feature: add native histogram support to latency metrics (#3737)

Note that this does not stop showing classic metrics, for now
it is up to the scrape config to decide whether to keep those instead or
both.

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>

cluster/channel.go

@@ -73,6 +73,10 @@ func NewChannel(
 		Name:                            "alertmanager_oversize_gossip_message_duration_seconds",
 		Help:                            "Duration of oversized gossip message requests.",
 		ConstLabels:                     prometheus.Labels{"key": key},
+		Buckets:                         prometheus.DefBuckets,
+		NativeHistogramBucketFactor:     1.1,
+		NativeHistogramMaxBucketNumber:  100,
+		NativeHistogramMinResetDuration: 1 * time.Hour,
 	})
 
 	reg.MustRegister(oversizeGossipDuration, oversizeGossipMessageFailureTotal, oversizeGossipMessageDroppedTotal, oversizeGossipMessageSentTotal)

cluster/delegate.go

@@ -107,6 +107,9 @@ func newDelegate(l log.Logger, reg prometheus.Registerer, p *Peer, retransmit in
 		Name:                            "alertmanager_cluster_pings_seconds",
 		Help:                            "Histogram of latencies for ping messages.",
 		Buckets:                         []float64{.005, .01, .025, .05, .1, .25, .5},
+		NativeHistogramBucketFactor:     1.1,
+		NativeHistogramMaxBucketNumber:  100,
+		NativeHistogramMinResetDuration: 1 * time.Hour,
 	}, []string{"peer"},
 	)
 

cmd/alertmanager/main.go

@@ -67,6 +67,9 @@ var (
 			Name:                            "alertmanager_http_request_duration_seconds",
 			Help:                            "Histogram of latencies for HTTP requests.",
 			Buckets:                         []float64{.05, 0.1, .25, .5, .75, 1, 2, 5, 20, 60},
+			NativeHistogramBucketFactor:     1.1,
+			NativeHistogramMaxBucketNumber:  100,
+			NativeHistogramMinResetDuration: 1 * time.Hour,
 		},
 		[]string{"handler", "method"},
 	)

nflog/nflog.go

@@ -141,6 +141,10 @@ func newMetrics(r prometheus.Registerer) *metrics {
 	m.queryDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
 		Name:                            "alertmanager_nflog_query_duration_seconds",
 		Help:                            "Duration of notification log query evaluation.",
+		Buckets:                         prometheus.DefBuckets,
+		NativeHistogramBucketFactor:     1.1,
+		NativeHistogramMaxBucketNumber:  100,
+		NativeHistogramMinResetDuration: 1 * time.Hour,
 	})
 	m.propagatedMessagesTotal = prometheus.NewCounter(prometheus.CounterOpts{
 		Name: "alertmanager_nflog_gossip_messages_propagated_total",

notify/notify.go

@@ -295,6 +295,9 @@ func NewMetrics(r prometheus.Registerer, ff featurecontrol.Flagger) *Metrics {
 			Name:                            "notification_latency_seconds",
 			Help:                            "The latency of notifications in seconds.",
 			Buckets:                         []float64{1, 5, 10, 15, 20},
+			NativeHistogramBucketFactor:     1.1,
+			NativeHistogramMaxBucketNumber:  100,
+			NativeHistogramMinResetDuration: 1 * time.Hour,
 		}, labels),
 		ff: ff,
 	}

silence/silence.go

@@ -273,6 +273,10 @@ func newMetrics(r prometheus.Registerer, s *Silences) *metrics {
 	m.queryDuration = prometheus.NewHistogram(prometheus.HistogramOpts{
 		Name:                            "alertmanager_silences_query_duration_seconds",
 		Help:                            "Duration of silence query evaluation.",
+		Buckets:                         prometheus.DefBuckets,
+		NativeHistogramBucketFactor:     1.1,
+		NativeHistogramMaxBucketNumber:  100,
+		NativeHistogramMinResetDuration: 1 * time.Hour,
 	})
 	m.propagatedMessagesTotal = prometheus.NewCounter(prometheus.CounterOpts{
 		Name: "alertmanager_silences_gossip_messages_propagated_total",