Google Cloud IoT-无效的MQTT发布主题

Question

我使用带有paho-mqtt的Python客户机发布Google Cloud IoT的特定主题:projects/my_project/topics/sm1。下面是基于Google IoT文档示例的代码：

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信息：

无效的MQTT发布主题:projects/my_project/topics/sm1

下面是输出：

连接到Google IoT Broker...
连接状态：0--msg：接受连接。
为真
发布...
数据未发布！！
('on_disconnect','some error arcest.1：内存不足。')

这真的很奇怪，因为主题就在那里，创建了，并且有一个与之相关的订阅！

任何帮助都将不胜感激。我已经阅读了以下文档和代码：

null

Answer 1

您的主题名称不正确。

这很令人困惑（我刚刚也击中了这个）。

客户端ID（与您拥有的一样）必须是：

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

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

在云iot核心中，MQTT主题与云PubSub主题是多对一的。对于安全性-设备只能发布到MQTT主题，主题前缀是它们的设备名称空间。然后，您可以将子主题匹配到其他Cloud PubSub主题，如这里所述，但最多只能匹配10个。这不是为了允许1：1映射设备到PubSub主题而设计的。