From 50e83e8f98c49b41ca00a13db2b63f8a17446d2a Mon Sep 17 00:00:00 2001
From: Oleg Zaytsev <mail@olegzaytsev.com>
Date: Tue, 5 Nov 2024 15:09:23 +0100
Subject: [PATCH] Export 'go_sync_mutex_wait_total_seconds_total' metric

This metric can be useful to debug mutex contention.

Ref: https://github.com/golang/go/issues/49881
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
---
 cmd/prometheus/main.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cmd/prometheus/main.go b/cmd/prometheus/main.go
index 8fb6d4d38..fcbc41988 100644
--- a/cmd/prometheus/main.go
+++ b/cmd/prometheus/main.go
@@ -27,6 +27,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	goregexp "regexp" //nolint:depguard // The Prometheus client library requires us to pass a regexp from this package.
 	"runtime"
 	"runtime/debug"
 	"strconv"
@@ -301,6 +302,7 @@ func main() {
 				collectors.WithGoCollectorRuntimeMetrics(
 					collectors.MetricsGC,
 					collectors.MetricsScheduler,
+					collectors.GoRuntimeMetricsRule{Matcher: goregexp.MustCompile(`^/sync/mutex/wait/total:seconds$`)},
 				),
 			),
 		)