Add --version and print the version atop every help and error screen

cmd/gpu-turnstile/main.go

@@ -44,9 +44,9 @@ func stdoutIsTerminal() bool {
 }
 
 // parseFlags extracts -config <path> (or -config=<path>), the
-// --install-service / --remove-service switches, --no-copy, -h/--help and
-// the hidden --elevated-child marker from args.
-func parseFlags(args []string) (configPath string, install, remove, noCopy, help, elevatedChild bool, rest []string) {
+// --install-service / --remove-service switches, --no-copy, -h/--help,
+// -v/--version and the hidden --elevated-child marker from args.
+func parseFlags(args []string) (configPath string, install, remove, noCopy, help, showVersion, elevatedChild bool, rest []string) {
 	rest = args[:0]
 	for i := 0; i < len(args); i++ {
 		switch {
@@ -63,21 +63,27 @@ func parseFlags(args []string) (configPath string, install, remove, noCopy, help
 			noCopy = true
 		case args[i] == "-h" || args[i] == "--help" || args[i] == "-help":
 			help = true
+		case args[i] == "-v" || args[i] == "--version" || args[i] == "-version":
+			showVersion = true
 		case args[i] == "--elevated-child":
 			elevatedChild = true
 		default:
 			rest = append(rest, args[i])
 		}
 	}
-	return configPath, install, remove, noCopy, help, elevatedChild, rest
+	return configPath, install, remove, noCopy, help, showVersion, elevatedChild, rest
 }
 
-const usageText = `gpu-turnstile — GPU arbitration proxy for Ollama + ComfyUI
+// versionLine is printed at the top of every help and error screen.
+func versionLine() string { return "gpu-turnstile " + version }
+
+const usageText = `GPU arbitration proxy for Ollama + ComfyUI
 
 Usage:
   gpu-turnstile -config <path>                                run the proxy
   gpu-turnstile --install-service [--no-copy] [-config path]  install + start as a service
   gpu-turnstile --remove-service                              stop + uninstall the service
+  gpu-turnstile -v | --version                                print just the version
   gpu-turnstile -h | --help                                   this help
 
 Options:
@@ -92,22 +98,40 @@ All runtime settings are environment variables or KEY=VALUE lines in the
 config file (OLLAMA_URL, COMFY_URL, LOGLEVEL, ...); see README.md.
 `
 
+// printHelp prints the version header plus the full help text.
+func printHelp() {
+	fmt.Printf("%s — %s", versionLine(), usageText)
+}
+
+// fatalUsage prints the version header, an error message and the one-line
+// usage summary, then exits with code 2.
+func fatalUsage(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, "%s\n\n", versionLine())
+	fmt.Fprintf(os.Stderr, format+"\n\n", args...)
+	fmt.Fprintln(os.Stderr, "usage: gpu-turnstile [-config path] [--install-service [--no-copy] | --remove-service]")
+	fmt.Fprintln(os.Stderr, "       gpu-turnstile service install|remove [-config path]")
+	os.Exit(2)
+}
+
 func main() {
-	configPath, install, remove, noCopy, help, elevatedChild, args := parseFlags(os.Args[1:])
+	configPath, install, remove, noCopy, help, showVersion, elevatedChild, args := parseFlags(os.Args[1:])
+	if showVersion {
+		fmt.Println(version)
+		return
+	}
 	bare := configPath == "" && !install && !remove && !elevatedChild && len(args) == 0
 	if help || (bare && stdoutIsTerminal()) {
 		// Bare invocation in a terminal (e.g. double-clicked on Windows)
 		// shows the help instead of starting a proxy window with no visible
 		// explanation. Without a terminal — Docker containers, services,
 		// pipes — a bare invocation starts the proxy as before.
-		fmt.Print(usageText)
+		printHelp()
 		return
 	}
 	if len(args) > 0 && args[0] == "service" {
 		// Legacy subcommand form: gpu-turnstile service install|remove.
 		if len(args) != 2 || (args[1] != "install" && args[1] != "remove") {
-			fmt.Fprintf(os.Stderr, "usage: gpu-turnstile service install|remove [-config path]\n")
-			os.Exit(2)
+			fatalUsage("error: expected 'service install' or 'service remove'")
 		}
 		install = args[1] == "install"
 		remove = !install
@@ -115,17 +139,14 @@ func main() {
 	}
 	switch {
 	case install && remove:
-		fmt.Fprintf(os.Stderr, "gpu-turnstile: --install-service and --remove-service are mutually exclusive\n")
-		os.Exit(2)
+		fatalUsage("error: --install-service and --remove-service are mutually exclusive")
 	case install:
 		os.Exit(serviceCommand(configPath, true, noCopy, elevatedChild))
 	case remove:
 		os.Exit(serviceCommand(configPath, false, noCopy, elevatedChild))
 	}
 	if len(args) > 0 {
-		fmt.Fprintf(os.Stderr, "usage: gpu-turnstile [-config path] [--install-service [--no-copy] | --remove-service]\n")
-		fmt.Fprintf(os.Stderr, "       gpu-turnstile service install|remove [-config path]\n")
-		os.Exit(2)
+		fatalUsage("error: unknown arguments: %s", strings.Join(args, " "))
 	}
 
 	if exePath, err := os.Executable(); err == nil {
@@ -134,7 +155,7 @@ func main() {
 
 	cfg, err := loadMergedConfig(configPath)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "gpu-turnstile: %v\n", err)
+		fmt.Fprintf(os.Stderr, "%s\n\ngpu-turnstile: %v\n", versionLine(), err)
 		os.Exit(1)
 	}
 	log, logOut, logCloser := newLogger(cfg)