From 865b259b95fb3c41ce09eb425b0487c48a311088 Mon Sep 17 00:00:00 2001
From: Matthias Seitz <matthias.seitz@outlook.de>
Date: Wed, 12 Jun 2024 20:47:28 +0200
Subject: [PATCH] fix: prometheus graceful shutdown (#8784)

---
 .../src/metrics/prometheus_exporter.rs        | 24 ++++++++++---------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/crates/node-core/src/metrics/prometheus_exporter.rs b/crates/node-core/src/metrics/prometheus_exporter.rs
index 1ce85346fb0e..b7a3ba7015c3 100644
--- a/crates/node-core/src/metrics/prometheus_exporter.rs
+++ b/crates/node-core/src/metrics/prometheus_exporter.rs
@@ -2,6 +2,7 @@
 
 use crate::metrics::version_metrics::register_version_metrics;
 use eyre::WrapErr;
+use futures::{future::FusedFuture, FutureExt};
 use http::Response;
 use metrics::describe_gauge;
 use metrics_exporter_prometheus::{PrometheusBuilder, PrometheusHandle};
@@ -65,17 +66,14 @@ async fn start_endpoint<F: Hook + 'static>(
         tokio::net::TcpListener::bind(listen_addr).await.wrap_err("Could not bind to address")?;
 
     task_executor.spawn_with_graceful_shutdown_signal(|signal| async move {
-        let mut shutdown = signal.ignore_guard();
+        let mut shutdown = signal.ignore_guard().fuse();
         loop {
-            let io = tokio::select! {
-                res = listener.accept() => match res {
-                    Ok((stream, _remote_addr)) => stream,
-                    Err(err) => {
-                        tracing::error!(%err, "failed to accept connection");
-                        continue;
-                    }
-                },
-                _ = &mut shutdown => break,
+            let io = match listener.accept().await {
+                Ok((stream, _remote_addr)) => stream,
+                Err(err) => {
+                    tracing::error!(%err, "failed to accept connection");
+                    continue;
+                }
             };
 
             let handle = handle.clone();
@@ -89,7 +87,11 @@ async fn start_endpoint<F: Hook + 'static>(
             if let Err(error) =
                 jsonrpsee::server::serve_with_graceful_shutdown(io, service, &mut shutdown).await
             {
-                tracing::error!(%error, "metrics endpoint crashed")
+                tracing::debug!(%error, "failed to serve request")
+            }
+
+            if shutdown.is_terminated() {
+                break;
             }
         }
     });