How to handle configuration files with distutils to respect unixen's FHS?

Question

Suppose we have a program called foo.

If use absolute path:

setup(...,
      data_files=[...,
              ('/etc', ['foo.cfg'])]
)

Then foo$ python setup.py --prefix=/usr/local and we will have /etc/foo.cfg. But we should have /usr/local/etc/foo.cfg instead according to FHS.

What if we use a relative path?

setup(...,
      data_files=[...,
              ('etc', ['foo.cfg'])]
)

Then if we use the default install path, i.e. install to /usr, we will have /usr/etc/foo.cfg. Bad luck again.

So how to do it right?

P.S. To avoid make the problem more complicated, we assume that this program foo cannot run under non unix environment.

Answer 1

Sub-classing distutils.command.install.install is not strictly necessary. Instead, data_files could be passed to setup, as per distutils documentation on 'Installing Additional Files'.

e.g.

setup(
    ...
    data_files = [
        (conf_path, ['foo.cfg'])
    ]
)

where conf_path is calculated as per your own requirements. i.e. construct it by testing sys.prefix (instead of self.prefix), like @weakish did above.

Answer 2

It seems there is no easy way. The problem is that config files are special data files and they deserve special treatment.

So, write our own class:

class myinstall(distutils.command.install.install):
    if self.prefix == '/usr':
        self.conf_prefix = '/etc'
    else:
        self.conf_prefix = self.prefix + '/etc'

    install.finalize_options(self)

    def install_conf(self):
        self.mkpath((self.root or '') + self.conf_prefix)
        for file in self.distribution.conf_files:
        dest = (self.root or '') + self.conf_prefix + '/' +
            os.path.basename(file)
        self.copy_file(file, dest)

    # blah blah blah

Then:

setup(# blah blah blah
  conf_files = ['foo.cfg']
  cmdclass = {'install': myinstall,
      # blah blah blah
  }
)