プログラム

MQTT サーバーから、次のような　JSON を受信するとします。

{"temperature": 20.4}

subscribe_influx.py

#! /usr/bin/python
#
#	subscribe_influx.py
#
#						Dec/05/2022
#
# ------------------------------------------------------------------
import sys
import json
from time import sleep
import paho.mqtt.client as mqtt
import time
import influxdb_client
from influxdb_client.client.write_api import SYNCHRONOUS

# ------------------------------------------------------------------
def influxdb_write_proc(json_str):
#	print(json_str)
	unit_aa = json.loads(json_str)
	value = unit_aa["temperature"]
	print(value)
#
	pp = influxdb_client.Point("data") \
		.field("temperature", value)
	write_api.write(bucket=bucket, org=org, record=pp)

# ------------------------------------------------------------------
def on_connect(client, userdata, flags, respons_code):
#	print('status {0}'.format(respons_code))
	client.subscribe(topic)

# ------------------------------------------------------------------
def on_message(client, userdata, msg):
#	print(msg.topic + ' ' + str(msg.payload,'utf-8'))
	influxdb_write_proc(str(msg.payload,'utf-8'))

# ------------------------------------------------------------------
sys.stderr.write("*** 開始 ***\n")

host = 'example.com'
port = 1883
topic = 'example/test'

bucket = "tochigi"
org = "ekzemplaro"
token = '****VpyyJg6nskHEwcl6bMsjc1vyzY9b11hSyGiQMOg=='
#
url="http://localhost:8086"

db_client = influxdb_client.InfluxDBClient(
   url=url,
   token=token,
   org=org
)

write_api = db_client.write_api(write_options=SYNCHRONOUS)

client = mqtt.Client(protocol=mqtt.MQTTv311)

client.on_connect = on_connect
client.on_message = on_message

client.connect(host, port=port, keepalive=60)

client.loop_forever()

sys.stderr.write("*** 終了 ***\n")
# ------------------------------------------------------------------

テスト用プログラム

MQTT サーバーに 1秒毎にデータをパブリッシュします。

publish.py

#! /usr/bin/python
#
#	publish.py
#
#					Dec/05/2012
#
# ------------------------------------------------------------------
import  sys
import  json
from time import sleep
import paho.mqtt.client as mqtt

# ------------------------------------------------------------------
sys.stderr.write("*** 開始 ***\n")

host = 'example.com'
port = 1883
topic = 'example/test'

client = mqtt.Client(protocol=mqtt.MQTTv311)

client.connect(host, port=port, keepalive=60)

ttx = [20.4,21.3,22.7,23.5,24.5,23.6,22.2,20.1]
for it in range(len(ttx)):
	unit_aa = {}
	unit_aa['temperature'] = ttx[it]
	json_str = json.dumps(unit_aa)
	print(json_str)
	client.publish(topic, json_str)
	sleep(1.0)
#
client.disconnect()

sys.stderr.write("*** 終了 ***\n")
# ------------------------------------------------------------------

書き込まれたデータの確認

InfluxDB に書き込まれたデータのプログラムは、
InfluxDB v2: 時系列データの取り扱い例
にある
query_temperature.py