Programmatically run container registry based on Docker's reference implementation distribution/distribution

registry.go

package main

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/distribution/distribution/v3/configuration"
	"github.com/distribution/distribution/v3/registry"
	_ "github.com/distribution/distribution/v3/registry/auth/htpasswd"
	_ "github.com/distribution/distribution/v3/registry/storage/driver/inmemory"
	"github.com/phayes/freeport"
)

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	// Registry config
	config := &configuration.Configuration{}
	port, err := freeport.GetFreePort()
	if err != nil {
		panic(fmt.Errorf("failed to get free port: %s", err))
	}
	dockerReg := fmt.Sprintf("localhost:%d", port)
	config.HTTP.Addr = fmt.Sprintf("127.0.0.1:%d", port)
	config.HTTP.DrainTimeout = time.Duration(10) * time.Second
	config.Storage = map[string]configuration.Parameters{"inmemory": map[string]interface{}{}}
	dockerRegistry, err := registry.NewRegistry(ctx, config)
	if err != nil {
		panic(fmt.Errorf("failed to create docker registry: %w", err))
	}

	c := make(chan os.Signal, 2)
	signal.Notify(c, os.Interrupt, syscall.SIGTERM)

	// Start Docker registry
	go dockerRegistry.ListenAndServe()

	fmt.Println("registry server started at:", dockerReg)
	<-c
	fmt.Println("shutting down the registry server")
}