async rust example

async.rs

use std::sync::Arc;
use tokio::sync::Mutex;
use tokio::time::{sleep, Duration};

// Our shared context that will be accessed by all workers
#[derive(Debug)]
struct SharedContext {
    counter: i32,
    last_updated_by: String,
}

// Worker function that will run asynchronously
async fn worker(id: i32, context: Arc<Mutex<SharedContext>>) {
    for i in 1..=5 {
        // Simulate some async work
        sleep(Duration::from_secs(1)).await;

        // Lock the context to modify it
        let mut locked_context = context.lock().await;
        locked_context.counter += 1;
        locked_context.last_updated_by = format!("Worker {}", id);

        println!(
            "Worker {} (iteration {}): Updated counter to {}",
            id, i, locked_context.counter
        );
    }
}

#[tokio::main]
async fn main() {
    // Create shared context wrapped in Arc (Atomic Reference Counting) and Mutex
    let shared_context = Arc::new(Mutex::new(SharedContext {
        counter: 0,
        last_updated_by: String::new(),
    }));

    // Create three worker tasks
    let mut handles = vec![];

    for worker_id in 1..=3 {
        // Clone the Arc to share ownership of the context
        let context_clone = Arc::clone(&shared_context);

        // Spawn a new async task
        let handle = tokio::spawn(async move {
            worker(worker_id, context_clone).await;
        });

        handles.push(handle);
    }

    // Wait for all workers to complete
    for handle in handles {
        handle.await.unwrap();
    }

    // Print final state
    let final_context = shared_context.lock().await;
    println!("\nFinal state:");
    println!("Counter: {}", final_context.counter);
    println!("Last updated by: {}", final_context.last_updated_by);
}