[Python-Dev] Fixing #7175: a standard location for Python config files

[Toshio Kuratomi]

On Fri, Aug 13, 2010 at 07:48:22AM +1000, Nick Coghlan wrote:
> 2010/8/12 Éric Araujo <merwok at netwok.org>:
> >> Choosing an arbitrary location we think is good on every system is fine
> >> and non risky I think, as long as Python let the various distribution
> >> change those paths though configuration.
> >
> > Don’t you have a bootstrapping problem? How do you know where to look at
> > the sysconfig file that tells where to look at config files?

I'd hardcode a list of locations.
  [os.path.join(os.path.dirname(__file__), 'sysconfig.cfg'),
   os.path.join('/etc', 'sysconfig.cfg')]

The distributor has a limited choice of options on where to look.

A good alternative would be to make the config file overridable.  That way
you can have sysconfig.cfg next to sysconfig.py or in a known config
directory relative to the python stdlib install but also let the
distributions and individual sites override the defaults by making changes
to /etc/python3/sysconfig.cfg for instance.

> 
> Personally, I'm not clear on what a separate syconfig.cfg file offers
> over clearly separating the directory configuration settings and
> continuing to have distributions patch sysconfig.py directly. The
> bootstrapping problem (which would encourage classifying synconfig.cfg
> as source code and placing it alongside syscongig.py) is a major part
> of that point of view.
> 
Here's some advantages but some of them are of dubious worth:

* Allows users/site-administrators to change paths and not have packaging
  systems overwrite the changes.
* Makes it conceptually cleaner to make this overridable via user defined
  config files since  it's now a matter of parsing several config files
  instead of having a hardcoded value in the file and overridable values
  outside of it.
* Allows sites to add additional paths to the config file.
* Makes it clear to distributions that the values in the config file are
  available for making changes to rather than having to look for it in code
  and not know the difference between thaat or say, the encoding parameter
  in python2.
* Documents the format to use for overriding the paths if individual sites
  can override the defaults that are shipped in the system version of
  python.

-Toshio
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