Changed prometheus metrics feature as optional

meilisearch-http/src/lib.rs

@@ -6,6 +6,7 @@ pub mod task;
 #[macro_use]
 pub mod extractors;
 pub mod option;
+pub mod route_metrics;
 pub mod routes;
 
 use std::sync::{atomic::AtomicBool, Arc};
@@ -140,56 +141,33 @@ pub fn dashboard(config: &mut web::ServiceConfig, _enable_frontend: bool) {
     config.service(web::resource("/").route(web::get().to(routes::running)));
 }
 
+pub fn configure_metrics_route(config: &mut web::ServiceConfig, enable_metrics_route: bool) {
+    if enable_metrics_route {
+        config.service(web::resource("/metrics").route(web::get().to(routes::get_metrics)));
+    }
+}
+
 #[macro_export]
 macro_rules! create_app {
     ($data:expr, $auth:expr, $enable_frontend:expr, $opt:expr, $analytics:expr) => {{
         use actix_cors::Cors;
         use actix_web::dev::Service;
+        use actix_web::middleware::Condition;
         use actix_web::middleware::TrailingSlash;
         use actix_web::App;
         use actix_web::{middleware, web};
         use meilisearch_http::error::MeilisearchHttpError;
         use meilisearch_http::metrics;
+        use meilisearch_http::route_metrics;
         use meilisearch_http::routes;
-        use meilisearch_http::{configure_data, dashboard};
+        use meilisearch_http::{configure_data, configure_metrics_route, dashboard};
         use meilisearch_types::error::ResponseError;
 
-        use lazy_static::lazy_static;
-        use prometheus::{
-            opts, register_histogram_vec, register_int_counter_vec, register_int_gauge,
-        };
-        use prometheus::{HistogramTimer, HistogramVec, IntCounterVec, IntGauge};
-
         App::new()
             .configure(|s| configure_data(s, $data.clone(), $auth.clone(), &$opt, $analytics))
             .configure(routes::configure)
             .configure(|s| dashboard(s, $enable_frontend))
-            .wrap_fn(|req, srv| {
+            .configure(|s| configure_metrics_route(s, $opt.enable_metrics_route))
-                let mut histogram_timer: Option<HistogramTimer> = 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(
-                        metrics::HTTP_RESPONSE_TIME_SECONDS
-                            .with_label_values(&[&request_method, request_path])
-                            .start_timer(),
-                    );
-                    metrics::HTTP_REQUESTS_TOTAL
-                        .with_label_values(&[&request_method, request_path])
-                        .inc();
-                }
-
-                let fut = srv.call(req);
-
-                async {
-                    let res = fut.await?;
-                    if let Some(histogram_timer) = histogram_timer {
-                        histogram_timer.observe_duration();
-                    };
-                    Ok(res)
-                }
-            })
             .wrap(
                 Cors::default()
                     .send_wildcard()
@@ -203,5 +181,9 @@ macro_rules! create_app {
             .wrap(middleware::NormalizePath::new(
                 middleware::TrailingSlash::Trim,
             ))
+            .wrap(Condition::new(
+                $opt.enable_metrics_route,
+                route_metrics::RouteMetrics,
+            ))
     }};
 }

meilisearch-http/src/option.rs

@@ -146,6 +146,10 @@ pub struct Opt {
     #[clap(long, env = "MEILI_LOG_LEVEL", default_value = "info")]
     pub log_level: String,
 
+    // Enables Prometheus metrics and /metrics route.
+    #[clap(long, requires = "enable-metrics-route")]
+    pub enable_metrics_route: bool,
+
     #[serde(flatten)]
     #[clap(flatten)]
     pub indexer_options: IndexerOpts,

meilisearch-http/src/route_metrics.rs

@@ -0,0 +1,75 @@
+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<S, B> Transform<S, ServiceRequest> for RouteMetrics
+where
+    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type InitError = ();
+    type Transform = RouteMetricsMiddleware<S>;
+    type Future = Ready<Result<Self::Transform, Self::InitError>>;
+
+    fn new_transform(&self, service: S) -> Self::Future {
+        ready(Ok(RouteMetricsMiddleware { service }))
+    }
+}
+
+pub struct RouteMetricsMiddleware<S> {
+    service: S,
+}
+
+impl<S, B> Service<ServiceRequest> for RouteMetricsMiddleware<S>
+where
+    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    dev::forward_ready!(service);
+
+    fn call(&self, req: ServiceRequest) -> Self::Future {
+        let mut histogram_timer: Option<HistogramTimer> = 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)
+        })
+    }
+}

meilisearch-http/src/routes/mod.rs

@@ -21,7 +21,6 @@ mod tasks;
 pub fn configure(cfg: &mut web::ServiceConfig) {
     cfg.service(web::scope("/tasks").configure(tasks::configure))
         .service(web::resource("/health").route(web::get().to(get_health)))
-        .service(web::resource("/metrics").route(web::get().to(get_metrics)))
         .service(web::scope("/keys").configure(api_key::configure))
         .service(web::scope("/dumps").configure(dump::configure))
         .service(web::resource("/stats").route(web::get().to(get_stats)))