Python logging practice

Ten hair 2021-01-20 20:44:17
python logging practice

Log for the development of system development 、 Debugging and running the whole process plays a very important role , During the debugging phase, you need to look at the log to find out what the problem is , In the runtime, if the program crashes , Log can record the cause of program crash . And sometimes python The role of the script is to return text to the caller , At this point, we need to distinguish the return value from the log used for debugging trace . This paper introduces python Common usage .

logging Two ways of log configuration are provided , Simple journal (logging.basicConfig And standard streaming framework

Simple journal

logging.basicConfig Configuration log , Standard output and files are generally supported ( Cannot be configured at the same time )

# -*- coding:utf-8 -*-
import logging
import sys
# Log output to file tenmao.log, Level is INFO, Configure log format and date time format at the same time
# format='%(asctime)s %(filename)s %(levelname)s %(message)s',
# datefmt='%a %d %b %Y %H:%M:%S',
# filename='tenmao.log',
# filemode='a')
# Log output to standard error sys.stderr( The default is standard output sys.stdout),filename and stream They are mutually exclusive. , It can't be configured at the same time
logging.basicConfig(level=logging.DEBUG, stream=sys.stderr,
format='%(asctime)s %(filename)s[line:%(lineno)d]%(levelname)s %(message)s')
logging.debug('This is debug message')'This is info message')
logging.warning('This is warning message')
logging.error('This is error message')
logging.critical('This is critical message')
  • Output log content : tenmao.log
Sat 16 Jan 2021 22:45:28 INFO This is info message
Sat 16 Jan 2021 22:45:28 WARNING This is warning message
Sat 16 Jan 2021 22:45:28 ERROR This is error message
Sat 16 Jan 2021 22:45:28 CRITICAL This is critical message

Standard configuration : Streaming

logging Modules include Logger,Handler,Filter,Formatter Four parts .

  • Logger Recorder , Used to set log collection .
  • Handler processor , Send the log record to the appropriate path .
  • Filter filter , Provides better granularity control , It can decide which logging to output .
  • Formatter formatter , Indicates the format of the log in the final output .
  • Configure sample code
# -*- coding:utf-8 -*-
import logging
# First step , Create a logger
# 1, Create a logger logger
logger = logging.getLogger()
# 2, Set the log level of the logger , The log level here is the lowest level that a logger can record , It's different from the back Handler in setLevel Log level of
# The second step , Create a log processor Handler. Create a Handler, Used to write logs to a file
# 3, Create a Handler, For writing log files , The path of the log file is self-defined
logFile = './log.txt'
fh = logging.FileHandler(logFile, mode='a', encoding='utf-8')
# 4, Set the log level saved to the file
# The third step , Definition Handler The output format of
# 5, The log output format is defined as follows
format= logging.Formatter('%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s')
# 6, Set up Write to the log file Handler The log format of
# Step four , take Handler Add to the logger logger in
# alike , Create a Handler For console output logs
ch = logging.StreamHandler()
# Output log"This is info message")
logger.warning("This is warning message")
logger.error("This is error message")
logger.critical("This is critical message")


  • Abnormal information
raise Exception("hello error")
except Exception as e:
logger.error(" Login error , The reason is :{}".format(e))
logger.error(" Login error ,stack trace", exc_info=True)
else:" Landing successful ...")

exc_info=True You can output the exception stack

The output is as follows

2021-01-16 23:01:42,203[line:35] INFO This is info message
2021-01-16 23:01:42,203[line:36] WARNING This is warning message
2021-01-16 23:01:42,204[line:37] ERROR This is error message
2021-01-16 23:01:42,204[line:38] CRITICAL This is critical message
2021-01-16 23:01:42,204[line:43] ERROR Login error , The reason is :hello error
2021-01-16 23:01:42,204[line:44] ERROR Login error ,stack trace
Traceback (most recent call last):
File "", line 41, in <module>
raise Exception("hello error")
Exception: hello error

Reference resources

Participation of this paper Tencent cloud media sharing plan , You are welcome to join us , share .

本文为[Ten hair]所创,转载请带上原文链接,感谢

  1. 利用Python爬虫获取招聘网站职位信息
  2. Using Python crawler to obtain job information of recruitment website
  3. Several highly rated Python libraries arrow, jsonpath, psutil and tenacity are recommended
  4. Python装饰器
  5. Python实现LDAP认证
  6. Python decorator
  7. Implementing LDAP authentication with Python
  8. Vscode configures Python development environment!
  9. In Python, how dare you say you can't log module? ️
  10. 我收藏的有关Python的电子书和资料
  11. python 中 lambda的一些tips
  12. python中字典的一些tips
  13. python 用生成器生成斐波那契数列
  14. python脚本转pyc踩了个坑。。。
  15. My collection of e-books and materials about Python
  16. Some tips of lambda in Python
  17. Some tips of dictionary in Python
  18. Using Python generator to generate Fibonacci sequence
  19. The conversion of Python script to PyC stepped on a pit...
  20. Python游戏开发,pygame模块,Python实现扫雷小游戏
  21. Python game development, pyGame module, python implementation of minesweeping games
  22. Python实用工具,email模块,Python实现邮件远程控制自己电脑
  23. Python utility, email module, python realizes mail remote control of its own computer
  24. 毫无头绪的自学Python,你可能连门槛都摸不到!【最佳学习路线】
  25. Python读取二进制文件代码方法解析
  26. Python字典的实现原理
  27. Without a clue, you may not even touch the threshold【 Best learning route]
  28. Parsing method of Python reading binary file code
  29. Implementation principle of Python dictionary
  30. You must know the function of pandas to parse JSON data - JSON_ normalize()
  31. Python实用案例,私人定制,Python自动化生成爱豆专属2021日历
  32. Python practical case, private customization, python automatic generation of Adu exclusive 2021 calendar
  33. 《Python实例》震惊了,用Python这么简单实现了聊天系统的脏话,广告检测
  34. "Python instance" was shocked and realized the dirty words and advertisement detection of the chat system in Python
  35. Convolutional neural network processing sequence for Python deep learning
  36. Python data structure and algorithm (1) -- enum type enum
  37. 超全大厂算法岗百问百答(推荐系统/机器学习/深度学习/C++/Spark/python)
  38. 【Python进阶】你真的明白NumPy中的ndarray吗?
  39. All questions and answers for algorithm posts of super large factories (recommended system / machine learning / deep learning / C + + / spark / Python)
  40. [advanced Python] do you really understand ndarray in numpy?
  41. 【Python进阶】Python进阶专栏栏主自述:不忘初心,砥砺前行
  42. [advanced Python] Python advanced column main readme: never forget the original intention and forge ahead
  43. python垃圾回收和缓存管理
  44. java调用Python程序
  45. java调用Python程序
  46. Python常用函数有哪些?Python基础入门课程
  47. Python garbage collection and cache management
  48. Java calling Python program
  49. Java calling Python program
  50. What functions are commonly used in Python? Introduction to Python Basics
  51. Python basic knowledge
  52. Anaconda5.2 安装 Python 库(MySQLdb)的方法
  53. Python实现对脑电数据情绪分析
  54. Anaconda 5.2 method of installing Python Library (mysqldb)
  55. Python implements emotion analysis of EEG data
  56. Master some advanced usage of Python in 30 seconds, which makes others envy it
  57. python爬取百度图片并对图片做一系列处理
  58. Python crawls Baidu pictures and does a series of processing on them
  59. python链接mysql数据库
  60. Python link MySQL database