From 31bc2a2434ed29b6cd020ee712722b4b865f32e1 Mon Sep 17 00:00:00 2001
From: Maxim Krasilnikov <mak.krasilnikov@gmail.com>
Date: Thu, 11 Apr 2019 12:56:19 +0300
Subject: [PATCH] metrics/prometheus: expose metrics in prometheus format too
(#17077)
* metrics/prometheus: added prometheus http server and metrics collector
* metrics/prometheus: minor cleanups
* metrics/prometheus: named keys instead name in tag
* metrics/prometheus: minor typo cleanups, sorted report
---
metrics/exp/exp.go | 2 +
metrics/prometheus/collector.go | 115 +++++++++++++++++++++++++++++++
metrics/prometheus/prometheus.go | 68 ++++++++++++++++++
3 files changed, 185 insertions(+)
create mode 100644 metrics/prometheus/collector.go
create mode 100644 metrics/prometheus/prometheus.go
diff --git a/metrics/exp/exp.go b/metrics/exp/exp.go
index 325a193c7..55820f1aa 100644
--- a/metrics/exp/exp.go
+++ b/metrics/exp/exp.go
@@ -9,6 +9,7 @@ import (
"sync"
"github.com/ethereum/go-ethereum/metrics"
+ "github.com/ethereum/go-ethereum/metrics/prometheus"
)
type exp struct {
@@ -42,6 +43,7 @@ func Exp(r metrics.Registry) {
// http.HandleFunc("/debug/vars", e.expHandler)
// haven't found an elegant way, so just use a different endpoint
http.Handle("/debug/metrics", h)
+ http.Handle("/debug/metrics/prometheus", prometheus.Handler(r))
}
// ExpHandler will return an expvar powered metrics handler.
diff --git a/metrics/prometheus/collector.go b/metrics/prometheus/collector.go
new file mode 100644
index 000000000..8350fa2aa
--- /dev/null
+++ b/metrics/prometheus/collector.go
@@ -0,0 +1,115 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package prometheus
+
+import (
+ "bytes"
+ "fmt"
+ "strconv"
+ "strings"
+
+ "github.com/ethereum/go-ethereum/metrics"
+)
+
+var (
+ typeGaugeTpl = "# TYPE %s gauge\n"
+ typeCounterTpl = "# TYPE %s counter\n"
+ typeSummaryTpl = "# TYPE %s summary\n"
+ keyValueTpl = "%s %v\n\n"
+ keyQuantileTagValueTpl = "%s {quantile=\"%s\"} %v\n\n"
+)
+
+// collector is a collection of byte buffers that aggregate Prometheus reports
+// for different metric types.
+type collector struct {
+ buff *bytes.Buffer
+}
+
+// newCollector createa a new Prometheus metric aggregator.
+func newCollector() *collector {
+ return &collector{
+ buff: &bytes.Buffer{},
+ }
+}
+
+func (c *collector) addCounter(name string, m metrics.Counter) {
+ c.writeGaugeCounter(name, m.Count())
+}
+
+func (c *collector) addGauge(name string, m metrics.Gauge) {
+ c.writeGaugeCounter(name, m.Value())
+}
+
+func (c *collector) addGaugeFloat64(name string, m metrics.GaugeFloat64) {
+ c.writeGaugeCounter(name, m.Value())
+}
+
+func (c *collector) addHistogram(name string, m metrics.Histogram) {
+ pv := []float64{0.5, 0.75, 0.95, 0.99, 0.999, 0.9999}
+ ps := m.Percentiles(pv)
+ c.writeSummaryCounter(name, m.Count())
+ for i := range pv {
+ c.writeSummaryPercentile(name, strconv.FormatFloat(pv[i], 'f', -1, 64), ps[i])
+ }
+}
+
+func (c *collector) addMeter(name string, m metrics.Meter) {
+ c.writeGaugeCounter(name, m.Count())
+}
+
+func (c *collector) addTimer(name string, m metrics.Timer) {
