telegraf/plugins/outputs/prometheus_client/prometheus_client.go

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package prometheus_client
import (
"fmt"
"log"
"net/http"
"regexp"
"strings"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/outputs"
"github.com/prometheus/client_golang/prometheus"
)
var (
sanitizedChars = strings.NewReplacer("/", "_", "@", "_", " ", "_", "-", "_", ".", "_")
// Prometheus metric names must match this regex
// see https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
metricName = regexp.MustCompile("^[a-zA-Z_:][a-zA-Z0-9_:]*$")
// Prometheus labels must match this regex
// see https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
labelName = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
)
type PrometheusClient struct {
Listen string
metrics map[string]*prometheus.UntypedVec
}
var sampleConfig = `
## Address to listen on
# listen = ":9126"
`
func (p *PrometheusClient) Start() error {
if p.Listen == "" {
p.Listen = "localhost:9126"
}
http.Handle("/metrics", prometheus.Handler())
server := &http.Server{
Addr: p.Listen,
}
p.metrics = make(map[string]*prometheus.UntypedVec)
go server.ListenAndServe()
return nil
}
func (p *PrometheusClient) Stop() {
// TODO: Use a listener for http.Server that counts active connections
// that can be stopped and closed gracefully
}
func (p *PrometheusClient) Connect() error {
// This service output does not need to make any further connections
return nil
}
func (p *PrometheusClient) Close() error {
// This service output does not need to close any of its connections
return nil
}
func (p *PrometheusClient) SampleConfig() string {
return sampleConfig
}
func (p *PrometheusClient) Description() string {
return "Configuration for the Prometheus client to spawn"
}
func (p *PrometheusClient) Write(metrics []telegraf.Metric) error {
if len(metrics) == 0 {
return nil
}
for _, point := range metrics {
key := point.Name()
key = sanitizedChars.Replace(key)
var labels []string
l := prometheus.Labels{}
for k, v := range point.Tags() {
k = sanitizedChars.Replace(k)
if len(k) == 0 {
continue
}
if !labelName.MatchString(k) {
continue
}
labels = append(labels, k)
l[k] = v
}
for n, val := range point.Fields() {
// Ignore string and bool fields.
switch val.(type) {
case string:
continue
case bool:
continue
}
// sanitize the measurement name
n = sanitizedChars.Replace(n)
var mname string
if n == "value" {
mname = key
} else {
mname = fmt.Sprintf("%s_%s", key, n)
}
// verify that it is a valid measurement name
if !metricName.MatchString(mname) {
continue
}
// Create a new metric if it hasn't been created yet.
if _, ok := p.metrics[mname]; !ok {
p.metrics[mname] = prometheus.NewUntypedVec(
prometheus.UntypedOpts{
Name: mname,
Help: "Telegraf collected metric",
},
labels,
)
if err := prometheus.Register(p.metrics[mname]); err != nil {
log.Printf("prometheus_client: Metric failed to register with prometheus, %s", err)
continue
}
}
switch val := val.(type) {
case int64:
m, err := p.metrics[mname].GetMetricWith(l)
if err != nil {
log.Printf("ERROR Getting metric in Prometheus output, "+
"key: %s, labels: %v,\nerr: %s\n",
mname, l, err.Error())
continue
}
m.Set(float64(val))
case float64:
m, err := p.metrics[mname].GetMetricWith(l)
if err != nil {
log.Printf("ERROR Getting metric in Prometheus output, "+
"key: %s, labels: %v,\nerr: %s\n",
mname, l, err.Error())
continue
}
m.Set(val)
default:
continue
}
}
}
return nil
}
func init() {
outputs.Add("prometheus_client", func() telegraf.Output {
return &PrometheusClient{}
})
}