offload configuration dependant on context

[zimoun]

Hi,

For nomadic people as I sometime am, they have sometimes access to
offload build machine, sometimes not.  To be concrete,

 1. when build machine is reachable, I want to *always* offload;
 2. when build machine is not reachable, I accept to burn some CPU.

Well, I can tweak /etc/machines.scm as proposed there [1] to detect
reachable machine.

However, #1 implies daemon option ’--max-jobs=0’ and #2 implies other
daemon configuration as ’--max-jobs=1 --cores=2’.  How could I achieve
that?  Dynamically speaking.


1: <https://issues.guix.gnu.org/issue/24496#3>


Cheers,
simon