[Distutils] Potential issue with multiple easy_install instances and single easy_install.pth

[Garrett Cooper (garrcoop)]

> -----Original Message-----
> From: Phillip J. Eby [mailto:pje at telecommunity.com] 
> Sent: Sunday, October 19, 2008 4:31 PM
> To: Garrett Cooper (garrcoop); distutils-sig at python.org
> Subject: Re: [Distutils] Potential issue with multiple 
> easy_install instances and single easy_install.pth
> 
> At 07:14 PM 10/18/2008 -0700, Garrett Cooper (garrcoop) wrote:
> >Hi Python folks,
> >         As part of a build system I work with, my group installs 
> >multiple Python packages via source using easy_install. One 
> such issue 
> >I've seen before in the past is that when using multiple 
> easy_install 
> >instances (via multiple make jobs), the last instance that opened up 
> >easy_install.pth records its changes; the file should 
> contain entries 
> >for all packages installed by easy_install.
> 
> easy_install doesn't support simultaneous parallel 
> installations to the same target directory, and there are no 
> plans at the moment to add that support.
> 
> Note, however, that if you use the -m (--multi-version) 
> option, then easy_install will  not save the .pth file unless 
> there was already a default version of the target package 
> present.  However, if you begin by deleting the .pth file 
> altogether, then using -m will avoid creating or updating it.
> 
> Of course, the downside of -m is that you will not be able to 
> access the installed packages except via setuptools-built 
> scripts or by using explicit require() calls.

Phillip,
	Do you or anyone else know where would I need to look into the
distutils source to implement this enhancement? I forsee using Python's
version of flock, with possibly the use of a simple semaphore
like-system.
Thanks for your quick feedback,
-Garrett