address pr feedback

core/corehttp/gateway_handler.go

@@ -23,6 +23,7 @@ import (
 	ipath "github.com/ipfs/interface-go-ipfs-core/path"
 	routing "github.com/libp2p/go-libp2p-core/routing"
 	"github.com/multiformats/go-multibase"
+	prometheus "github.com/prometheus/client_golang/prometheus"
 )
 
 const (
@@ -35,12 +36,32 @@ const (
 type gatewayHandler struct {
 	config GatewayConfig
 	api    coreiface.CoreAPI
+
+	unixfsGetMetric *prometheus.SummaryVec
 }
 
 func newGatewayHandler(c GatewayConfig, api coreiface.CoreAPI) *gatewayHandler {
+	unixfsGetMetric := prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Namespace: "ipfs",
+			Subsystem: "http",
+			Name:      "unixfs_get_latency_seconds",
+			Help:      "The time till the first block is received when 'getting' a file from the gateway.",
+		},
+		[]string{"gateway"},
+	)
+	if err := prometheus.Register(unixfsGetMetric); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			unixfsGetMetric = are.ExistingCollector.(*prometheus.SummaryVec)
+		} else {
+			log.Errorf("failed to register unixfsGetMetric: %v", err)
+		}
+	}
+
 	i := &gatewayHandler{
-		config: c,
-		api:    api,
+		config:          c,
+		api:             api,
+		unixfsGetMetric: unixfsGetMetric,
 	}
 	return i
 }
@@ -178,7 +199,7 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	unixfsGetMetric.WithLabelValues(parsedPath.Namespace()).Observe(time.Since(begin).Seconds())
+	i.unixfsGetMetric.WithLabelValues(parsedPath.Namespace()).Observe(time.Since(begin).Seconds())
 
 	defer dr.Close()
 

core/corehttp/metrics.go

@@ -29,16 +29,6 @@ func MetricsCollectionOption(handlerName string) ServeOption {
 			Objectives:  map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
 		}
 
-		if handlerName == "gateway" {
-			if err := prometheus.Register(unixfsGetMetric); err != nil {
-				if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
-					unixfsGetMetric = are.ExistingCollector.(*prometheus.SummaryVec)
-				} else {
-					return nil, err
-				}
-			}
-		}
-
 		reqCnt := prometheus.NewCounterVec(
 			prometheus.CounterOpts{
 				Namespace:   opts.Namespace,
@@ -110,16 +100,6 @@ var (
 		[]string{"transport"},
 		nil,
 	)
-
-	unixfsGetMetric = prometheus.NewSummaryVec(
-		prometheus.SummaryOpts{
-			Namespace: "ipfs",
-			Subsystem: "http",
-			Name:      "unixfs_get_latency_seconds",
-			Help:      "The time till the first block is received when 'getting' a file from the gateway.",
-		},
-		[]string{"gateway"},
-	)
 )
 
 type IpfsNodeCollector struct {