bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

[Mathieu Othacehe <othacehe@gnu.org>]

Hello Pierre,

> I've set up my desktop and laptop to use the new substitute discovery
> feature, it's awesome!

Glad you like it, and sorry for the late answer.

> substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host

Once your laptop goes to sleep, Avahi should detect that the publish
service is gone and remove it from the cache at
/var/guix/discovery/publish.

I'm having troubles reproducing it at home. Could you please run
"avahi-browse -a" on your desktop, put your laptop to sleep, and check
if the publish server disappears this way:

--8<---------------cut here---------------start------------->8---
- enp7s0f0 IPv6 guix-publish-cervin                           _guix_publish._tcp   local
- enp7s0f0 IPv4 guix-publish-cervin                           _guix_publish._tcp   local
--8<---------------cut here---------------end--------------->8---

Regarding the reboot issue, that's because the cache wasn't cleaned-up,
it should by fixed with: ee94cd265e03d12eeeccf58cbaf74b90008fcd14.

Thanks,

Mathieu