flow_guard/
limiter.rs

1/* * Created and Developed by: Cleiton Augusto Correa Bezerra
2 */
3
4use crate::LimitStrategy;
5use std::sync::Arc;
6use tokio::sync::Semaphore;
7use std::time::Instant;
8use crate::error::FlowError; // Importando o erro que criamos acima
9
10pub struct FlowGuard<S: LimitStrategy> {
11    strategy: Arc<S>,
12    semaphore: Arc<Semaphore>,
13}
14
15impl<S: LimitStrategy + 'static> FlowGuard<S> {
16    pub fn new(strategy: S) -> Self {
17        let initial_limit = strategy.current_limit();
18        Self {
19            strategy: Arc::new(strategy),
20            // Iniciamos o semáforo com o limite definido pela estratégia
21            semaphore: Arc::new(Semaphore::new(initial_limit)),
22        }
23    }
24
25    pub async fn run<F, T, E>(&self, f: F) -> Result<T, FlowError<E>>
26    where
27        F: std::future::Future<Output = Result<T, E>>,
28    {
29        // 1. Tenta adquirir permissão (Backpressure dinâmico)
30        let _permit = self.semaphore.acquire().await
31            .map_err(|_| FlowError::Dropped)?;
32
33        let start = Instant::now();
34
35        // 2. Executa a tarefa do usuário
36        let result = f.await;
37
38        let duration = start.elapsed();
39
40        // 3. Informa a estratégia sobre o sucesso ou falha para ajustar o limite
41        match &result {
42            Ok(_) => self.strategy.on_success(duration),
43            Err(_) => self.strategy.on_error(),
44        }
45
46        // 4. Retorna o resultado mapeando o erro interno para FlowError::AppError
47        result.map_err(FlowError::AppError)
48    }
49}
flow_guard/limiter.rs

flow_guard/
limiter.rs
