telegraf/plugins/inputs/prometheus/prometheus.go

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package prometheus
import (
"errors"
"fmt"
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"io/ioutil"
"net"
"net/http"
"sync"
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"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
"github.com/influxdata/telegraf/plugins/inputs"
)
const acceptHeader = `application/vnd.google.protobuf;proto=io.prometheus.client.MetricFamily;encoding=delimited;q=0.7,text/plain;version=0.0.4;q=0.3`
type Prometheus struct {
Urls []string
// Bearer Token authorization file path
BearerToken string `toml:"bearer_token"`
ResponseTimeout internal.Duration `toml:"response_timeout"`
// Path to CA file
SSLCA string `toml:"ssl_ca"`
// Path to host cert file
SSLCert string `toml:"ssl_cert"`
// Path to cert key file
SSLKey string `toml:"ssl_key"`
// Use SSL but skip chain & host verification
InsecureSkipVerify bool
}
var sampleConfig = `
## An array of urls to scrape metrics from.
urls = ["http://localhost:9100/metrics"]
## Use bearer token for authorization
# bearer_token = /path/to/bearer/token
## Specify timeout duration for slower prometheus clients (default is 3s)
# response_timeout = "3s"
## Optional SSL Config
# ssl_ca = /path/to/cafile
# ssl_cert = /path/to/certfile
# ssl_key = /path/to/keyfile
## Use SSL but skip chain & host verification
# insecure_skip_verify = false
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`
func (p *Prometheus) SampleConfig() string {
return sampleConfig
}
func (p *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 (p *Prometheus) Gather(acc telegraf.Accumulator) error {
var wg sync.WaitGroup
var outerr error
for _, serv := range p.Urls {
wg.Add(1)
go func(serv string) {
defer wg.Done()
outerr = p.gatherURL(serv, acc)
}(serv)
}
wg.Wait()
return outerr
}
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var tr = &http.Transport{
ResponseHeaderTimeout: time.Duration(3 * time.Second),
}
var client = &http.Client{
Transport: tr,
Timeout: time.Duration(4 * time.Second),
}
func (p *Prometheus) gatherURL(url string, acc telegraf.Accumulator) error {
var req, err = http.NewRequest("GET", url, nil)
req.Header.Add("Accept", acceptHeader)
var token []byte
var resp *http.Response
tlsCfg, err := internal.GetTLSConfig(
p.SSLCert, p.SSLKey, p.SSLCA, p.InsecureSkipVerify)
if err != nil {
return err
}
var rt http.RoundTripper = &http.Transport{
Dial: (&net.Dialer{
Timeout: 5 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 5 * time.Second,
TLSClientConfig: tlsCfg,
ResponseHeaderTimeout: p.ResponseTimeout.Duration,
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DisableKeepAlives: true,
}
if p.BearerToken != "" {
token, err = ioutil.ReadFile(p.BearerToken)
if err != nil {
return err
}
req.Header.Set("Authorization", "Bearer "+string(token))
}
resp, err = rt.RoundTrip(req)
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)
}
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body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return fmt.Errorf("error reading body: %s", err)
}
metrics, err := Parse(body, resp.Header)
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if err != nil {
return fmt.Errorf("error reading metrics for %s: %s",
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url, err)
}
// Add (or not) collected metrics
for _, metric := range metrics {
tags := metric.Tags()
tags["url"] = url
acc.AddFields(metric.Name(), metric.Fields(), tags, metric.Time())
}
return nil
}
func init() {
inputs.Add("prometheus", func() telegraf.Input {
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return &Prometheus{ResponseTimeout: internal.Duration{Duration: time.Second * 3}}
})
}