NodeMCU script to control two relays via MQTT

relay.lua

connected = false

-- GPIO helpers

function blink_led(on, off, times, callback)
    if times == 0 then
        if type(callback) == "function" then
            callback()
        end
        return
    end
    gpio.write(0, gpio.LOW)
    gpio.mode(0, gpio.OUTPUT)
    tmr.create():alarm(on, tmr.ALARM_SINGLE, function()
        gpio.write(0, gpio.HIGH)
        tmr.create():alarm(off, tmr.ALARM_SINGLE, function()
            blink_led(on, off, times - 1, callback)
        end)
    end)
end

function toggle(pin)
    blink_led(200, 200, 3)
    gpio.write(pin, gpio.HIGH)
    tmr.create():alarm(1000, tmr.ALARM_SINGLE, function()
        gpio.write(pin, gpio.LOW)
    end)
end

-- all the code is event driven, so each function calls the
-- next one through a callback
function startup()
    if file.open("init.lua") == nil then
        print("init.lua deleted or renamed")
    else
        print("Running")
        file.close("init.lua")
        main()
    end
end

-- blink the LED until Wifi is connected, then do a rapid on-off sequence
-- runs asynchronously in the background until Wifi is connected
function blink()
    blink_led(500, 500, 1, function()
        if not connected then
            blink()
        else
            blink_led(50, 50, 5)
        end
    end)
end

function main()
    gpio.mode(0, gpio.INPUT)
    if gpio.read(0) == 0 or file.open("eus_params.lua") == nil then
        print("Starting enduser portal")
        blink()
        enduser_setup.start(connect_wifi,
            function(err, str)
                print("enduser_setup: Err #" .. err .. ": " .. str)
            end
        )
        return
    end

    file.close("eus_params.lua")
    blink()
    connect_wifi()
end

function connect_wifi()
    local p = {}
    local x = dofile("eus_params.lua")
    p.ssid = x["wifi_ssid"]
    p.pwd = x["wifi_password"]
    p.save = false
    p.auto = false
    wifi.setmode(wifi.STATION)
    wifi.sta.config(p)

    wifi.eventmon.register(wifi.eventmon.STA_DISCONNECTED, wifi_badstuff)
    wifi.eventmon.register(wifi.eventmon.STA_DHCP_TIMEOUT, wifi_badstuff)
    wifi.eventmon.register(wifi.eventmon.STA_GOT_IP, got_wifi)
    wifi.sta.connect()
end

-- a reset the easiest way to clear all state :)
function wifi_badstuff()
    print("Wifi disconnected, restarting")
    node.restart()
end

function got_wifi()
    if connected then
        return
    end

    print("Connected to wifi")
    connected = true
    try_mqtt()
end

function try_mqtt()
    m = mqtt.Client("entrata", 120)
    m:lwt("/entrata/status", "offline", 1, 1)
    m:on("message",
        function(client, topic, data)
            if topic == "/entrata/cancello" then toggle(1) end
            if topic == "/entrata/garage" then toggle(2) end
        end
    )
    m:on("offline", function(client)
          tmr.create():alarm(1000, tmr.ALARM_SINGLE, try_mqtt)
        end
    )

    -- add this: <input name=mqtt_broker type=text placeholder='MQTT broker IP address' />
    -- to the default enduser_setup.html to customize the IP address for the MQTT broker
    --
    local x = dofile("eus_params.lua")
    if not x["mqtt_broker"] then
        x["mqtt_broker"] = "192.168.10.191"
    end

    m:connect(x["mqtt_broker"], 1883, false,
        function(client)
            print("Connected to MQTT")
            client:subscribe("/entrata/cancello", 0)
            client:subscribe("/entrata/garage", 0)
            client:publish("/entrata/status", 'online', 1, 1)
        end,
        function(client, reason)
            print("failed reason: " .. reason)
            tmr.create():alarm(1000, tmr.ALARM_SINGLE, try_mqtt)
        end
    )
end

gpio.write(1, gpio.LOW)
gpio.write(2, gpio.LOW)
gpio.mode(1, gpio.OUTPUT)
gpio.mode(2, gpio.OUTPUT)

print("Startup will resume momentarily, you have 3 seconds to abort.")
print("Press USER button to enable the Wifi setup portal.")
print("Waiting...")
blink_led(50, 950, 4, startup)