Cheapest tokio-sponsored blue collar worker you could hire

a-worker-with-tokio.rs

use tokio::time::{sleep, Duration, Instant};
use anyhow::Result;
use thiserror::Error;

#[derive(Error,Debug)]
enum WorkerError {
    #[error("Worker {0} encountered an error")]
    Failed(isize),
}

async fn worker(idx: isize) -> Result<(), WorkerError> {
    println!("starting worker {idx}");
    // <do some I/O op here>
    sleep(Duration::from_secs(2)).await;
    // sim an error for demonstration
    if idx == 3 {
        return Err(WorkerError::Failed(idx));
    }
    println!("worker {idx} done");
    Ok(())
}

#[tokio::main]
async fn main() -> Result<()> {
    let start_ts = Instant::now();
    let range_of_souls = 1..10;
    let handles: Vec<_> = range_of_souls
        .map(|id| tokio::spawn(worker(id)))
        .collect();
    for handle in handles {
        // 1st `?` handles the JoinHandle Type
        // 2nd `?` unwrap the result
        handle.await??;
    }

    println!("all workers done. took {:?}", start_ts.elapsed());
    Ok(())
}