Project Structure

A practical Go project layout starts small and grows when package boundaries become useful.

For a tiny command-line program, go.mod and main.go are sufficient. Larger repositories commonly place executable entry points in cmd/, share public package code in appropriate directories, and reserve internal/ for packages that Go intentionally restricts to eligible importers.

No single directory layout is mandatory. Design around responsibilities and the number of programs, rather than copying a large template on day one. Tests conventionally live alongside the code they test as _test.go files.

Follow this diagram before executing the example. Check where a value or decision changes what runs next.

Example as a project grows

myapp/
  go.mod
  cmd/
    server/
      main.go
  internal/
    config/
      config.go
  README.md

The layout is an option, not a Go requirement. More details: Organizing a Go module.

This example is a complete program. Save it as main.go or paste it into the Go Playground.

Go code

package main

import "fmt"

type Config struct{ AppName string }

func printBanner(c Config) { fmt.Println("App:", c.AppName) }
func main()                { printBanner(Config{AppName: "go-tools"}) }

Output

App: go-tools

The program separates configuration data and a printing function without splitting it into unnecessary packages. If the project grows, those responsibilities can be moved into new directories.

• Go does not require src/ inside every module.
• internal/ is a special import-visibility convention, not merely a descriptive folder name.

Sketch a two-command repository using cmd/server and cmd/worker, plus an internal/config package.

Tip: Edit the example above, predict the output, and run the modified code to test your reasoning.

You have practiced Go Project Structure in a small, self-contained program. The important habit is to predict what runs, inspect the actual output and distinguish the language rule from the particular example.

Before continuing, make sure you can explain the program to someone who has not seen it, including the line that changes its result.