BROKER は localhost
TOPIC は /topic/register
です。

プログラム

subscribe_redis.py

#! /usr/bin/python
#
#	subscribe_redis.py
#
#						Mar/31/2025
#
# ------------------------------------------------------------------
import sys
import json
import paho.mqtt.subscribe as subscribe
import redis

# ------------------------------------------------------------------
def redis_write_proc(key,value):
#
	sys.stderr.write("*** redis_write_proc ***\n")
	rr = redis.Redis(host='localhost', port=6379, db=0)
	rr.set(key, value)
# ------------------------------------------------------------------
def on_message_print(client, userdata, message):
	print("%s %s" % (message.topic, message.payload))
	json_str = message.payload
	unit_aa = json.loads(json_str)
	cpid = unit_aa['cpid']
	version = unit_aa['version']
	print(cpid)
	print(version)
	key = "cpid:" + cpid
	redis_write_proc(key,version)
#
# ------------------------------------------------------------------
sys.stderr.write("*** 開始 ***\n")
#
broker = 'localhost'
port = 1883
topic = '/topic/register'
#
#
subscribe.callback(on_message_print, topic, hostname=broker, userdata={"message_count": 0})
#
sys.stderr.write("*** 終了 ***\n")
# ------------------------------------------------------------------

テスト用スクリプト

#
BROKER="localhost"
TOPIC="/topic/register"
#
echo $BROKER
message="{\"cpid\": \"A1B2C3D9\",\"version\": \"2025-3-31 AM 11:09\"}"
mosquitto_pub -d -m "${message}" \
    -h  $BROKER \
    --topic $TOPIC
#

Systemd でプログラムを動かす

プログラムを
/usr/local/subscribe に置く

サービスの作成

subscribe_redis.service

[Unit]
Description = start up mqtt_client subscribe_redis

[Service]
WorkingDirectory=/var/tmp/subscribe_redis
ExecStart=/usr/local/subscribe/subscribe_redis.py
Type=simple

[Install]
WantedBy=default.target

作業用の Directory を作成

mkdir /var/tmp/subscribe_redis

起動

sudo systemctl start subscribe_redis

起動の確認

sudo systemctl status subscribe_redis