Add cli options to print version

Signed-off-by: Yilun <[email protected]>

Makefile

@@ -1,7 +1,8 @@
 .DEFAULT_GOAL:=local_or_with_proxy
 
 USE_PROXY=GOPROXY=https://goproxy.io
-BUILD=go build -ldflags "-s -w"
+VERSION:=$(shell git describe --abbrev=7 --dirty --always --tags)
+BUILD=go build -ldflags "-s -w -X main.Version=$(VERSION)"
 BUILD_DIR=build
 BIN_DIR=$(GOOS)-$(GOARCH)
 BIN_NAME=nkn-tunnel

bin/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/hex"
 	"flag"
+	"fmt"
 	"log"
 	"strings"
 
@@ -12,6 +13,10 @@ import (
 	"github.com/nknorg/tuna"
 )
 
+var (
+	Version string
+)
+
 func main() {
 	numClients := flag.Int("n", 4, "number of clients")
 	seedHex := flag.String("s", "", "secret seed")
@@ -23,9 +28,15 @@ func main() {
 	tunaMaxPrice := flag.String("tuna-max-price", "0.01", "tuna max price in unit of NKN/MB")
 	mtu := flag.Int("mtu", 0, "ncp session mtu")
 	verbose := flag.Bool("v", false, "show logs on dialing/accepting connection")
+	version := flag.Bool("version", false, "print version")
 
 	flag.Parse()
 
+	if *version {
+		fmt.Println(Version)
+		return
+	}
+
 	if len(*from) == 0 {
 		log.Fatal("From address is empty")
 	}