local-dht-connector.py

#!/usr/bin/env python

import paho.mqtt.client as paho  # pip install paho-mqtt
import time
import logging
import sys
import weathermath
from config import *

from pigpio_dht import DHT22


MQTT_PREFIX = 'rpi'
FREQUENCY_S = 300

dhtDevice = DHT22(4)


def data(retry=True):

    values = {}

    try:
        result = dhtDevice.read()

        if result['valid']:
            values['waschkueche/temp'] = result['temp_c']
            values['waschkueche/humidity'] = result['humidity']
            values['waschkueche/humidity_abs'] = weathermath.AF(result['humidity'], result['temp_c'])
            logging.info("{:.1f} C, {} %, {:.2f} g/m3 ".format(values['waschkueche/temp'],
                                                           values['waschkueche/humidity'],
                                                           values['waschkueche/humidity_abs']))
        else:
            logging.info("data not valid")

    except TimeoutError as error:
        logging.info("DHT error: ".format(str(error)))

        if retry:
            logging.info("Retrying in 3 sec...")
            time.sleep(3)
            values = data(False)
        else:
            logging.info("Not retrying again")

    return values


if __name__ == '__main__':
    logging.basicConfig(stream=sys.stderr, level=logging.INFO)

    mqttc = paho.Client('local-dht-connector', clean_session=True)
    # mqttc.enable_logger()
    mqttc.will_set("{}/connectorstatus".format(MQTT_PREFIX), "Local DHT Connector: LOST_CONNECTION", 0, retain=True)

    mqttc.connect(BROKER_HOST, BROKER_PORT, 60)
    logging.info("Connected to {}:{}".format(BROKER_HOST, BROKER_PORT))

    mqttc.publish("{}/connectorstatus".format(MQTT_PREFIX), "Local DHT Connector: ON-LINE", retain=True)

    mqttc.loop_start()
    while True:
        try:
            values = data()
            for k, v in values.items():
                (result, mid) = mqttc.publish("{}/{}".format(MQTT_PREFIX, k), str(v), qos=0, retain=True)
                logging.debug("Pubish Result: {} MID: {} for {}: {}".format(result, mid, k, v))  # noqa E501                

            time.sleep(FREQUENCY_S)
        except KeyboardInterrupt:
            break
        except Exception:
            raise

    mqttc.publish("{}/connectorstatus".format(MQTT_PREFIX), "Local DHT Connector: OFF-LINE", retain=True)

    mqttc.disconnect()
    mqttc.loop_stop()  # waits, until DISCONNECT message is sent out
    logging.info("Disconnected from to {}:{}".format(BROKER_HOST, BROKER_PORT))