[Distutils] virtualenv and buildout integration ?

[Gary Poster]

On Aug 27, 2009, at 3:46 AM, Chris Withers wrote:

> Gary Poster wrote:
>> While it has the functionality that I believe you want (that is,  
>> you can entirely exclude the normal Python site-packages),
>
> Cool :-)
>
>> we're using it successfully on Launchpad right now to do something  
>> similar to what you describe, but different.  We allow site- 
>> packages through, so we get system lxml and pyopenssl, for  
>> instance, but we explicitly get distributions via buildout for the  
>> bits that are more closely tied to the application, even if  
>> conflicting eggs are installed for the system.  We've only had the  
>> changes in place for a couple of weeks, but things seem to be  
>> *much* smoother with them now.
>
> Indeed. Sounds great. However, what do you do if the system  
> installed libraries are the wrong very (eg: the buildout specifies a  
> particular version, and the one in site-packages isn't it)?

Using a whitelist in your .cfg, some or all of the eggs in site- 
packages are simply ignored when buildout assembles dependencies (even  
if they are or claim to be the right versions); and then the eggs that  
buildout chooses have precedence over site-packages (they come before  
site-packages in sys.path).

Gary