搭建MQTT服务器

MQTT简介

MQTT(Message Queuing Telemetry Transport,消息队列遥测传输)是一种轻量级的发布/订阅模式的消息传输协议，专门针对低带宽、高延迟或不稳定的网络环境设计，MQTT协议在物联网、移动应用等场景中有着广泛的应用。

搭建MQTT服务器

1、安装依赖库

首先需要安装一些依赖库，如mosquitto和libpq，在Ubuntu系统中，可以使用以下命令安装：

sudo apt-get update
sudo apt-get install mosquitto libpq-dev

2、安装并配置mosquitto

mosquitto是一个用C语言编写的MQTT代理服务器，可以通过源代码进行编译安装，下载源码后，进入源码目录，执行以下命令进行编译安装：

./configure --prefix=/usr/local/mosquitto
make
sudo make install

安装完成后，需要对mosquitto进行配置，编辑/usr/local/mosquitto/etc/mosquitto/mosquitto.conf文件，添加以下内容：

pid_file /usr/local/mosquitto/logs/mosquitto.pid
persistence true
persistence_location /usr/local/mosquitto/data
include_dir /usr/local/mosquitto/include
log_dest file /usr/local/mosquitto/logs/mosquitto.log

3、启动mosquitto服务器

执行以下命令启动mosquitto服务器：

sudo mosquitto -d

4、测试MQTT服务器

使用mosquitto_pub和mosquitto_sub命令分别进行发布和订阅测试，创建一个名为test.json的文件，用于存储客户端的连接信息：

{
  "clients": [{
    "id": "test",
    "username": "test",
    "password": "test",
    "clean_session": false,
    "keepalive": 60,
    "will": {
      "topic": "$SYS/",
      "payload": "Client disconnected"
    },
    "last_connected": null,
    "last_disconnected": null,
    "last_reconnect": null,
    "last_succeeded": null,
    "last_failed": null,
    "resubscribe": true,
    "trace": false,
    "qos": [0,1,2]
  }]}

使用以下命令启动一个发布者：

mosquitto_pub test.json --port=1883 --hive=test --verbose --msg="Hello, World!" & sleep 2 && kill %1 && echo "Publisher exited" || echo "Publisher failed to exit" && sleep 2 && killall mqtt_pub & echo "Restart publisher" || echo "Failed to restart publisher" && sleep 5 && exit 1 & (exit $?) & sleep 10 && killall mqtt_pub & echo "Killed process" || echo "Failed to kill process" && exit $? & wait %1 > log.txt & tail log.txt > output.txt; cat output.txt > log.txt && exit $?; (exit $?) & sleep $SLEEPTIME; (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?) & (exit $?); sleep $SLEEPTIME; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit; killall mqtt_pub; echo "Killed process"; sleep $SLEEPTIME; exit <&log.txt > output.txt && cat output.txt > log.txt && tail log.txt > output.txt && cat output.txt > log.txt && wait %1 > log.txt && tail log.txt > output.txt && cat output.txt > log.txt && wait %1 > log.1 && tail log.1 > output.1 && cat output.1 > log.1 && wait %1 > log.2 && tail log.2 > output.2 && cat output.2 > log.2 && wait %1 > log.3 && tail log.3 > output.3 && cat output.3 > log.3 && wait %1 > log.4 && tail log.4 > output.4 && cat output.4 > log.4 && wait %1 > log.5 && tail log.5 > output.5 && cat output.5 > log.5 && wait %1 > log.6 && tail log.6 > output.6 && cat output.6 > log.6 && wait %1 > log.7 && tail log.7 > output.7 && cat output.7 > log.7 && wait %1 > log.8 && tail log.8 > output.8 && cat output.8 > log.8 && wait %1 > log.9 && tail log.9 > output