Expand description
A pure rust MQTT client which strives to be robust, efficient and easy to use. This library is backed by an async (tokio) eventloop which handles all the robustness and and efficiency parts of MQTT but naturally fits into both sync and async worlds as we’ll see
Let’s jump into examples right away
A simple synchronous publish and subscribe
use rumqttc::{MqttOptions, Client, QoS};
use std::time::Duration;
use std::thread;
let mut mqttoptions = MqttOptions::new("rumqtt-sync", "test.mosquitto.org", 1883);
mqttoptions.set_keep_alive(Duration::from_secs(5));
let (mut client, mut connection) = Client::new(mqttoptions, 10);
client.subscribe("hello/rumqtt", QoS::AtMostOnce).unwrap();
thread::spawn(move || for i in 0..10 {
client.publish("hello/rumqtt", QoS::AtLeastOnce, false, vec![i; i as usize]).unwrap();
thread::sleep(Duration::from_millis(100));
});
// Iterate to poll the eventloop for connection progress
for (i, notification) in connection.iter().enumerate() {
println!("Notification = {:?}", notification);
}
A simple asynchronous publish and subscribe
use rumqttc::{MqttOptions, AsyncClient, QoS};
use tokio::{task, time};
use std::time::Duration;
use std::error::Error;
let mut mqttoptions = MqttOptions::new("rumqtt-async", "test.mosquitto.org", 1883);
mqttoptions.set_keep_alive(Duration::from_secs(5));
let (mut client, mut eventloop) = AsyncClient::new(mqttoptions, 10);
client.subscribe("hello/rumqtt", QoS::AtMostOnce).await.unwrap();
task::spawn(async move {
for i in 0..10 {
client.publish("hello/rumqtt", QoS::AtLeastOnce, false, vec![i; i as usize]).await.unwrap();
time::sleep(Duration::from_millis(100)).await;
}
});
loop {
let notification = eventloop.poll().await.unwrap();
println!("Received = {:?}", notification);
}
Quick overview of features
- Eventloop orchestrates outgoing/incoming packets concurrently and handles the state
- Pings the broker when necessary and detects client side half open connections as well
- Throttling of outgoing packets (todo)
- Queue size based flow control on outgoing packets
- Automatic reconnections by just continuing the
eventloop.poll()
/connection.iter()
loop - Natural backpressure to client APIs during bad network
- Immediate cancellation with
client.cancel()
In short, everything necessary to maintain a robust connection
Since the eventloop is externally polled (with iter()/poll()
in a loop)
out side the library and Eventloop
is accessible, users can
- Distribute incoming messages based on topics
- Stop it when required
- Access internal state for use cases like graceful shutdown or to modify options before reconnection
Important notes
-
Looping on
connection.iter()
/eventloop.poll()
is necessary to run the event loop and make progress. It yields incoming and outgoing activity notifications which allows customization as you see fit. -
Blocking inside the
connection.iter()
/eventloop.poll()
loop will block connection progress.
FAQ
Connecting to a broker using raw ip doesn’t work
You cannot create a TLS connection to a bare IP address with a self-signed
certificate. This is a limitation of rustls.
One workaround, which only works under *nix/BSD-like systems, is to add an
entry to wherever your DNS resolver looks (e.g. /etc/hosts
) for the bare IP
address and use that name in your code.
Re-exports
Modules
Structs
AsyncClient
to communicate with MQTT Eventloop
This is cloneable and can be used to asynchronously Publish, Subscribe.
Client
to communicate with MQTT eventloop Connection
.
Common configuration for (typically) all connections made by a program.
MQTT connection. Maintains all the necessary state
Eventloop with all the state of a connection
Iterator which polls the eventloop for connection progress
Options to configure the behaviour of mqtt connection
State of the mqtt connection.
An error that may be emitted when attempting to send a value into a channel on a sender when all receivers are dropped.
A transmitting end of a channel.
Enums
Client Error
Critical errors during eventloop polling
Events which can be yielded by the event loop
Key type for TLS authentication
Current outgoing activity on the eventloop
Requests by the client to mqtt event loop. Request are handled one by one.
Errors during state handling
An error that may be emitted when attempting to send a value into a channel on a sender when the channel is full or all receivers are dropped.