upower backend for battery widget WIP

[eylles]

this PR ain't complete, rather i opened it to get some feedback

since acpi can't detect the remaining time of battery for my laptop but upower can i decided to try and add the option to use upower as backend for the battery widget based on the watch widget recipe examples from https://awesomewm.org/recipes/watch/

i still have to clean stuff up and parse the information for the notification.

expected output from upower -i $(upower -e | grep BAT)

  native-path:          BAT0
  vendor:               Hewlett-Packard
  model:                Primary
  serial:               18267 2020/07/08
  power supply:         yes
  updated:              Mon 24 May 2021 03:47:30 PM CST (26 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               charging
    warning-level:       none
    energy:              35.2621 Wh
    energy-empty:        0 Wh
    energy-full:         44.6754 Wh
    energy-full-design:  44.6754 Wh
    energy-rate:         22.7256 W
    voltage:             12.588 V
    time to full:        24.9 minutes
    percentage:          78%
    capacity:            100%
    technology:          lithium-ion
    icon-name:          'battery-full-charging-symbolic'

expected output from upower -i $(upower -e | grep BAT) | sed -n '/present/,/icon-name/p'

    present:             yes
    rechargeable:        yes
    state:               charging
    warning-level:       none
    energy:              35.2621 Wh
    energy-empty:        0 Wh
    energy-full:         44.6754 Wh
    energy-full-design:  44.6754 Wh
    energy-rate:         22.7256 W
    voltage:             12.588 V
    time to full:        24.9 minutes
    percentage:          78%
    capacity:            100%
    technology:          lithium-ion
    icon-name:          'battery-full-charging-symbolic'

from what i understand this widget can display information for more than one battery with acpi but i only have one battery on my laptop.

i will push some cleanups later.

anyway waiting for feedback 👍

[streetturtle]

This is awesome!
I think ideally the logic for processing the output of a command can be put in a separate file. But you can leave it as it is, and I can refactor it some time later.

[eylles]

aaaaaand managed to add a notification with the upower backend, but couldn't parse the output of upower -i properly with lua so i gave up and used a "small" awk command since that was the only way i could figure out to do it.