python & django logging 小结

[TOC]

python

基本

一次配置, 多处生效

import logging
logging.basicConfig(format='%(asctime)s %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p')
logging.warning('is when this event was logged.')

>>>12/12/2010 11:46:36 AM is when this event was logged.

高级

• log_record

  filters 会用到, 一个和 log 信息有关的对象

• loggers

  接口, 被应用层 (我们开发者) 调用的

• handlers

  写文件的, 挂在 logger 上

• filters

  过滤文本的, 可以给 logger 用, 也可以给 handler 用

• formatters

  定义 log 的格式, 给 handler 用

formatter

• fmt

  message 的格式

• datefmt

  时间格式

• style

  分隔符

  • %(asctime)s – %(levelname)s – %(message)s
  • &(asctime)s – &(levelname)s – &(message)s

例子

my_formater = logging.Formatter(fmt='%(asctime)s - %(levelname)s - %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p', style='%')

详细参数

源码里面有, 也可以看文档

filter

• 返回 True 或者 False
• False 将会被过滤
• 可以是一个类, 也可以是函数.
• 建议用类的形式, 因为带 name, 将来想 remove filter 更方便

• Filter 类长这样

  class Filter(object):
      def __init__(self, name=''):
          self.name = name
          self.nlen = len(name)
      def filter(self, record):
          return True

• 函数

  def my_filter(record):
      return False

handler

• logging 模块提供了很多 handler.
• logging.StreamHandler(sys.stdout) 和 logging.RotatingFileHandler 常见
• handler.addFilter()
• handler.setFormatter()
• my_handler.setLevel()

logger

• 定义 logger

  logger = logging.getLogger('666')

• set level

  logger.setLevel(logging.DEBUG)

• logger.addFilter()
• logger.addHandler()
• logger.info(‘message’)

例子

import logging
logger = logging.getLogger('spam_application')
logger.setLevel(logging.DEBUG)
my_handler = logging.StreamHandler()
my_handler.setLevel(logging.DEBUG)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
my_handler.setFormatter(formatter)
logger.addHandler(my_handler)
logger.info('creating an instance of auxiliary_module.Auxiliary')
>>> 2019-07-03 16:02:30,952 - spam_application - INFO - creating an instance of auxiliary_module.Auxiliary
my_filter = lambda record: True
my_handler.addFilter(my_filter)
logger.info('creating an instance of auxiliary_module.Auxiliary')
>>> 2019-07-03 16:03:06,858 - spam_application - INFO - creating an instance of auxiliary_module.Auxiliary
my_filter = lambda record: False
my_handler.addFilter(my_filter)
logger.info('creating an instance of auxiliary_module.Auxiliary')

配置日志记录

三种方式

1. 像上面用方法配置

2. dict

   LOGGING = {
       'version': 1,
       'disable_existing_loggers': True,
       'formatters': {
           'standard': {'format': '[%(asctime)s][%(filename)s] - %(funcName)s[line:%(lineno)d] - [%(levelname)s]: %(message)s'
           },
       },
       'filters': { },
       'handlers': {
           'security_log': {
               'level': 'DEBUG',
               'class': 'logging.handlers.RotatingFileHandler',
               'filename': os.path.join(cf['log']['path'], 'security_log.log'),
               'maxBytes': 1024 * 1024 * 10,
               'backupCount': 10,
               'formatter': 'standard',
           },
           'event_log': {
               'level': 'DEBUG',
               'class': 'logging.handlers.RotatingFileHandler',
               'filename': os.path.join(cf['log']['path'], 'event_log.log'),
               'maxBytes': 1024 * 1024 * 10,
               'backupCount': 10,
               'formatter': 'standard',
           },
           'console': {
               'level': 'ERROR',
               'class': 'logging.StreamHandler',
               'formatter': 'standard'
           },
       },
       'loggers': {
           'eventLog': {'handlers': ['event_log', 'console'],
               'level': 'DEBUG',
               'propagate': False
           },
           'security': {'handlers': ['security_log', 'console', 'security_db'],
               'level': 'DEBUG',
               'propagate': False
           },
           'system': {'handlers': ['system_log', 'console', 'system_db'],
               'level': 'DEBUG',
               'propagate': False
           },
       }
   }

3. file

   略

django

django 默认使用 dict 方式.

logging_settings == settings.LOGGING

logging_config == logging.config.dictConfig

def configure_logging(logging_config, logging_settings):
    if logging_config:
        # First find the logging configuration function ...
        logging_config_func = import_string(logging_config)

        logging.config.dictConfig(DEFAULT_LOGGING)

        # ... then invoke it with the logging settings
        if logging_settings:
            logging_config_func(logging_settings)

例子

理想情况下, 如果在 settings 中配置了 LOGGING, 直接使用即可.

# import the logging library
import logging

# Get an instance of a logger
logger = logging.getLogger(__name__)

def my_view(request, arg1, arg):
    ...
    if bad_mojo:
        # Log an error message
        logger.error('Something went wrong!')

最佳实践

1. disable_existing_loggers == False

   django 本身是有一个 logging 配置的, 这里有一个标志位去决定是否需要取消掉.

2. 灵活运用propagate 和 logging.getLogger(__name__)

   通过 . 找父亲.

   ‘a.b’ 是‘a.b.c’的父亲.‘a.b’是 logger name