go-ethereum/metrics/prometheus/collector.go
turboboost55 7dc100714d
metrics: add cpu counters (#26796)
This PR adds counter metrics for the CPU system and the Geth process.
Currently the only metrics available for these items are gauges. Gauges are
fine when the consumer scrapes metrics data at the same interval as Geth
produces new values (every 3 seconds), but it is likely that most consumers
will not scrape that often. Intervals of 10, 15, or maybe even 30 seconds
are probably more common.

So the problem is, how does the consumer estimate what the CPU was doing in
between scrapes. With a counter, it's easy ... you just subtract two
successive values and divide by the time to get a nice, accurate average.
But with a gauge, you can't do that. A gauge reading is an instantaneous
picture of what was happening at that moment, but it gives you no idea
about what was going on between scrapes. Taking an average of values is
meaningless.
2023-03-23 14:13:50 +01:00

125 lines
3.8 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
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"
)
// collector is a collection of byte buffers that aggregate Prometheus reports
// for different metric types.
type collector struct {
buff *bytes.Buffer
}
// newCollector creates 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) addCounterFloat64(name string, m metrics.CounterFloat64) {
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())
c.buff.WriteString(fmt.Sprintf(typeSummaryTpl, mutateKey(name)))
for i := range pv {
c.writeSummaryPercentile(name, strconv.FormatFloat(pv[i], 'f', -1, 64), ps[i])
}
c.buff.WriteRune('\n')
}
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())
c.buff.WriteString(fmt.Sprintf(typeSummaryTpl, mutateKey(name)))
for i := range pv {
c.writeSummaryPercentile(name, strconv.FormatFloat(pv[i], 'f', -1, 64), ps[i])
}
c.buff.WriteRune('\n')
}
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.buff.WriteString(fmt.Sprintf(typeSummaryTpl, mutateKey(name)))
c.writeSummaryPercentile(name, "0.50", ps[0])
c.writeSummaryPercentile(name, "0.95", ps[1])
c.writeSummaryPercentile(name, "0.99", ps[2])
c.buff.WriteRune('\n')
}
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(keyQuantileTagValueTpl, name, p, value))
}
func mutateKey(key string) string {
return strings.ReplaceAll(key, "/", "_")
}