How can I get cli arguments just after building?

[EaGitro]

I want to get cli arguments.
I am making GUI app called on the terminal with an argument , and if no arguments are given, it should abort.

for example:

main.go:

package main

import (
	"context"
	"embed"
	// "fmt"
	"os"
	"strings"

	"github.com/wailsapp/wails/v2"
	"github.com/wailsapp/wails/v2/pkg/options"
	"github.com/wailsapp/wails/v2/pkg/options/assetserver"
)

//go:embed all:frontend/dist
var assets embed.FS

func main() {

	app := &App{}

	// if len(os.Args) < 2 {
	// 	panic(fmt.Sprintf("Missing args: ", os.Args))
	// }

	app.path = strings.Join(os.Args, "+")
	println(app.path)

	err := wails.Run(&options.App{
		Title:  "get-cli",
		Width:  1024,
		Height: 768,
		AssetServer: &assetserver.Options{
			Assets: assets,
		},
		BackgroundColour: &options.RGBA{R: 27, G: 38, B: 54, A: 1},
		OnStartup:        app.startup,
		Bind: []interface{}{
			app,
		},
	})

	if err != nil {
		println("Error:", err.Error())
	}
}

type App struct {
	ctx  context.Context
	path string
}

func (a *App) startup(ctx context.Context) {
	a.ctx = ctx
}

// Greet returns a greeting for the given name
func (a *App) GetCliArgs() string {
	return a.path
}

main.ts:

import { GetCliArgs } from '../wailsjs/go/main/App';


GetCliArgs().then((res) => {
    document.querySelector('#app')!.innerHTML = res;
});

shell:

$ wails dev -appargs "arg"
Wails CLI v2.10.1

Executing: go mod tidy
  • Generating bindings: 2025/03/29 11:33:43 /tmp/wailsbindings

Done.
  • Installing frontend dependencies: Done.
  • Compiling frontend: Done.

At first glance, it seems that the app can get arguments successfully.

---

But if these statements are uncommented, it seems that apps cannot get arguments.

// main.go
// uncomments here: 
if len(os.Args) < 2 {
    panic(fmt.Sprintf("Missing args: ", os.Args))
}

# shell
$ wails dev -appargs "arg"
Wails CLI v2.10.1

Executing: go mod tidy
  • Generating bindings:
  ERROR
          panic: Missing args: %!(EXTRA []string=[/tmp/wailsbindings])

          goroutine 1 [running]:
          main.main()
                /home/xxx/xxx/get-cli/main.go:23 +0x2fa

          exit status 2
 ♥   If Wails is useful to you or your company, please consider sponsoring the project:
https://github.com/sponsors/leaanthony

Even wails build fails:

$ wails build
Wails CLI v2.10.1


# Build Options

Platform(s)        | linux/amd64
Compiler           | /usr/bin/go
Skip Bindings      | false
Build Mode         | production
Devtools           | false
Frontend Directory | /home/xxx/xxx/get-cli/frontend
Obfuscated         | false
Skip Frontend      | false
Compress           | false
Package            | true
Clean Bin Dir      | false
LDFlags            |
Tags               | []
Race Detector      | false


# Building target: linux/amd64

  • Generating bindings:   ERROR
          panic: Missing args: %!(EXTRA []string=[/tmp/wailsbindings])

          goroutine 1 [running]:
          main.main()
                /home/xxx/xxx/get-cli/main.go:23 +0x2fa

          exit status 2

  ERROR
          panic: Missing args: %!(EXTRA []string=[/tmp/wailsbindings])

          goroutine 1 [running]:
          main.main()
                /home/xxx/xxx/get-cli/main.go:23 +0x2fa

          exit status 2
 ♥   If Wails is useful to you or your company, please consider sponsoring the project:
https://github.com/sponsors/leaanthony

How can I get cli arguments just after building?

And when are the arguments passed?

[EaGitro]

kron6876 has helped me in official discord sarver.

here is his/her solution:

Wails runs it first (where it first panics) without args then does args on it. There might be an easier way but one solution is to use go build constraints to see if you're in production or dev modes.

Create two files, call them what you want:

1. utils_production.go

//go:build production

package main

func IsProduction() bool {
    return true
}

2. utils_notproduction.go

//go:build !production

package main

func IsProduction() bool {
    return false
}

Now from within your main(), use IsProduction():

fmt.Println("IsProduction:", IsProduction())
fmt.Println("len args:", len(os.Args))
fmt.Println(os.Args)

if IsProduction() {
  // Crash here under 2 if you want
  if len(os.Args) < 2 {
    panic(fmt.Sprintln("Missing args:", os.Args))
  }
}