erigon-pulse/metrics/prometheus.go
Mark Holt 0bdca6c457
Metrics label fixes (#8339)
Fixes for label discrepancies in collector for summaries etc which have
a template which includes a quantile.

Initial native Prometheus client implementation of metrics - which is
currently turned off except for local testing and interface exports.
2023-10-02 17:19:02 +01:00

96 lines
2.9 KiB
Go

// 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 metrics
import (
"fmt"
"net/http"
"sort"
metrics2 "github.com/VictoriaMetrics/metrics"
"github.com/ledgerwatch/log/v3"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/expfmt"
)
// Handler returns an HTTP handler which dump metrics in Prometheus format.
// Output format can be cheched here: https://o11y.tools/metricslint/
func Handler(reg Registry) http.Handler {
prometheus.DefaultRegisterer.MustRegister(defaultSet)
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)
w.Header().Set("Access-Control-Allow-Origin", "*")
metrics2.WritePrometheus(w, false)
contentType := expfmt.Negotiate(r.Header)
enc := expfmt.NewEncoder(w, contentType)
mf, err := prometheus.DefaultGatherer.Gather()
if err != nil {
return
}
for _, m := range mf {
enc.Encode(m)
}
// Aggregate all the metris into a Prometheus collector
c := newCollector()
c.buff.WriteRune('\n')
var typeName string
var prevTypeName string
for _, name := range names {
i := reg.Get(name)
typeName = stripLabels(name)
switch m := i.(type) {
case *metrics2.Counter:
if m.IsGauge() {
c.writeGauge(name, m.Get(), typeName != prevTypeName)
} else {
c.writeCounter(name, m.Get(), typeName != prevTypeName)
}
case *metrics2.Gauge:
c.writeGauge(name, m, typeName != prevTypeName)
case *metrics2.FloatCounter:
c.writeFloatCounter(name, m, typeName != prevTypeName)
case *metrics2.Histogram:
c.writeHistogram(name, m, typeName != prevTypeName)
case *metrics2.Summary:
c.writeTimer(name, m, typeName != prevTypeName)
default:
log.Warn("Unknown Prometheus metric type", "type", fmt.Sprintf("%T", i))
}
prevTypeName = typeName
}
w.Header().Add("Content-Type", "text/plain")
w.Header().Add("Content-Length", fmt.Sprint(c.buff.Len()))
w.Write(c.buff.Bytes())
})
}