python - 将日志记录“打印”功能更改为“tqdm.write”，这样日志记录就不会干扰进度条

Question

我有一个简单的问题：如何将内置 Python 记录器的print功能更改为tqdm.write使记录消息不会干扰 tqdm 的进度条？谢谢！

Answer 1

您需要一个自定义日志记录处理程序：

import logging
import tqdm

class TqdmLoggingHandler(logging.Handler):
    def __init__(self, level=logging.NOTSET):
        super().__init__(level)

    def emit(self, record):
        try:
            msg = self.format(record)
            tqdm.tqdm.write(msg)
            self.flush()
        except Exception:
            self.handleError(record)  

然后将其添加到日志链中：

import time

log = logging.getLogger(__name__)
log.setLevel(logging.INFO)
log.addHandler(TqdmLoggingHandler())
for i in tqdm.tqdm(range(100)):
    if i == 50:
        log.info("Half-way there!")
    time.sleep(0.1)

编辑：修复了调用超级 TqdmLoggingHandler 的 init 方法中的一个错误，这是由勤奋的读者 @BlaineRogers 在评论中指出的。（如果有人想进一步了解 Python 的这个阴暗领域，我推荐https://fuhm.net/super-harmful/）

Answer 2

tqdm现在有一个用于重定向记录器的内置上下文管理器：

import logging
from tqdm import trange
from tqdm.contrib.logging import logging_redirect_tqdm

LOG = logging.getLogger(__name__)

if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO)
    with logging_redirect_tqdm():
        for i in trange(9):
            if i == 4:
                LOG.info("console logging redirected to `tqdm.write()`")
    # logging restored

复制自 tqdm 文档

Answer 3

最简单的方法是更改StreamHandler​​对象流，例如：

import logging
from tqdm import tqdm, trange
import time

log = logging.getLogger(__name__)
log.setLevel(logging.INFO)
handler = logging.StreamHandler()
handler.setStream(tqdm) # <-- important
handler = log.addHandler(handler)

for i in trange(100):
    if i == 50:
        log.info("Half-way there!")
    time.sleep(0.1)

Answer 4

根据上面 RolKau 的回答，简化：

import logging
from tqdm import tqdm


class TqdmLoggingHandler(logging.StreamHandler):
    """Avoid tqdm progress bar interruption by logger's output to console"""
    # see logging.StreamHandler.eval method:
    # https://github.com/python/cpython/blob/d2e2534751fd675c4d5d3adc208bf4fc984da7bf/Lib/logging/__init__.py#L1082-L1091
    # and tqdm.write method:
    # https://github.com/tqdm/tqdm/blob/f86104a1f30c38e6f80bfd8fb16d5fcde1e7749f/tqdm/std.py#L614-L620

    def emit(self, record):
        try:
            msg = self.format(record)
            tqdm.write(msg, end=self.terminator)
        except RecursionError:
            raise
        except Exception:
            self.handleError(record)

测试：

import time

log = logging.getLogger(__name__)
log.setLevel(logging.INFO)
log.addHandler(TqdmLoggingHandler())
#   ^-- Assumes this will be the unique handler emitting messages to sys.stdout.
#       If other handlers output to sys.stdout (without tqdm.write),
#       progress bar will be interrupted by those outputs

for i in tqdm(range(20)):
    log.info(f"Looping {i}")
    time.sleep(0.1)

警告：如果您在 Jupyter 笔记本中工作，进度条将被打断，AFAIK 无法避免。

Answer 5

一种不那么优雅的简单解决方案是将 tqdm 对象转换为字符串。之后，您可以记录消息（或根据需要处理）。“format_dict”属性也可能有用：

from tqdm import tqdm
import time

#loop with progressbar:
it=tqdm(total=10)
for i in range(10):
    time.sleep(0.1)
    it.update(1)

it.close()
print("\n","--"*10)

# Convert tdqm object last output to sting
str_bar_msg = str(it)
print(str_bar_msg)

# See attributes:
print(it.format_dict)

输出：

100%|██████████| 10/10 [00:01<00:00,  8.99it/s]
 --------------------
100%|██████████| 10/10 [00:01<00:00,  8.98it/s]
{'n': 10, 'total': 10, 'elapsed': 1.1145293712615967, 'ncols': None, 'nrows': None, 'prefix': '', 'ascii': False, 'unit': 'it', 'unit_scale': False, 'rate': None, 'bar_format': None, 'postfix': None, 'unit_divisor': 1000, 'initial': 0, 'colour': None}

此致