日志汇总：logging、logger

1、日志输出到文件
2、日志输出到屏幕
3、设置输出等级
4、设置多个日志输出对象
5、日志的配置
6、记录异常
7、设置日志输出样式

import logging

logging.basicConfig(filename=‘example.log‘, level=logging.DEBUG)
logging.debug(‘This message should go to the log file‘)

import logging

logging.basicConfig(level=logging.DEBUG)
logging.debug(‘This message should go to the log file‘)

import logging

logging.basicConfig(level=logging.INFO)
# start reading database
logging.info(‘Start reading database‘)
# update records here
logging.info(‘Finish updating records‘)

import logging

logging.basicConfig(level=logging.INFO)#必须有初始等级

logger1 = logging.getLogger(‘log1‘)
logger1.setLevel(logging.INFO)
# Start reading database
logger1.info(‘Start reading database‘)
# update records here
logger1.info(‘Finish updating records‘)

logger2 = logging.getLogger(‘log2‘)
logger2.setLevel(logging.DEBUG)
# Start reading database
logger2.info(‘Start reading database‘)
logger2.debug(‘666‘)
# update records here
logger2.info(‘Finish updating records‘)

import logging

logging.basicConfig(level=logging.INFO)
# 获取logger实例，如果参数为空则返回root
logger1 = logging.getLogger(‘log1‘)
# Start reading database
logger1.info(‘Start reading database‘)
# update records here
logger1.info(‘Finish updating records‘)

logger2 = logging.getLogger(‘log2‘)
logger2.setLevel(logging.DEBUG)
# Start reading database
logger2.info(‘Start reading database‘)
logger2.debug(‘666‘)
# update records here
logger2.info(‘Finish updating records‘)

try:
1 / 0
except:
# 等同于error级别，但是会额外记录当前抛出的异常堆栈信息
logger.exception(‘this is an exception message‘)

import logging
import time

# 日志初始配置：写入日志文件
logging.basicConfig(
level=logging.DEBUG, # 设置写入级别。日志级别大小关系为：CRITICAL > ERROR > WARNING > INFO > DEBUG > NOTSET
# 设置写入样式。‘2018-01-12 13:09:02|mytest.py|<module>|line:9|INFO|start runing‘
format=‘%(asctime)s|%(filename)s|%(funcName)s|line:%(lineno)d|%(levelname)s|%(message)s‘,
datefmt=‘%Y-%m-%d %X‘,
filename=time.strftime("%Y%m%d") + ‘.log‘ # 写入文件位置和文件名
)

# 控制台打印输出日志
console = logging.StreamHandler() # 定义一个StreamHandler，将INFO级别或更高的日志信息打印到标准错误，并将其添加到当前的日志处理对象
formatter = logging.Formatter(fmt=‘%(asctime)s|%(name)-8s: %(levelname)-8s| %(message)s‘,datefmt=‘%Y-%m-%d %H:%M:%S‘) # 控制台输出样式
console.setFormatter(formatter)
logging.getLogger(‘‘).addHandler(console)
console.setLevel(logging.INFO) # 设置要打印日志的等级，低于这一等级，不会打印

# 定义日志内容（用于写入日志文件和控制台的打印）
logging.critical(‘CRITICAL le‘) # 定义严重日志内容
logging.error(‘error le‘) # 定义错误日志内容
try:
1 / 0
except Exception as e:
logging.warning(‘exception: %s‘, e) # 定义警告日志内容
logging.info(‘start runing‘) # 定义消息日志内容
logging.info(‘login done‘)
str1 = ‘lalala‘
logging.debug("\n%s\n", str1) # 定义调试日志内容

import logging
import sys

# 获取logger实例，如果参数为空则返回root logger
logger = logging.getLogger("AppName")

# 指定logger输出格式
formatter = logging.Formatter(‘%(asctime)s %(levelname)-8s: %(message)s‘)

# 文件日志
file_handler = logging.FileHandler("test.log")#创建文件的日志处理器
file_handler.setFormatter(formatter) # 可以通过setFormatter指定输出格式

# 控制台日志
console_handler = logging.StreamHandler(sys.stdout)#创建控制台的日志处理器
console_handler.formatter = formatter # 也可以直接给formatter赋值

# 为logger添加的日志处理器
logger.addHandler(file_handler)
logger.addHandler(console_handler)

# 指定日志的最低输出级别，默认为WARN级别
logger.setLevel(logging.INFO)

# 输出不同级别的log
logger.debug(‘this is debug info‘)
logger.info(‘this is information‘)
logger.warning(‘this is warning message‘)
logger.error(‘this is error message‘)
logger.fatal(‘this is fatal message, it is same as logger.critical‘)
logger.critical(‘this is critical message‘)