use std::future::{ready, Ready}; use actix_web::{ dev::{self, Service, ServiceRequest, ServiceResponse, Transform}, Error, }; use futures_util::future::LocalBoxFuture; use prometheus::HistogramTimer; pub struct RouteMetrics; // Middleware factory is `Transform` trait from actix-service crate // `S` - type of the next service // `B` - type of response's body impl Transform for RouteMetrics where S: Service, Error = Error>, S::Future: 'static, B: 'static, { type Response = ServiceResponse; type Error = Error; type InitError = (); type Transform = RouteMetricsMiddleware; type Future = Ready>; fn new_transform(&self, service: S) -> Self::Future { ready(Ok(RouteMetricsMiddleware { service })) } } pub struct RouteMetricsMiddleware { service: S, } impl Service for RouteMetricsMiddleware where S: Service, Error = Error>, S::Future: 'static, B: 'static, { type Response = ServiceResponse; type Error = Error; type Future = LocalBoxFuture<'static, Result>; dev::forward_ready!(service); fn call(&self, req: ServiceRequest) -> Self::Future { let mut histogram_timer: Option = None; let request_path = req.path(); let is_registered_resource = req.resource_map().has_resource(request_path); if is_registered_resource { let request_method = req.method().to_string(); histogram_timer = Some( crate::metrics::HTTP_RESPONSE_TIME_SECONDS .with_label_values(&[&request_method, request_path]) .start_timer(), ); crate::metrics::HTTP_REQUESTS_TOTAL .with_label_values(&[&request_method, request_path]) .inc(); } let fut = self.service.call(req); Box::pin(async move { let res = fut.await?; if let Some(histogram_timer) = histogram_timer { histogram_timer.observe_duration(); }; Ok(res) }) } }