collectors/version: Allow for custom label

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

Author: mrueg

go.mod

@@ -1,6 +1,6 @@
 module github.com/prometheus/client_golang
 
-go 1.23.0
+go 1.24.0
 
 require (
 	github.com/beorn7/perks v1.0.1
@@ -13,6 +13,7 @@ require (
 	github.com/prometheus/common v0.65.0
 	github.com/prometheus/procfs v0.17.0
 	go.uber.org/goleak v1.3.0
+	golang.org/x/exp v0.0.0-20250819193227-8b4c13bb791b
 	golang.org/x/sys v0.34.0
 	google.golang.org/protobuf v1.36.6
 )

go.sum

@@ -48,6 +48,8 @@ github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOf
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
+golang.org/x/exp v0.0.0-20250819193227-8b4c13bb791b h1:DXr+pvt3nC887026GRP39Ej11UATqWDmWuS99x26cD0=
+golang.org/x/exp v0.0.0-20250819193227-8b4c13bb791b/go.mod h1:4QTo5u+SEIbbKW1RacMZq1YEfOBqeXa19JeshGi+zc4=
 golang.org/x/net v0.40.0 h1:79Xs7wF06Gbdcg4kdCCIQArK11Z1hr5POQ6+fIYHNuY=
 golang.org/x/net v0.40.0/go.mod h1:y0hY0exeL2Pku80/zKK7tpntoX23cqL3Oa6njdgRtds=
 golang.org/x/oauth2 v0.30.0 h1:dnDm7JmhM45NNpd8FDDeLhK6FwqbOf4MLCM9zb1BOHI=

prometheus/collectors/version/version.go

@@ -19,11 +19,30 @@ import (
 	"github.com/prometheus/common/version"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"golang.org/x/exp/maps"
 )
 
 // NewCollector returns a collector that exports metrics about current version
 // information.
 func NewCollector(program string) prometheus.Collector {
+	return NewCollectorWithLabels(program, nil)
+}
+
+// NewCollectorWithLabels returns a collector that exports metrics about current
+// version information and allows to set additional custom labels.
+func NewCollectorWithLabels(program string, labels prometheus.Labels) prometheus.Collector {
+
+	constLabels := prometheus.Labels{
+		"version":   version.Version,
+		"revision":  version.GetRevision(),
+		"branch":    version.Branch,
+		"goversion": version.GoVersion,
+		"goos":      version.GoOS,
+		"goarch":    version.GoArch,
+		"tags":      version.GetTags(),
+	}
+	maps.Copy(constLabels, labels)
+
 	return prometheus.NewGaugeFunc(
 		prometheus.GaugeOpts{
 			Namespace: program,
@@ -32,16 +51,9 @@ func NewCollector(program string) prometheus.Collector {
 				"A metric with a constant '1' value labeled by version, revision, branch, goversion from which %s was built, and the goos and goarch for the build.",
 				program,
 			),
-			ConstLabels: prometheus.Labels{
-				"version":   version.Version,
-				"revision":  version.GetRevision(),
-				"branch":    version.Branch,
-				"goversion": version.GoVersion,
-				"goos":      version.GoOS,
-				"goarch":    version.GoArch,
-				"tags":      version.GetTags(),
-			},
+			ConstLabels: constLabels,
 		},
 		func() float64 { return 1 },
 	)
+
 }