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

[Bob Ippolito]

On Oct 22, 2004, at 18:04, Bob Ippolito wrote:

> On Oct 22, 2004, at 17:18, Fred L. Drake, Jr. wrote:
>
>> One thing that no one has mentioned in this thread is the 
>> "command-packages"
>> support I added to distutils for Python 2.4.  I think this supports 
>> Bob's use
>> case well.
>>
>> What's needed is to install a Python package containing the new 
>> commands
>> somewhere on the search path (preferably in .../site-packages).  Then 
>> edit
>> the Python installations distutils config file (bet you didn't know 
>> about
>> that!) to include
>>
>>     [global]
>>     command-packages=my.pkg
>>
>> The new commands will be available for all setup.py scripts.
>>
>> This is a documented feature; you can read more about it at
>>
>>     http://www.python.org/dev/doc/devel/dist/node29.html
>
> That does indeed support this use case.. I may have to move things 
> around in the package a bit to support it, but it may just work.
>
> Now what about the "Python installations distutils config file"?  
> Where's that located?  I don't see it referenced in the 
> documentation..  Can that file be placed somewhere on site-packages 
> like sitecustomize (good), or does it require editing a root-owned 
> vendor file (bad)?

Ok, I tracked it down to distutils.dist.  Unfortunately, it looks like 
this feature won't be very useful for my use case after all.  There are 
only a few locations searched for distutils configuration files:

- 'distutils.cfg' must either go inside the distutils package itself 
(vendor files, bad)
- '.pydistutils.cfg' ('pydistutils.cfg' in win32/macos classic) located 
in the user's home directory (per-user, bad)
- 'setup.cfg' in the current directory (per-package, worse)

I need an editable file in a system-wide directory such as 
site-packages that isn't "owned" by the Python installation.  Even if 
this were the case, it would be a real pain to implement, because it 
would have to be done as a very careful postflight script that merges 
the user's current config file with the necessary additions (in this 
case, make sure to preserve anything else in the command-packages list 
if there is one).

-bob