[fixup post review 1.2] share regiustry metrrics

cmd/scality-cosi-driver/cmd.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/scality/cosi-driver/pkg/driver"
 	"k8s.io/klog/v2"
 
@@ -57,7 +58,14 @@ func init() {
 }
 
 func run(ctx context.Context) error {
-	metricsServer, err := metrics.StartMetricsServer(*metricsAddress)
+	registry := prometheus.NewRegistry()
+
+	if err := registry.Register(metrics.RequestsTotal); err != nil {
+		return fmt.Errorf("failed to register custom metrics: %w", err)
+	}
+
+	// Start the Prometheus metrics server with the shared registry
+	metricsServer, err := metrics.StartMetricsServerWithRegistry(*metricsAddress, registry)
 	if err != nil {
 		return fmt.Errorf("failed to start metrics server: %w", err)
 	}
@@ -74,7 +82,7 @@ func run(ctx context.Context) error {
 		return fmt.Errorf("failed to start the provisioner server: %w", err)
 	}
 
-	err = server.Run(ctx)
+	err = server.Run(ctx, registry)
 	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer shutdownCancel()
 	if shutdownErr := metricsServer.Shutdown(shutdownCtx); shutdownErr != nil {

pkg/grpcfactory/server.go

@@ -34,9 +34,11 @@ type COSIProvisionerServer struct {
 	listenOpts        []grpc.ServerOption
 }
 
-func (s *COSIProvisionerServer) Run(ctx context.Context) error {
+func (s *COSIProvisionerServer) Run(ctx context.Context, registry prometheus.Registerer) error {
 	srvMetrics := grpcprom.NewServerMetrics()
-	prometheus.MustRegister(srvMetrics)
+	if err := registry.Register(srvMetrics); err != nil {
+		return fmt.Errorf("failed to register gRPC metrics: %w", err)
+	}
 
 	addr, err := url.Parse(s.address)
 	if err != nil {

pkg/metrics/metrics.go

@@ -21,21 +21,22 @@ var (
 	)
 )
 
-func init() {
-	prometheus.MustRegister(RequestsTotal)
-}
-
-func StartMetricsServer(addr string) (*http.Server, error) {
+// StartMetricsServerWithRegistry starts an HTTP metrics server with a custom Prometheus registry.
+func StartMetricsServerWithRegistry(addr string, registry prometheus.Gatherer) (*http.Server, error) {
 	listener, err := net.Listen("tcp", addr)
 	if err != nil {
 		return nil, err
 	}
-	return StartMetricsServerWithListener(listener)
+	return StartMetricsServerWithListenerAndRegistry(listener, registry)
 }
 
-func StartMetricsServerWithListener(listener net.Listener) (*http.Server, error) {
+// StartMetricsServerWithListenerAndRegistry starts an HTTP server with a custom registry and listener.
+func StartMetricsServerWithListenerAndRegistry(listener net.Listener, registry prometheus.Gatherer) (*http.Server, error) {
 	mux := http.NewServeMux()
-	mux.Handle(c.MetricsPath, promhttp.Handler())
+
+	mux.Handle(c.MetricsPath, promhttp.HandlerFor(registry, promhttp.HandlerOpts{
+		EnableOpenMetrics: true,
+	}))
 
 	srv := &http.Server{
 		Handler: mux,