Quorum: Add metrics over http urls

apps/quorum/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "quorum"
-version = "0.1.3"
+version = "0.2.0"
 edition = "2021"
 
 [dependencies]
@@ -23,3 +23,4 @@ time = "0.3.41"
 serde_json = "1.0.140"
 futures = "0.3.31"
 serde_wormhole = "0.1.0"
+axum-prometheus = "0.8.0"

apps/quorum/src/api.rs

@@ -3,6 +3,7 @@ use axum::{
     routing::{get, post},
     Json, Router,
 };
+use axum_prometheus::{EndpointLabel, PrometheusMetricLayerBuilder};
 use secp256k1::{
     ecdsa::{RecoverableSignature, RecoveryId},
     Message, Secp256k1,
@@ -26,16 +27,24 @@ pub type Payload<'a> = &'a RawMessage;
 pub async fn run(listen_address: SocketAddr, state: State) -> anyhow::Result<()> {
     tracing::info!("Starting server...");
 
+    let (prometheus_layer, _) = PrometheusMetricLayerBuilder::new()
+        .with_metrics_from_fn(|| state.metrics_recorder.clone())
+        .with_endpoint_label_type(EndpointLabel::MatchedPathWithFallbackFn(|_| {
+            "unknown".to_string()
+        }))
+        .build_pair();
+
     let routes = Router::new()
         .route("/live", get(|| async { "OK" }))
         .route("/observation", post(post_observation))
         .route("/ws", get(ws_route_handler))
+        .layer(prometheus_layer)
         .with_state(state);
     let listener = tokio::net::TcpListener::bind(&listen_address).await?;
 
     axum::serve(listener, routes)
         .with_graceful_shutdown(async {
-            let _ = crate::server::EXIT.subscribe().changed().await;
+            crate::server::wait_for_exit().await;
             tracing::info!("Shutting down server...");
         })
         .await?;

apps/quorum/src/main.rs

@@ -4,6 +4,7 @@ use std::io::IsTerminal;
 use crate::server::RunOptions;
 
 mod api;
+mod metrics_server;
 mod pythnet;
 mod server;
 mod ws;

apps/quorum/src/metrics_server.rs

@@ -0,0 +1,38 @@
+use axum::{routing::get, Router};
+use axum_prometheus::{
+    metrics_exporter_prometheus::{PrometheusBuilder, PrometheusHandle},
+    PrometheusMetricLayerBuilder,
+};
+
+use crate::server::{wait_for_exit, RunOptions, State};
+
+pub const DEFAULT_METRICS_BUCKET: &[f64; 20] = &[
+    0.005, 0.01, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.25, 1.5, 2.0,
+    3.0, 5.0, 10.0,
+];
+
+pub fn setup_metrics_recorder() -> anyhow::Result<PrometheusHandle> {
+    PrometheusBuilder::new()
+        .set_buckets(DEFAULT_METRICS_BUCKET)?
+        .install_recorder()
+        .map_err(|err| anyhow::anyhow!("Failed to set up metrics recorder: {:?}", err))
+}
+
+pub async fn run(run_options: RunOptions, state: State) -> anyhow::Result<()> {
+    tracing::info!("Starting Metrics Server...");
+
+    let (_, metric_handle) = PrometheusMetricLayerBuilder::new()
+        .with_metrics_from_fn(|| state.metrics_recorder.clone())
+        .build_pair();
+    let app = Router::new();
+    let app = app.route("/metrics", get(|| async move { metric_handle.render() }));
+
+    let listener = tokio::net::TcpListener::bind(&run_options.server.metrics_addr).await?;
+    axum::serve(listener, app)
+        .with_graceful_shutdown(async {
+            let _ = wait_for_exit().await;
+            tracing::info!("Shutting down metrics server...");
+        })
+        .await?;
+    Ok(())
+}