Dependency Injection

GoFrame uses Uber FX to manage dependency injection and application lifecycle.

How it works

FX works with constructors that declare their dependencies as parameters:


// Constructor without dependencies
func NewUserService() *UserService {
    return &UserService{}
}
 
// Constructor with dependencies
func NewOrderService(userService *UserService, db *sql.DB) *OrderService {
    return &OrderService{
        userService: userService,
        db: db,
    }
}

Organization in GoFrame

internal/app/module.go: Central point where all dependencies are registered
registry.go files: Auto-generated by CLI, list dependencies per package
Pattern: Use fx.Provide(package.Dependencies...) to inject groups of dependencies

Practical example


// internal/app/module.go
func Module(cfg *config.Config) []fx.Option {
    return []fx.Option{
        // Provide dependencies
        fx.Supply(cfg),                          // Existing instance
        fx.Provide(NewDatabase),                 // Constructor
        fx.Provide(repository.Dependencies...),  // Group of dependencies
        fx.Provide(service.Dependencies...),
 
        // Start application
        fx.Invoke(StartHTTPServer),
    }
}

Key functions

fx.Provide(): Register a constructor
fx.Supply(): Provide an existing instance
fx.Invoke(): Run a function at startup
fx.Options(): Group multiple modules

FX automatically resolves dependency order and manages their lifecycle.