add version flag to tiller binary (#2965)

add version flag to tiller binary

* TODO comment on tiller.go

cmd/tiller/tiller.go

@@ -77,6 +77,7 @@ var (
 	certFile             = flag.String("tls-cert", tlsDefaultsFromEnv("tls-cert"), "path to TLS certificate file")
 	caCertFile           = flag.String("tls-ca-cert", tlsDefaultsFromEnv("tls-ca-cert"), "trust certificates signed by this CA")
 	maxHistory           = flag.Int("history-max", historyMaxFromEnv(), "maximum number of releases kept in release history, with 0 meaning no limit")
+	printVersion         = flag.Bool("version", false, "print the version number")
 
 	// rootServer is the root gRPC server.
 	//
@@ -92,8 +93,14 @@ var (
 )
 
 func main() {
+	// TODO: use spf13/cobra for tiller instead of flags
 	flag.Parse()
 
+	if *printVersion {
+		fmt.Println(version.GetVersion())
+		os.Exit(0)
+	}
+
 	if *enableTracing {
 		log.SetFlags(log.Lshortfile)
 	}