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Google云IoT-无效的MQTT发布主题

google-cloud-iot paho iot mqtt google-cloud-platform

Dalton Cézane · 技术社区 · 6 年前

我正在使用一个带有paho mqtt的Python客户端在Google Cloud IoT的这个特定主题中发布: projects/my_project/topics/sm1 .我的代码如下,基于谷歌物联网文档的示例:

import paho.mqtt.client as mqtt
import ssl, random, jwt_maker
from time import sleep

root_ca = './../roots.pem'
public_crt = './../my_cert.pem'
private_key = './../my_pr.pem'

mqtt_url = "mqtt.googleapis.com"
mqtt_port = 8883
mqtt_topic = "/projects/my_project/topics/sm1"
project_id   = "my_project"
cloud_region = "us-central1"
registry_id  = "sm1"
device_id    = "sm1"

connflag = False

def error_str(rc):
    """Convert a Paho error to a human readable string."""
    return "Some error occurred. {}: {}".format(rc, mqtt.error_string(rc))

def on_disconnect(unused_client, unused_userdata, rc):
    """Paho callback for when a device disconnects."""
    print("on_disconnect", error_str(rc))

def on_connect(client, userdata, flags, response_code):
    global connflag
    connflag = True
    print("Connected with status: {0}".format(response_code))

def on_publish(client, userdata, mid):
    print("User data: {0} -- mid: {1}".format(userdata, mid))
    #client.disconnect()

if __name__ == "__main__":

    client = mqtt.Client("projects/{}/locations/{}/registries/{}/devices/{}".format(
                         project_id,
                         cloud_region,
                         registry_id,
                         device_id))

    client.username_pw_set(username='unused',
                           password=jwt_maker.create_jwt(project_id,
                                               private_key,
                                               algorithm="RS256"))

    client.tls_set(root_ca,
                   certfile = public_crt,
                   keyfile = private_key,
                   cert_reqs = ssl.CERT_REQUIRED,
                   tls_version = ssl.PROTOCOL_TLSv1_2,
                   ciphers = None)

    client.on_connect = on_connect
    client.on_publish = on_publish
    client.on_disconnect = on_disconnect

    print("Connecting to Google IoT Broker...")
    client.connect(mqtt_url, mqtt_port, keepalive=60)
    client.loop_start() 

    while True:
        sleep(0.5)
        print connflag
        if connflag == True:
            print("Publishing...")
            ap_measurement = random.uniform(25.0, 150.0)
            #payload = "sm1/sm1-payload-{}".format(ap_measurement)
            res = client.publish(mqtt_topic, ap_measurement, qos=1)
            if not res.is_published():
               print("Data not published!!")
            else:
               print("ActivePower published: %.2f" % ap_measurement)
        else:
            print("Waiting for connection...")

当我运行时,客户端连接但不发布。在Google IoT控制台,我可以看到以下错误消息:

无效的MQTT发布主题:projects/my\u project/topics/sm1

以下是输出:

正在连接到Google IoT Broker。。。
已连接,状态:0--消息:已接受连接。
符合事实的
正在发布。。。
数据未发布!!
('on\u disconnect','发生了一些错误。1:内存不足。“)

这真的很奇怪,因为主题就在那里,创建了,并且有一个与之关联的订阅!

任何帮助都将不胜感激。我已经阅读了以下文档和代码:

2 回复 | 直到 6 年前

halfer Rahul Baradia 3 年前

您的主题名称不正确。

这很让人困惑(我也打了这个)。

客户端ID(如您所拥有的)必须是:

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

主题必须采用以下形式:

/devices/{}/config
/devices/{}/state
/devices/{}/events
/devices/{}/events/some/other/topic

如@ptone的评论所述:

在云物联网核心中,MQTT主题与云PubSub主题是多对一主题。为了安全起见,设备只能发布到以其设备名称空间为前缀的MQTT主题。然后您可以匹配 sub-topics to other Cloud PubSub topics as noted here ,但最多只有10个。这不是为了允许将设备1:1映射到PubSub主题。

Dat 6 年前

当我更改 mqtt_topic 从…起 events 到 state .在本例中,我试图将当前温度和湿度从我的设备上载到Google IoT Core。

  ...
  data =  {'temp': temperature, 'humid': humidity}
  device_id = 'freedgePrototype'
  topic = 'state'

  mqtt_topic = '/devices/{}/{}'.format(device_id, topic)
  payload = json.dumps(data)
  print('Publishing message  {}'.format(payload))

  client.publish(mqtt_topic, payload, qos=1)

结果是这样的。