98 lines
2.6 KiB
Go
98 lines
2.6 KiB
Go
package metrics
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import (
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"context"
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"fmt"
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"net"
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"net/http"
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_ "net/http/pprof"
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"runtime"
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"sync"
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"time"
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"github.com/gorilla/mux"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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"github.com/rs/zerolog"
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"golang.org/x/net/trace"
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)
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const (
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shutdownTimeout = time.Second * 15
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startupTime = time.Millisecond * 500
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)
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func newMetricsHandler(readyServer *ReadyServer, quickTunnelHostname string) *mux.Router {
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router := mux.NewRouter()
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router.PathPrefix("/debug/").Handler(http.DefaultServeMux)
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router.Handle("/metrics", promhttp.Handler())
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router.HandleFunc("/healthcheck", func(w http.ResponseWriter, r *http.Request) {
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_, _ = fmt.Fprintf(w, "OK\n")
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})
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if readyServer != nil {
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router.Handle("/ready", readyServer)
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}
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router.HandleFunc("/quicktunnel", func(w http.ResponseWriter, r *http.Request) {
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_, _ = fmt.Fprintf(w, `{"hostname":"%s"}`, quickTunnelHostname)
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})
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return router
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}
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func ServeMetrics(
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l net.Listener,
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shutdownC <-chan struct{},
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readyServer *ReadyServer,
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quickTunnelHostname string,
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log *zerolog.Logger,
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) (err error) {
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var wg sync.WaitGroup
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// Metrics port is privileged, so no need for further access control
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trace.AuthRequest = func(*http.Request) (bool, bool) { return true, true }
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// TODO: parameterize ReadTimeout and WriteTimeout. The maximum time we can
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// profile CPU usage depends on WriteTimeout
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h := newMetricsHandler(readyServer, quickTunnelHostname)
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server := &http.Server{
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ReadTimeout: 10 * time.Second,
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WriteTimeout: 10 * time.Second,
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Handler: h,
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}
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wg.Add(1)
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go func() {
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defer wg.Done()
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err = server.Serve(l)
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}()
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log.Info().Msgf("Starting metrics server on %s", fmt.Sprintf("%v/metrics", l.Addr()))
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// server.Serve will hang if server.Shutdown is called before the server is
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// fully started up. So add artificial delay.
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time.Sleep(startupTime)
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<-shutdownC
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ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
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_ = server.Shutdown(ctx)
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cancel()
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wg.Wait()
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if err == http.ErrServerClosed {
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log.Info().Msg("Metrics server stopped")
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return nil
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}
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log.Err(err).Msg("Metrics server failed")
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return err
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}
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func RegisterBuildInfo(buildTime string, version string) {
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buildInfo := prometheus.NewGaugeVec(
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prometheus.GaugeOpts{
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// Don't namespace build_info, since we want it to be consistent across all Cloudflare services
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Name: "build_info",
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Help: "Build and version information",
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},
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[]string{"goversion", "revision", "version"},
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)
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prometheus.MustRegister(buildInfo)
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buildInfo.WithLabelValues(runtime.Version(), buildTime, version).Set(1)
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}
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