MQTT Google Cloud iot connection

[minusplusminus]

Hi,

I'm researching if it's possible to connect Google Cloud. Could not get further than this:

First I tried with the embedded libraries of LoBo based on this tutorial:

connecting-micropython-devices-to-google-cloud-iot-core

from third_party import string
import machine
import network
import utime
from third_party import rsa

from ubinascii import b2a_base64
#from machine import Pin
#import ntptime
from umqtt.simple import MQTTClient
import ujson
import config
import time

sta_if = network.WLAN(network.STA_IF)
#led_pin = machine.Pin(config.device_config['led_pin'], Pin.OUT)  # built-in LED pin
#led_pin.value(1)

def connect():
    if not sta_if.isconnected():
        print('connecting to network...')
        sta_if.active(True)
        sta_if.connect(config.wifi_config['ssid'], config.wifi_config['password'])
        while not sta_if.isconnected():
            pass
    print('network config: {}'.format(sta_if.ifconfig()))

# def set_time():
#     ntptime.settime()
#     tm = utime.localtime()
#     tm = tm[0:3] + (0,) + tm[3:6] + (0,)
#     machine.RTC().datetime(tm)
#    print('current time: {}'.format(utime.localtime()))

def b42_urlsafe_encode(payload):
    return string.translate(b2a_base64(payload)[:-1].decode('utf-8'), {ord('+'): '-', ord('/'): '_'})

# password generation
def create_jwt(project_id, private_key, algorithm, token_ttl):
    print("Creating JWT...")
    private_key = rsa.PrivateKey(*private_key)

    # Epoch_offset is needed because micropython epoch is 2000-1-1 and unix is 1970-1-1. Adding 946684800 (30 years)
    epoch_offset = 946684800
    claims = {
        # The time that the token was issued at
        'iat': utime.time() + epoch_offset,
        # The time the token expires.
        'exp': utime.time() + epoch_offset + token_ttl,
        # The audience field should always be set to the GCP project id.
        'aud': project_id
    }

    # This only supports RS256 at this time.
    header = {"alg": algorithm, "typ": "JWT"}
    content = b42_urlsafe_encode(ujson.dumps(header).encode('utf-8'))
    content = content + '.' + b42_urlsafe_encode(ujson.dumps(claims).encode('utf-8'))
    signature = b42_urlsafe_encode(rsa.sign(content, private_key, 'SHA-256'))
    return content + '.' + signature  # signed JWT

def conncb(task):
    print("[{}] Connected".format(task))

def disconncb(task):
    print("[{}] Disconnected".format(task))

def subscb(task):
    print("[{}] Subscribed".format(task))

def pubcb(pub):
    print("[{}] Published: {}".format(pub[0], pub[1]))

def datacb(msg):
    print("[{}] Data arrived from topic: {}, Message:\n".format(msg[0], msg[1]), msg[2])

connect()

rtc = machine.RTC()
rtc.ntp_sync(server="time.google.com")
print(rtc.synced())
while rtc.synced() == False:
    utime.sleep_ms(1000)
    print(rtc.synced())
print(utime.gmtime())

print(utime.localtime())

print('starting..')

jwt = create_jwt(config.google_cloud_config['project_id'],
                 config.jwt_config['private_key'],
                 config.jwt_config['algorithm'],
                 config.jwt_config['token_ttl'])
# mqtt = network.mqtt(name, server [optional_arguments])
print(jwt)
project_id = config.google_cloud_config['project_id']
cloud_region = config.google_cloud_config['cloud_region']
registry_id = config.google_cloud_config['registry_id']
device_id = config.google_cloud_config['device_id']

client_id = 'projects/{}/locations/{}/registries/{}/devices/{}'.format(project_id, cloud_region, registry_id,
                                                                       device_id)

print('init thing')
thing = network.mqtt("googlecloud",
                     'mqtts://{}'.format(config.google_cloud_config['mqtt_bridge_hostname']),
                     port=config.google_cloud_config['mqtt_bridge_port'],
                     user=b'ignored',
                     clientid=client_id.encode('utf-8'),
                     password=jwt.encode('utf-8'),
                    # cleansession=True,
                     autoreconnect=True,
                     disconnected_cb=disconncb,
                     subscribed_cb=subscb,
                     published_cb=pubcb,
                     data_cb=datacb)

thing.start()

tmo = 0
while thing.status()[0] != 2:
    utime.sleep_ms(100)
    tmo += 1
    #print(thing.status())
    if tmo > 300:
        print("Not connected")
        break

#thing.subscribe('/devices/{}/config'.format(device_id), 1)
#thing.subscribe('/devices/{}/commands/#'.format(device_id), 1)
# subscribe to channel
# thing.subscribe(subchan)

# subscribe to field
# thing.subscribe(subfield)

# publish to channel
# Payload can include any of those fields separated b< ';':
# "field1=value;field2=value;...;field8=value;latitude=value;longitude=value;elevation=value;status=value"
# thing.publish(pubchan, "field1=25.2;status=On line")

# Publish to field
# thing.publish(pubfield, "24.5")

while True:
    print('looping')
    print(thing.status())
    message = {
        "device_id": config.google_cloud_config['device_id'],
        "temp": "1"
    }
    print("Publishing message " + str(ujson.dumps(message)))
    #led_pin.value(1)
    mqtt_topic = '/devices/{}/{}'.format(config.google_cloud_config['device_id'], 'events')
    thing.publish(mqtt_topic.encode('utf-8'), ujson.dumps(message).encode('utf-8'))
    #led_pin.value(0)

    # client.check_msg()  # Check for new messages on subscription
    utime.sleep(10)  # Delay for 10 seconds.
    #time.sleep_ms(5000)

the result is:

init thing
[googlecloud] Disconnected
[googlecloud] Disconnected
(3, 'Wait timeout')

Sadly enough Google cloud console detected one time. But I don't know when this happened. "mqtt: The connection broke or was closed by the client."

