[Distutils] Extending distutils with 3rd party build commands?

[M.-A. Lemburg]

Bob Ippolito wrote:
> On Oct 20, 2004, at 18:38, Bob Ippolito wrote:
> 
>> On Oct 20, 2004, at 18:10, M.-A. Lemburg wrote:
>>
>>> Bob Ippolito wrote:
>>>
>>>> I've developed two bdist commands (bdist_pkg and bdist_mpkg) for 
>>>> usage on OS X.  These commands apply to any setup.py that supports 
>>>> an "install" command, similar to bdist_wininst, so it would be nice 
>>>> if every setup.py didn't have to explicitly import something in 
>>>> order to get the commands there.
>>>> I know I can make it work with a pth file that imports bdist_pkg, 
>>>> but that seems a bit costly to do because it will end up importing a 
>>>> bunch of stuff (distutils, mainly).
>>>> Is there another way to do it?
>>>
>>>
>>> Submit them for inclusion in the standard distribution ;-)
>>
>>
>> I will, for 2.5... but there's quite some time between now and then.
> 
> 
> Well I did find another way, thanks to PEP 302.
> 
> How "evil" would it be if I had this module imported by a pth file?  It 
> does do what I want it to do, but I'm not sure if it's safe to inflict 
> on users or not..

Import hooks are bad. Avoid them if you can.

What so bad in adding a sinlge import to all your setup.pys ?
That import could then trigger the installation of the new
command by importing distutils and tweaking the cmdclass
in distutils, e.g.

import biDistutilsExtensions

> -- 
> 
> import sys
> import imp
> try:
>     set
> except NameError:
>     from sets import Set as set
> 
> class DistutilsHook(object):
>     def __init__(self, package='distutils', hooks=('py2app', 
> 'bdist_mpkg')):
>         self.package = package
>         self.hooks = set(hooks)
>         self.hooks.add(package)
> 
>     def find_module(self, fullname, path=None):
>         if fullname in self.hooks:
>             self.hooks.remove(fullname)
>         if fullname != self.package:
>             return None
>         try:
>             sys.meta_path.remove(self)
>         except ValueError:
>             pass
>         try:
>             fileobj, filename, stuff = imp.find_module(fullname, None)
>         except ImportError:
>             return None
>         hooks = list(self.hooks)
>         self.hooks.clear()
>         return ImpLoader(fileobj, filename, stuff, hooks)
> 
> class ImpLoader(object):
>     def __init__(self, fileobj, filename, stuff, hooks):
>         self.fileobj = fileobj
>         self.filename = filename
>         self.stuff = stuff
>         self.hooks = hooks
> 
>     def load_module(self, fullname):
>         mod = imp.load_module(fullname, self.fileobj, self.filename, 
> self.stuff)
>         if self.fileobj:
>             self.fileobj.close()
>         for hook in self.hooks:
>             try:
>                 __import__(hook)
>             except:
>                 pass
>         return mod
> 
> sys.meta_path.insert(0, DistutilsHook())
> 
> _______________________________________________
> Distutils-SIG maillist  -  Distutils-SIG at python.org
> http://mail.python.org/mailman/listinfo/distutils-sig

-- 
Marc-Andre Lemburg
eGenix.com

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