首先你會需要安裝套件

pip install paho-mqtt 
或者 
pip3 install paho-mqtt

Python Publish 程式碼

import paho.mqtt.client as mqtt
import random
import json  
import datetime 
import time

client_id = "david"
server_ip = "127.0.0.1"
server_port = 1883
publish_uri ="/mqtt/4"
# 設置日期時間的格式
ISOTIMEFORMAT = '%m/%d %H:%M:%S'

# 連線設定
# 初始化地端程式

client = mqtt.Client(client_id=client_id)

# 設定登入帳號密碼
#client.username_pw_set("try","xxxx")

# 設定連線資訊(IP, Port, 連線時間)
client.connect(server_ip, server_port, 60)

while True:
    t0 = random.randint(0,30)
    t = datetime.datetime.now().strftime(ISOTIMEFORMAT)
    payload = {'Temperature' : t0 , 'Time' : t}
    print (json.dumps(payload))
    #要發布的主題和內容
    client.publish(publish_uri, json.dumps(payload))
    time.sleep(5)

參考文章: Day27 – 使用 Python 進行 Publish & Subscribe