telegraf/plugins/outputs/prometheus_client/prometheus_client.go

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package prometheus_client
import (
"context"
"crypto/subtle"
"fmt"
"log"
"net/http"
"os"
"regexp"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
"github.com/influxdata/telegraf/plugins/outputs"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
var invalidNameCharRE = regexp.MustCompile(`[^a-zA-Z0-9_]`)
// SampleID uniquely identifies a Sample
type SampleID string
// Sample represents the current value of a series.
type Sample struct {
// Labels are the Prometheus labels.
Labels map[string]string
// Value is the value in the Prometheus output. Only one of these will populated.
Value float64
HistogramValue map[float64]uint64
SummaryValue map[float64]float64
// Histograms and Summaries need a count and a sum
Count uint64
Sum float64
// Expiration is the deadline that this Sample is valid until.
Expiration time.Time
}
// MetricFamily contains the data required to build valid prometheus Metrics.
type MetricFamily struct {
// Samples are the Sample belonging to this MetricFamily.
Samples map[SampleID]*Sample
// Need the telegraf ValueType because there isn't a Prometheus ValueType
// representing Histogram or Summary
TelegrafValueType telegraf.ValueType
// LabelSet is the label counts for all Samples.
LabelSet map[string]int
}
type PrometheusClient struct {
Listen string
TLSCert string `toml:"tls_cert"`
TLSKey string `toml:"tls_key"`
BasicUsername string `toml:"basic_username"`
BasicPassword string `toml:"basic_password"`
ExpirationInterval internal.Duration `toml:"expiration_interval"`
Path string `toml:"path"`
CollectorsExclude []string `toml:"collectors_exclude"`
StringAsLabel bool `toml:"string_as_label"`
server *http.Server
sync.Mutex
// fam is the non-expired MetricFamily by Prometheus metric name.
fam map[string]*MetricFamily
// now returns the current time.
now func() time.Time
}
var sampleConfig = `
## Address to listen on
# listen = ":9273"
## Use TLS
#tls_cert = "/etc/ssl/telegraf.crt"
#tls_key = "/etc/ssl/telegraf.key"
## Use http basic authentication
#basic_username = "Foo"
#basic_password = "Bar"
## Interval to expire metrics and not deliver to prometheus, 0 == no expiration
# expiration_interval = "60s"
## Collectors to enable, valid entries are "gocollector" and "process".
## If unset, both are enabled.
collectors_exclude = ["gocollector", "process"]
# Send string metrics as Prometheus labels.
# Unless set to false all string metrics will be sent as labels.
string_as_label = true
`
func (p *PrometheusClient) basicAuth(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if p.BasicUsername != "" && p.BasicPassword != "" {
w.Header().Set("WWW-Authenticate", `Basic realm="Restricted"`)
username, password, ok := r.BasicAuth()
if !ok ||
subtle.ConstantTimeCompare([]byte(username), []byte(p.BasicUsername)) != 1 ||
subtle.ConstantTimeCompare([]byte(password), []byte(p.BasicPassword)) != 1 {
http.Error(w, "Not authorized", 401)
return
}
}
h.ServeHTTP(w, r)
})
}
func (p *PrometheusClient) Start() error {
defaultCollectors := map[string]bool{
"gocollector": true,
"process": true,
}
for _, collector := range p.CollectorsExclude {
delete(defaultCollectors, collector)
}
registry := prometheus.NewRegistry()
for collector, _ := range defaultCollectors {
switch collector {
case "gocollector":
registry.Register(prometheus.NewGoCollector())
case "process":
registry.Register(prometheus.NewProcessCollector(os.Getpid(), ""))
default:
return fmt.Errorf("unrecognized collector %s", collector)
}
}
registry.Register(p)
if p.Listen == "" {
p.Listen = "localhost:9273"
}
if p.Path == "" {
p.Path = "/metrics"
}
mux := http.NewServeMux()
mux.Handle(p.Path, p.basicAuth(promhttp.HandlerFor(
registry, promhttp.HandlerOpts{ErrorHandling: promhttp.ContinueOnError})))
p.server = &http.Server{
Addr: p.Listen,
Handler: mux,
}
go func() {
var err error
if p.TLSCert != "" && p.TLSKey != "" {
err = p.server.ListenAndServeTLS(p.TLSCert, p.TLSKey)
} else {
err = p.server.ListenAndServe()
}
if err != nil && err != http.ErrServerClosed {
log.Printf("E! Error creating prometheus metric endpoint, err: %s\n",
err.Error())
}
}()
return nil
}
func (p *PrometheusClient) Stop() {
// plugin gets cleaned up in Close() already.
