Add way to dynamically profile

Added new `--http-pprof` option, example: "--http-pprof :8181"
It starts web server on given address, and expose special /debug/pprof
endpoint

See https://golang.org/pkg/net/http/pprof/

gor.go

@@ -9,6 +9,7 @@ import (
 	"log"
 	"net/http"
 	"net/http/httputil"
+	_ "net/http/pprof"
 	"os"
 	"os/signal"
 	"runtime"
@@ -77,6 +78,12 @@ func main() {
 		profileCPU(*cpuprofile)
 	}
 
+	if Settings.pprof != "" {
+		go func() {
+			log.Println(http.ListenAndServe(Settings.pprof, nil))
+		}()
+	}
+
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
 	go func() {

settings.go

@@ -30,6 +30,8 @@ type AppSettings struct {
 	stats     bool
 	exitAfter time.Duration
 
+	pprof string
+
 	splitOutput bool
 
 	inputDummy   MultiOption
@@ -83,6 +85,7 @@ func usage() {
 func init() {
 	flag.Usage = usage
 
+	flag.StringVar(&Settings.pprof, "http-pprof", "", "Enable profiling. Starts  http server on specified port, exposing special /debug/pprof endpoint. Example: `:8181`")
 	flag.BoolVar(&Settings.verbose, "verbose", false, "Turn on more verbose output")
 	flag.BoolVar(&Settings.debug, "debug", false, "Turn on debug output, shows all intercepted traffic. Works only when with `verbose` flag")
 	flag.BoolVar(&Settings.stats, "stats", false, "Turn on queue stats output")