fix: littDB metrics

litt/littbuilder/build_utils.go

@@ -244,29 +244,33 @@ func buildMetrics(config *litt.Config, logger logging.Logger) (*metrics.LittDBMe
 	var registry *prometheus.Registry
 	var server *http.Server
 
-	if config.MetricsRegistry == nil && config.MetricsEnabled {
-		registry = prometheus.NewRegistry()
-		registry.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))
-		registry.MustRegister(collectors.NewGoCollector())
-
-		logger.Infof("Starting metrics server at port %d", config.MetricsPort)
-		addr := fmt.Sprintf(":%d", config.MetricsPort)
-		mux := http.NewServeMux()
-		mux.Handle("/metrics", promhttp.HandlerFor(
-			registry,
-			promhttp.HandlerOpts{},
-		))
-		server = &http.Server{
-			Addr:    addr,
-			Handler: mux,
-		}
-
-		go func() {
-			err := server.ListenAndServe()
-			if err != nil && !strings.Contains(err.Error(), "http: Server closed") {
-				logger.Errorf("metrics server error: %v", err)
+	if config.MetricsEnabled {
+		if config.MetricsRegistry == nil {
+			registry = prometheus.NewRegistry()
+			registry.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))
+			registry.MustRegister(collectors.NewGoCollector())
+
+			logger.Infof("Starting metrics server at port %d", config.MetricsPort)
+			addr := fmt.Sprintf(":%d", config.MetricsPort)
+			mux := http.NewServeMux()
+			mux.Handle("/metrics", promhttp.HandlerFor(
+				registry,
+				promhttp.HandlerOpts{},
+			))
+			server = &http.Server{
+				Addr:    addr,
+				Handler: mux,
 			}
-		}()
+
+			go func() {
+				err := server.ListenAndServe()
+				if err != nil && !strings.Contains(err.Error(), "http: Server closed") {
+					logger.Errorf("metrics server error: %v", err)
+				}
+			}()
+		} else {
+			registry = config.MetricsRegistry
+		}
 	}
 
 	return metrics.NewLittDBMetrics(registry, config.MetricsNamespace), server

litt/littdb_config.go

@@ -122,6 +122,7 @@ type Config struct {
 	MetricsRegistry *prometheus.Registry
 
 	// The port to use for the metrics server. Ignored if MetricsEnabled is false or MetricsRegistry is not nil.
+	// The default is 9101.
 	MetricsPort int
 
 	// The interval at which various DB metrics are updated. The default is 1 second.
@@ -162,7 +163,7 @@ func DefaultConfig(paths ...string) (*Config, error) {
 		DoubleWriteProtection:    false,
 		MetricsEnabled:           false,
 		MetricsNamespace:         "litt",
-		MetricsPort:              8080,
+		MetricsPort:              9101,
 		MetricsUpdateInterval:    time.Second,
 	}, nil
 }