Get Mutex protected value in Coroutine from none-coroutine threads without mpsc?

Question

How to get Mutex protected value in Coroutine from none-coroutine threads in Rust. Without using mpsc.

struct S1 {
    value: Arc<tokio::sync::Mutex<f64>>,
}

impl S1 {
    fn start(&self) {
        let v = self.value.clone();
        RT.spawn(async move {
            loop {
                let lk = v.lock().await;
                *lk += 1.0;
                drop(lk);
                // sleep 1s
            }
        });
        
        //sleep 5s
        let lk = self.value.lock() //`start` is not an async function, so you can't call self.value.lock().await here.
    }
}

Answer 1

You should use tokio::sync::Mutex::blocking_lock() for locking a tokio mutex outside of async context.

    fn start(&self) {
        let v = self.value.clone();
        RT.spawn(async move {
            loop {
                let lk = v.lock().await;
                *lk += 1.0;
                drop(lk);
                // sleep 1s
            }
        });
        
        // sleep 5s
        let lk = self.value.blocking_lock();
        // ...
    }

However note that you should prefer std::sync::Mutex as long as you don't need to hold the lock across .await points.