Merge pull request #6406 from ipfs/feat/gateway-metric

add unixfs get metric

core/corehttp/gateway_handler.go

@@ -123,6 +123,7 @@ func (i *gatewayHandler) optionsHandler(w http.ResponseWriter, r *http.Request)
 }
 
 func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request) {
+	begin := time.Now()
 	urlPath := r.URL.Path
 	escapedURLPath := r.URL.EscapedPath()
 
@@ -173,6 +174,8 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
 		return
 	}
 
+	unixfsGetMetric.WithLabelValues(parsedPath.Namespace()).Observe(time.Since(begin).Seconds())
+
 	defer dr.Close()
 
 	// Check etag send back to us

core/corehttp/metrics.go

@@ -97,6 +97,13 @@ var (
 	peersTotalMetric = prometheus.NewDesc(
 		prometheus.BuildFQName("ipfs", "p2p", "peers_total"),
 		"Number of connected peers", []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{"namespace"})
 )
 
 type IpfsNodeCollector struct {