How to Avoid DI Frameworks and Use Plain Go

You avoid DI frameworks in Go by using constructor functions, interfaces, and dependency injection via function parameters or struct fields. This approach keeps your code simple, testable, and free of external dependencies.

// Define an interface for your dependency
type Logger interface {
    Log(msg string)
}

// Define a concrete implementation
type StdLogger struct{}

func (s *StdLogger) Log(msg string) {
    fmt.Println(msg)
}

// Define your service with dependency injection
type Service struct {
    logger Logger
}

// Constructor function to inject dependencies
func NewService(logger Logger) *Service {
    return &Service{logger: logger}
}

// Usage
func main() {
    logger := &StdLogger{}
    service := NewService(logger)
    service.logger.Log("Hello, World!")
}

Instead of using complex frameworks to manage how your code pieces connect, you simply pass the pieces you need directly into your functions or structs. Think of it like handing a worker the exact tools they need for a job, rather than having a manager figure out which tools to bring. This makes your code easier to understand and test because you control exactly what gets used.