Using zc.buildout to run setup scripts

zc buildout has a convenience command for running setup scripts. Why? There are two reasons. If a setup script doesn’t import setuptools, you can’t use any setuptools-provided commands, like bdist_egg. When buildout runs a setup script, it arranges to import setuptools before running the script so setuptools-provided commands are available.

If you use a squeaky-clean Python to do your development, the setup script that would import setuptools because setuptools isn’t in the path. Because buildout requires setuptools and knows where it has installed a setuptools egg, it adds the setuptools egg to the Python path before running the script. To run a setup script, use the buildout setup command, passing the name of a script or a directory containing a setup script and arguments to the script. Let’s look at an example:

>>> mkdir('test')
>>> cd('test')
>>> write('setup.py',
... '''
... from distutils.core import setup
... setup(name='sample')
... ''')

We’ve created a super simple (stupid) setup script. Note that it doesn’t import setuptools. Let’s try running it to create an egg. We’ll use the buildout script from our sample buildout:

>>> print_(system(buildout+' setup'), end='')
... 
Error: The setup command requires the path to a setup script or
directory containing a setup script, and its arguments.

Oops, we forgot to give the name of the setup script:

>>> print_(system(buildout+' setup setup.py bdist_egg'))
... 
Running setup script 'setup.py'.
...
>>> ls('dist')
-  sample-0.0.0-py2.5.egg

Note that we can specify a directory name. This is often shorter and preferred by the lazy :)

>>> print_(system(buildout+' setup . bdist_egg')) 
Running setup script './setup.py'.
...