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.DEBUG)
logger.debug('Loging %s lewel', 'DEBUG')
logger.info('Loging %s lewel', 'INFO')
logger.warning('Loging %s lewel', 'WARN')
logger.error('Loging %s lewel', 'ERROR')
logger.critical('Loging %s lewel', 'CRITICAL')
Example 6: testing logging python
# can be done by using unittest's assertLogs
from unittest import TestCase
class MyTest(TestCase):
def test_logs(self):
with self.assertLogs('foo', level='INFO') as cm:
logging.getLogger('foo').info('first message')
logging.getLogger('foo.bar').error('second message')
self.assertEqual(cm.output, ['INFO:foo:first message',
'ERROR:foo.bar:second message'])