factory.go

func main() {
  assasinService := &KindOfAssasinService{}
  transporter := NewTransporter(assasinService)
  hitman := NewHitMan(assasinService);
}

type KindOfAssasinService {}
func (ass *KindOfAssasinService) GetVehicle(t string) Vehicle {
  if t == "car" {
    return &Car{}
  }
  
  return &Tank{}
}

func (ass *KindOfAssasinService) GetWeapon(t string) Weapon {
  if t == "gun" {
    return &Gun{}
  }
  
  return &Dagger{}
}

hitman.go

type WeaponFactory interface {
  GetWeapon(t string) Weapon
}

type Hitman struct {
  weaponFactory WeaponFactory
}

func (h *Hitman) doHitmanStuff() {
  h.weaponFactory.GetWeapon("gun").KickSomeAss()
}

transporter3.go

type VehicleFactory interface {
  GetVehicle(t string) Vehicle
}

type Transporter struct {
  vehicle Vehicle
}

func (t *Transporter) makeOutWith(pretty Lady) {
  // ...
}

func (t *) hitAllTheBadGuysAt(dest Desination) {
  t.vehicle.Move(dest)
}

func NewTransporter(f VehicleFactory) *Transporter {
  return &Transporter{
    vehicle: f.Getvehicle("car"),
  } 
}