安裝 Mosquitto MQTT

取得key後進行安裝

sudo wget http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key
sudo apt-key add mosquitto-repo.gpg.key
cd /etc/apt/sources.list.d/
sudo wget http://repo.mosquitto.org/debian/mosquitto-jessie.list
sudo apt-get update
sudo apt-get install mosquitto

安裝三個 Mosquitto proper 會用到的程式庫
mosquitto – the MQTT broker (or in other words, a server)
mosquitto-clients – command line clients, very useful in debugging
python-mosquitto – the Python language bindings

sudo apt-get install mosquitto mosquitto-clients python-mosquitto 

安裝完後mosquitto會立即執行，但還需要進行部分設定，所以先停止

sudo /etc/init.d/mosquitto stop 

開啟設定檔案

sudo nano /etc/mosquitto/mosquitto.conf 

修改找到 log_dest 列，將後面改為 topic，如下

log_dest topic

並再增加下面六個參數後存檔

log_type error
log_type warning
log_type notice
log_type information
connection_messages true
log_timestamp true 

重新啟動mosquitto

sudo /etc/init.d/mosquitto start 

進行測試，開啟終端機，輸入下列指令

mosquitto_sub -d -t hello/world 

再開啟另一個終端機，輸入下列指令

mosquitto_pub -d -t hello/world -m "Hello from Terminal 2!" 

會在第一個開啟的終端機看到如上畫面

會在第二個開啟的終端機看到如上畫面