How to Build a Pub/Sub System in Rust

You build a Pub/Sub system in Rust by using the tokio runtime for async I/O and tokio::sync::broadcast or tokio::sync::mpsc channels to decouple publishers from subscribers.

use tokio::sync::broadcast;

#[tokio::main]
async fn main() {
    let (tx, mut rx1) = broadcast::channel::<String>(16);
    let mut rx2 = tx.subscribe();

    tokio::spawn(async move {
        tx.send("Hello from publisher").unwrap();
    });

    println!("Subscriber 1: {}", rx1.recv().await.unwrap());
    println!("Subscriber 2: {}", rx2.recv().await.unwrap());
}

Add tokio = { version = "1", features = ["full"] } to your Cargo.toml.

A Pub/Sub system lets different parts of your program send and receive messages without knowing about each other. Think of it like a radio station broadcasting a signal that multiple radios can tune into independently. You use this pattern when you need to send updates to many listeners efficiently without blocking the sender.