brightnessctl: Add service to store screen brightness

[mamins1376]

Thought it would be nice to have this in the original package.

[CameronNemo]

There are valid arguments against expanding the use of oneshot runit services using pause. Please consider using rc.local and rc.shutdown for these use cases.

[abenson]

There are valid arguments against expanding the use of oneshot runit services using pause.

I've considered we need a /etc/oneshot directory type thing for packages that need a oneshot, and similarly enable them in something like /var/oneshot. Or something. I'm not sure what's best.

[mamins1376]

@CameronNemo: Originally I was using the solution you mentioned. Then I saw alsa-util's and found that pretty clever, with the added bonus of having the store and restore in one directory.

Is there any doc's indicating the downsides? Why this is not applied to ALSA?

[CameronNemo]

Lots of services like alsa, iptables, ufw, etc used the mechanism you have here. At first glance it is fairly clever, but it is weak for a couple reasons:

• no way to tell if or when the task has actually completed
• two useless processes hanging around (memory and clutter concerns)

Indeed having the boot/shutdown task in the same place is a nice quality of this mechanism. Hopefully we can maintain that while solving the above problems. It will require additions to void-runit.

[mamins1376]

Based on @abenson's suggestion; /etc/rc.local:

for f in /var/oneshot/*/start; do
    [ -x $f ] && $f;
done

And a similar one with /var/oneshot/*/stop; So that packages can add their own hooks and even do some sort of dependency satisfaction through number prefixes.
This is kind of borrowed from /etc/X11/xinit/xinitrc.

[Anachron]

How is the progress here? @abenson