gemqtt provides an MQTT client for Gleam projects running on the BEAM. It does so by wrapping the emqx/emqtt library written in Erlang.
At the time of writing (March 19th, 2024), this package is stuck on emqtt version 1.2 due to a dependency issue. That version of the underlying emqx/emqtt library only works with Erlang OTP version 25.x, not 26+.
This package is a work in progress. If it is missing an emqtt feature you need, please send a PR.
- Connect to unencrypted MQTT servers over TCP
- Connect to TLS encrypted MQTT servers over TCP
- Connect to unencrypted MQTT servers over websocket
- Connect to TLS encrypted MQTT servers over websocket
- Supports emqtt properties for connect, publish, and subscribe
- User + password authentication
- Message auto acknowledgement
- Clean start
- Client ID
- Connect timeout
- Erlang server name
- Owner PID (for disconnect notifications)
- Port number
- TLS enable + raw options
- TCP options
- Websocket path
- Bridge mode
- Proto version
- Keep alive
- Max in-flight
- Retry interval
- Will topic
- Will payload
- Will retain
- Will QoS
- Will properties
- Ack timeout
- Force ping
- QoS
- Retain
- Local Echo
- QoS
- Retain as published
- Retain handling
gleam add gleam_erlang
gleam add gemqttimport gemqtt
import gemqtt/publisher
import gemqtt/subscriber
import gleam/bit_array
import gleam/erlang/process
import gleam/io
pub fn main() {
let topic = "gemqtt/readme/example"
// Create a client and connect to the test server.
let assert Ok(client) =
gemqtt.new("test.mosquitto.org")
|> gemqtt.start_link
let assert Ok(_) = gemqtt.connect(client)
io.println("Connected.")
// Subscribe to messages from the topic.
let assert Ok(_) =
client
|> subscriber.new
|> subscriber.add(topics: [topic])
io.println("Subscribed.")
// Publish a test message to the topic.
let assert Ok(_) =
publisher.new(client, topic)
|> publisher.publish(bit_array.from_string("Hello from Gleam!"))
io.println("Sent message.")
// Attempt to receive a message from the topic.
let assert Ok(got_msg) =
process.new_selector()
|> subscriber.selecting_mqtt_messages(Ok)
|> process.select_forever
io.println("Received message:")
io.debug(got_msg)
let assert Ok(_) = subscriber.remove(client, [topic])
let assert Ok(_) = gemqtt.disconnect(client)
}Further documentation can be found at https://hexdocs.pm/gemqtt.
gleam test # Run the tests
gleam shell # Run an Erlang shell