Files
telegraf/plugins/prometheus/prometheus.go
T
Tait ClarridgeandCameron Sparr 4449f7f2fb Add prometheus_client service output module, update prometheus client
- Adds a client implementation using the prometheus go_client library
  that exposes metrics.

- Adds a new type of output "ServiceOutput" which follows inline with
  the "ServicePlugin", adding a Stop and Start method for the service

This change also requires the newer prometheus/client_golang code, so
the prometheus plugin needed to be changed.

Added the following to Godep:
    - bitbucket.org/ww/goautoneg (in github.com/common/expfmt/encode.go)
    - prometheus/common/expfmt (in plugins/prometheus.go)
    - github.com/prometheus/common/model (in plugins/prometheus.go)
    - github.com/prometheus/procfs (in github.com/client_golang/prometheus)
    - github.com/beorn7/perks/quantile (in github.com/client_golang/prometheus)

X-Github-Meta: closes #306
2015-10-28 15:28:39 -06:00

102 lines
2.1 KiB
Go

package prometheus
import (
"errors"
"fmt"
"github.com/influxdb/telegraf/plugins"
"github.com/prometheus/common/expfmt"
"github.com/prometheus/common/model"
"io"
"net/http"
"sync"
)
type Prometheus struct {
Urls []string
}
var sampleConfig = `
# 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)
}
format := expfmt.ResponseFormat(resp.Header)
decoder := expfmt.NewDecoder(resp.Body, format)
options := &expfmt.DecodeOptions{
Timestamp: model.Now(),
}
sampleDecoder := &expfmt.SampleDecoder{
Dec: decoder,
Opts: options,
}
for {
var samples model.Vector
err := sampleDecoder.Decode(&samples)
if err == io.EOF {
break
} else if err != nil {
return fmt.Errorf("error getting processing samples for %s: %s", url, err)
}
for _, sample := range samples {
tags := map[string]string{}
for key, value := range sample.Metric {
if key == model.MetricNameLabel {
continue
}
tags[string(key)] = string(value)
}
acc.Add(string(sample.Metric[model.MetricNameLabel]), float64(sample.Value), tags)
}
}
return nil
}
func init() {
plugins.Add("prometheus", func() plugins.Plugin {
return &Prometheus{}
})
}