Demonstrating go-containerregistry basic auth keychain

main.go

package main

import (
	"fmt"
	"log"

	"github.com/google/go-containerregistry/pkg/authn"
	"github.com/google/go-containerregistry/pkg/crane"
	"github.com/google/go-containerregistry/pkg/v1/google"
)

func main() {
	keychain := authn.NewMultiKeychain(
		basicKeychain{"abc.xyz", "username", "password"},
		basicKeychain{"def.xyz", "otheruser", "otherpass"},
		google.Keychain, // for gcr.io
	)

	if err := crane.Copy("abc.xyz/foo/bar", "def.xyz/foo/bar",
		crane.WithAuthFromKeychain(keychain)); err != nil {
		log.Fatal(err)
	}
}

type basicKeychain struct{ registry, username, password string }

func (b basicKeychain) Resolve(r authn.Resource) (authn.Authenticator, error) {
	if r.RegistryStr() != b.registry {
		return nil, fmt.Errorf("basicKeychain: only %q is supported", b.registry)
	}
	return b, nil
}

func (b basicKeychain) Authorization() (*authn.AuthConfig, error) {
	return &authn.AuthConfig{
		Username: b.username,
		Password: b.password,
	}, nil
}