“OSError: [Errno 22] 无效参数";在带有 print() 和管道输出的 Windows 上

“OSError: [Errno 22] 无效参数

问题描述：

在将 Python 脚本的输出通过无效参数通过管道传输到 wc 时，我遇到了一些(对我而言)奇怪的行为.

I've come across some (to me) weird behaviour when piping the output of a Python script into wc with invalid arguments.

λ python test.py
Hello!
λ python test.py | wc -li
wc: unknown option -- i
Try 'wc --help' for more information.
Exception ignored in: <_io.TextIOWrapper name='<stdout>' mode='w' encoding='cp1252'>
OSError: [Errno 22] Invalid argument

这里发生了什么?

我的配置是

Windows 10
指挥官
msysgit 2.5.1.windows.1

答

As @AChampion 指出，这是 IOError:[Errno 32] 管道破裂:`prog.py |othercmd` 并添加了一个警告，即 Python 无法引发正确的异常(即 BrokenPipeError).

As @AChampion noted, this is the Windows version of IOError: [Errno 32] Broken pipe when piping: `prog.py | othercmd` with the added caveat that Python fails to raise the correct exception (i.e. BrokenPipeError).

问题 35754 "[Windows] I/O 可能在损坏的管道上引发 EINVAL OSError 而不是 BrokenPipeError Python 的错误跟踪器.

There's issue 35754 "[Windows] I/O on a broken pipe may raise an EINVAL OSError instead of BrokenPipeError" Python's bug tracker.

在修复之前，我没有看到处理它的通用方法.

Until it's fixed, I don't see a general way to handle it.

如何将 sys.stdout 复制到日志文件? 有助于解决基于 Python 的输出(通过 sys.stdout):

How to duplicate sys.stdout to a log file? helps solve this for Python-based output (printing via sys.stdout):

class IgnoreBrokenPipe(object):
    def __init__(self, stream):
        self.stream = stream
        def ignore_einval(fn):
            from functools import wraps
            @wraps(fn)
            def wrapper(*args, **kwargs):
                try:
                    return fn(*args, **kwargs)
                except OSError as exc:
                    if exc.errno != 22:
                        raise exc
                    else:  # mimicking the default SIGPIPE behavior on Windows
                        sys.exit(1)
            return wrapper

        self.write = ignore_einval(lambda data: self.stream.write(data))
        self.flush = ignore_einval(lambda: self.stream.flush())

import sys
sys.stdout = IgnoreBrokenPipe(sys.stdout)

“OSError: [Errno 22] 无效参数";在带有 print() 和管道输出的 Windows 上

相关推荐