Re: [PATCH 03/10] python/machine: use subprocess.run instead of subprocess.Popen

[Wainer dos Santos Moschetta <wainersm@redhat.com>]

Hi,

On 5/12/21 6:46 PM, John Snow wrote:
> use run() instead of Popen() -- to assert to pylint that we are not
> forgetting to close a long-running program.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>   python/qemu/machine.py | 15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/python/qemu/machine.py b/python/qemu/machine.py
> index 41f51bd27d0..c13ff9b32bf 100644
> --- a/python/qemu/machine.py
> +++ b/python/qemu/machine.py
> @@ -223,13 +223,16 @@ def send_fd_scm(self, fd: Optional[int] = None,
>               assert fd is not None
>               fd_param.append(str(fd))
>   
> -        proc = subprocess.Popen(
> -            fd_param, stdin=subprocess.DEVNULL, stdout=subprocess.PIPE,
> -            stderr=subprocess.STDOUT, close_fds=False
> +        proc = subprocess.run(
> +            fd_param,
> +            stdin=subprocess.DEVNULL,
> +            stdout=subprocess.PIPE,
> +            stderr=subprocess.STDOUT,
> +            check=True,
> +            close_fds=False,
>           )

Now it might throw a CalledProcessError given that `check=True`. 
Shouldn't it capture the exception and (possible) re-throw as an 
QEMUMachineError?

- Wainer

> -        output = proc.communicate()[0]
> -        if output:
> -            LOG.debug(output)
> +        if proc.stdout:
> +            LOG.debug(proc.stdout)
>   
>           return proc.returncode
>