cmd/infra/ursrv/serve/prometheus.go
Rama main · réplica de lectura del repositorio original.
// Copyright (C) 2024 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package serve
import (
"context"
"fmt"
"log/slog"
"reflect"
"slices"
"strconv"
"strings"
"sync"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/syncthing/syncthing/lib/ur/contract"
)
const namePrefix = "syncthing_usage_"
type metricsSet struct {
srv *server
gauges map[string]prometheus.Gauge
gaugeVecs map[string]*prometheus.GaugeVec
gaugeVecLabels map[string][]string
summaries map[string]*metricSummary
collectMut sync.RWMutex
collectCutoff time.Duration
}
func newMetricsSet(srv *server) *metricsSet {
s := &metricsSet{
srv: srv,
gauges: make(map[string]prometheus.Gauge),
gaugeVecs: make(map[string]*prometheus.GaugeVec),
gaugeVecLabels: make(map[string][]string),
summaries: make(map[string]*metricSummary),
collectCutoff: -24 * time.Hour,
}
var initForType func(reflect.Type)
initForType = func(t reflect.Type) {
for field := range t.Fields() {
if field.Type.Kind() == reflect.Struct {
initForType(field.Type)
continue
}
name, typ, label := fieldNameTypeLabel(field)
sname, labels := nameConstLabels(name)
switch typ {
case "gauge":
s.gauges[name] = prometheus.NewGauge(prometheus.GaugeOpts{
Name: namePrefix + sname,
ConstLabels: labels,
})
case "summary":
s.summaries[name] = newMetricSummary(namePrefix+sname, nil, labels)
case "gaugeVec":
s.gaugeVecLabels[name] = append(s.gaugeVecLabels[name], label)
case "summaryVec":
s.summaries[name] = newMetricSummary(namePrefix+sname, []string{label}, labels)
}
}
}
initForType(reflect.ValueOf(contract.Report{}).Type())
for name, labels := range s.gaugeVecLabels {
s.gaugeVecs[name] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Name: namePrefix + name,
}, labels)
}
return s
}
func fieldNameTypeLabel(rf reflect.StructField) (string, string, string) {
metric := rf.Tag.Get("metric")
name, typ, ok := strings.Cut(metric, ",")
if !ok {
return "", "", ""
}
gv, label, ok := strings.Cut(typ, ":")
if ok {
typ = gv
}
return name, typ, label
}
func nameConstLabels(name string) (string, prometheus.Labels) {
if name == "-" {
return "", nil
}
name, labels, ok := strings.Cut(name, "{")
if !ok {
return name, nil
}
lls := strings.Split(labels[:len(labels)-1], ",")
m := make(map[string]string)
for _, l := range lls {
k, v, _ := strings.Cut(l, "=")
m[k] = v
}
return name, m
}
func (s *metricsSet) Serve(ctx context.Context) error {
s.recalc()
const recalcInterval = 5 * time.Minute
next := time.Until(time.Now().Truncate(recalcInterval).Add(recalcInterval))
recalcTimer := time.NewTimer(next)
defer recalcTimer.Stop()
for {
select {
case <-recalcTimer.C:
s.recalc()
next := time.Until(time.Now().Truncate(recalcInterval).Add(recalcInterval))
recalcTimer.Reset(next)
case <-ctx.Done():
return ctx.Err()
}
}
}
func (s *metricsSet) recalc() {
s.collectMut.Lock()
defer s.collectMut.Unlock()
t0 := time.Now()
defer func() {
dur := time.Since(t0)
slog.Info("Metrics recalculated", "d", dur.String())
metricsRecalcSecondsLast.Set(dur.Seconds())
metricsRecalcSecondsTotal.Add(dur.Seconds())
metricsRecalcsTotal.Inc()
}()
for _, g := range s.gauges {
g.Set(0)
}
for _, g := range s.gaugeVecs {
g.Reset()
}
for _, g := range s.summaries {
g.Reset()
}
cutoff := time.Now().Add(s.collectCutoff)
s.srv.reports.Range(func(key string, r *contract.Report) bool {
if s.collectCutoff < 0 && r.Received.Before(cutoff) {
s.srv.reports.Delete(key)
return true
}
s.addReport(r)
return true
})
}
func (s *metricsSet) addReport(r *contract.Report) {
gaugeVecs := make(map[string][]string)
s.addReportStruct(reflect.ValueOf(r).Elem(), gaugeVecs)
for name, lv := range gaugeVecs {
s.gaugeVecs[name].WithLabelValues(lv...).Add(1)
}
}
func (s *metricsSet) addReportStruct(v reflect.Value, gaugeVecs map[string][]string) {
