[packagekit] GNOME summit and more about GPG keys

[Richard Hughes]

On Tue, 2007-10-09 at 21:11 -0400, Robin Norwood wrote:
> ...There was a
> bit of a discussion about "How applications can install plugins with
> PackageKit".  For instance, gimp plugins and gstreamer codecs.  To be
> able to do this, we should probably have simple python and C bindings to
> install things with a semantic of "give me a package which provides
> 'x'".  The bindings we have now are pretty close, and maybe just example
> code needs to be easily available.
> 
> However, one problem is that there isn't a consistant cross-distro way
> that I know of to name these sorts of deps...so either distros will need
> to become consistant or the deps need to be generated and maintained
> somewhere.
> 
> Thoughts on this?

Okay, this is a hard problem to solve. I don't think we can think for
one second that we can get all the distros to agree on common names for
packages, it's just not going to be possible politically.

I think there are three potential ways of working around this:

1. Each backend allows a what_provides(divx-codec) type parameter, which
is basically shifting the work onto the backends - something that isn't
going to be popular or possible with most of the backends. Also,
multiple packages could provide functionality, for instance
gstreamer-plugins-bad, vlc or mplayer.

2. We provide a big long compatability list on name->distro_name, so we
have firefox->firefox-bin on ubuntu and firefox->mozilla-firefox on
conary (made up examples) - this would be a long list, which has to be
updated for each distro version and for each installable package. Not
cool.

3. We do the brute force solution and shift this on to the packagers.
Upstream would hardcode firefox-bin, and in the fedora spec file we
would add a patch to change this to the distro name, e.g.
mozilla-firefox. This would mean that we only have to patch one software
package in each distro, and don't have to mainain giant lists or require
each backend to track the files installed. We also get the GNOME tools
to install the gnome plugins, and similar with KDE.

Solution 3 seems to have least drawbacks in my eyes. Totem could be
patched to install gstreamer-codec-bad on fedora and install
restricted-codecs on ubuntu - totem already knows what codec it needs.
This should mean that as package names change, the distro people are
able to make immediate changes without ensuring some sort of
compatibilty with certain versions of a compatibility list.

To actually do this, the code is already in place. Look in
gnome-packagekit/src/* at the pk-install-package binary. Basically this
resolves the name "firefox" to "firefox-bin;2.01;x64;fedora" and
installs the result with a progress UI. Applications could use that
helper executable, or just use the libpackagekit API directly, it's only
a few tens of lines of code.

Richard.