micropython - ESP32 - MQTT 异常 4 - 谷歌云物联网

Question

我希望使用 micropython 通过 ESP32 板将传感器数据发送到 Google IoT Cloud。

我在这里找到了一个实现示例：https://nihal-pasham.medium.com/you-could-try-freezing-the-pyasn-1-9afd6533cd7a

但它抛出以下错误消息：

Traceback (most recent call last):
  File "main.py", line 50, in <module>
  File "main.py", line 44, in get_mqtt_client
  File "umqtt/simple.py", line 99, in connect
MQTTException: 4

这是我正在使用的板： https://www.amazon.com/gp/product/B0718T232Z/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

这是我使用的 micropython 版本： esp32-idf3-20200902-v1.13.bin

这是我的代码：

from third_party import rsa
import config
from third_party import string
from umqtt.simple import MQTTClient
from ubinascii import b2a_base64
import ujson
import utime

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

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

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)

我已经通过其他示例检查了我对 Google Cloud 的凭据，并且我能够使用我的计算机发布/接收消息，所以从那一边应该没问题。

有人遇到过类似的问题吗？请问有人可以帮忙吗？

谢谢