Disarchive update

["Ludovic Courtès" <ludovic.courtes@inria.fr>]

Hello Guix!

This job is disassembling all the .tar.gz files packages refer to, using
the recently-added ‘etc/disarchive-manifest.scm’ file:

  https://ci.guix.gnu.org/jobset/disarchive

It has just succeeded for the first time.  :-)

  https://ci.guix.gnu.org/eval/29213?status=succeeded

If you run:

  guix build /gnu/store/nnl67m8c2x9rwqbnych1agc6p7g5473g-disarchive-collection.drv

or:

  guix build -m etc/disarchive-manifest.scm

and if you’re patient :-), you eventually get a 579 MB directory
containing Disarchive metadata for 8,413 tarballs out of 9,113 (the
missing tarballs are those that “disarchive disassemble” fails to
handle, for instance because it couldn’t guess what compression method
is being used.)

Where to go from here?  Timothy Sample had already set up a Disarchive
database at <https://disarchive.ngyro.com>, which (guix download) uses
as a fallback; I’m not sure exactly how it’s populated.  The goal here
would be for the Guix project to set up infrastructure populating a
database automatically and creating backups, possibly via SWH (we’ll
have to discuss it with them).

A plan we can already deploy would be:

  1. Add the disarchive.guix.gnu.org DNS entry, pointing to berlin.

  2. On berlin, add an mcron job that periodically copies the output of
     the latest “disarchive-collection” build to a directory, say
     /srv/disarchive.  Thus, the database would accumulate tarball
     metadata over time.

  3. Add an nginx route so that /srv/disarchive is served at
     https://disarchive.guix.gnu.org.

  4. Add disarchive.guix.gnu.org to (guix download).

How does that sound?  Thoughts?

Ludo’.