}
func (p *PrometheusClient) Connect() error {
// This service output does not need to make any further connections
return nil
}
func (p *PrometheusClient) Close() error {
ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
defer cancel()
err := p.server.Shutdown(ctx)
prometheus.Unregister(p)
return err
}
func (p *PrometheusClient) SampleConfig() string {
return sampleConfig
}
func (p *PrometheusClient) Description() string {
return "Configuration for the Prometheus client to spawn"
}
// Implements prometheus.Collector
func (p *PrometheusClient) Describe(ch chan<- *prometheus.Desc) {
prometheus.NewGauge(prometheus.GaugeOpts{Name: "Dummy", Help: "Dummy"}).Describe(ch)
}
// Expire removes Samples that have expired.
func (p *PrometheusClient) Expire() {
now := p.now()
for name, family := range p.fam {
for key, sample := range family.Samples {
if p.ExpirationInterval.Duration != 0 && now.After(sample.Expiration) {
for k, _ := range sample.Labels {
family.LabelSet[k]--
}
delete(family.Samples, key)
if len(family.Samples) == 0 {
delete(p.fam, name)
}
}
}
}
}
// Collect implements prometheus.Collector
func (p *PrometheusClient) Collect(ch chan<- prometheus.Metric) {
p.Lock()
defer p.Unlock()
p.Expire()
for name, family := range p.fam {
// Get list of all labels on MetricFamily
var labelNames []string
for k, v := range family.LabelSet {
if v > 0 {
labelNames = append(labelNames, k)
}
}
desc := prometheus.NewDesc(name, "Telegraf collected metric", labelNames, nil)
for _, sample := range family.Samples {
// Get labels for this sample; unset labels will be set to the
// empty string
var labels []string
for _, label := range labelNames {
v := sample.Labels[label]
labels = append(labels, v)
}
var metric prometheus.Metric
var err error
switch family.TelegrafValueType {
case telegraf.Summary:
metric, err = prometheus.NewConstSummary(desc, sample.Count, sample.Sum, sample.SummaryValue, labels...)
case telegraf.Histogram:
metric, err = prometheus.NewConstHistogram(desc, sample.Count, sample.Sum, sample.HistogramValue, labels...)
default:
metric, err = prometheus.NewConstMetric(desc, getPromValueType(family.TelegrafValueType), sample.Value, labels...)
}
if err != nil {
log.Printf("E! Error creating prometheus metric, "+
"key: %s, labels: %v,\nerr: %s\n",
name, labels, err.Error())
}
ch <- metric
}
}
}
func sanitize(value string) string {
return invalidNameCharRE.ReplaceAllString(value, "_")
}
func getPromValueType(tt telegraf.ValueType) prometheus.ValueType {
switch tt {
case telegraf.Counter:
return prometheus.CounterValue
case telegraf.Gauge:
return prometheus.GaugeValue
default:
return prometheus.UntypedValue
}
}
// CreateSampleID creates a SampleID based on the tags of a telegraf.Metric.
