import logging
import sys
fmt = logging.Formatter("%(asctime)s - %(name)s - %(ip)s - %(username)s - %(message)s")
h_console = logging.StreamHandler(sys.stdout)
h_console.setFormatter(fmt)
logger = logging.getLogger("myPro")
logger.setLevel(logging.DEBUG)
logger.addHandler(h_console)
extra_dict = {"ip": "113.208.78.29", "username": "Petter"}
logger.debug("User Login!", extra=extra_dict)
extra_dict = {"ip": "223.190.65.139", "username": "Jerry"}
logger.info("User Access!", extra=extra_dict)

class LoggerAdapter(object):
 """
 An adapter for loggers which makes it easier to specify contextual
 information in logging output.
 """
 def __init__(self, logger, extra):
  """
  Initialize the adapter with a logger and a dict-like object which
  provides contextual information. This constructor signature allows
  easy stacking of LoggerAdapters, if so desired.
  You can effectively pass keyword arguments as shown in the
  following example:
  adapter = LoggerAdapter(someLogger, dict(p1=v1, p2="v2"))
  """
  self.logger = logger
  self.extra = extra
 def process(self, msg, kwargs):
  """
  Process the logging message and keyword arguments passed in to
  a logging call to insert contextual information. You can either
  manipulate the message itself, the keyword args or both. Return
  the message and kwargs modified (or not) to suit your needs.
  Normally, you'll only need to override this one method in a
  LoggerAdapter subclass for your specific needs.
  """
  kwargs["extra"] = self.extra
  return msg, kwargs
 def debug(self, msg, *args, **kwargs):
  """
  Delegate a debug call to the underlying logger, after adding
  contextual information from this adapter instance.
  """
  msg, kwargs = self.process(msg, kwargs)
  self.logger.debug(msg, *args, **kwargs)

import logging
import sys
# 初始化一个要传递给LoggerAdapter构造方法的logger实例
fmt = logging.Formatter("%(asctime)s - %(name)s - %(ip)s - %(username)s - %(message)s")
h_console = logging.StreamHandler(sys.stdout)
h_console.setFormatter(fmt)
init_logger = logging.getLogger("myPro")
init_logger.setLevel(logging.DEBUG)
init_logger.addHandler(h_console)
# 初始化一个要传递给LoggerAdapter构造方法的上下文字典对象
extra_dict = {"ip": "IP", "username": "USERNAME"}
# 获取一个LoggerAdapter类的实例
logger = logging.LoggerAdapter(init_logger, extra_dict)
# 应用中的日志记录方法调用
logger.info("User Login!")
logger.info("User Login!", extra={"ip": "113.208.78.29", "username": "Petter"})
logger.extra = {"ip": "113.208.78.29", "username": "Petter"}
logger.info("User Login!")
logger.info("User Login!")

# 使用extra默认值：{"ip": "IP", "username": "USERNAME"}
2017-05-14 17:23:15,148 - myPro - IP - USERNAME - User Login!
# info(msg, extra)方法中传递的extra方法没有覆盖默认值
2017-05-14 17:23:15,148 - myPro - IP - USERNAME - User Login!
# extra默认值被修改了
2017-05-14 17:23:15,148 - myPro - 113.208.78.29 - Petter - User Login!
2017-05-14 17:23:15,148 - myPro - 113.208.78.29 - Petter - User Login!

import logging
import sys
class MyLoggerAdapter(logging.LoggerAdapter):
 def process(self, msg, kwargs):
  if 'extra' not in kwargs:
   kwargs["extra"] = self.extra
  return msg, kwargs
if __name__ == '__main__':
 # 初始化一个要传递给LoggerAdapter构造方法的logger实例
 fmt = logging.Formatter("%(asctime)s - %(name)s - %(ip)s - %(username)s - %(message)s")
 h_console = logging.StreamHandler(sys.stdout)
 h_console.setFormatter(fmt)
 init_logger = logging.getLogger("myPro")
 init_logger.setLevel(logging.DEBUG)
 init_logger.addHandler(h_console)
 # 初始化一个要传递给LoggerAdapter构造方法的上下文字典对象
 extra_dict = {"ip": "IP", "username": "USERNAME"}
 # 获取一个自定义LoggerAdapter类的实例
 logger = MyLoggerAdapter(init_logger, extra_dict)
 # 应用中的日志记录方法调用
 logger.info("User Login!")
 logger.info("User Login!", extra={"ip": "113.208.78.29", "username": "Petter"})
 logger.info("User Login!")
 logger.info("User Login!")

# 使用extra默认值：{"ip": "IP", "username": "USERNAME"}
2017-05-22 17:35:38,499 - myPro - IP - USERNAME - User Login!
# info(msg, extra)方法中传递的extra方法已覆盖默认值
2017-05-22 17:35:38,499 - myPro - 113.208.78.29 - Petter - User Login!
# extra默认值保持不变
2017-05-22 17:35:38,499 - myPro - IP - USERNAME - User Login!
2017-05-22 17:35:38,499 - myPro - IP - USERNAME - User Login!

import logging
from random import choice
class ContextFilter(logging.Filter):
  ip = 'IP'
  username = 'USER'
  def filter(self, record):
   record.ip = self.ip
   record.username = self.username
   return True
if __name__ == '__main__':
 levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL)
 users = ['Tom', 'Jerry', 'Peter']
 ips = ['113.108.98.34', '219.238.78.91', '43.123.99.68']
 logging.basicConfig(level=logging.DEBUG,
      format='%(asctime)-15s %(name)-5s %(levelname)-8s %(ip)-15s %(username)-8s %(message)s')
 logger = logging.getLogger('myLogger')
 f = ContextFilter()
 logger.addFilter(f)
 logger.debug('A debug message')
 logger.info('An info message with %s', 'some parameters')
 for x in range(5):
  lvl = choice(levels)
  lvlname = logging.getLevelName(lvl)
  filter.ip = choice(ips)
  filter.username = choice(users)
  logger.log(lvl, 'A message at %s level with %d %s', lvlname, 2, 'parameters')