i3blocks extension that gets the indicated keyboard led status without using xset (useful for Sway, which uses Wayland)

keyindicator-nox

#!/usr/bin/env python

from sys import argv
from evdev import InputDevice, ecodes

# usage: keystate-nonx [-h] [-i INPUT_DEVICE_CODE] [-oc OUTPUT_COLOR] [-ic INPUT_COLOR] [-b BLOCK_INSTANCE]

INSTANCE = "CAPS"
EVENT_NUMBER = "0"
COLOR_OFF = "#222222" 
COLOR_ON =  "#00FF00"
KEYBOARD_EVENT_PATH = "/dev/input/event"

#Returns a string with the input path
def keyboard_definition():
   if (len(argv) == 1):
     return ''.join([KEYBOARD_EVENT_PATH,EVENT_NUMBER])
   else:
     return ''.join([KEYBOARD_EVENT_PATH,argv[1]])

#Return the input device according to the keyboard definition
def set_input_device(keyboard_path):
   return InputDevice(keyboard_path)

#Return the dictionary of leds available
def set_leds_dictionary(input_device):
   full_led_list = input_device.capabilities(verbose=True)[('EV_LED', ecodes.EV_LED)]
   return dict(full_led_list)

#Returns list of active leds on input device
def get_active_leds(input_device):
   active_leds = input_device.leds()
   return active_leds

def get_keystate(leds_dictionary, instance, active_leds):
   uppercaseInstance = instance.upper()
   if leds_dictionary['LED_'+uppercaseInstance+'L'] in active_leds:
      return ''.join([uppercaseInstance,"\n",uppercaseInstance,"\n",COLOR_ON])
   else:
      return ''.join([uppercaseInstance,"\n",uppercaseInstance,"\n",COLOR_OFF])
   
if __name__=="__main__":
   key_path = keyboard_definition()
   input_device = set_input_device(key_path)
   leds_dic = set_leds_dictionary(input_device)
   active_leds = get_active_leds(input_device)
print(get_keystate(leds_dic, INSTANCE, active_leds))

Thanks for creating this. I've taken the liberty of tweaking it to work with different colours and the NUM key, amongst other things. Here it is: https://github.com/ForgottenUmbrella/dotfiles/blob/master/i3/scripts/keyindicator-nox