提高连接到AWS IOT核心连接的稳定性

Question

我正在尝试将亚马逊网络服务的IoT与Python结合使用。我正在实现一个MQTT客户端：

#Exte codigo SOLO SIRVE para escritorio
#NO USARLO en una PYCOM

#
from AWSIoTPythonSDK.MQTTLib import AWSIoTMQTTClient 
from pathlib import Path
import time

#
cert_folder=Path("certificados")

# user specified callback function
def customCallback(client, userdata, message):
    print("Received a new message: ")
    print(message.payload)
    print("from topic: ")
    print(message.topic)
    print("--------------\n\n")

# AWS general configuration
AWS_PORT = 8883
AWS_HOST = '*****.amazonaws.com'
AWS_ROOT_CA = cert_folder / "*****.pem"
AWS_CLIENT_CERT = cert_folder / "*****.cert.pem"
AWS_PRIVATE_KEY = cert_folder / "*****.private.key"

# For certificate based connection
myMQTTClient = AWSIoTMQTTClient("Pycom-client")
# For Websocket connection
# myMQTTClient = AWSIoTMQTTClient("Pycom-client", useWebsocket=True)

# Configurations
# For TLS mutual authentication
myMQTTClient.configureEndpoint(AWS_HOST, 8883)
# For Websocket
# myShadowClient.configureEndpoint(AWS_HOST, 443)
myMQTTClient.configureCredentials(AWS_ROOT_CA, AWS_PRIVATE_KEY, AWS_CLIENT_CERT)
# For Websocket, we only need to configure the root CA
# myMQTTClient.configureCredentials(AWS_ROOT_CA)

myMQTTClient.configureOfflinePublishQueueing(-1)  # Infinite offline Publish queueing
myMQTTClient.configureDrainingFrequency(2)  # Draining: 2 Hz
myMQTTClient.configureConnectDisconnectTimeout(10)  # 10 sec
myMQTTClient.configureMQTTOperationTimeout(50)  # 5 sec

#
if myMQTTClient.connect():
    print('AWS connection succeeded')

myMQTTClient.publish("topic_1", "Hola AWS!!!", 0)

# Subscribe to topic
myMQTTClient.subscribe("topic_2", 1, customCallback)

myMQTTClient.disconnect()

#Ciclo principal
while True:

    myMQTTClient.connect()

    myMQTTClient.publish("topic_1", "Hola AWS!!!", 0)

    # Subscribe to topic
    myMQTTClient.subscribe("topic_2", 1, customCallback)

    myMQTTClient.disconnect()

然而，连接仍然非常不稳定。我经常收到超时或服务器拒绝消息。我可以发送几条消息并接收其他消息。但是通过订阅接收消息很困难，我不知道是否应该使用额外的代码来改进它。

Answer 1

据我所知，您希望使用IoT将MQTT消息从您的设备发布到。此外，您还希望看到通过订阅相关主题发布的消息。您代码中的主要问题是您没有与AWS IoT消息代理建立持久会话。在while语句中，您不断地连接、发布、订阅和断开连接。

我建议您更新代码，如下所示：

# Connect and subscribe to AWS IoT
myMQTTClient.connect()
myMQTTClient.subscribe(your_topic_name, 1, customCallback)
time.sleep(1)
 
# Publish to the same topic in a loop forever
while True:
    myMQTTClient.publish(your_topic_name, "Hola AWS!!!", 0)
    time.sleep(1)

在本例中，您不需要myMQTTClient.disconnect()，因为您有一个无限的while循环。