switch prometheus listener to fasthttp

pkg/metrics/server.go

@@ -3,7 +3,6 @@
 package metrics
 
 import (
-	"context"
 	"errors"
 	"net/http"
 	"net/http/pprof"
@@ -11,13 +10,16 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/fasthttp/router"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/valyala/fasthttp"
+	"github.com/valyala/fasthttp/fasthttpadaptor"
 
 	"github.com/sot-tech/mochi/pkg/log"
 )
 
 const (
-	readTimeout  = 5 * time.Second
+	readTimeout  = time.Minute
 	writeTimeout = readTimeout * 2
 )
 
@@ -34,7 +36,7 @@ func Enabled() bool {
 // Server represents a standalone HTTP server for serving a Prometheus metrics
 // endpoint.
 type Server struct {
-	srv *http.Server
+	srv *fasthttp.Server
 }
 
 // AddressFamily returns the label value for reporting the address family of an IP address.
@@ -51,35 +53,37 @@ func AddressFamily(ip netip.Addr) string {
 
 // Close shuts down the server.
 func (s *Server) Close() error {
-	return s.srv.Shutdown(context.Background())
+	return s.srv.Shutdown()
 }
 
 // NewServer creates a new instance of a Prometheus server that asynchronously
 // serves requests.
 func NewServer(addr string) *Server {
-	mux := http.NewServeMux()
+	if len(addr) == 0 {
+		panic("metrics listen address not provided")
+	}
 
-	mux.Handle("/metrics", promhttp.Handler())
-	mux.HandleFunc("/debug/pprof/", pprof.Index)
-	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
-	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
-	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
-	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+	r := router.New()
+	r.GET("/metrics", fasthttpadaptor.NewFastHTTPHandler(promhttp.Handler()))
+	r.GET("/debug/pprof/", fasthttpadaptor.NewFastHTTPHandlerFunc(pprof.Index))
+	r.GET("/debug/pprof/cmdline", fasthttpadaptor.NewFastHTTPHandlerFunc(pprof.Cmdline))
+	r.GET("/debug/pprof/profile", fasthttpadaptor.NewFastHTTPHandlerFunc(pprof.Profile))
+	r.GET("/debug/pprof/symbol", fasthttpadaptor.NewFastHTTPHandlerFunc(pprof.Symbol))
+	r.GET("/debug/pprof/trace", fasthttpadaptor.NewFastHTTPHandlerFunc(pprof.Trace))
 
 	s := &Server{
-		srv: &http.Server{
-			Addr:              addr,
-			Handler:           mux,
-			ReadTimeout:       readTimeout,
-			ReadHeaderTimeout: readTimeout,
-			WriteTimeout:      writeTimeout,
+		srv: &fasthttp.Server{
+			Handler:      r.Handler,
+			GetOnly:      true,
+			ReadTimeout:  readTimeout,
+			WriteTimeout: writeTimeout,
 		},
 	}
 
 	go func() {
 		atomic.AddInt32(serverCounter, 1)
 		defer atomic.AddInt32(serverCounter, -1)
-		if err := s.srv.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
+		if err := s.srv.ListenAndServe(addr); !errors.Is(err, http.ErrServerClosed) {
 			logger.Error().Err(err).Msg("failed while serving prometheus")
 		}
 	}()