Proxy settings wrt guix daemon

[Vincent Legoll]

Hello,

following the packaging of squid, I have been
searching how to configure the guix daemon
to use a proxy, and this looks problematic.

I found very sparse info in the documentation,
at least something explaining that this area is
WIP would have helped. [1]

I found the following config.scm snippet on the
ML [2]:

      (modify-services %desktop-services
        (guix-service-type config =>
                           (guix-configuration
                            (inherit config)
                            (http-proxy
                             "http://<IP>:<PORT>"))))

but as mentionned in [3], this will not fly in the
case of an intermittently available proxy, as guix
system-reconfigure will depends on this working
properly to reset it back to no proxy usage.

There is an issue about the problem [4], but it
does not looks like it is making progress.

Could something be done from shepherd PoV,
like easily setting environment vars for specific
services, in /etc/... config files ? So that can be
easily modified with a simple text editor in case
of failure.

[1] https://lists.gnu.org/archive/html/help-guix/2017-02/msg00090.html
[2] https://lists.gnu.org/archive/html/help-guix/2019-07/msg00031.html
[3] https://lists.gnu.org/archive/html/guix-devel/2017-10/msg00206.html
[4] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25569

Solving this would be awesome for the imminent
release. I'd like to help as much as I can.

WDYT ?

-- 
Vincent Legoll