[#667] node: Add --version flag support

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

cmd/neofs-node/main.go

@@ -5,6 +5,7 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"os"
 	"os/signal"
 	"syscall"
 
@@ -13,6 +14,11 @@ import (
 	"go.uber.org/zap"
 )
 
+const (
+	// SuccessReturnCode returns when application closed without panic
+	SuccessReturnCode = 0
+)
+
 // prints err to standard logger and calls os.Exit(1).
 func fatalOnErr(err error) {
 	if err != nil {
@@ -29,8 +35,20 @@ func fatalOnErrDetails(details string, err error) {
 
 func main() {
 	configFile := flag.String("config", "", "path to config")
+	versionFlag := flag.Bool("version", false, "neofs-ir node version")
 	flag.Parse()
 
+	if *versionFlag {
+		fmt.Printf(
+			"Version: %s \nBuild: %s \nDebug: %s\n",
+			misc.Version,
+			misc.Build,
+			misc.Debug,
+		)
+
+		os.Exit(SuccessReturnCode)
+	}
+
 	c := initCfg(*configFile)
 
 	initApp(c)