Add runtime check to metrics middleware

meilisearch/src/lib.rs

@@ -114,10 +114,7 @@ pub fn create_app(
         .configure(routes::configure)
         .configure(|s| dashboard(s, enable_dashboard));
 
-    let app = app.wrap(actix_web::middleware::Condition::new(
+    let app = app.wrap(middleware::RouteMetricsMiddlewareFactory::new(index_scheduler));
-        opt.experimental_enable_metrics,
-        middleware::RouteMetrics,
-    ));
     app.wrap(
         Cors::default()
             .send_wildcard()

meilisearch/src/middleware.rs

@@ -4,15 +4,28 @@ use std::future::{ready, Ready};
 
 use actix_web::dev::{self, Service, ServiceRequest, ServiceResponse, Transform};
 use actix_web::Error;
+use actix_web::web::Data;
 use futures_util::future::LocalBoxFuture;
+use index_scheduler::IndexScheduler;
 use prometheus::HistogramTimer;
 
 pub struct RouteMetrics;
 
+pub struct RouteMetricsMiddlewareFactory {
+    index_scheduler: Data<IndexScheduler>,
+}
+
+impl RouteMetricsMiddlewareFactory {
+    pub fn new(index_scheduler: Data<IndexScheduler>) -> Self {
+        RouteMetricsMiddlewareFactory { index_scheduler }
+    }
+}
+
+
 // Middleware factory is `Transform` trait from actix-service crate
 // `S` - type of the next service
 // `B` - type of response's body
-impl<S, B> Transform<S, ServiceRequest> for RouteMetrics
+impl<S, B> Transform<S, ServiceRequest> for RouteMetricsMiddlewareFactory
 where
     S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
     S::Future: 'static,
@@ -25,12 +38,13 @@ where
     type Future = Ready<Result<Self::Transform, Self::InitError>>;
 
     fn new_transform(&self, service: S) -> Self::Future {
-        ready(Ok(RouteMetricsMiddleware { service }))
+        ready(Ok(RouteMetricsMiddleware { service, index_scheduler: self.index_scheduler.clone() }))
     }
 }
 
 pub struct RouteMetricsMiddleware<S> {
     service: S,
+    index_scheduler: Data<IndexScheduler>,
 }
 
 impl<S, B> Service<ServiceRequest> for RouteMetricsMiddleware<S>
@@ -47,6 +61,7 @@ where
 
     fn call(&self, req: ServiceRequest) -> Self::Future {
         let mut histogram_timer: Option<HistogramTimer> = None;
+        if let Ok(()) = self.index_scheduler.features().and_then(|features| features.check_metrics()) {
             let request_path = req.path();
             let is_registered_resource = req.resource_map().has_resource(request_path);
             if is_registered_resource {
@@ -60,6 +75,7 @@ where
                     .with_label_values(&[&request_method, request_path])
                     .inc();
             }
+        };
 
         let fut = self.service.call(req);