source: trunk/moap/util/deps.py @ 204

# -*- Mode: Python -*-
# vi:si:et:sw=4:sts=4:ts=4

# code to handle import errors and tell us more information about the
# missing dependency

from moap.util import distro

import sys

class Dependency:
    module = None
    name = None
    homepage = None

    def install(self, distro):
        """
        Return an explanation on how to install the given dependency
        for the given distro/version/arch.

        @rtype:   str or None
        @returns: an explanation on how to install the dependency, or None.
        """
        name = distro.tag + '_install'
        m = getattr(self, name, None)
        if m:
            return m(distro)


class RDF(Dependency):
    module = 'RDF'
    name = "Redland RDF Python Bindings"
    homepage = "http://librdf.org/docs/python.html"

    def fedora_install(self, distro):
        if distro.version >= '5':
            return "You can install RDF on Fedora with:\n" \
                "su -c \"yum install python-redland\" -"

        return "Your version of Fedora does not have python-redland available."


class genshi(Dependency):
    module = 'genshii'
    name = "Genshi templating language"
    homepage = "http://genshi.edgewall.com/"

    def fedora_install(self, distro):
        return "genshi is not yet available in Fedora Extras.\n"

def handleImportError(exception):
    """
    Handle dependency import errors by displaying more information about
    the dependency.
    """
    first = exception.args[0]
    if first.find('No module named ') < 0:
        raise
    module = first[len('No module named '):]
    module = module.split('.')[0]
    deps = {}
    for dep in [RDF(), genshi()]:
        deps[dep.module] = dep

    if module in deps.keys():
        dep = deps[module]
        sys.stderr.write("Could not import python module '%s'\n" % module)
        sys.stderr.write('This module is part of %s.\n' % dep.name)
        if dep.homepage:
            sys.stderr.write('See %s for more information.\n\n' % dep.homepage)

        d = distro.getDistroFromRelease()
        if d:
            howto = dep.install(d)
            if howto:
                sys.stderr.write(howto)
            else:
                sys.stderr.write(
                    "On %s, MOAP does not know how to install %s.\n" 
                    "Please file a bug so we can add this dependency.\n" % (
                        d.name, dep.module))
        else:
            sys.stderr.write("""MOAP does not know your distribution.
Please file a bug so we can add your distribution.
""")

        sys.stderr.write('\n')

        sys.stderr.write('Please install %s and try again.\n' % module)
        sys.stderr.write(
            'You can confirm it is installed by starting Python and running:\n')
        sys.stderr.write('import %s\n' % module)


        return

    raise