subprocess.run 的异常处理

Question

我使用以下代码来测试向 shell 发送命令时的错误捕获：

#!/usr/bin/python3

'''Trying to get a better error capture for subprocess.run'''

import subprocess
import argparse

cmd = 'ixconfig'
useShell = False

if useShell:
    myCommand = cmd
else:
    myCommand = cmd.split()
    
try:
    result = subprocess.run(myCommand,
                            capture_output=True,
                            check=True,
                            shell=useShell,
                            text=True,
                            timeout=1,
                           )
except subprocess.TimeoutExpired:
    print('Timeout occurred')
    result = argparse.Namespace(err=f'"{myCommand}" timed out')
except subprocess.CalledProcessError as subErr:
    print('subprocess.CalledProcessError')
    result = argparse.Namespace(err=subErr)
except subprocess.SubprocessError as subErr:
    print('except subprocess.SubprocessError')
    result = argparse.Namespace(err=subErr)
# except:
#     result = 'Poor way to handle an exception'

print(f'{result=}')

在大多数情况下它是有效的。当我尝试列出无效目录 (

cmd = 'ls /var/log/xxx'

) 或超时 (

cmd = 'sleep 5'

) 时，我可能会收到 CalledProcessError。

但是，如果我发送错误的命令，例如

cmd = 'ixconfig'

，我会得到回溯而不是通过 SubprocessError 捕获：

Traceback (most recent call last):
  File "/Users/shepherd/prog/aws/BBEditRunTemp-testSubprocess.py", line 17, in <module>
    result = subprocess.run(myCommand,
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/subprocess.py", line 489, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/subprocess.py", line 1702, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'ixconfig'

如果我取消注释直接的

except:

部分，异常会被正确捕获，但我知道裸异常是糟糕的编程。如何正确捕获正确的运行时异常？

Answer 1

@andrej-kesely 提供了有效的答案：

except FileNotFoundError as subErr:
    print('FileNotFoundError')
    result = argparse.Namespace(err=subErr)