How to gracefully shutdown async tasks in tokio

Gracefully shutdown async tasks in Tokio by awaiting their JoinHandles or using tokio::select! to cancel them on a shutdown signal.

use tokio::task::JoinHandle;

async fn my_task() {
    // Task logic here
}

#[tokio::main]
async fn main() {
    let handle: JoinHandle<()> = tokio::spawn(my_task());
    
    // Wait for the task to finish gracefully
    handle.await.expect("Task panicked");
}

For immediate cancellation on a signal (like Ctrl+C), use tokio::select! to race the task against the shutdown event, which drops the task if the signal arrives first.

Graceful shutdown means telling your background tasks to finish their current work before the program closes, rather than killing them instantly. Think of it like asking a worker to finish wrapping up their current box before leaving the warehouse, instead of just turning off the lights while they are still working. You use this pattern to ensure data isn't lost and resources are cleaned up properly when your application stops.