t := v.Type()
for i := range v.NumField() {
field := v.Field(i)
if field.Kind() == reflect.Struct {
s.addReportStruct(field, gaugeVecs)
continue
}
name, typ, label := fieldNameTypeLabel(t.Field(i))
switch typ {
case "gauge":
switch v := field.Interface().(type) {
case int:
s.gauges[name].Add(float64(v))
case string:
s.gaugeVecs[name].WithLabelValues(v).Add(1)
case bool:
if v {
s.gauges[name].Add(1)
}
}
case "gaugeVec":
var labelValue string
switch v := field.Interface().(type) {
case string:
labelValue = v
case int:
labelValue = strconv.Itoa(v)
case map[string]int:
for k, v := range v {
labelValue = k
field.SetInt(int64(v))
break
}
}
if _, ok := gaugeVecs[name]; !ok {
gaugeVecs[name] = make([]string, len(s.gaugeVecLabels[name]))
}
for i, l := range s.gaugeVecLabels[name] {
if l == label {
gaugeVecs[name][i] = labelValue
break
}
}
case "summary", "summaryVec":
switch v := field.Interface().(type) {
case int:
s.summaries[name].Observe("", float64(v))
case float64:
s.summaries[name].Observe("", v)
case []int:
for _, v := range v {
s.summaries[name].Observe("", float64(v))
}
case map[string]int:
for k, v := range v {
if k == "" {
// avoid empty string labels as those are the sign
// of a non-vec summary
k = "unknown"
}
s.summaries[name].Observe(k, float64(v))
}
}
}
}
}
func (s *metricsSet) Describe(c chan<- *prometheus.Desc) {
for _, g := range s.gauges {
g.Describe(c)
}
for _, g := range s.gaugeVecs {
g.Describe(c)
}
for _, g := range s.summaries {
g.Describe(c)
}
}
func (s *metricsSet) Collect(c chan<- prometheus.Metric) {
s.collectMut.RLock()
defer s.collectMut.RUnlock()
t0 := time.Now()
defer func() {
dur := time.Since(t0).Seconds()
metricsCollectSecondsLast.Set(dur)
metricsCollectSecondsTotal.Add(dur)
metricsCollectsTotal.Inc()
}()
for _, g := range s.gauges {
c <- g
}
for _, g := range s.gaugeVecs {
g.Collect(c)
}
for _, g := range s.summaries {
g.Collect(c)
}
}
type metricSummary struct {
name string
values map[string][]float64
zeroes map[string]int
qDesc *prometheus.Desc
countDesc *prometheus.Desc
sumDesc *prometheus.Desc
zDesc *prometheus.Desc
}
func newMetricSummary(name string, labels []string, constLabels prometheus.Labels) *metricSummary {
return &metricSummary{
name: name,
values: make(map[string][]float64),
zeroes: make(map[string]int),
qDesc: prometheus.NewDesc(name, "", append(labels, "quantile"), constLabels),
countDesc: prometheus.NewDesc(name+"_nonzero_count", "", labels, constLabels),
sumDesc: prometheus.NewDesc(name+"_sum", "", labels, constLabels),
zDesc: prometheus.NewDesc(name+"_zero_count", "", labels, constLabels),
}
}
func (q *metricSummary) Observe(labelValue string, v float64) {
if v == 0 {
q.zeroes[labelValue]++
return
}
q.values[labelValue] = append(q.values[labelValue], v)
}
func (q *metricSummary) Describe(c chan<- *prometheus.Desc) {
c <- q.qDesc
c <- q.countDesc
c <- q.sumDesc
c <- q.zDesc
}
func (q *metricSummary) Collect(c chan<- prometheus.Metric) {
for lv, vs := range q.values {
var labelVals []string
if lv != "" {
labelVals = []string{lv}
}
c <- prometheus.MustNewConstMetric(q.countDesc, prometheus.GaugeValue, float64(len(vs)), labelVals...)
c <- prometheus.MustNewConstMetric(q.zDesc, prometheus.GaugeValue, float64(q.zeroes[lv]), labelVals...)
var sum float64
for _, v := range vs {
sum += v
}
c <- prometheus.MustNewConstMetric(q.sumDesc, prometheus.GaugeValue, sum, labelVals...)
if len(vs) == 0 {
return
}
slices.Sort(vs)
pctiles := []float64{0, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 0.75, 0.9, 0.95, 0.975, 0.99, 1}
for _, pct := range pctiles {
idx := int(float64(len(vs)-1) * pct)
c <- prometheus.MustNewConstMetric(q.qDesc, prometheus.GaugeValue, vs[idx], append(labelVals, fmt.Sprint(pct))...)
}
}
}
func (q *metricSummary) Reset() {
clear(q.values)
clear(q.zeroes)
}