MQTT: Paho の使い方

こちらを参考にしました。
paho-mqtt 2.1.0

必要なライブラリーのインストール

sudo apt install python3-paho-mqtt

Publish

publish.py

#! /usr/bin/python
#
#	publish.py
#
#					Mar/31/2025
#
# ------------------------------------------------------------------
import paho.mqtt.publish as publish
import	sys

sys.stderr.write("*** 開始 ***\n")
message = "Good Afternoon"
topic = "/paho/test/topic"
publish.single(topic, message, hostname="localhost")
sys.stderr.write("*** 終了 ***\n")
# ------------------------------------------------------------------

Subscribe

subscribe_callback.py

#! /usr/bin/python
#
#	subscribe_callback.py
#
#					Mar/31/2025
#
# ------------------------------------------------------------------
import paho.mqtt.subscribe as subscribe
import sys
# ------------------------------------------------------------------
def on_message_print(client, userdata, message):
    print("%s %s" % (message.topic, message.payload))
    userdata["message_count"] += 1
    if userdata["message_count"] >= 5:
        # it's possible to stop the program by disconnecting
        client.disconnect()

# ------------------------------------------------------------------
sys.stderr.write("*** 開始 ***\n")
topic = "/paho/test/topic"
subscribe.callback(on_message_print, topic, hostname="localhost", userdata={"message_count": 0})
sys.stderr.write("*** 終了 ***\n")
# ------------------------------------------------------------------

確認したバージョン

$ python --version
Python 3.12.7

テストに使ったスクリプト

go_pub.sh

BROKER="localhost"
TOPIC="/paho/test/topic"
#
echo $BROKER
message="{\"key\": \"A1B2C3D4\",\"version\": \"2025-3-31 AM 11:09\"}"
mosquitto_pub -d -t orz -m "${message}" \
    -h  $BROKER \
    --topic $TOPIC

go_sub.sh

BROKER="localhost"
TOPIC="/paho/test/topic"
#
mosquitto_sub -d -h $BROKER --topic $TOPIC