Simulate a lamp for use with homA (https://github.com/binarybucks/homA)

lamp.py

#!/usr/bin/env python

# lamp.py (C)2013 by Jan-Piet Mens <jpmens()gmail.com>
# Simulate a lamp for use with homA (https://github.com/binarybucks/homA)
# The lamp is switched on by creating a file in the current directory.
# Switching it off, removes the file.

import mosquitto
import sys, os

roomname = "My office"
devname = "Desk Lamp"
systemid = '69001-lamp'
prefix = "/devices/" + systemid 
semafile = 'lamp.status'


def on_connect(mosq, userdata, rc):

    mqttc.subscribe("/devices/" + systemid + "/controls/" + devname + "/on", 0)

    # Publish (retained) our room and device name

    mqttc.publish("/devices/" + systemid + "/meta/room", roomname, qos=0, retain=True)
    mqttc.publish("/devices/" + systemid + "/meta/name", devname, qos=0, retain=True)

    # Create (if it doesn't yet exist), a switch control. If it exists (previously
    # retained), this simply "overwrites" retained values.

    mqttc.publish("/devices/" + systemid + "/controls/" + devname + "/meta/type", "switch", qos=0, retain=True)

def on_disconnect(mosq, userdata, rc):
    print "OOOOPS! disconnect"

def semaphore(on):

    print "Switching lamp to %d" % on
    try:
        if on:
            f = open(semafile, 'w')
            f.write("Lamp is on")
            f.close()
        else:
            os.remove(semafile)
    except OSError:
        pass

def on_message(mosq, userdata, msg):

    if msg.topic == "/devices/" + systemid + "/controls/" + devname + "/on":
        on = int(msg.payload)
        semaphore(on)

        # Now publish the status back. Note the missing "/on" !
        mqttc.publish("/devices/" + systemid + "/controls/" + devname, on, qos=0, retain=True)


def on_log(mosq, userdata, level, string):
    print(string)

mqttc = mosquitto.Mosquitto()
mqttc.on_connect = on_connect
mqttc.on_message = on_message
mqttc.on_disconnect = on_disconnect
#mqttc.on_log = on_log

mqttc.connect(os.getenv('HOMA_BROKERHOST', 'localhost'),
        int(os.getenv('HOMA_BROKERPORT', '1883')))

try:
    mqttc.loop_forever()
except KeyboardInterrupt:
    sys.exit(1)