Tools

Tools

Use case: Create a pip requirements file based on a buildout.cfg

"I don't want to install your application as a buildout environment." Why would anyone not want to use buildout? Perhaps there are enough build tools in the mix that adding one more is just a pain in the ass. Maybe like me this case, tends to see zc.buildout's design flaws and shy away from it.

Let's use Plone as a very good example, because the issues are very apparent. Plone application releases (different from Plone the Python distribution) are basically a versions.cfg file located at http://dist.plone.org/releases/<version>/versions.cfg. So the following does squat for us because nothing in the Zope/Plone world is pinned in the distributions themselves.

$ pip install Plone

While the above would complete and all the Plone dependencies would install, it would also likely not have an official released version of the application. And the plone application may or may not run as expected.

This case is about using an alternative to buildout. This could be pip, but also some other tool unknown to this developer. But pip's requirements file format is fairly general and should help anyone out of the buildout predicament.

The end result of this use case should be a tool that looks something likes this:

$ bo2pip buildout.cfg
x==1.0
y==2.0
z==1.1
a>=4.0

And all of that should be done without actually running the buildout.