messages.py

import collections
import json
import logging
import socket
import sys
import paho.mqtt.client as mqtt
import mqtt_config

logging.basicConfig(level=logging.WARNING)
logger = logging.getLogger('messages')

messages = collections.deque()


def on_connect(client, userdata, flags, rc):
    logger.info('connected result code=%s', str(rc))
    logger.info('subscribe topic=%s', mqtt_config.TOPIC)
    client.subscribe(mqtt_config.TOPIC, 0)


def on_log(client, userdata, level, string):
    logger.info('log %s %s', level, string)


def on_message(client, userdata, msg):
    logger.info('message topic=%s timestamp=%s payload=%s', msg.topic, msg.timestamp, msg.payload)
    messages.append(msg)


def on_publish(client, userdata, rc):
    logger.info('published result code=%s', rc)


def on_disconnect(client, userdata, other):
    logger.info('disconnected result code=%s', other)

client = mqtt.Client('xmas-lights', clean_session=False)
client.on_connect = on_connect
client.on_message = on_message
client.on_disconnect = on_disconnect
client.on_publish = on_publish

if mqtt_config.hostname:
    if mqtt_config.username:
        client.username_pw_set(mqtt_config.username, mqtt_config.password)
    try:
        client.connect(mqtt_config.hostname, 1883, 60)
        client.loop_start()
        logger.info('subscribed to %s', mqtt_config.hostname)
    except socket.error as err:
        print >> sys.stderr, 'MQTT:', err
        print >> sys.stderr, 'Continuing without subscriptions'


def get_message():
    if not messages:
        return None
    message = messages.popleft()
    logger.info('receive %s', message.payload)
    return json.loads(message.payload)

if __name__ == '__main__':
    print 'Waiting for messages'
    logger.setLevel(logging.INFO)
    while True:
        message = get_message()
        if message:
            print message