从 Influxdb 输出数据到 MQTT broker/server

Question

这是我第一次使用 MQTT，我想从 influxdb 获取数据到 Snowflake，但在此之前我必须：

从influxdb获取数据到MQTT，我在网上找不到任何例子。

我尝试使用以下脚本将数据从 mqtt 保存到 InfluxDB：

"""A MQTT to InfluxDB Bridge
This script receives MQTT data and saves those to InfluxDB.
"""

import re
from typing import NamedTuple

import paho.mqtt.client as mqtt
from influxdb import InfluxDBClient

INFLUXDB_ADDRESS = '10.10.10.247'
INFLUXDB_USER = 'iotuser'
INFLUXDB_PASSWORD = 'iotpassword'
INFLUXDB_DATABASE = 'homeiot_db'

MQTT_ADDRESS = '10.10.10.247'
MQTT_USER = 'iotuser'
MQTT_PASSWORD = 'iotpassword'
MQTT_TOPIC = 'home/+/+'  # [room]/[temperature|humidity|light|status]
MQTT_REGEX = 'home/([^/]+)/([^/]+)'
MQTT_CLIENT_ID = 'MQTTInfluxDBBridge'

influxdb_client = InfluxDBClient(INFLUXDB_ADDRESS, 8086, INFLUXDB_USER, INFLUXDB_PASSWORD, None)


class SensorData(NamedTuple):
    location: str
    measurement: str
    value: float


def on_connect(client, userdata, flags, rc):
    """ The callback for when the client receives a CONNACK response from the server."""
    print('Connected with result code ' + str(rc))
    client.subscribe(MQTT_TOPIC)


def on_message(client, userdata, msg):
    """The callback for when a PUBLISH message is received from the server."""
    print(msg.topic + ' ' + str(msg.payload))
    sensor_data = _parse_mqtt_message(msg.topic, msg.payload.decode('utf-8'))
    if sensor_data is not None:
        _send_sensor_data_to_influxdb(sensor_data)


def _parse_mqtt_message(topic, payload):
    match = re.match(MQTT_REGEX, topic)
    if match:
        location = match.group(1)
        measurement = match.group(2)
        if measurement == 'status':
            return None
        return SensorData(location, measurement, float(payload))
    else:
        return None


def _send_sensor_data_to_influxdb(sensor_data):
    json_body = [
        {
            'measurement': sensor_data.measurement,
            'tags': {
                'location': sensor_data.location
            },
            'fields': {
                'value': sensor_data.value
            }
        }
    ]
    print (json_body)
    influxdb_client.write_points(json_body)


def _init_influxdb_database():
    databases = influxdb_client.get_list_database()
    if len(list(filter(lambda x: x['name'] == INFLUXDB_DATABASE, databases))) == 0:
        influxdb_client.create_database(INFLUXDB_DATABASE)
    influxdb_client.switch_database(INFLUXDB_DATABASE)


def main():
    _init_influxdb_database()

    mqtt_client = mqtt.Client(MQTT_CLIENT_ID)
    mqtt_client.username_pw_set(MQTT_USER, MQTT_PASSWORD)
    mqtt_client.on_connect = on_connect
    mqtt_client.on_message = on_message

    mqtt_client.connect(MQTT_ADDRESS, 1883)
    mqtt_client.loop_forever()


if __name__ == '__main__':
    print('MQTT to InfluxDB bridge')
    main()

如果有人以前做过这个或者知道如何解决这个问题，我将非常感谢任何帮助。

Answer 1

如果您只需要将数据从 InfluxDB 传输到 Snowflake，您可以尝试充分利用下面现有的 API：

import "sql"
  
data
    |> sql.to(
        driverName: "snowflake",
        dataSourceName: "user:password@account/db/exampleschema?warehouse=wh",
        table: "example_table",
    )

查看更多详情here。

好吧，如果你坚持使用 MQTT，有一个 official and easy way 可以通过 Flux 完成这个任务（你可以在 InfluxDB 2.0 UI 上配置这些）而不是 Python：

import "mqtt"
from(bucket: "telegraf")
    |> range(start: -task.every)
    |> filter(fn: (r) =>
        (r._measurement == "cpu"))
    |> filter(fn: (r) =>
        (r._field == "usage_system"))
    |> filter(fn: (r) =>
        (r.cpu == "cpu-total"))
    |> last()
    |> mqtt.to(
        broker: "tcp://davidgs.com:8883",
        topic: "cpu",
        clientid: "cpu-flux",
        valueColumns: ["_value"],
        tagColumns: ["cpu", "host"],
    )

从 Influxdb 输出数据到 MQTT broker/server

Output data from Influxdb to MQTT broker/server

python

mqtt

iot

influxdb

dataflow