Just a simple script to be used with i3bar

i3status.py

#!/usr/bin/python3
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from mpd import (MPDClient, CommandError)
import sys
import os
import pytz
import socket
import fcntl
import struct
import time
from datetime import datetime

def rprint(text):
    sys.stdout.write(text)

def battery_state():
    now=float(open("/sys/bus/acpi/drivers/battery/PNP0C0A:00/power_supply/BAT0/energy_now").read().rstrip())
    full=float(open("/sys/bus/acpi/drivers/battery/PNP0C0A:00/power_supply/BAT0/energy_full").read().rstrip())
    percent=now/full*100.0
    if percent < 20:
        color='#FF0000'
    elif percent < 50:
        color='#FFA500'
    else:
        color='#A0A0A0'
    battery_bars = ""
    for state in (10, 20, 30, 40, 50, 60, 70, 80, 90, 100):
        if percent >= state:
            battery_bars = "%s■" % battery_bars
        else:
            battery_bars = "%s□" % battery_bars
    rprint("""{\n\t\t"name": "battery",\n\t\t"color": "%s",\n\t\t"full_text": "%s (%.0f%%)"\n\t}""" % (color,battery_bars,percent))

def disk_info():
    color='#A0A0A0'
    s = os.statvfs('/home')
    ges = s.f_bfree*s.f_bsize/1073741824.0
    free = s.f_bavail*s.f_bsize/1073741824.0
    percent = free/ges*100.0
    rprint("""{\n\t\t"name": "disk_info",\n\t\t"color": "%s",\n\t\t"full_text": "%.1f GB"\n\t}""" % (color,free))

def current_time():
    now = datetime.now(pytz.timezone('Europe/Berlin'))
    rprint("""{\n\t\t"name": "tztime",\n\t\t"color": "#A0A0A0",\n\t\t"full_text": "%s"\n\t}""" % now.strftime("%d.%m.%Y %H:%M:%S"))

def load_avg():
    loadavg = os.getloadavg()[1]
    if loadavg < 2:
        color = '#A0A0A0'
    elif loadavg < 5:
        color = '#FFA500'
    else:
        color = '#FF0000'
    rprint("""{\n\t\t"name": "load",\n\t\t"color": "%s",\n\t\t"full_text": "%.2f"\n\t}""" % (color,loadavg))

def cpu_temperature():
    temp = int(open("/sys/devices/virtual/thermal/thermal_zone0/temp").read().rstrip())/1000
    if temp < 50:
        color = '#A0A0A0'
    elif temp < 70:
        color = '#FFA500'
    else:
        color = '#FF0000'
    rprint("""{\n\t\t"name": "cpu_temperature",\n\t\t"color": "%s",\n\t\t"full_text": "T: %d °C"\n\t}""" % (color,temp))

def mpd_status():
    global client
    currentsong = client.currentsong()
    title = currentsong['title']
    artist = currentsong['artist']
    status = client.status()['time'].split(':')
    length = time.strftime('%M:%S', time.gmtime(int(status[1])))
    elapsed = time.strftime('%M:%S', time.gmtime(int(status[0])))
    rprint("""{\n\t\t"name": "mpd",\n\t\t"color": "#A0A0A0",\n\t\t"full_text": "MPD: %s - %s (%s / %s)"\n\t}""" % (artist,title,elapsed,length))

client = MPDClient()
client.connect(host='127.0.0.1', port=6600)

rprint('{"version":1}\n')
rprint('[\n')

def status_bar():
    rprint("\t[\n\t")
    if client.status()['state'] == 'play':
        mpd_status();
        rprint(",\n\t")    
    disk_info();
    rprint(",\n\t")
    load_avg()
    rprint(",\n\t")
    cpu_temperature()
    rprint(",\n\t")
    battery_state()
    rprint(",\n\t")
    current_time()
    rprint("\n\t]")
    sys.stdout.flush()

status_bar()
while True:
    time.sleep(1)
    rprint(",\n")
    status_bar()