Python modules using distutils and setuptools are known to make linux distributors unhappy, for various reasons. One of them is that distutils does not make possible to install softwares according to the FHS without a lot of effort. This document is only concerned with the requirements to fix this situation at a minimal cost for python developers.
Generally, a python packaged with distutils will be installed as follows:
python setup.py install --prefix=$PREFIX
This will install the package in $PREFIX/lib/python-$PYVER/site-packages on Linux, plus scripts into $PREFIX/bin. The documentation, python source files (.py) and architecture dependent files (C extensions) are all installed in one directory, thus violating the FHS.
Many open source softwares are distributed using autoconf. The steps to install a package from sources are:
./configure --prefix=$PREFIX make make install
The make install step will do something very similar to the distutils install command. The main difference is additional options available from the configure script for customization:
--bindir=DIR user executables [EPREFIX/bin] --sbindir=DIR system admin executables [EPREFIX/sbin] --libexecdir=DIR program executables [EPREFIX/libexec] --sysconfdir=DIR read-only single-machine data [PREFIX/etc] --sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com] --localstatedir=DIR modifiable single-machine data [PREFIX/var] --libdir=DIR object code libraries [EPREFIX/lib] --includedir=DIR C header files [PREFIX/include] --oldincludedir=DIR C header files for non-gcc [/usr/include] --datarootdir=DIR read-only arch.-independent data root [PREFIX/share] --datadir=DIR read-only architecture-independent data [DATAROOTDIR] --infodir=DIR info documentation [DATAROOTDIR/info] --localedir=DIR locale-dependent data [DATAROOTDIR/locale] --mandir=DIR man documentation [DATAROOTDIR/man] --docdir=DIR documentation root [DATAROOTDIR/doc/libsndfile] --htmldir=DIR html documentation [DOCDIR] --dvidir=DIR dvi documentation [DOCDIR] --pdfdir=DIR pdf documentation [DOCDIR] --psdir=DIR ps documentation [DOCDIR]
Each of this option can be set independently if desired - the autotools handle each category independently. This has several advantages:
- the options can be set such as to follow the FHS as much as possible
- no policy is implemented by the developer. It is the job of the package developer to set those paths accordingly
- different policies can be implemented. For example, distributions like gobolinux which do not follow the FHS at all happily use autoconf-based packages
The solution is easy, at least in principle. Instead of indistinctively installing everything at one location, distutils should be able to deal correctly with the following kind of options:
python setup.py install --bindir=$BINDIR --sbindir=$SBINDIR
to install the software as desired. Note that distutils does NOT have to know how to install things as required as the FHS: distutils does not need to implement any policy. Some Linux distributions do not follow the FHS - and happily package autoconf-based packages as they want (example: gobolinux).
Here are categories which are necessary to build a Debian package:
- scripts/binaries: bindir concept
- architecture independent files (.py, .pyc): datadir
- architecture dependent files (.so, .pyo ?): libdir
- html doc (htmldir)
- pdf doc (pdfdir)
- man doc (mandir)
TODO: others - include path, header path, var path for log, etc... Other distributions, OS ?
Obviously distutils should internally keep separate lists for each kind of files.
- how to tag those files: for .py, .so and binaries, this is already done. Needs work for documentation, log
- UI to set the installation directories: this should not be difficult
- How to retrieve the files within the package. I have no idea how this is done in a standard C program in autoconf (but this is much less of a
problem in that case, I guess - in python, using file and co is oftenly used).