data packages

Hello!

In media res:
At present there is no possibility for a package to have a affiliated
data package.

The wast majority of packages doesn't need a data package but let's take
admin/runit <URL:http://smarden.org/runit/> as an example for a package
needing one - at least in my opinion.

Gerrit Pape has registered admin/runit. Binary and documentation files
are installed into /package/admin/runit-xxx, but the configuration
files - describing how you want to have your system booted - still live
in /etc/runit as do the files used to signal runit to bring the system
down.

It's obvious that the configuration files can not be put into
/package/admin/runit-xxx - that would make them affiliated to version
xxx of admin/runit.
The state files also can not be put there because you may want to have
/package mounted read only.

So, I would suggest putting these files into package/admin/runit-data -
the same way as Paul Jarc is doing it for configuration files of
slashpackage-foreign packages <URL:http://multivac.cwru.edu./spf/>.

Doing so would (or could) result in this layout:

/package/admin/runit-xxx/conf/runit-data -> /package/admin/runit-data
/package/admin/runit-yyy/conf/runit-data -> /package/admin/runit-data-old
/package/admin/runit-data -> runit-data-default
/package/admin/runit-data-default and
/package/admin/runit-data-old are either directories or symlinks.

runit would then access its configuration and state files using
/package/admin/runit-xxx/conf/runit-date/* and when installing a new
version package/build should just create the symlink
/package/admin/runit-zzz/conf/runit-data -> /package/admin/runit-data.

Configuration files could be in /package/admin/runit-data/conf/*.
Data that will get modified while a program of the package is running
could be in /package/admin/runit-data/var/* - whereas .../var could be
symlinked to /fs/std-var/package/admin/runit-data/var.

Packages providing services to be run via daemontools etc. could also
have e.g. /package/web/djbdns-data/service/dnscache. This directory
then again would get symlinked to /service.

A web proxy could store its cache in /package/web/proxy-data/cache -
with /package/web/proxy-data/cache again beeing symlinked to
/fs/std-var/package/web/proxy-data/cache.

The proxy itself would not even know about the data package. It would
just store the cached sites in
/package/web/proxy-xxx/conf/proxy-data/cache/.

A virus scanner could use virus definition files located in
/package/misc/virscan-xxx/conf/virscan-data/data. In fact they would
reside in /fs/std-var/package/misc/virscan-data/data - on a partition
mounted read write so that the definition files could be updated
although /package being mounted read only and they could be updated
without installing a new version of misc/virscan.

What do you think about that?

Regards,
 Thomas