adds "version" command to print build-time embedded git version tag i…

…nto console

Makefile

@@ -1,9 +1,10 @@
 VERSION := $(shell git describe --tags --always --dirty)
+LDFLAGS := -ldflags "-X 'main.Version=$(VERSION)'"
 
 .PHONY: build
 
 build:
 	mkdir -p build/$(VERSION)
-	GOOS=darwin GOARCH=amd64 go build -o build/$(VERSION)/ovpn-auth-darwin-x64 ./cmd/ovpn-auth
-	GOOS=darwin GOARCH=arm64 go build -o build/$(VERSION)/ovpn-auth-darwin-arm ./cmd/ovpn-auth
-	GOOS=linux GOARCH=amd64 go build -o build/$(VERSION)/ovpn-auth-linux-x64 ./cmd/ovpn-auth
+	GOOS=darwin GOARCH=amd64 go build $(LDFLAGS) -o build/$(VERSION)/ovpn-auth-darwin-x64 ./cmd/ovpn-auth
+	GOOS=darwin GOARCH=arm64 go build $(LDFLAGS) -o build/$(VERSION)/ovpn-auth-darwin-arm ./cmd/ovpn-auth
+	GOOS=linux  GOARCH=amd64 go build $(LDFLAGS) -o build/$(VERSION)/ovpn-auth-linux-x64  ./cmd/ovpn-auth

cmd/ovpn-auth/main.go

@@ -22,6 +22,8 @@ import (
 	"github.com/ufukty/ovpn-auth/internal/register"
 )
 
+var Version = ""
+
 func dispatch() error {
 	if len(os.Args) < 2 {
 		return fmt.Errorf("not enough argument")
@@ -31,6 +33,8 @@ func dispatch() error {
 		if err := register.WithInteraction(); err != nil {
 			return fmt.Errorf("performing registration interaction: %w", err)
 		}
+	case "version":
+		fmt.Println(Version)
 	default:
 		if err := login.WithFile(arg); err != nil {
 			return fmt.Errorf("checking login: %w", err)