mirror of
https://github.com/pomerium/pomerium.git
synced 2025-05-05 05:16:04 +02:00
83 lines
2.3 KiB
Go
83 lines
2.3 KiB
Go
package metrics
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import (
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"fmt"
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"io/ioutil"
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"net/http"
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"net/url"
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ocprom "contrib.go.opencensus.io/exporter/prometheus"
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prom "github.com/prometheus/client_golang/prometheus"
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"go.opencensus.io/stats/view"
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"github.com/pomerium/pomerium/internal/envoy"
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log "github.com/pomerium/pomerium/internal/log"
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"github.com/pomerium/pomerium/internal/urlutil"
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)
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var envoyURL = envoy.EnvoyAdminURL
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// PrometheusHandler creates an exporter that exports stats to Prometheus
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// and returns a handler suitable for exporting metrics.
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func PrometheusHandler() (http.Handler, error) {
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if err := registerDefaultViews(); err != nil {
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return nil, fmt.Errorf("telemetry/metrics: failed registering views")
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}
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reg := prom.DefaultRegisterer.(*prom.Registry)
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exporter, err := ocprom.NewExporter(
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ocprom.Options{
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Namespace: "pomerium",
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Registry: reg,
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})
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if err != nil {
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return nil, fmt.Errorf("telemetry/metrics: prometheus exporter: %w", err)
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}
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view.RegisterExporter(exporter)
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mux := http.NewServeMux()
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envoyMetricsURL, err := urlutil.ParseAndValidateURL(fmt.Sprintf("%s/stats/prometheus", envoyURL))
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if err != nil {
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return nil, fmt.Errorf("telemetry/metrics: invalid proxy URL: %w", err)
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}
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mux.Handle("/metrics", newProxyMetricsHandler(exporter, *envoyMetricsURL))
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return mux, nil
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}
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func registerDefaultViews() error {
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var views []*view.View
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for _, v := range DefaultViews {
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views = append(views, v...)
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}
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return view.Register(views...)
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}
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// newProxyMetricsHandler creates a subrequest to the envoy control plane for metrics and
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// combines them with our own
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func newProxyMetricsHandler(promHandler http.Handler, envoyURL url.URL) http.HandlerFunc {
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return func(w http.ResponseWriter, r *http.Request) {
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defer promHandler.ServeHTTP(w, r)
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r, err := http.NewRequestWithContext(r.Context(), "GET", envoyURL.String(), nil)
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if err != nil {
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log.Error().Err(err).Msg("telemetry/metrics: failed to create request for envoy")
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return
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}
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resp, err := http.DefaultClient.Do(r)
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if err != nil {
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log.Error().Err(err).Msg("telemetry/metrics: fail to fetch proxy metrics")
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return
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}
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defer resp.Body.Close()
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envoyBody, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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log.Error().Err(err).Msg("telemetry/metric: failed to read proxy metrics")
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return
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}
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w.Write(envoyBody)
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}
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}
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