[Python-Dev] deprecate commands.getstatus()
titus at caltech.edu
Fri Mar 16 18:19:04 CET 2007
On Fri, Mar 16, 2007 at 09:50:29AM -0700, Guido van Rossum wrote:
-> > What do people think of this basic interface?
-> > (status, output) = subprocess.get_status_output(cmd)
-> > output = subprocess.get_output(cmd)
-> > Here 'status' is the 'returncode' from subprocess.Popen, and 'output'
-> > would be the combined stdout/stderr. 'commands.getstatus' would be
-> > removed entirely .
-> > 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?
Yes; subprocess has only two "convenience" functions apart from the main
class, in fact, and their names are quite short and simple.
-> > 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.
My preference would be to push people towards subprocess, and the more
capable & complex API there, by deprecating commands completely. I'm
happy to do it either way.
-> > An additional function that I would personally like is:
-> > (status, output, errout) = subprocess.get_status_output_err(cmd)
-> > although the name is hideous. I'd like to change 'get_status_output'
-> > 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.
I believe that this is what
subprocess.Popen(..., stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
does, but I will check to be sure.
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