python logging模块配置

日志级别对应值如下表所示。了解这些有助于你定义自己的日志级别的相对关系。如果你定义的级别与已有的数值相同，则原有的级别会被覆盖。

级别	数值
CRITICAL	50
ERROR	40
WARNING	30
INFO	20
DEBUG	10
NOTSET	0

 

生成log的几个方法， 这几个方法安重要程度依次排开， logger的设置可以影响一部分呢不重要的内容记录到日志当中。

• debug(log_message, [*args[, **kwargs]])
• info(log_message, [*args[, **kwargs]])
• warning(log_message, [*args[, **kwargs]])
• error(log_message, [*args[, **kwargs]])
• critical(log_message, [*args[, **kwargs]])
• exception(message[, *args])
• log(log_level, log_message, [*args[, **kwargs]])

 

Handler 是处理器， 可以把log记录到文件系统中， 输出到终端设备， 或者网络sockt或者邮件等。

• StreamHandler
• FileHandler
• RotatingFileHandler
• TimedRotatingFileHandler
• SocketHandler
• DatagramHandler
• SysLogHandler
• NTEventLogHandler
• SMTPHandler
• MemoryHandler
• HTTPHandler

LoggerFormatter， log的格式， 使用这个可以更容易的根据错误检错。

%(name)s            Name of the logger (logging channel)
%(levelno)s         Numeric logging level for the message (DEBUG, INFO,
                    WARNING, ERROR, CRITICAL)
%(levelname)s       Text logging level for the message ("DEBUG", "INFO",
                    "WARNING", "ERROR", "CRITICAL")
%(pathname)s        Full pathname of the source file where the logging
                    call was issued (if available)
%(filename)s        Filename portion of pathname
%(module)s          Module (name portion of filename)
%(lineno)d          Source line number where the logging call was issued
                    (if available)
%(created)f         Time when the LogRecord was created (time.time()
                    return value)
%(asctime)s         Textual time when the LogRecord was created
%(msecs)d           Millisecond portion of the creation time
%(relativeCreated)d Time in milliseconds when the LogRecord was created,
                    relative to the time the logging module was loaded
                    (typically at application startup time)
%(thread)d          Thread ID (if available)
%(process)d         Process ID (if available)
%(message)s         The result of record.getMessage(), computed just as
                    the record is emitted

下面是一个简单的demo， 其中使用了两个handler分别将log记录到标准输出和文件中,因为handler是可以加多个的额， 所以你可以任意添加自己的handler。

#!/usr/bin/env python

import logging

#create logger
logger = logging.getLogger("simple_example")
logger.setLevel(logging.DEBUG)
#create console handler and set level to error
ch = logging.StreamHandler()
ch.setLevel(logging.ERROR)
#create file handler and set level to debug
fh = logging.FileHandler("spam.log")
fh.setLevel(logging.DEBUG)
#create formatter
formatter = logging.Formatter("%(asctime)s - %(name)s - %(levelname)s -
   %(message)s")
#add formatter to ch and fh
ch.setFormatter(formatter)
fh.setFormatter(formatter)
#add ch and fh to logger
logger.addHandler(ch)
logger.addHandler(fh)

#"application" code
logger.debug("debug message")
logger.info("info message")
logger.warn("warn message")
logger.error("error message")
logger.critical("critical message")