使用Python的日志记录覆盖之前的控制台行

Question

我想使用Python的日志库来覆盖之前的控制台行。当进程运行时，它应该在控制台上显示

...

，然后在进程完成后用

OK

覆盖它，如此 Python 代码所示。

import time

for i in range(10):
    print(f'Progress: {i+1}/10 ...', end='')
    time.sleep(1)
    print(f'\rProgress: {i+1}/10  OK')

我想使用

logging

库实现相同的结果，但我当前的解决方案感觉太冗长且不符合 Python 风格。有人有更好的方法吗？谢谢！

import logging
import sys
import time

class OverwriteStreamHandler(logging.StreamHandler):
    def __init__(self, stream, overwrite=False):
        super().__init__(stream)
        self.overwrite = overwrite

    def emit(self, record):
        msg = self.format(record)
        stream = self.stream
        if self.overwrite:
            stream.write('\r' + msg)
        else:
            stream.write(msg)
        stream.flush()

def create_logger(name, overwrite=False):
    handler = OverwriteStreamHandler(sys.stdout, overwrite=overwrite)
    handler.setLevel(logging.DEBUG)
    formatter = logging.Formatter('%(message)s')
    handler.setFormatter(formatter)
    logger = logging.getLogger(name)
    logger.setLevel(logging.DEBUG)
    logger.addHandler(handler)
    return logger

logger1 = create_logger('logger1')
logger2 = create_logger('logger2', overwrite=True)

for i in range(10):
    logger1.info(f'Progress: {i+1}/10 ...')
    time.sleep(1)
    logger2.info(f'Progress: {i+1}/10  Ok\n')

Answer 1

有2个选择： 1-添加带有空终止符的处理程序并手动添加行终止符。 2- 创建一个附加记录器，并在处理程序中配置终止符。

选项1

import logging
import time

logging.basicConfig(level=logging.INFO)

logger1 = logging.getLogger("SO_log")
logger2 = logging.getLogger("SO_log")

ch = logging.StreamHandler()
ch.terminator=''
ch.setLevel(logging.INFO)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
ch.setFormatter(formatter)

logger2.addHandler(ch)
logger2.propagate = False

logger1.info('Started\n')


for i in range(10):
    msg = f'Progress: {i+1:>2}/10 {"..."}\r'
    logger1.info(msg)
    time.sleep(0.21)
    msg = f'Progress: {i+1:>2}/10 {"Ok":>3}\r'
    if i == 10:
        msg += "\n"
    logger1.info(msg)
    # additional delay to get a chance to see the Ok msg
    time.sleep(0.21)

logger1.info('\n')

输出日期和消息的最后 9 个字符将交替出现

2024-12-18 23:44:32,535 - SO_log1 - INFO - Started
2024-12-18 23:44:34,638 - SO_log1 - INFO - Progress: 10/10  Ok

选项2

使用 2 个记录器并在处理程序上设置行终止符

import logging
import time

logging.basicConfig(level=logging.INFO)

logger1 = logging.getLogger("SO_log1")
logger2 = logging.getLogger("SO_log2")

ch1 = logging.StreamHandler()
ch1.setLevel(logging.INFO)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
ch1.setFormatter(formatter)
logger1.addHandler(ch1)
logger1.propagate = False

ch2 = logging.StreamHandler()
ch2.terminator='\r'
ch2.setLevel(logging.INFO)
ch2.setFormatter(formatter)
logger2.addHandler(ch2)
logger2.propagate = False

logger1.info('Started opt 2')

for i in range(10):
    msg = f'Progress: {i+1:>2}/10 {"..."}'
    logger2.info(msg)
    time.sleep(0.21)
    msg = f'Progress: {i+1:>2}/10 {"Ok":>3}'
    #logger2.info(msg)

    if i < 10:
        logger2.info(msg)
    else:
        logger1.info(msg)
    time.sleep(0.21)

logger1.info("\n")

输出2

2024-12-19 00:03:38,262 - SO_log1 - INFO - Started opt 2
2024-12-19 00:03:42,467 - SO_log1 - INFO - Progress: 10/10  Ok