pkg: prepend library when using registry mirror

pkg/image/image_util.go

@@ -21,6 +21,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
+	"strings"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/cache"
 	"github.com/GoogleContainerTools/kaniko/pkg/config"
@@ -117,6 +118,11 @@ func remoteImage(image string, opts *config.KanikoOptions) (v1.Image, error) {
 			return nil, err
 		}
 
+		ref, err = normalizeReference(ref, image)
+		if err != nil {
+			return nil, err
+		}
+
 		toSet = true
 	}
 
@@ -134,16 +140,31 @@ func remoteImage(image string, opts *config.KanikoOptions) (v1.Image, error) {
 			tag.Repository.Registry = newReg
 			ref = tag
 		}
+
 		if digest, ok := ref.(name.Digest); ok {
 			digest.Repository.Registry = newReg
 			ref = digest
 		}
 	}
 
+	logrus.Infof("Retrieving image %s", ref)
+
 	rOpts := remoteOptions(registryName, opts)
 	return remote.Image(ref, rOpts...)
 }
 
+// normalizeReference adds the library/ prefix to images without it.
+//
+// It is mostly useful when using a registry mirror that is not able to perform
+// this fix automatically.
+func normalizeReference(ref name.Reference, image string) (name.Reference, error) {
+	if !strings.ContainsRune(image, '/') {
+		return name.ParseReference("library/"+image, name.WeakValidation)
+	}
+
+	return ref, nil
+}
+
 func remoteOptions(registryName string, opts *config.KanikoOptions) []remote.Option {
 	tr := util.MakeTransport(opts, registryName)
 

pkg/image/image_util_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/google/go-containerregistry/pkg/name"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 	"github.com/google/go-containerregistry/pkg/v1/empty"
 	"github.com/moby/buildkit/frontend/dockerfile/instructions"
@@ -109,6 +110,25 @@ func Test_ScratchImageFromMirror(t *testing.T) {
 	testutil.CheckErrorAndDeepEqual(t, false, err, expected, actual)
 }
 
+func Test_normalizeReference(t *testing.T) {
+	image := "debian"
+	expected := "index.docker.io/library/debian:latest"
+
+	ref, err := name.ParseReference(image)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ref2, err := normalizeReference(ref, image)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if ref2.Name() != ref.Name() || ref2.Name() != expected {
+		t.Errorf("%s should have been normalized to %s, got %s", ref2.Name(), expected, ref.Name())
+	}
+}
+
 // parse parses the contents of a Dockerfile and returns a list of commands
 func parse(s string) ([]instructions.Stage, error) {
 	p, err := parser.Parse(bytes.NewReader([]byte(s)))