ifacegen

README

ifacegen

ifacegen is a Go code generation tool that scans Go packages to automatically generate interfaces based on struct method sets. It's particularly useful for creating abstractions such as Service, Repository, or similar patterns.

Features

• Generates interfaces for structs matching configurable name patterns (e.g., *Service, *Repository).
• Skips specific structs or methods via // ifacegen:skip comment.
• Includes structs explicitly marked with // ifacegen:generate, even if their name doesn't match patterns.
• Preserves method comments in the generated interfaces.
• Resolves types using go/types for accurate imports and signatures.
• Handles cross-package imports with proper aliasing.
• Concurrently processes multiple packages for improved performance.
• Outputs one file per package (default name: iface_gen.go).
• Automatically formats and organizes the output with goimports.

Installation

go install github.com/seyyedaghaei/ifacegen@latest

Usage

ifacegen -match '*Service,*Repository' -output iface_gen.go ./...

Flags

Flag	Description
-match	Comma-separated list of glob patterns to match struct names (e.g., *Service).
-output	Output filename used inside each package (default: iface_gen.go).
-name	Pattern for naming interfaces, using {} as the placeholder (default: I{}).
-help	Show usage information.

Skipping and Including Structs or Methods

You can exclude specific structs or methods from interface generation using the // ifacegen:skip comment:

// ifacegen:skip
type AuthService struct {
	// ...
}

// ifacegen:skip
func (s *UserService) InternalLogic() {}

You can explicitly include structs (even if they don't match -match) with the // ifacegen:generate comment:

// ifacegen:generate
type Special struct {
	// ...
}

Example

Given this struct:

// UserService handles user-related operations.
type UserService struct {}

func (s *UserService) CreateUser(name string) error {
	return nil
}

Running:

ifacegen -match '*Service' ./...

Generates:

// UserService handles user-related operations.
type IUserService interface {
	CreateUser(name string) error
}

Output Location

The generated file is written once per package, in the same directory as the structs, using the filename from -output (default iface_gen.go). If the content hasn't changed, the file won't be overwritten.

License

MIT © Morteza SeyyedAgahei