add pprof performance profiling support

Add --pprof command line option to enable performance profiling

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

config.go

@@ -44,6 +44,7 @@ type Config struct {
 	LocalAuth            bool
 	Password             string
 	AllowOrigins         bool
+	PprofAddr            string
 }
 
 func (cfg *Config) Parse(c *cli.Command) error {
@@ -66,6 +67,7 @@ func (cfg *Config) Parse(c *cli.Command) error {
 	getFlagOpt(c, "token", &cfg.Token)
 	getFlagOpt(c, "password", &cfg.Password)
 	getFlagOpt(c, "allow-origins", &cfg.AllowOrigins)
+	getFlagOpt(c, "pprof", &cfg.PprofAddr)
 
 	return nil
 }

main.go

@@ -26,6 +26,7 @@ package main
 
 import (
 	"context"
+	_ "net/http/pprof"
 	"os"
 	"runtime"
 	"runtime/debug"
@@ -118,6 +119,10 @@ func main() {
 				Name:  "allow-origins",
 				Usage: "allow all origins for cross-domain request",
 			},
+			&cli.StringFlag{
+				Name:  "pprof",
+				Usage: "enable pprof and listen on specified address (e.g. localhost:6060)",
+			},
 			&cli.BoolFlag{
 				Name:    "verbose",
 				Aliases: []string{"V"},

server.go

@@ -25,6 +25,8 @@
 package main
 
 import (
+	"net"
+	"net/http"
 	"sync"
 	"sync/atomic"
 
@@ -46,12 +48,39 @@ type DeviceGroup struct {
 func (srv *RttyServer) Run() error {
 	log.Debug().Msgf("%+v", srv.cfg)
 
+	if srv.cfg.PprofAddr != "" {
+		go srv.ListenPprof()
+	}
+
 	go srv.ListenDevices()
 	go srv.ListenHttpProxy()
 
 	return srv.ListenAPI()
 }
 
+func (srv *RttyServer) ListenPprof() {
+	ln, err := net.Listen("tcp", srv.cfg.PprofAddr)
+	if err != nil {
+		log.Error().Err(err).Msgf("Failed to start pprof server")
+		return
+	}
+	defer ln.Close()
+
+	addr := ln.Addr().(*net.TCPAddr)
+	log.Info().Msgf("Starting pprof server on: %s", addr)
+
+	host := addr.IP.String()
+	if host == "0.0.0.0" || host == "::" {
+		host = "localhost"
+	}
+	log.Info().Msgf("Access pprof at: http://%s:%d/debug/pprof/", host, addr.Port)
+
+	err = http.Serve(ln, nil)
+	if err != nil {
+		log.Error().Err(err).Msgf("pprof server failed")
+	}
+}
+
 func (srv *RttyServer) GetDevice(group, id string) *Device {
 	srv.mu.RLock()
 	defer srv.mu.RUnlock()