On 9 Mar 2022, at 14:42, mangelozzi@gmail.com wrote:
I often wish to perform the action of `subprocess.check_output`, i.e. print STDOUT live, and check the return code is 0 on exit. However if there is an error, I would like the STDERR to be printed. When looking at log files and just seeing the return code is often not very beneficial.
E.g.:
```py subprocess.check_call(['ping', '-c', '1', 'github.com2']) ```
Will generate this error: ``` subprocess.CalledProcessError: Command '['ping', '-c', '1', 'github.com2']' returned non-zero exit status 2. ```
Here we are left wondering why it failed, on real world examples it becomes critical to be able to see what the actual error is. So I find I always have to wrap such calls in something like this to be able to see STDERR:
``` import subprocess cmds = ['ping', '-c', '1', 'github.com2'] result = subprocess.run(cmds, stderr=subprocess.PIPE) if result.returncode != 0: msg = result.stderr.decode().strip() raise subprocess.CalledProcessError(f"CALLED SUBPROCESS ERROR: Command: {' '.join(cmds)}\nReturn code {result.returncode}\nSTDERR: {msg}\n") ```
With the above one gets to see that STDERR is: ``` ping: github.com2: Temporary failure in name resolution ```
I think you are saying you can do what you want with subprocess.run(). What did you need a change to support? I often wrap code around subprocess.run() to get the exact behaviour that I need. Seems to work well. Barry
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