VictoriaMetrics/app/victoria-metrics/self_scraper.go
2022-09-30 18:35:53 +03:00

105 lines
2.9 KiB
Go

package main
import (
"flag"
"sync"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/app/vmstorage"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/appmetrics"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompb"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
)
var (
selfScrapeInterval = flag.Duration("selfScrapeInterval", 0, "Interval for self-scraping own metrics at /metrics page")
selfScrapeInstance = flag.String("selfScrapeInstance", "self", "Value for 'instance' label, which is added to self-scraped metrics")
selfScrapeJob = flag.String("selfScrapeJob", "victoria-metrics", "Value for 'job' label, which is added to self-scraped metrics")
)
var selfScraperStopCh chan struct{}
var selfScraperWG sync.WaitGroup
func startSelfScraper() {
selfScraperStopCh = make(chan struct{})
selfScraperWG.Add(1)
go func() {
defer selfScraperWG.Done()
selfScraper(*selfScrapeInterval)
}()
}
func stopSelfScraper() {
close(selfScraperStopCh)
selfScraperWG.Wait()
}
func selfScraper(scrapeInterval time.Duration) {
if scrapeInterval <= 0 {
// Self-scrape is disabled.
return
}
logger.Infof("started self-scraping `/metrics` page with interval %.3f seconds", scrapeInterval.Seconds())
var bb bytesutil.ByteBuffer
var rows prometheus.Rows
var mrs []storage.MetricRow
var labels []prompb.Label
t := time.NewTicker(scrapeInterval)
var currentTimestamp int64
for {
select {
case <-selfScraperStopCh:
t.Stop()
logger.Infof("stopped self-scraping `/metrics` page")
return
case currentTime := <-t.C:
currentTimestamp = currentTime.UnixNano() / 1e6
}
bb.Reset()
appmetrics.WritePrometheusMetrics(&bb)
s := bytesutil.ToUnsafeString(bb.B)
rows.Reset()
rows.Unmarshal(s)
mrs = mrs[:0]
for i := range rows.Rows {
r := &rows.Rows[i]
labels = labels[:0]
labels = addLabel(labels, "", r.Metric)
labels = addLabel(labels, "job", *selfScrapeJob)
labels = addLabel(labels, "instance", *selfScrapeInstance)
for j := range r.Tags {
t := &r.Tags[j]
labels = addLabel(labels, t.Key, t.Value)
}
if len(mrs) < cap(mrs) {
mrs = mrs[:len(mrs)+1]
} else {
mrs = append(mrs, storage.MetricRow{})
}
mr := &mrs[len(mrs)-1]
mr.MetricNameRaw = storage.MarshalMetricNameRaw(mr.MetricNameRaw[:0], labels)
mr.Timestamp = currentTimestamp
mr.Value = r.Value
}
if err := vmstorage.AddRows(mrs); err != nil {
logger.Errorf("cannot store self-scraped metrics: %s", err)
}
}
}
func addLabel(dst []prompb.Label, key, value string) []prompb.Label {
if len(dst) < cap(dst) {
dst = dst[:len(dst)+1]
} else {
dst = append(dst, prompb.Label{})
}
lb := &dst[len(dst)-1]
lb.Name = bytesutil.ToUnsafeBytes(key)
lb.Value = bytesutil.ToUnsafeBytes(value)
return dst
}