[Python-Dev] deprecate commands.getstatus() (original) (raw)

Guido van Rossum guido at python.org
Fri Mar 16 17:50:29 CET 2007

On 3/16/07, Titus Brown <titus at caltech.edu> wrote:

-> > >> What about reimplementing commands.* using subprocess? Or providing a -> > >> commands.*-compatible interface in the subprocess module?

OK, so as I understand it, the next step would be for me to provide a patch implementing this, right? Or is this PEP-required (please no...)?

No pep.

What do people think of this basic interface?

(status, output) = subprocess.getstatusoutput(cmd) output = subprocess.getoutput(cmd) Here 'status' is the 'returncode' from subprocess.Popen, and 'output' would be the combined stdout/stderr. 'commands.getstatus' would be removed entirely [0]. This mimics 'commands' fairly closely, while adhering to PEP 8 guidelines; it's a simple API; and it should be dead easy to implement.

Right. Does it also match the style of the API provided by the subprocess module?

It will also have the various advantages people have mentioned:

* better error trapping; * better post-fork behavior; * multi-platform support; If this sort of thing goes in, I guess commands.* would then be deprecated with a note saying "go look at these similar commands in subprocess", right?

Yes. Another intermediate step might be to rewrite the commands module to call the new APIs in the subprocess module.

An additional function that I would personally like is:

(status, output, errout) = subprocess.getstatusoutputerr(cmd) although the name is hideous. I'd like to change 'getstatusoutput' to return a triple, but I'm not sure how big a change that would be relative to the expected behavior from the ancestral commands function.

Call it get_status_output_errors and you have my blessings. If at all possible, get_status_output should not just concatenate the output and errors from this API, but attempt to really merge the stdout and stderr stream so that if they are interleaved they come out in the right order. That's what the old getstatusoutput() did by putting '2>&1' around the command.

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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