telegraf/plugins/inputs/prometheus/prometheus.go

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package prometheus
import (
"context"
"errors"
"fmt"
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"io/ioutil"
"log"
"net"
"net/http"
"net/url"
"sync"
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"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
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"github.com/influxdata/telegraf/internal/tls"
"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 {
// An array of urls to scrape metrics from.
URLs []string `toml:"urls"`
// An array of Kubernetes services to scrape metrics from.
KubernetesServices []string
// Location of kubernetes config file
KubeConfig string
// Bearer Token authorization file path
BearerToken string `toml:"bearer_token"`
ResponseTimeout internal.Duration `toml:"response_timeout"`
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tls.ClientConfig
client *http.Client
// Should we scrape Kubernetes services for prometheus annotations
MonitorPods bool `toml:"monitor_kubernetes_pods"`
lock sync.Mutex
kubernetesPods []URLAndAddress
cancel context.CancelFunc
wg sync.WaitGroup
}
var sampleConfig = `
## An array of urls to scrape metrics from.
urls = ["http://localhost:9100/metrics"]
## An array of Kubernetes services to scrape metrics from.
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# kubernetes_services = ["http://my-service-dns.my-namespace:9100/metrics"]
## Kubernetes config file to create client from.
# kube_config = "/path/to/kubernetes.config"
## Scrape Kubernetes pods for the following prometheus annotations:
## - prometheus.io/scrape: Enable scraping for this pod
## - prometheus.io/scheme: If the metrics endpoint is secured then you will need to
## set this to 'https' & most likely set the tls config.
## - prometheus.io/path: If the metrics path is not /metrics, define it with this annotation.
## - prometheus.io/port: If port is not 9102 use this annotation
# monitor_kubernetes_pods = true
## Use bearer token for authorization
# bearer_token = /path/to/bearer/token
## Specify timeout duration for slower prometheus clients (default is 3s)
# response_timeout = "3s"
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## Optional TLS Config
# tls_ca = /path/to/cafile
# tls_cert = /path/to/certfile
# tls_key = /path/to/keyfile
## Use TLS 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")
func (p *Prometheus) AddressToURL(u *url.URL, address string) *url.URL {
host := address
if u.Port() != "" {
host = address + ":" + u.Port()
}
reconstructedURL := &url.URL{
Scheme: u.Scheme,
Opaque: u.Opaque,
User: u.User,
Path: u.Path,
RawPath: u.RawPath,
ForceQuery: u.ForceQuery,
RawQuery: u.RawQuery,
Fragment: u.Fragment,
Host: host,
}
return reconstructedURL
}
type URLAndAddress struct {
OriginalURL *url.URL
URL *url.URL
Address string
Tags map[string]string
}
func (p *Prometheus) GetAllURLs() ([]URLAndAddress, error) {
allURLs := make([]URLAndAddress, 0)
for _, u := range p.URLs {
URL, err := url.Parse(u)
if err != nil {
log.Printf("prometheus: Could not parse %s, skipping it. Error: %s", u, err.Error())
continue
}
allURLs = append(allURLs, URLAndAddress{URL: URL, OriginalURL: URL})
}
p.lock.Lock()
defer p.lock.Unlock()
// loop through all pods scraped via the prometheus annotation on the pods
allURLs = append(allURLs, p.kubernetesPods...)
