== Inside building RPMs with Python distutils

For reasons outlined in [[../sysadmin/CPANProblem]], I don't install
Python packages using their setup tools; I build them into RPMs and
install the RPMs. Python's distutils (the setup system used by most
Python packages) have a command to do this, called ((bdist_rpm)), but
it has some issues that have caused me to become quite familiar with
its inner workings.

((bdist_rpm)) works in the following steps:
# use the distutils _sdist_ command to create a source tarball.
# write an RPM specfile.
# create a local RPM build tree and put the specfile and tarball into
  it.
# run _rpmbuild_ in the local RPM build tree to create the source or
  binary RPM.

My experience is that the simpler the package and the package's
_setup.py_, the more likely that everything will go fine. Otherwise,
you can run into a variety of problems.

Because of step #1, ((bdist_rpm)) is only really suitable for building
binary RPMs for internal usage. If you want to build public RPMs you
should use ((bdist_rpm)) only to generate the specfile, and put this
together with the package's real source distribution yourself.  Using
((bdist_rpm)) just to get the specfile is also the 'least moving
parts' option if it's giving you a lot of trouble.

Distutils has three ways of figuring out what to put in the step #1
source tarball, documented in more detail in the
[[creating a source distribution|http://docs.python.org/dist/source-dist.html]]
section of the
[[Distributing Python Modules|http://docs.python.org/dist/dist.html]]
documentation. They are, in order of preference:

* a _MANIFEST_ file that lists all files that should be included, or
* a _MANIFEST.in_ file that gives general directions (often also using
  stuff from _setup.py_), or
* reverse-engineering the list of sources from _setup.py_.

If this step is omitting files you want, the big hammer is to just
write a _MANIFEST_ file (or modify the one _sdist_ leaves sitting
around).

The RPM specfile created in step #2 automatically picks up and
packages everything that a normal installation of the package
creates. At most, you may find that it's omitting extra documentation
or examples or the like that you want packaged up. (It's supposed to
automatically package up _README_ files as _%doc_ files, but this
doesn't always work.)

Steps #3 and #4 assume a standard RPM subdirectory
layout. Unfortunately this explodes if you have used a
_$HOME/.rpmmacros_ file to rearrange things more cleanly. The easiest
workaround is to use something like
'((HOME=/ python setup.py bdist_rpm))', so that it doesn't consult
your _.rpmmacros_ file.