Merge pull request ipfs/kubo#3189 from ipfs/feat/metrics/interface

metrics: introduce go-metrics-interface

This commit was moved from ipfs/kubo@f23cd5c

gateway/core/corehttp/metrics.go

@@ -4,9 +4,9 @@ import (
 	"net"
 	"net/http"
 
-	prometheus "gx/ipfs/QmdhsRK1EK2fvAz2i2SH5DEfkL6seDuyMYEsxKa9Braim3/client_golang/prometheus"
-
 	core "github.com/ipfs/go-ipfs/core"
+
+	prometheus "gx/ipfs/QmR3KwhXCRLTNZB59vELb2HhEWrGy9nuychepxFtj3wWYa/client_golang/prometheus"
 )
 
 // This adds the scraping endpoint which Prometheus uses to fetch metrics.
@@ -53,6 +53,9 @@ func (c IpfsNodeCollector) Collect(ch chan<- prometheus.Metric) {
 
 func (c IpfsNodeCollector) PeersTotalValues() map[string]float64 {
 	vals := make(map[string]float64)
+	if c.Node.PeerHost == nil {
+		return vals
+	}
 	for _, conn := range c.Node.PeerHost.Network().Conns() {
 		tr := ""
 		for _, proto := range conn.RemoteMultiaddr().Protocols() {