Can you explain what a Registry is and how it is used?

Registry is a design pattern that represents a centralized storage for objects or services, which can be accessed from different parts of a program. In Go, it is often used for dependency management or for storing configurations and services to avoid global variables and simplify access to shared resources.

Example of a simple Registry in Go:

package main

import "fmt"

type Service interface {
    Do()
}

type Registry struct {
    services map[string]Service
}

func NewRegistry() *Registry {
    return &Registry{services: make(map[string]Service)}
}

func (r *Registry) Register(name string, service Service) {
    r.services[name] = service
}

func (r *Registry) Get(name string) Service {
    return r.services[name]
}
}

// Example service
 type MyService struct{}

func (s *MyService) Do() {
    fmt.Println("Service is doing something")
}

func main() {
    registry := NewRegistry()
    registry.Register("myService", &MyService{})

    service := registry.Get("myService")
    if service != nil {
        service.Do()
    }
}

This approach helps to centralize the creation and access to objects, making dependency management easier.