+ pv := []float64{0.5, 0.75, 0.95, 0.99, 0.999, 0.9999}
+ ps := m.Percentiles(pv)
+ c.writeSummaryCounter(name, m.Count())
+ for i := range pv {
+ c.writeSummaryPercentile(name, strconv.FormatFloat(pv[i], 'f', -1, 64), ps[i])
+ }
+}
+
+func (c *collector) addResettingTimer(name string, m metrics.ResettingTimer) {
+ if len(m.Values()) <= 0 {
+ return
+ }
+ ps := m.Percentiles([]float64{50, 95, 99})
+ val := m.Values()
+ c.writeSummaryCounter(name, len(val))
+ c.writeSummaryPercentile(name, "0.50", ps[0])
+ c.writeSummaryPercentile(name, "0.95", ps[1])
+ c.writeSummaryPercentile(name, "0.99", ps[2])
+}
+
+func (c *collector) writeGaugeCounter(name string, value interface{}) {
+ name = mutateKey(name)
+ c.buff.WriteString(fmt.Sprintf(typeGaugeTpl, name))
+ c.buff.WriteString(fmt.Sprintf(keyValueTpl, name, value))
+}
+
+func (c *collector) writeSummaryCounter(name string, value interface{}) {
+ name = mutateKey(name + "_count")
+ c.buff.WriteString(fmt.Sprintf(typeCounterTpl, name))
+ c.buff.WriteString(fmt.Sprintf(keyValueTpl, name, value))
+}
+
+func (c *collector) writeSummaryPercentile(name, p string, value interface{}) {
+ name = mutateKey(name)
+ c.buff.WriteString(fmt.Sprintf(typeSummaryTpl, name))
+ c.buff.WriteString(fmt.Sprintf(keyQuantileTagValueTpl, name, p, value))
+}
+
+func mutateKey(key string) string {
+ return strings.Replace(key, "/", "_", -1)
+}
diff --git a/metrics/prometheus/prometheus.go b/metrics/prometheus/prometheus.go
new file mode 100644
index 000000000..9ad5ec7e9
--- /dev/null
+++ b/metrics/prometheus/prometheus.go
@@ -0,0 +1,68 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package prometheus exposes go-metrics into a Prometheus format.
+package prometheus
+
+import (
+ "fmt"
+ "net/http"
+ "sort"
+
+ "github.com/ethereum/go-ethereum/log"
+ "github.com/ethereum/go-ethereum/metrics"
+)
+
+// Handler returns an HTTP handler which dump metrics in Prometheus format.
+func Handler(reg metrics.Registry) http.Handler {
+ return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ // Gather and pre-sort the metrics to avoid random listings
+ var names []string
+ reg.Each(func(name string, i interface{}) {
+ names = append(names, name)
+ })
+ sort.Strings(names)
+
+ // Aggregate all the metris into a Prometheus collector
+ c := newCollector()
+
+ for _, name := range names {
+ i := reg.Get(name)
+
+ switch m := i.(type) {
+ case metrics.Counter:
+ c.addCounter(name, m.Snapshot())
+ case metrics.Gauge:
+ c.addGauge(name, m.Snapshot())
+ case metrics.GaugeFloat64:
+ c.addGaugeFloat64(name, m.Snapshot())
+ case metrics.Histogram:
+ c.addHistogram(name, m.Snapshot())
+ case metrics.Meter:
+ c.addMeter(name, m.Snapshot())
+ case metrics.Timer:
+ c.addTimer(name, m.Snapshot())
+ case metrics.ResettingTimer:
+ c.addResettingTimer(name, m.Snapshot())
+ default:
+ log.Warn("Unknown Prometheus metric type", "type", fmt.Sprintf("%T", i))
+ }
+ }
+ w.Header().Add("Content-Type", "text/plain")
+ w.Header().Add("Content-Length", fmt.Sprint(c.buff.Len()))
+ w.Write(c.buff.Bytes())
+ })
+}
--
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