[bug#63402] bug#63403: [PATCH 1/1] services: wireguard: Implement a dynamic IP monitoring feature.

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> Hi,
>
> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>
>> * gnu/services/vpn.scm (<wireguard-configuration>)
>> [monitor-ips?, monitor-ips-internal]: New fields.
>> * gnu/services/vpn.scm (define-with-source): New syntax.
>> (wireguard-service-name, strip-port/maybe)
>> (ipv4-address?, ipv6-address?, host-name?)
>> (endpoint-host-names): New procedure.
>> (wireguard-monitoring-jobs): Likewise.
>> (wireguard-service-type): Register it.
>> * tests/services/vpn.scm: New file.
>> * Makefile.am (SCM_TESTS): Register it.
>> * doc/guix.texi (VPN Services): Update doc.
>
> As discussed on IRC the other day, I tend to think that this is “not our
> job” but rather upstream’s.  (As a rule of thumb, I think services
> should merely expose what upstream implements.)
>
> You mentioned that upstream has a shell script to do something similar.
> Using that may not be as nice as what you propose here in terms of
> integration, but the upside is that we wouldn’t have to maintain it
> ourselves.

Yeah, upstream offers a contrib shell script called reresolve-dns.sh
[0], that works a bit differently (it's doesn't actually monitor IPs but
just keep a watch on when was the last successful handshake made).

[0]  https://github.com/WireGuard/wireguard-tools/blob/master/contrib/reresolve-dns/reresolve-dns.

> Would that be a viable option?  WDYT?

I think my Guile script is more precise in terms of what it does and
also produces useful output.  If I knew of the shell script existence
when I started I probably wouldn't have bothered re-implementing it in
Scheme, but since it's here, and better, I see no reason to not use it
:-).  I don't foresee high maintenance for the stable APIs involved
(resolving host names and setting an endpoint with 'wg set').

-- 
Thanks,
Maxim