On Thu, 2012-12-06 at 07:06 -0800, Adam Williamson wrote: > On Thu, 2012-12-06 at 15:30 +0100, Nicolas Mailhot wrote: > > IMHO use of software collections is a symptom of a badly run organisation > > not devoting enough cycles to maintain the software it uses, and hoping > > (as in wishful thinking) no problem will go critical before the product > > they built on top of those collections is end-of-lifed > > > > I completely fail to see how entities with that problem will manage to > > maintain the package number explosion creating software collections will > > induce. > > On the one hand, I agree completely - I think the 'share all > dependencies dynamically' model that Linux distros have traditionally > embraced is the right one, and that we're a strong vector for spreading > the gospel when it comes to that model, and it'd be a shame to > compromise that. > > On the other hand, we've been proselytizing the Java heretics for over a > decade now, and the Ruby ones for a while, and neither shows any signs > of conversion or just plain going away, so we may have to call it an > ecumenical matter and deal with their models somehow. Sucky as it may > be. I don't know, I'm a bit conflicted. It's interesting that you call out Java and Ruby folks as being heretics. I guess that means all is kosher with Python? OpenStack is getting burned by API instability in some Python packages, so I've started a thread on Python's distutils-sig to try and guage the level of heresy amongst Python folks :) It started here: http://mail.python.org/pipermail/distutils-sig/2013-February/020030.html and now we're talking about Software Collections here: http://mail.python.org/pipermail/distutils-sig/2013-March/020074.html Two things I'm picking up from the thread: - A trend towards "semantic versioning" and, implicit in that, an acceptance of API breakages so long as the major number of a library version is incremented - Supporting the parallel installation of incompatible versions of libraries isn't seen as an issue because you can "just use virtual environments" ... which amounts to Python Software Collections. The combination of those two things suggests to me that the Python world will start looking a lot less sane to packagers - i.e. library maintainers breaking API compatibility more often and assuming we can just use SC or similar to have multiple incompatible versions installed. I can see OpenStack upstream reacting to this by "capping" its required version range for each library it depends so that if the library does release an incompatible version, OpenStack sticks with the latest compatible version. If that happens, I think OpenStack packagers will need to look seriously at using Software Collections. Basically, we'd look to package and maintain our own stack of all the Python libraries we need above the core Python libraries. So, you'd have openstack-nova, openstack-glance, etc. all installed as normal in /usr, /var, etc. but they'd require python libraries from the openstack-grizzly SC like openstack-grizzly-python-eventlet which would be installed in /opt/fedora/openstack-grizzly/root/usr/lib/python. I'd appreciate it if someone else with a Fedora Python packaging background could look into this and, hopefully, explain how the discussion on distutils-sig isn't so terrifying after all. Cheers, Mark. -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
