mqtt.publish() function

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

import "experimental/mqtt"

mqtt.publish(
  broker: "tcp://localhost:8883",
  topic: "example-topic",
  message: "Example message",
  qos: 0,
  retain: false,
  clientid: "flux-mqtt",
  username: "username",
  password: "password",
  timeout: 1s
)

Parameters

broker

The MQTT broker connection string.

topic

The MQTT topic to send data to.

message

The message to send to the MQTT broker.

qos

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

retain

The MQTT retain flag. Default is false.

clientid

The MQTT client ID.

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.

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.

timeout

The MQTT connection timeout. Default is 1s.

Examples

Send a message to an MQTT endpoint

import "experimental/mqtt"

mqtt.publish(
  broker: "tcp://localhost:8883",
  topic: "alerts",
  message: "wake up",
  clientid: "alert-watcher",
  retain: true
)

Send a message to an MQTT endpoint using input data

import "experimental/mqtt"
import "influxdata/influxdb/sample"

sample.data(set: "airSensor")
  |> range(start: -20m)
  |> last()
  |> map(fn: (r) => ({
    r with
      sent: mqtt.publish(
        broker: "tcp://localhost:8883",
        topic: "air-sensors/last/${r.sensorID}",
        message: string(v: r._value),
        clientid: "sensor-12a4"
      )
  }))