guide: Skill for Claude Code

Scaffold a new Go backend project following Clean Architecture with domain/infrastructure separation, Dig DI, testify testing, and standard naming conventions.

For detailed Go conventions, refer to the Go rule. For architecture patterns, refer to the Architecture rule. For testing standards, refer to the Testing rule. For Makefile setup, refer to the CI/CD rule.

Directory Structure

Create the following layout:

<project>/
├── cmd/
│   └── <app>/
│       ├── main.go
│       └── dig.go
├── internal/
│   ├── container.go
│   ├── domain/
│   │   ├── commands/
│   │   │   └── container.go
│   │   ├── entities/
│   │   │   └── container.go
│   │   └── repositories/
│   └── infrastructure/
│       ├── controllers/
│       │   ├── container.go
│       │   ├── mappers/
│       │   ├── requests/
│       │   └── responses/
│       └── repositories/
│           ├── container.go
│           ├── mappers/
│           └── models/
├── test/
│   ├── domain/
│   │   ├── builders/
│   │   ├── doubles/
│   │   │   └── repositories/
│   │   └── helpers/
│   └── infrastructure/
│       └── doubles/
│           └── repositories/
├── go.mod
├── go.sum
├── Makefile
└── README.md

Step-by-Step

1. Initialize the module

mkdir <project> && cd <project>
go mod init <module-path>

2. Create the domain layer -- entities (pure, no framework tags)

// internal/domain/entities/user.go
package entities

type User struct {
    ID    string
    Name  string
    Email string
}

3. Create repository contracts

// internal/domain/repositories/users_repository.go
package repositories

import "module/internal/domain/entities"

type UsersRepository interface {
    FindAll() ([]entities.User, error)
    FindByID(id string) (*entities.User, error)
    Insert(entity *entities.User) error
}

4. Create commands (business logic)

// internal/domain/commands/list_users_command.go
package commands

import (
    "module/internal/domain/entities"
    "module/internal/domain/repositories"
)

type ListUsersCommand struct {
    repo repositories.UsersRepository
}

func NewListUsersCommand(repo repositories.UsersRepository) *ListUsersCommand {
    return &ListUsersCommand{repo: repo}
}

func (c *ListUsersCommand) Execute() ([]entities.User, error) {
    return c.repo.FindAll()
}