Python3: MQTT クライアントのサンプル

こちらで定めた仕様を満たすクライアントです。
IOT: MQTT クライアントのサンプル

Raspberry Pi で確認しました。

GPIO16 に接続した LED を ON/OFF します。

環境設定
ユーザーを gpio グループに所属させます。

sudo gpasswd -a uchida gpio

ライブラリーのインストール

sudo apt install python3-rpi.gpio

プログラム

subscribe_paho.py

# ! /usr/bin/python3
#
#	subscribe_paho.py
#
#					Oct/05/2021
# ------------------------------------------------------------------
import paho.mqtt.client as mqtt
import ssl
import sys
import json
import RPi.GPIO as GPIO

broker = "example.com"
topic = "example/test01"

# ------------------------------------------------------------------
def report_proc(on_off):
	rvalue = {}
	rvalue["state"] = {}
	rvalue["state"]["reported"] = {}
	rvalue["state"]["reported"]["led"] = on_off
	str_json = json.dumps(rvalue)
	client.publish(topic, str_json)
# ------------------------------------------------------------------
def led_proc(on_off):
	sys.stderr.write("led_proc " + on_off + "\n")
	if on_off == "on":
		GPIO.output(16,1)
	elif on_off == "off":
		GPIO.output(16,0)
	report_proc(on_off)
# ------------------------------------------------------------------
def on_connect(client, userdata, flags, respons_code):
	print('status {0}'.format(respons_code))
	client.subscribe(topic)

# ------------------------------------------------------------------
def on_message(client, userdata, msg):
	print(msg.topic + ' ' + str(msg.payload))
	bb = msg.payload
	str_json = bb.decode()
	print(str_json)
	try:
		dict_aa = json.loads(str_json)
		state = dict_aa['state']
		if 'desired' in state:
			desired = state['desired']
			on_off = desired['led']
			print(on_off)
			led_proc(on_off)
	except Exception as ee:
		sys.stderr.write("*** error *** in json.loads ***\n")
		sys.stderr.write(str(ee) + "\n")
	print()

# ------------------------------------------------------------------
sys.stderr.write("*** subscribe_paho *** start ***\n")
GPIO.setmode (GPIO.BCM)
GPIO.setup (16,GPIO.OUT)

client = mqtt.Client(client_id= "python",protocol=mqtt.MQTTv311)

client.on_connect = on_connect
client.on_message = on_message

# client.connect(broker, port=port, keepalive=6)
client.connect(broker, keepalive=6)
client.loop_forever()
#
sys.stderr.write("*** subscribe_paho *** end ***\n")
# ------------------------------------------------------------------