simplified RPi system sensors MQTT announcements (incl. Home Assistant auto-discovery)

sensors.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

# Simplified RPi system sensors MQTT announcements
# Inspired by the great work done by @Sennevds
#
# This script is meant to be executed via crontab.
# It does NOT maintain a persistent connection and/or employ a loop function to keep sending messages at defined intervals.
# Therefor, in order to make use of the LWT function, added the keepAlive flag to the connecion.
#
# Make sure to make your keepAlive time slightly longer than the crontab interval time! 

# MQTT connection info
mqttuser        = "****"
mqttpwd         = "****"
mqtthost	= "****"
mqttport	= 1883
mqttkeepalive	= 60

# RPi-related info
piname          = "****"
disk_path       = "/"

#
# (Hopefully) no need to edit past this line -------------------------------------------
#

import sys, os, re, subprocess, socket, json, time, datetime
import paho.mqtt.client as paho

tot_m, used_m, free_m = map(int, os.popen('free -t -m').readlines()[-1].split()[1:])
CPU_Pct = str(round(float(os.popen('''grep 'cpu ' /proc/stat | awk '{usage=($2+$4)*100/($2+$4+$5)} END {print usage }' ''').readline()),2))

# CPU usage
cpu = "%.1f" % float(CPU_Pct)
# Memory usage
memory = "%.1f" % ( float(tot_m - used_m) / tot_m * 100 )
# Temperature
treading = subprocess.check_output(['vcgencmd', 'measure_temp']).decode('UTF-8')
temp = str(re.findall('\d+.\d+', treading)[0])
# Clock speed
creading = subprocess.check_output(['vcgencmd', 'measure_clock','arm']).decode('UTF-8')
clock = str(int(re.findall('\d+', creading)[1]) / 1000000)
# Hostname
host = socket.gethostname()
# Last message (UTC, ISO)
lastmsg = datetime.datetime.utcnow().strftime('%Y-%m-%dT%H:%M:%SZ')

# @see https://stackoverflow.com/questions/54458308
def disk_usage(path):
        st = os.statvfs(path)
        free = st.f_bavail * st.f_frsize
        total = st.f_blocks * st.f_frsize
        used = (st.f_blocks - st.f_bfree) * st.f_frsize
        return "%.1f" % ( float(used) / total * 100 )

# @see https://github.com/Sennevds/system_sensors/blob/master/src/sensors.py#L164
def get_host_ip():
	try:
		sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
		sock.connect(('8.8.8.8', 80))
		return sock.getsockname()[0]
	except socket.error:
		try:
			return socket.gethostbyname(socket.gethostname())
		except socket.gaierror:
			return '127.0.0.1'
	finally:
		sock.close()

pinamelc = piname.lower()
topic = "system-sensors/sensor/%s" % (pinamelc)

sensors = {
	"temperature": temp,
	"clock_speed": clock,
	"memory_use": memory,
	"cpu_usage": cpu,
	"disk_use": disk_usage(disk_path),
	"hostname": host,
	"last_message": lastmsg,
	"ip": get_host_ip()
}

ha_sensors = {
	"temperature": {
		"name": "Temperature",
		"unit": "°C",
		"icon": "thermometer",
		"class": "temperature"},
	"clock_speed": {
		"name": "Clock speed",
		"unit": "Hz",
		"icon": "speedometer"},
	"memory_use": {
		"name": "Memory usage",
		"unit": "%",
		"icon": "memory"},
	"cpu_usage": {
		"name": "CPU usage",
		"unit": "%",
		"icon": "cpu-64-bit"},
	"disk_use": {
                "name": "Disk usage",
                "unit": "%",
                "icon": "micro-sd"},
	"hostname": {
		"name": "Hostname",
		"icon": "card-account-details"},
	"last_message": {
                "name": "Last message",
                "icon": "clock-check",
                "class": "timestamp"},
	"ip": {
		"name": "Host IP",
		"icon": "lan"}
}

def add_device_info(config):
	config['device'] = {
		"identifiers": ["%s_sensor" % (pinamelc)],
		"name": "%s Sensors" % (piname),
		"model": "RPI %s" % (piname),
		"manufacturer": "RPI"}
	return config

def add_availability_topic(config):
	config["availability_topic"] = "%s/availability" % (topic)
	config["payload_available"] = "online"
	config["payload_not_available"] = "offline"
	return config

client = paho.Client()
client.username_pw_set(mqttuser, mqttpwd)
client.connect(mqtthost, mqttport, mqttkeepalive)
client.will_set("%s/availability" % (topic), "offline", 1, True)

client.publish("%s/state" % (topic), json.dumps(sensors), 1, False)
for index, sensor in ha_sensors.items():
	config = {
		"name": "%s %s" % (piname, sensor['name']),
		"state_topic": "%s/state" % (topic),
		"value_template": "{{ value_json.%s }}" % (index),
		"unique_id": "%s_sensor_%s" % (pinamelc, index),
		"icon": "mdi:%s" % (sensor['icon'])
	}
	if "unit" in sensor:
		config['unit_of_measurement'] = sensor['unit']
	if "class" in sensor:
		config['device_class'] = sensor['class']

	config = json.dumps(add_device_info(add_availability_topic(config)))
	client.publish("homeassistant/sensor/%s/%s/config" % (pinamelc, index), config, 1, True)

client.publish("%s/availability" % (topic), "online", 1, True)
client.publish("homeassistant/binary_sensor/%s/connected/config" % (pinamelc), json.dumps(add_device_info({
	"name": "%s Connected" % (sensors['hostname']),
	"state_topic": "%s/availability" % (topic),
	"value_template": "{{ value }}",
	"unique_id": "%s_sensor_connected" % (pinamelc),
	"payload_on": "online",
	"payload_off": "offline",
	"device_class": "connectivity"
})), 1, True)

time.sleep(1)
client.disconnect()
sys.exit()