更简单的方法来启用详细日志记录

Question

我想添加一个调试print语句测试,如果我--verbose从命令行启用,如果我在脚本中有以下内容.

logger.info("test")

我经历了以下问题,但无法得到答案......

• 如何在脚本中实现--verbose或-v选项？

• Python日志记录 - DEBUG下面有什么东西吗？

Answer 1

我发现--verbose(对于用户而言)和--debug(对于开发人员)都很有用.以下是我如何使用logging和argparse:

import argparse
import logging

parser = argparse.ArgumentParser()
parser.add_argument(
    '-d', '--debug',
    help="Print lots of debugging statements",
    action="store_const", dest="loglevel", const=logging.DEBUG,
    default=logging.WARNING,
)
parser.add_argument(
    '-v', '--verbose',
    help="Be verbose",
    action="store_const", dest="loglevel", const=logging.INFO,
)
args = parser.parse_args()    
logging.basicConfig(level=args.loglevel)

因此,如果--debug设置,则将日志记录级别设置为DEBUG.如果--verbose,日志记录设置为INFO.如果两者都没有,缺少--debug将日志记录级别设置为默认值WARNING.

Answer 2

您需要将Argparse教程的智慧与Python的Logging HOWTO结合起来.这是一个例子......

> cat verbose.py 
#!/usr/bin/env python

import argparse
import logging

parser = argparse.ArgumentParser(
    description='A test script for http://stackoverflow.com/q/14097061/78845'
)
parser.add_argument("-v", "--verbose", help="increase output verbosity",
                    action="store_true")

args = parser.parse_args()
if args.verbose:
    logging.basicConfig(level=logging.DEBUG)

logging.debug('Only shown in debug mode')

运行帮助:

> ./verbose.py -h
usage: verbose.py [-h] [-v]

A test script for http://stackoverflow.com/q/14097061/78845

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose  increase output verbosity

以详细模式运行:

> ./verbose.py -v
DEBUG:root:Only shown in debug mode

默默地运行:

> ./verbose.py   
> 

Answer 3

这是一个更简洁的方法,它执行边界检查,并将在帮助中列出有效值:

parser = argparse.ArgumentParser(description='This is a demo.')
parser.add_argument("-l", "--log", dest="logLevel", choices=['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'], help="Set the logging level")

args = parser.parse_args()
if args.logLevel:
    logging.basicConfig(level=getattr(logging, args.logLevel))

用法:

demo.py --log DEBUG

Answer 4

另一种变体是计算数量-v并使用计数作为a的索引list,其实际级别来自logging:

import argparse
import logging

parser = argparse.ArgumentParser()
parser.add_argument('-v', '--verbose', action='count', default=0)
args = parser.parse_args()

levels = [logging.WARNING, logging.INFO, logging.DEBUG]
level = levels[min(len(levels)-1,args.verbose)]  # capped to number of levels

logging.basicConfig(level=level,
                    format="%(asctime)s %(levelname)s %(message)s")

logging.debug("a debug message")
logging.info("a info message")
logging.warning("a warning message")

这适用于-vvvv,-vvv,-vv,-v,-v -v,等,如果没有-v则logging.WARNING选择更多,如果-v提供的话,将会给INFO和DEBUG

Answer 5

您可以明确指定一个级别作为-v标志后的整数:

parser = argparse.ArgumentParser()
parser.add_argument("-v", "--verbose", const=1, default=0, type=int, nargs="?",
                    help="increase verbosity: 0 = only warnings, 1 = info, 2 = debug. No number means info. Default is no verbosity.")
args = parser.parse_args()

logger = logging.getLogger()
if args.verbose == 0:
    logger.setLevel(logging.WARN) 
elif args.verbose == 1:
    logger.setLevel(logging.INFO) 
elif args.verbose == 2:
    logger.setLevel(logging.DEBUG)