MQTT to Influx relay script

readme.md

MQTT to Influx relay script

This script subscribes to certain mqtt topics and adds any (numeric/boolean!) values to your influx db to e.g. display the stats in grafana.

Example scenario

• Retreive smartphone battery charge in mqtt using an app like Presence Publisher.
• Use the script to put that data into an influx db.
• Display that data in grafana

mqtt_influx_relay.py

#!/usr/bin/env python3

# Bases on snippet from this tutorial:
# https://gonzalo123.com/2018/06/04/playing-with-docker-mqtt-grafana-influxdb-python-and-arduino/

import paho.mqtt.client
from influxdb import InfluxDBClient
import datetime
import logging

INFLUXDB_HOST = 'localhost'
INFLUXDB_PORT = 8086

MQTT_HOST = 'localhost'
MQTT_PORT = 1883
# TOPICS should receive numeric or boolean (on/off or true/false) values
# Json support should be easily addable
MQTT_TOPICS = [
  'stat/chargecontroller/power',
  'stat/v30/battery',
]

def on_message(client, userdata, msg):
  # Get numeric value from msg
  rawValue = msg.payload.decode('UTF-8')
  rawValueLc = rawValue.lower()
  value = None
  if rawValueLc == 'on' or rawValueLc == 'true':
    value = int(True)
  elif rawValueLc == 'off' or rawValueLc == 'false':
    value = int(False)
  else:
    value = int(rawValue)

  # Create data for influxdb
  current_time = datetime.datetime.utcnow().isoformat()
  json_body = [
    {
      "measurement": "message",  # Similar to table
      "tags": {
        "server": '%s:%d' % (MQTT_HOST, MQTT_PORT), # May be discarded
        "topic": msg.topic
      },
      "time": current_time,
      "fields": {
        "value": value
      }
    }
  ]
  logging.info('%s = %d (raw: %s)' % (msg.topic, value, rawValue))
  influx_client.write_points(json_body)


def on_connect(client, mosq, obj, rc):
  logging.info('Connected to mqtt')
  for topic in MQTT_TOPICS:
    client.subscribe(topic)
    logging.info('Subscribed to %s' % topic)


logging.basicConfig(level=logging.INFO)

influx_client = InfluxDBClient(INFLUXDB_HOST, INFLUXDB_PORT, database='mqtt')

mqttClient = paho.mqtt.client.Client()
mqttClient.on_connect = on_connect
mqttClient.on_message = on_message
mqttClient.connect(MQTT_HOST, MQTT_PORT, 60)
mqttClient.loop_forever()