Regularly updating data files

[Оlе Ѕtrеісhеr]

Hi,

in Debian-astro and Debian-science, we just had a small discussion on
how to handle regularly updated data files. My initial posting [1] is
here:

-----------
For an astronomy library package, there is a data library needed to be
downloaded. This data files are updated ~weekly; however I have the
feeling that most updates are really minor.

The question is now how to model this in Debian. I see three ways here:

* provide a package that contains the data and update this on a regular
base. Disadvantage is that the package is not updated on stable and
other releases (Ubuntu), so it will be outdated probably already when
the release is published

* provide a shell script that does the download (this is already
included in the package). Disadvantage is that it requires some action
by the user and may be forgotten so that he stays with old data.

* install a cronjob that runs the script every week or so. Disadvantage
is that this may be considered as privacy breach.

* create an extra "-data-downloader" package that installs the cronjob
and states this clearly in its description. Suggest this in the main
package.

What is the best way here?
-----------

Since the package in question shall be also (and maybe mainly) used in
Ubuntu, I'd like to get your opinion here too. Especially, I got an
answer from Drew Parsons, which seems a good solution for Debian [2]:

| Isn't this the sort of thing that stable-updates (and testing-updates)
| is intended for?  cf. https://www.debian.org/News/2011/20110215
| https://wiki.debian.org/StableUpdates
[...]
| A separate package for the "volatile" data would be the right
| solution, if stable-updates is the right mechanism.

Is there a similar mechanism available in Ubuntu and Ubuntu LTS?

Best regards

Ole

[1] https://lists.debian.org/debian-astro/2014/04/msg00004.html
[2] https://lists.debian.org/debian-astro/2014/04/msg00015.html