Second try was with umqtt.simple

import machine

from third_party import string
import network
import utime
from third_party import rsa
from umqtt.simple import MQTTClient
from ubinascii import b2a_base64
from machine import Pin

import ujson
import config

# https://github.com/GoogleCloudPlatform/iot-core-micropython/blob/master/main.py

sta_if = network.WLAN(network.STA_IF)

# led_pin = machine.Pin(config.device_config['led_pin'], Pin.OUT)  # built-in LED pin
# led_pin.value(1)

def on_message(topic, message):
    print((topic, message))

def connect():
    if not sta_if.isconnected():
        print('connecting to network...')
        sta_if.active(True)
        sta_if.connect(config.wifi_config['ssid'], config.wifi_config['password'])
        while not sta_if.isconnected():
            pass
    print('network config: {}'.format(sta_if.ifconfig()))

def set_time():
    rtc = machine.RTC()
    rtc.ntp_sync(server="0.nl.pool.ntp.org", tz="Europe/Amsterdam")
    print(rtc.synced())
    while rtc.synced() == False:
        utime.sleep_ms(1000)
        print(rtc.synced())
    print(utime.gmtime())

    print(utime.localtime())

def b42_urlsafe_encode(payload):
    return string.translate(b2a_base64(payload)[:-1].decode('utf-8'), {ord('+'): '-', ord('/'): '_'})

def create_jwt(project_id, private_key, algorithm, token_ttl):
    print("Creating JWT...")
    private_key = rsa.PrivateKey(*private_key)

    # Epoch_offset is needed because micropython epoch is 2000-1-1 and unix is 1970-1-1. Adding 946684800 (30 years)
    epoch_offset = 946684800
    claims = {
        # The time that the token was issued at
        'iat': utime.time() + epoch_offset,
        # The time the token expires.
        'exp': utime.time() + epoch_offset + token_ttl,
        # The audience field should always be set to the GCP project id.
        'aud': project_id
    }

    # This only supports RS256 at this time.
    header = {"alg": algorithm, "typ": "JWT"}
    content = b42_urlsafe_encode(ujson.dumps(header).encode('utf-8'))
    content = content + '.' + b42_urlsafe_encode(ujson.dumps(claims).encode('utf-8'))
    signature = b42_urlsafe_encode(rsa.sign(content, private_key, 'SHA-256'))
    return content + '.' + signature  # signed JWT

def get_mqtt_client(project_id, cloud_region, registry_id, device_id, jwt):
    """Create our MQTT client. The client_id is a unique string that identifies
    this device. For Google Cloud IoT Core, it must be in the format below."""
    client_id = 'projects/{}/locations/{}/registries/{}/devices/{}'.format(project_id, cloud_region, registry_id,
                                                                           device_id)
    print('Sending message with password {}'.format(jwt))
    client = MQTTClient(client_id.encode('utf-8'), server=config.google_cloud_config['mqtt_bridge_hostname'], port=
    config.google_cloud_config['mqtt_bridge_port'], user=b'ignored', password=jwt.encode('utf-8'), ssl=True)
    client.set_callback(on_message)

    client.connect()

    channel = b'/devices/{}/config'.format(device_id)
    print(channel)
    client.subscribe(channel)
    # client.subscribe('/devices/{}/commands/#'.format(device_id), 1)
    return client

connect()
# Need to be connected to the internet before setting the local RTC.
set_time()

jwt = create_jwt(config.google_cloud_config['project_id'], config.jwt_config['private_key'],
                 config.jwt_config['algorithm'], config.jwt_config['token_ttl'])
client = get_mqtt_client(config.google_cloud_config['project_id'], config.google_cloud_config['cloud_region'],
                         config.google_cloud_config['registry_id'], config.google_cloud_config['device_id'], jwt)

while True:
    message = {
        "device_id": config.google_cloud_config['device_id'],
        "temp": "1"
    }
    print("Publishing message " + str(ujson.dumps(message)))
    # led_pin.value(1)
    mqtt_topic = '/devices/{}/{}'.format(config.google_cloud_config['device_id'], 'events')
    client.publish(mqtt_topic.encode('utf-8'), ujson.dumps(message).encode('utf-8'))
    # led_pin.value(0)

    client.check_msg()  # Check for new messages on subscription
    utime.sleep(10)  # Delay for 10 seconds.

MQTTException: 4 I don't know where the integer stand for.

Thanks in advance

[minusplusminus]

got it

epoch_offset = 0