MQTT : 簡易服務部署與操作指南

nofear195 included in Learning-Note

2024-05-27 2024-05-28 About 800 words 2 minutes - views - comments

Contents

MQTT: A Simple Guide to Service Deployment and Operation

Introduction

MQTT（Message Queuing Telemetry Transport）是一種輕量級的訊息傳輸協議，專為低頻寬、高延遲或不穩定的網絡環境設計。
廣泛應用於物聯網（IoT）設備的通訊。
主要角色
- MQTT Broker : 可比喻為燈塔，是訊息傳送的媒介，負責接收訊息與廣播訊息
- MQTT Client : 傳送訊息給 MQTT broker 的裝置，也是接收 MQTT broker 廣播訊息的裝置
- 基本設置：一個 MQTT Broker，多個 Client 端

Preparation

安裝 Docker 環境以及 Docker Compose tool

檔案結構：

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mqtt-broker/
│
├── config/
│     └── mosquitto.conf # 基本參數設定
│     └── passwd # 帳密
│ 
├── log/
│ 
├── docker-compose.yml
└── create_user.sh # 單次使用者與密碼生成執行檔
└── create_user_batch.sh # 批次使用者與密碼生成執行檔

mosquitto.conf (基本參數設定)

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# Enable persistent storage
persistence true
persistence_location /mosquitto/data/

# Logging
log_dest file /mosquitto/log/mosquitto.log

# Security settings
allow_anonymous false  # Disable anonymous access
password_file /mosquitto/config/passwd

# MQTT listener
listener 1883
protocol mqtt

# Websockets listener
# listener 9001
# protocol websockets

docker-compose.yml

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services:
  mqtt-broker:
    image: eclipse-mosquitto:2.0.18
    container_name: mqtt-broker
    restart: always
    volumes:
      - ./config/mosquitto.conf:/mosquitto/config/mosquitto.conf
      - ./config/passwd:/mosquitto/config/passwd
      - ./log/:/mosquitto/log/
      - mosquitto-data:/mosquitto/data/
    ports:
      - 1883:1883
      #- 9001:9001

volumes:
  mosquitto-data:

新增 MQTT 使用者與密碼
- 指令 mosquitto_passwd
- 使用者與密碼格式： username:password (username 不可包含 “:”)
- 參考連結：https://mosquitto.org/man/mosquitto_passwd-1.html
- 自製簡易執行檔
  - create_user.sh
    - 單次生成執行檔
    - 指令：mosquitto_passwd -b /mosquitto/config/passwd $username $password
  - create_user_batch.sh
    - 批次生成執行檔
    - 指令：mosquitto_passwd -U /mosquitto/config/passwd (更新文件內所有使用者與密碼組合)
  - 使用執行檔前需變更檔案模式 chmod +x create_user.sh

Deploying the MQTT Broker

cd ./mqtt-broker (切換至 docker-compose.yml 所在資料夾)
./create_user.sh or ./create_user_batch.sh (新增可連接使用 MQTT Broker 的使用者與密碼)
docker compose up -d (使用 docker-compose 工具部署 MQTT broker 服務)

Operation and Testing

測試工具：MQTT Explorer

MQTT Client example in JavaScript

publisher.js

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const mqtt = require('mqtt');

const client = mqtt.connect('mqtt://mqtt-broker:1883',{
    username:'user',
    password:'user'
});

client.on('connect', () => {
  console.log('Publisher connected to MQTT broker');
  setInterval(() => {
    client.publish('test/topic', 'Hello, MQTT!'); // Publish a message to a topic
  }, 1000);
});

client.on('close', () => {
  console.log('Publisher disconnected from MQTT broker');
  client.end()
});

subscriber.js

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const mqtt = require('mqtt');

const client = mqtt.connect('mqtt://mqtt-broker:1883',{
    username:'user',
    password:'user'
});

client.on('connect', () => {
  console.log('Subscriber connected to MQTT broker');
  client.subscribe('test/topic'); // Subscribe to a topic
});

client.on('message', (topic, message) => {
  console.log(`Received message on topic ${topic}: ${message.toString()}`);
});

client.on('close', () => {
  console.log('Subscriber disconnected from MQTT broker');
  client.end()
});

MQTT : 簡易服務部署與操作指南

Introduction

Preparation

Deploying the MQTT Broker

Operation and Testing

Reference