for _, service := range p.KubernetesServices {
URL, err := url.Parse(service)
if err != nil {
return nil, err
}
resolvedAddresses, err := net.LookupHost(URL.Hostname())
if err != nil {
log.Printf("prometheus: Could not resolve %s, skipping it. Error: %s", URL.Host, err.Error())
continue
}
for _, resolved := range resolvedAddresses {
serviceURL := p.AddressToURL(URL, resolved)
allURLs = append(allURLs, URLAndAddress{URL: serviceURL, Address: resolved, OriginalURL: URL})
}
}
return allURLs, nil
}
// 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 {
if p.client == nil {
client, err := p.createHTTPClient()
if err != nil {
return err
}
p.client = client
}
var wg sync.WaitGroup
allURLs, err := p.GetAllURLs()
if err != nil {
return err
}
for _, URL := range allURLs {
wg.Add(1)
go func(serviceURL URLAndAddress) {
defer wg.Done()
acc.AddError(p.gatherURL(serviceURL, acc))
}(URL)
}
wg.Wait()
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return nil
}
func (p *Prometheus) createHTTPClient() (*http.Client, error) {
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tlsCfg, err := p.ClientConfig.TLSConfig()
if err != nil {
return nil, err
}
client := &http.Client{
Transport: &http.Transport{
TLSClientConfig: tlsCfg,
DisableKeepAlives: true,
},
Timeout: p.ResponseTimeout.Duration,
}
return client, nil
}
func (p *Prometheus) gatherURL(u URLAndAddress, acc telegraf.Accumulator) error {
var req *http.Request
var err error
var uClient *http.Client
if u.URL.Scheme == "unix" {
path := u.URL.Query().Get("path")
if path == "" {
path = "/metrics"
}
req, err = http.NewRequest("GET", "http://localhost"+path, nil)
// ignore error because it's been handled before getting here
tlsCfg, _ := p.ClientConfig.TLSConfig()
uClient = &http.Client{
Transport: &http.Transport{
TLSClientConfig: tlsCfg,
DisableKeepAlives: true,
Dial: func(network, addr string) (net.Conn, error) {
c, err := net.Dial("unix", u.URL.Path)
return c, err
},
},
Timeout: p.ResponseTimeout.Duration,
}
} else {
if u.URL.Path == "" {
u.URL.Path = "/metrics"
}
req, err = http.NewRequest("GET", u.URL.String(), nil)
}
req.Header.Add("Accept", acceptHeader)
var token []byte
if p.BearerToken != "" {
token, err = ioutil.ReadFile(p.BearerToken)
if err != nil {
return err
}
req.Header.Set("Authorization", "Bearer "+string(token))
}
var resp *http.Response
if u.URL.Scheme != "unix" {
resp, err = p.client.Do(req)
} else {
resp, err = uClient.Do(req)
}
if err != nil {
return fmt.Errorf("error making HTTP request to %s: %s", u.URL, err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return fmt.Errorf("%s returned HTTP status %s", u.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",
u.URL, err)
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}
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for _, metric := range metrics {
tags := metric.Tags()
// strip user and password from URL
u.OriginalURL.User = nil
tags["url"] = u.OriginalURL.String()
if u.Address != "" {
tags["address"] = u.Address
}
for k, v := range u.Tags {
tags[k] = v
}
switch metric.Type() {
case telegraf.Counter:
acc.AddCounter(metric.Name(), metric.Fields(), tags, metric.Time())
case telegraf.Gauge:
acc.AddGauge(metric.Name(), metric.Fields(), tags, metric.Time())
case telegraf.Summary:
acc.AddSummary(metric.Name(), metric.Fields(), tags, metric.Time())
case telegraf.Histogram:
acc.AddHistogram(metric.Name(), metric.Fields(), tags, metric.Time())
default:
acc.AddFields(metric.Name(), metric.Fields(), tags, metric.Time())
}
}
return nil
}
// Start will start the Kubernetes scraping if enabled in the configuration
func (p *Prometheus) Start(a telegraf.Accumulator) error {
if p.MonitorPods {
var ctx context.Context
ctx, p.cancel = context.WithCancel(context.Background())
return p.start(ctx)
}
return nil
}
func (p *Prometheus) Stop() {
if p.MonitorPods {
p.cancel()
}
p.wg.Wait()
}
func init() {
inputs.Add("prometheus", func() telegraf.Input {
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return &Prometheus{ResponseTimeout: internal.Duration{Duration: time.Second * 3}}
})
}