func CreateSampleID(tags map[string]string) SampleID {
pairs := make([]string, 0, len(tags))
for k, v := range tags {
pairs = append(pairs, fmt.Sprintf("%s=%s", k, v))
}
sort.Strings(pairs)
return SampleID(strings.Join(pairs, ","))
}
func addSample(fam *MetricFamily, sample *Sample, sampleID SampleID) {
for k, _ := range sample.Labels {
fam.LabelSet[k]++
}
fam.Samples[sampleID] = sample
}
func (p *PrometheusClient) addMetricFamily(point telegraf.Metric, sample *Sample, mname string, sampleID SampleID) {
var fam *MetricFamily
var ok bool
if fam, ok = p.fam[mname]; !ok {
fam = &MetricFamily{
Samples: make(map[SampleID]*Sample),
TelegrafValueType: point.Type(),
LabelSet: make(map[string]int),
}
p.fam[mname] = fam
}
addSample(fam, sample, sampleID)
}
func (p *PrometheusClient) Write(metrics []telegraf.Metric) error {
p.Lock()
defer p.Unlock()
now := p.now()
for _, point := range metrics {
tags := point.Tags()
sampleID := CreateSampleID(tags)
labels := make(map[string]string)
for k, v := range tags {
labels[sanitize(k)] = v
}
// Prometheus doesn't have a string value type, so convert string
// fields to labels if enabled.
if p.StringAsLabel {
for fn, fv := range point.Fields() {
switch fv := fv.(type) {
case string:
labels[sanitize(fn)] = fv
}
}
}
switch point.Type() {
case telegraf.Summary:
var mname string
var sum float64
var count uint64
summaryvalue := make(map[float64]float64)
for fn, fv := range point.Fields() {
var value float64
switch fv := fv.(type) {
case int64:
value = float64(fv)
case uint64:
value = float64(fv)
case float64:
value = fv
default:
continue
}
switch fn {
case "sum":
sum = value
case "count":
count = uint64(value)
default:
limit, err := strconv.ParseFloat(fn, 64)
if err == nil {
summaryvalue[limit] = value
}
}
}
sample := &Sample{
Labels: labels,
SummaryValue: summaryvalue,
Count: count,
Sum: sum,
Expiration: now.Add(p.ExpirationInterval.Duration),
}
mname = sanitize(point.Name())
p.addMetricFamily(point, sample, mname, sampleID)
case telegraf.Histogram:
var mname string
var sum float64
var count uint64
histogramvalue := make(map[float64]uint64)
for fn, fv := range point.Fields() {
var value float64
switch fv := fv.(type) {
case int64:
value = float64(fv)
case uint64:
value = float64(fv)
case float64:
value = fv
default:
continue
}
switch fn {
case "sum":
sum = value
case "count":
count = uint64(value)
default:
limit, err := strconv.ParseFloat(fn, 64)
if err == nil {
histogramvalue[limit] = uint64(value)
}
}
}
sample := &Sample{
Labels: labels,
HistogramValue: histogramvalue,
Count: count,
Sum: sum,
Expiration: now.Add(p.ExpirationInterval.Duration),
}
mname = sanitize(point.Name())
p.addMetricFamily(point, sample, mname, sampleID)
default:
for fn, fv := range point.Fields() {
// Ignore string and bool fields.
var value float64
switch fv := fv.(type) {
case int64:
value = float64(fv)
case uint64:
value = float64(fv)
case float64:
value = fv
default:
continue
}
sample := &Sample{
Labels: labels,
Value: value,
Expiration: now.Add(p.ExpirationInterval.Duration),
}
// Special handling of value field; supports passthrough from
// the prometheus input.
var mname string
switch point.Type() {
case telegraf.Counter:
if fn == "counter" {
mname = sanitize(point.Name())
}
case telegraf.Gauge:
if fn == "gauge" {
mname = sanitize(point.Name())
}
}
if mname == "" {
if fn == "value" {
mname = sanitize(point.Name())
} else {
mname = sanitize(fmt.Sprintf("%s_%s", point.Name(), fn))
}
}
p.addMetricFamily(point, sample, mname, sampleID)
}
}
}
return nil
}
func init() {
outputs.Add("prometheus_client", func() telegraf.Output {
return &PrometheusClient{
ExpirationInterval: internal.Duration{Duration: time.Second * 60},
StringAsLabel: true,
fam: make(map[string]*MetricFamily),
now: time.Now,
}
})
}