ESP8266 + MQTT relay

mqtt_relay.py

import machine
import network
import ubinascii

from umqtt.simple import MQTTClient

SSID = ''
PASSWORD = ''
BROKER = ''
TOPIC = ''

CLIENT_ID = b'esp8266_' + ubinascii.hexlify(machine.unique_id())

client = None
relay = machine.Pin(5, machine.Pin.OUT)

def connect():
    sta_if = network.WLAN(network.STA_IF)
    ap_if = network.WLAN(network.AP_IF)

    if ap_if.active():
        ap_if.active(False)

    if not sta_if.isconnected():
        sta_if.active(True)
        sta_if.connect(SSID, PASSWORD)
        while not sta_if.isconnected():
            pass

def callback(topic, message):
    if message == b'on':
        relay.value(1)
    elif message == b'off':
        relay.value(0)
    elif message == b'toggle':
        relay.value(1 - relay.value())

def main():
    connect()

    client = MQTTClient(CLIENT_ID, BROKER)
    client.set_callback(callback)
    client.connect()
    client.subscribe(TOPIC)

    try:
        while True:
            client.wait_msg()
    finally:
        client.disconnect()

if __name__ == '__main__':
    relay.value(0)
    main()