add version flag

Makefile

@@ -0,0 +1,6 @@
+VERSION=`git describe --tags --dirty --always`
+
+LDFLAGS=-ldflags "-X main.version=${VERSION}"
+
+build:
+	go build ${LDFLAGS} ${OPTS}

config.go

@@ -19,9 +19,10 @@ type config struct {
 	Interface     string   `desc:"name of the wireguard interface to create and manage" default:"wgoverlay"`
 	NoEtcHosts    bool     `id:"no-etc-hosts" desc:"disable writing of entries to /etc/hosts"`
 	LogLevel      string   `id:"log-level" desc:"set the verbosity (debug/info/warn/error)" default:"warn"`
+	Version       bool     `desc:"display current version and exit"`
 
-	// for easier local testing
-	UseIPAsName bool `default:"false" opts:"hidden"`
+	// for easier local testing; will break etchosts entry
+	UseIPAsName bool `id:"ip-as-name" default:"false" opts:"hidden"`
 }
 
 func loadConfig() (*config, error) {

main.go

@@ -1,6 +1,7 @@
 package main // import "github.com/costela/wesher"
 
 import (
+	"fmt"
 	"os"
 	"os/signal"
 	"syscall"
@@ -10,11 +11,17 @@ import (
 	"github.com/costela/wesher/etchosts"
 )
 
+var version = "dev"
+
 func main() {
 	config, err := loadConfig()
 	if err != nil {
 		logrus.Fatal(err)
 	}
+	if config.Version {
+		fmt.Println(version)
+		os.Exit(0)
+	}
 	logLevel, err := logrus.ParseLevel(config.LogLevel)
 	if err != nil {
 		logrus.Fatalf("could not parse loglevel: %s", err)