Python MQTT Alsa volume controller

#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
#
# Python/MQTT volume controller (ALSA).
#
# Every 2 second it checks the current system volume. If it has
# changed, it is reported via MQTT. If a setvolume command is
# received through MQTT, the system volume is set to the incoming
# value.
#
# This script can run as a service, for a user that has the necessary
# rights to control the alsa volume (f.ex. logged in user). No
# guarantees for security holes/bugs if run as root.

import paho.mqtt.client as mqtt
import alsaaudio
import time
import socket

mqtt_broker = 'raaserv'
mqtt_port = 1883

sleeptime = 2 # seconds
topic = socket.gethostname() + "/volume"

currentvolume = 0

def on_connect(client, userdata, flags, rc):
    print "Connected to MQTT"
    client.subscribe(socket.gethostname() + '/setvolume')


def on_message(client, userdata, msg):
    print "Got message " + str(msg.payload)
    alsaaudio.Mixer().setvolume(int(msg.payload))

client = mqtt.Client()
client.on_connect = on_connect
client.connect(mqtt_broker, mqtt_port)
client.on_message = on_message

time.sleep(1)

while True:
    newvolume = int(alsaaudio.Mixer().getvolume()[0])
    print newvolume
    if newvolume != currentvolume:
        client.publish(topic, str(newvolume))
        currentvolume = newvolume
        print "changed: " + str(newvolume)
    client.loop(sleeptime)