python logging 自定义formatter

问题

自定义log formatter， 如添加request_id

方法

• 定义Logging Filter

  class ServerFilter(logging.Filter):
      ...
      def filter(self, record):
          record.request_id = xxx
          return True
  
  handler.addFilter(ServerFilter())
  handler.setFormatter(ServerFormatter(f"%(asctime)s - {hostname} - [%(levelname)s] - %(filename)s:%(lineno)s: %(name)s: |%(request_id)s| %(message)s"))
  

• 定义logging Formater

  class ServerFormatter(logging.Formatter):
      ...
      def format(self, record):
          record.request_id = xxx
          
          return super(ServerFormatter, self).format(record)
     
      handler.setFormatter(ServerFormatter(f"%(asctime)s - {hostname} - [%(levelname)s] - %(filename)s:%(lineno)s: %(name)s: |%(request_id)s| %(message)s"))
  

• 深度自定义Formatter

  class JsonFormatter(logging.Formatter):
      def __init__(self, fmt=None, datefmt=None, style='%', mid="mid_unknown", event_id=None):
          super().__init__(fmt, datefmt, style)
          self.mid = mid
          self.event_id = event_id
  
      def format(self, record):
          # 将 record.message 转换为 JSON 字符串
          if isinstance(record.msg, dict):
              record.msg = json.dumps(record.msg, ensure_ascii=False)
          # 添加 mid 到 record
          record.mid = self.mid
          if 'event_id' in record.__dict__:
              record.event_id = record.__dict__['event_id']
          else:
              record.event_id = self.event_id
          
          # 创建日志字典
          log_dict = {
              "time_stamp": self.formatTime(record, self.datefmt),
              "mid": record.mid,
              "event_id": record.event_id,
              "level": record.levelname,
              "message": record.msg,
              "msg_type": "json" if isinstance(record.msg, str) and record.msg.startswith('{') else "text"
          }
          # print(f"================={record}")
          
          # 将日志字典转换为 JSON 字符串
          return json.dumps(log_dict, ensure_ascii=False)
  
  
  class ElapsedLog(logging.Logger):
      """
      日志记录
      """
  
      def __init__(self, name=None, verbose=False, file_handler=True, mid="mid_unknown", event_id=None):
          """
              verbose==False, 表示INFO level
              verbose==True, 表示DEBUG level
              file_handler=False, 表示不写入到文件
              file_handler=True, 表示写入到文件
          """
          super().__init__(name)
          super().setLevel(logging.DEBUG if verbose else logging.INFO)
  
          # 设置日志打印格式
          self.formatter = JsonFormatter(mid=mid, event_id=event_id)
  
          if file_handler:
              if not os.path.exists(log_dir):
                  os.makedirs(log_dir)
              file_handler = handlers.TimedRotatingFileHandler(
                  filename=log_path, when=when, backupCount=backupCount, encoding="utf-8")
              file_handler.suffix = "%Y%m%d-%H-%M-%S.log"
              file_handler.extMatch = re.compile(r"^\d{8}-\d{2}-\d{2}-\d{2}.log$")
              file_handler.setFormatter(self.formatter)
              self.addHandler(file_handler)
  
          stream_handler = logging.StreamHandler()
          stream_handler.setFormatter(self.formatter)
          self.addHandler(stream_handler)
  
      def set_mid(self, mid):
          """设置 mid"""
          self.formatter.mid = mid
  
      def set_event_id(self, event_id):
          """设置 event id"""
          self.formatter.event_id = event_id
  

# 创建日志记录器实例
logger = ElapsedLog(file_handler=True)

if __name__ == '__main__':
   # 设置 mid
   logger.set_mid('123456789')
   logger.set_event_id('ElapsedEvent')

   a = {"x": True}

问题

1. 如何对自定义变量赋值？比如上述record.request_id = xxx， xxx的值如何获取？
   • 方式1: 使用app的request上下文，自动获取request_id并赋值
   • 方式2: 在打印日志的时候，Formatter 手动赋值self.formatter.request_id = "xxxx"
   • 方式3: 在打印日志的时候，手动赋值log.$filter.request_id = "xxxx" ,针对sanic可以在@bp.on_request阶段设置log.filter.request_id
   • 方式4： 打印日志的时候，手动赋值extra， log.info("", extra=extra)；extra["request_id"] = "xxx"