System Tray Icon Widget.

battery-status.py

#!/usr/bin/env python2.7
# Depends on oxygen-icon-theme. Change /usr/share/icons/oxygen to your desired theme.
import code
import gtk
import gobject
import threading
import time
import os, sys
import signal

DEBUG = os.environ.get('DEBUG', False)
ALERT_WAIT = 300 # Number of seconds to wait before alerting for low battery again.
ALERT_THRESHOLD = 10 # Percent at which this applet should alert for low battery.

BATTERY_ERROR = '/usr/share/icons/oxygen/32x32/status/battery-missing.png'
BATTERY10 = '/usr/share/icons/oxygen/32x32/status/battery-low.png'
BATTERY20 = '/usr/share/icons/oxygen/32x32/status/battery-caution.png'
BATTERY40 = '/usr/share/icons/oxygen/32x32/status/battery-040.png'
BATTERY60 = '/usr/share/icons/oxygen/32x32/status/battery-060.png'
BATTERY80 = '/usr/share/icons/oxygen/32x32/status/battery-080.png'
BATTERY100 = '/usr/share/icons/oxygen/32x32/status/battery-100.png'

BATTERY_CHARGING10 = '/usr/share/icons/oxygen/32x32/status/battery-charging-low.png'
BATTERY_CHARGING20 = '/usr/share/icons/oxygen/32x32/status/battery-charging-caution.png'
BATTERY_CHARGING40 = '/usr/share/icons/oxygen/32x32/status/battery-charging-040.png'
BATTERY_CHARGING60 = '/usr/share/icons/oxygen/32x32/status/battery-charging-060.png'
BATTERY_CHARGING80 = '/usr/share/icons/oxygen/32x32/status/battery-charging-080.png'
BATTERY_CHARGING100 = '/usr/share/icons/oxygen/32x32/status/battery-charging.png'

def message(data=None):
  "Function to display messages to the user."
  
  msg=gtk.MessageDialog(None, gtk.DIALOG_MODAL, gtk.MESSAGE_INFO, gtk.BUTTONS_OK, data)
  msg.run()
  msg.destroy()
  Main.alerting = False

def get_battery_info():
  '''
  Checks /sys for battery info and returns as a data structure.
  '''
  result = {}
  with open('/sys/class/power_supply/BAT0/uevent') as fd:
    for line in fd:
      try:
        name, value = line.strip().split('=')
      except ValueError:
        name = line.strip().split('=').pop()
        value = None
      result[name.replace('POWER_SUPPLY_', '')] = value
  return result

def update_icon():
  '''
  Checks the battery and upates the icon as necessary.
  Alerts me if needed.
  '''
  battery = get_battery_info()
  energy_now = int(battery['ENERGY_NOW'])
  energy_full = int(battery['ENERGY_FULL'])
  charging = battery['STATUS'] != 'Discharging'
  energy_pcent = int( float(energy_now) / float(energy_full) * 100.0 )
  if energy_pcent < ALERT_THRESHOLD:
    if not Main.alerting:
      if Main.alerted <= time.time() - ALERT_WAIT:
        Main.alerting = True
        Main.alerted = time.time()
        message('Battery under %d!!!' % ALERT_THRESHOLD)
  if charging:
    BATTERY_OPTIONS = dict(
      [ (x, BATTERY_CHARGING100) for x in range(81, 101) ]
      + [ (x, BATTERY_CHARGING80) for x in range(61, 80) ]
      + [ (x, BATTERY_CHARGING60) for x in range(41, 60) ]
      + [ (x, BATTERY_CHARGING40) for x in range(21, 40) ]
      + [ (x, BATTERY_CHARGING20) for x in range(11, 20) ]
      + [ (x, BATTERY_CHARGING10) for x in range(0, 10) ]
    )
  else:
    BATTERY_OPTIONS = dict(
      [ (x, BATTERY100) for x in range(81, 101) ]
      + [ (x, BATTERY80) for x in range(61, 80) ]
      + [ (x, BATTERY60) for x in range(41, 60) ]
      + [ (x, BATTERY40) for x in range(21, 40) ]
      + [ (x, BATTERY20) for x in range(11, 20) ]
      + [ (x, BATTERY10) for x in range(0, 10) ]
    )
  BATTERY_ICON = BATTERY_OPTIONS.get(int(energy_pcent), BATTERY_ERROR)
  Main.icon.set_from_file(BATTERY_ICON)
  return True

class Main(object):
  icon = None
  alerting = False
  alerted = 0

  @staticmethod
  def sigint(sig=None):
    sys.exit(127)

  @staticmethod
  def sigterm(sig=None):
    sys.exit(128)

  @staticmethod
  def main():
    signal.signal(2, Main.sigint)
    signal.signal(15, Main.sigterm)
    Main.icon = gtk.status_icon_new_from_file(BATTERY_ERROR)
    update_icon()
    gobject.timeout_add(1000, update_icon)
    gtk.main()
    return 0

if __name__ == '__main__':
  try:
    sys.exit(Main.main())
  except KeyboardInterrupt:
    sys.exit(126)