telegraf/plugins/prometheus/prometheus.go

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package prometheus
import (
"errors"
"fmt"
"net/http"
"sync"
"time"
"github.com/influxdb/telegraf/plugins"
"github.com/prometheus/client_golang/extraction"
"github.com/prometheus/client_golang/model"
)
type Prometheus struct {
Urls []string
}
var sampleConfig = `
2015-08-26 15:21:39 +00:00
# An array of urls to scrape metrics from.
urls = ["http://localhost:9100/metrics"]
`
func (r *Prometheus) SampleConfig() string {
return sampleConfig
}
func (r *Prometheus) Description() string {
return "Read metrics from one or many prometheus clients"
}
var ErrProtocolError = errors.New("prometheus protocol error")
// Reads stats from all configured servers accumulates stats.
// Returns one of the errors encountered while gather stats (if any).
func (g *Prometheus) Gather(acc plugins.Accumulator) error {
var wg sync.WaitGroup
var outerr error
for _, serv := range g.Urls {
wg.Add(1)
go func(serv string) {
defer wg.Done()
outerr = g.gatherURL(serv, acc)
}(serv)
}
wg.Wait()
return outerr
}
func (g *Prometheus) gatherURL(url string, acc plugins.Accumulator) error {
resp, err := http.Get(url)
if err != nil {
return fmt.Errorf("error making HTTP request to %s: %s", url, err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return fmt.Errorf("%s returned HTTP status %s", url, resp.Status)
}
processor, err := extraction.ProcessorForRequestHeader(resp.Header)
if err != nil {
return fmt.Errorf("error getting extractor for %s: %s", url, err)
}
ingestor := &Ingester{
acc: acc,
}
options := &extraction.ProcessOptions{
Timestamp: model.TimestampFromTime(time.Now()),
}
err = processor.ProcessSingle(resp.Body, ingestor, options)
if err != nil {
return fmt.Errorf("error getting processing samples for %s: %s", url, err)
}
return nil
}
type Ingester struct {
acc plugins.Accumulator
}
// Ingest implements an extraction.Ingester.
func (i *Ingester) Ingest(samples model.Samples) error {
for _, sample := range samples {
tags := map[string]string{}
for key, value := range sample.Metric {
if key == model.MetricNameLabel {
continue
}
tags[string(key)] = string(value)
}
i.acc.Add(string(sample.Metric[model.MetricNameLabel]), float64(sample.Value), tags)
}
return nil
}
func init() {
plugins.Add("prometheus", func() plugins.Plugin {
return &Prometheus{}
})
}