mqtt.to() function

The mqtt.to() function outputs data to an MQTT broker using MQTT protocol.

Function type: Output

import "experimental/mqtt"

mqtt.to(
  broker: "tcp://localhost:8883",
  topic: "example-topic",
  message: "Example message",
  qos: 0,
  clientid: "flux-mqtt",
  username: "username",
  password: "password",
  name: "name-example",
  timeout: 1s,
  timeColumn: "_time",
  tagColumns: ["tag1", "tag2"],
  valueColumns: ["_value"]
)

Parameters

broker

The MQTT broker connection string.

Data type: String

topic

The MQTT topic to send data to.

Data type: String

message

The message or payload to send to the MQTT broker. The default payload is an output table. If there are multiple output tables, it sends each table as a separate MQTT message.

Data type: String

qos

The MQTT Quality of Service (QoS) level. Values range from [0-2]. Default is 0.

Data type: Integer

clientid

The MQTT client ID.

Data type: String

username

The username to send to the MQTT broker. Username is only required if the broker requires authentication. If you provide a username, you must provide a password.

Data type: String

password

The password to send to the MQTT broker. Password is only required if the broker requires authentication. If you provide a password, you must provide a username.

Data type: String

name

(Optional) The name for the MQTT message.

Data type: String

timeout

The MQTT connection timeout. Default is 1s.

Data type: Duration

timeColumn

The column to use as time values in the output line protocol. Default is "_time".

Data type: String

tagColumns

The columns to use as tag sets in the output line protocol. Default is [].

Data type: Array of strings

valueColumns

The columns to use as field values in the output line protocol. Default is ["_value"].

Data type: Array of strings

Examples

Send data to an MQTT endpoint

import "experimental/mqtt"

from(bucket: "example-bucket")
  |> range(start: -5m)
  |> filter(fn: (r) => r._measurement == "airSensor")
  |> mqtt.to(
    broker: "tcp://localhost:8883",
    topic: "air-sensors",
    clientid: "sensor-12a4",
    tagColumns: ["sensorID"],
    valueColumns: ["_value"]
  )