op-node: Use a continuously updated histogram rather than replacing it on each update.

op-node/metrics/histogram_snapshot.go

-package metrics
-
-import (
-	"sync/atomic"
-
-	"github.com/prometheus/client_golang/prometheus"
-)
-
-type ReplaceableHistogramVec struct {
-	current        *atomic.Value
-	opts           prometheus.HistogramOpts
-	variableLabels []string
-}
-
-func NewReplaceableHistogramVec(registry *prometheus.Registry, opts prometheus.HistogramOpts, variableLabels []string) *ReplaceableHistogramVec {
-	metric := &ReplaceableHistogramVec{
-		current:        &atomic.Value{},
-		opts:           opts,
-		variableLabels: variableLabels,
-	}
-	metric.current.Store(prometheus.NewHistogramVec(opts, variableLabels))
-	registry.MustRegister(metric)
-	return metric
-}
-
-func (c *ReplaceableHistogramVec) Replace(updater func(h *prometheus.HistogramVec)) {
-	h := prometheus.NewHistogramVec(c.opts, c.variableLabels)
-	updater(h)
-	c.current.Store(h)
-}
-
-func (c *ReplaceableHistogramVec) Describe(ch chan<- *prometheus.Desc) {
-	collector, ok := c.current.Load().(prometheus.Collector)
-	if ok {
-		collector.Describe(ch)
-	}
-}
-
-func (c *ReplaceableHistogramVec) Collect(ch chan<- prometheus.Metric) {
-	collector, ok := c.current.Load().(prometheus.Collector)
-	if ok {
-		collector.Collect(ch)
-	}
-}

op-node/metrics/metrics.go

@@ -142,7 +142,7 @@ type Metrics struct {
 	IPUnbans            prometheus.Counter
 	Dials               *prometheus.CounterVec
 	Accepts             *prometheus.CounterVec
-	PeerScoresHistogram *ReplaceableHistogramVec
+	PeerScoresHistogram *prometheus.HistogramVec
 
 	ChannelInputBytes prometheus.Counter
 
@@ -324,7 +324,7 @@ func NewMetrics(procName string) *Metrics {
 		}, []string{
 			"band",
 		}),
-		PeerScoresHistogram: NewReplaceableHistogramVec(registry, prometheus.HistogramOpts{
+		PeerScoresHistogram: factory.NewHistogramVec(prometheus.HistogramOpts{
 			Namespace: ns,
 			Name:      "peer_scores_histogram",
 			Help:      "Histogram of currrently connected peer scores",
@@ -462,17 +462,15 @@ func NewMetrics(procName string) *Metrics {
 // SetPeerScores updates the peer score [prometheus.GaugeVec].
 // This takes a map of labels to scores.
 func (m *Metrics) SetPeerScores(scores map[string]float64, allScores []store.PeerScores) {
-	m.PeerScoresHistogram.Replace(func(h *prometheus.HistogramVec) {
-		for _, scores := range allScores {
-			h.WithLabelValues("total").Observe(scores.Gossip.Total)
-			h.WithLabelValues("ipColocation").Observe(scores.Gossip.IPColocationFactor)
-			h.WithLabelValues("behavioralPenalty").Observe(scores.Gossip.BehavioralPenalty)
-			h.WithLabelValues("blocksFirstMessage").Observe(scores.Gossip.Blocks.FirstMessageDeliveries)
-			h.WithLabelValues("blocksTimeInMesh").Observe(scores.Gossip.Blocks.TimeInMesh)
-			h.WithLabelValues("blocksMessageDeliveries").Observe(scores.Gossip.Blocks.MeshMessageDeliveries)
-			h.WithLabelValues("blocksInvalidMessageDeliveries").Observe(scores.Gossip.Blocks.InvalidMessageDeliveries)
-		}
-	})
+	for _, scores := range allScores {
+		m.PeerScoresHistogram.WithLabelValues("total").Observe(scores.Gossip.Total)
+		m.PeerScoresHistogram.WithLabelValues("ipColocation").Observe(scores.Gossip.IPColocationFactor)
+		m.PeerScoresHistogram.WithLabelValues("behavioralPenalty").Observe(scores.Gossip.BehavioralPenalty)
+		m.PeerScoresHistogram.WithLabelValues("blocksFirstMessage").Observe(scores.Gossip.Blocks.FirstMessageDeliveries)
+		m.PeerScoresHistogram.WithLabelValues("blocksTimeInMesh").Observe(scores.Gossip.Blocks.TimeInMesh)
+		m.PeerScoresHistogram.WithLabelValues("blocksMessageDeliveries").Observe(scores.Gossip.Blocks.MeshMessageDeliveries)
+		m.PeerScoresHistogram.WithLabelValues("blocksInvalidMessageDeliveries").Observe(scores.Gossip.Blocks.InvalidMessageDeliveries)
+	}
 	for label, score := range scores {
 		m.PeerScores.WithLabelValues(label).Set(score)
 	}