RaspberryからAWS IoT にsubscribe/publishする

モチベーション

前回のRaspberryからAWS IoT にsubscribeするの逆のpublishをしたい。

環境

• RaspberryPi3B+
• Raspbian 9.8

参考文献

こちらを参考に
https://github.com/aws/aws-iot-device-sdk-python/blob/master/samples/basicPubSub/basicPubSub.py

ソースコード

コマンドラインから様々な変数を変更できるようにしていますが、前回のコードと同じように、pythonコードの中に定義する形にして、一度subscribeし、1秒毎に無限回publishするようにしたコードが以下。

mqttsubpub.py

# coding: utf-8
from AWSIoTPythonSDK.MQTTLib import AWSIoTMQTTClient
import logging
import time
import argparse
import json

CLIENT_ID = "test_client_id"
ENDPOINT = "a1zpik1blw3qlv-ats.iot.us-east-1.amazonaws.com"
PORT = 8883
ROOT_CA = "./cert/AmazonRootCA1.pem"
PRIVATE_KEY = "./cert/786b47188a-private.pem.key"
CERTIFICATE = "./cert/786b47188a-certificate.pem.crt"
TOPIC = "RasPi3B/sample"


def main():
    client = AWSIoTMQTTClient(CLIENT_ID)
    client.configureEndpoint(ENDPOINT, PORT)
    client.configureCredentials(ROOT_CA, PRIVATE_KEY, CERTIFICATE)

    # AWSIoTMQTTClient connection configuration
    client.configureAutoReconnectBackoffTime(1, 32, 20)
    client.configureOfflinePublishQueueing(-1)  # Infinite offline Publish queueing
    client.configureDrainingFrequency(2)  # Draining: 2 Hz
    client.configureConnectDisconnectTimeout(10)  # 10 sec
    client.configureMQTTOperationTimeout(5)  # 5 sec

    # Connect and subscribe to AWS IoT
    client.connect()
    # TOPICが起動したら呼ばれる関数を登録する
    client.subscribe(TOPIC, 1, mycallback)
    time.sleep(2)

    # Publish to the same topic in a loop forever
    loopCount = 0
    while True:
        message = {}
        message['message'] = 'Hellow AWS IoT'
        message['sequence'] = loopCount
        messageJson = json.dumps(message)
        # publish(topic, payload, QoS)
        client.publish(TOPIC, messageJson, 1)
        loopCount += 1
        time.sleep(1)

# Custom MQTT message callback
def mycallback(client, userdata, message):
    print("Received a new message: ")
    print(message.payload)
    print("from topic: ")
    print(message.topic)
    print("--------------\n\n")


if __name__ == "__main__":
    main()

実行結果も載せておきます。
5回pub/subした後に、Ctrl-zで中止しました。

pi@raspberrypi:~ $ python mqttsubpub.py
Received a new message:
{"message": "Hellow AWS IoT", "sequence": 0}
from topic:
RasPi3B/sample
--------------


Received a new message:
{"message": "Hellow AWS IoT", "sequence": 1}
from topic:
RasPi3B/sample
--------------


Received a new message:
{"message": "Hellow AWS IoT", "sequence": 2}
from topic:
RasPi3B/sample
--------------


Received a new message:
{"message": "Hellow AWS IoT", "sequence": 3}
from topic:
RasPi3B/sample
--------------


Received a new message:
{"message": "Hellow AWS IoT", "sequence": 4}
from topic:
RasPi3B/sample
--------------


Received a new message:
{"message": "Hellow AWS IoT", "sequence": 5}
from topic:
RasPi3B/sample
--------------


^Z
[3]+  停止                  python mqttsubpub.py
pi@raspberrypi:

APIリファレンス
https://s3.amazonaws.com/aws-iot-device-sdk-python-docs/sphinx/html/index.html#