Building a CLI Tool in Go: Part 1 - Project Setup

Every side project starts with optimism. This one started with go mod init and a vague sense of dread.

In this series, we’ll build a real CLI tool in Go — something that actually solves a problem rather than just proving we can parse flags. We’ll use Cobra for the CLI framework and ship it with proper tests and CI.

Project Structure

// main.go
package main

import "github.com/fparch/ddd-cli/cmd"

func main() {
	cmd.Execute()
}

// cmd/root.go
package cmd

import (
	"fmt"
	"os"

	"github.com/spf13/cobra"
)

var rootCmd = &cobra.Command{
	Use:   "ddd",
	Short: "A CLI that does things you probably don't need",
	Long:  `But you'll build it anyway because that's what we do.`,
}

func Execute() {
	if err := rootCmd.Execute(); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

Why Cobra?

Three reasons:

1. Subcommand support out of the box
2. Auto-generated help and completions
3. It’s what kubectl uses, and if it’s good enough for Kubernetes…

What’s Next

In Part 2, we’ll add actual commands and wire up configuration with Viper.

Need help building developer tools or CLI applications? Let’s talk.

AUTHOR

Matthew FitzPatrick

I write about Go, AWS, infrastructure, and developer tools — and I help teams ship modernization without the outages.