On Wed, 25 May 2011 09:41:46 -0400 Barry Warsaw wrote:

On May 25, 2011, at 10:24 AM, Sandro Tosi wrote:

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before opening an issue to track the request, I'd like to ask advice here about this: extend os.chown() to accept even user/group names instead of just uid and gid.

On a Unix system, you can call chown command passing either id or names, so it seems (to me at least) natural to expect os.chown() to behave similarly; but that's not the case.

I can see os module wants to be a thin wrapper around OS syscalls and chown(2) accepts only uid/gid as input, so what would be best: extend os.chown() or provide a chown() function in shutil module for this purpose?

I think it would be a nice feature, and I can see the conflict. OT1H you want to keep os.chown() a thin wrapper, but OTOH you'd rather not have to add a new, arguably more difficult to discover, function. Given those two choices, I still think I'd come down on adding a new function and shutil.chown() seems an appropriate place for it.

+1 for shutil.chown(). Regards Antoine.

On Wed, May 25, 2011 at 15:41, Barry Warsaw wrote:

I think it would be a nice feature, and I can see the conflict.  OT1H you want to keep os.chown() a thin wrapper, but OTOH you'd rather not have to add a new, arguably more difficult to discover, function.  Given those two choices, I still think I'd come down on adding a new function and shutil.chown() seems an appropriate place for it.

Right. Please add a mention of shutil.chown() to the os.chown() docs, though. Cheers, Dirkjan

On 5/25/2011 1:17 PM, Victor Stinner wrote:

Le mercredi 25 mai 2011 à 18:46 +0200, Charles-François Natali a écrit :

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While we're at it, adding a "recursive" argument to this shutil.chown could also be useful.

I don't like the idea of a recursive flag. I would prefer a "map-like" function to "apply" a function on all files of a directory. Something like shutil.apply_recursive(shutil.chown)...

... maybe with options to choose between deep-first search and breadth-first search, filter (filenames, file size, files only, directories only, other attributes?), directory before files (may be need for chmod(0o000)), etc.

You can do all of this with an appropriate application of os.walk(). Eric.

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While we're at it, adding a "recursive" argument to this shutil.chown could also be useful.

I don't like the idea of a recursive flag. I would prefer a "map-like" function to "apply" a function on all files of a directory. Something like shutil.apply_recursive(shutil.chown)...

I was also thinking about this possibility. The advantage is that we could factor-out the recursive walk logic to make it available for other functions (chown, chmod...). It doesn't map well to the Unix command, though.

You can do all of this with an appropriate application of os.walk().

Then, I wonder why shutil.copytree and shutil.rmtree are provided. Recursive rm/copy/chown/chmod are extremely useful in system administration scripts. Furthermore, it's not as simple as it seems because of symlinks, see for example http://bugs.python.org/issue4489 .

Nick Coghlan wrote:

2011/5/26 Charles-François Natali :

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Then, I wonder why shutil.copytree and shutil.rmtree are provided. Recursive rm/copy/chown/chmod are extremely useful in system administration scripts. Furthermore, it's not as simple as it seems because of symlinks, see for example http://bugs.python.org/issue4489

Rather than a fixed binary flag, I would suggest following the precedent of copytree and rmtree, and provide recursive functionality as a separate shutil function (i.e. shutil.chmodtree, shutil.chowntree).

+1

As noted, while these *can* be written manually, it is convenient to have the logic for handling symlinks dealt with for you, as well as not having to look up the particular incantation for correctly linking os.walk and the relevant operations.

This is exactly what I meant when saying that the -R option to chown and chmod shell commands is useful. I *could* do it without them, but writing the same logic every time with error handling would be cumbersome. Petri

On Fri, Jun 3, 2011 at 12:34 PM, Ross Lagerwall wrote:

.. What should the name of the (seconds, nanoseconds) tuple be? st_atim, st_ctim and st_mtim has bee suggested and is what the POSIX specification uses. This is confusingly similar to the existing st_atime, st_ctime and st_mtime.

Still, inventing new names would make it even more confusing. +1 for POSIX names.

Also, should it be that these attributes are always defined (and just have 0 for nanoseconds if the OS doesn't support it) or should it be that they are only defined if the OS supports nanosecond precision. If they are always defined, it would make usage simpler.

+1 to have them always defined.

2011/5/26 Victor Stinner

Le mercredi 25 mai 2011 à 18:46 +0200, Charles-François Natali a écrit :

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While we're at it, adding a "recursive" argument to this shutil.chown could also be useful.

I don't like the idea of a recursive flag. I would prefer a "map-like" function to "apply" a function on all files of a directory. Something like shutil.apply_recursive(shutil.chown)...

... maybe with options to choose between deep-first search and breadth-first search, filter (filenames, file size, files only, directories only, other attributes?), directory before files (may be need for chmod(0o000)), etc.

Pass an iterable to shutil.chown()? Then you could call it like: shutil.chown(os.walk(path)) Then of course you have the difficulty of wanting to pass either an iterator or a single path - probably prefer two functions e.g.: shutil.chown(path) shutil.chown_many(iter) Tim Delaney

Wiadomość napisana przez Martin v. Löwis w dniu 2011-06-01, o godz. 08:48:

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Le mercredi 25 mai 2011 à 18:46 +0200, Charles-François Natali a écrit :

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While we're at it, adding a "recursive" argument to this shutil.chown could also be useful.

I don't like the idea of a recursive flag.

I think shutil.chown should aim to mimic chown(1). At least GNU chown has a -R flag (not sure about POSIX chown), and it's useful in practice.

cp(1) and rm(1) also have "-r", still there are `shutil.copytree` and `shutil.rmtree`. I would like to keep that consistency, e.g. to have `shutil.chown` and `shutil.chowntree` as previously discussed by Charles-François, Nick and Petri. -- Best regards, Łukasz Langa Senior Systems Architecture Engineer IT Infrastructure Department Grupa Allegro Sp. z o.o.