plugeth/metrics/prometheus/prometheus.go

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// 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 metrics 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())
})
}