WIP: Adds OCI image support

go.mod

@@ -7,6 +7,8 @@ require (
 	github.com/alessio/shellescape v1.4.1
 	github.com/evanphx/json-patch/v5 v5.6.0
 	github.com/mattn/go-isatty v0.0.14
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.0.2 // indirect
 	github.com/pelletier/go-toml v1.9.4
 	github.com/pkg/errors v0.9.1
 	github.com/spf13/cobra v1.4.0

go.sum

@@ -17,6 +17,10 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
 github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
+github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
+github.com/opencontainers/image-spec v1.0.2 h1:9yCKha/T5XdGtO0q9Q9a6T5NUCsTn/DrBg0D7ufOcFM=
+github.com/opencontainers/image-spec v1.0.2/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zMzWCbyJoFRP3s7yZA0=
 github.com/pelletier/go-toml v1.9.4 h1:tjENF6MfZAg8e4ZmZTeWaWiT2vXtsoO6+iuOjFhECwM=
 github.com/pelletier/go-toml v1.9.4/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=

pkg/build/nodeimage/internal/container/docker/archive.go

@@ -27,6 +27,7 @@ import (
 	"os"
 	"strings"
 
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"sigs.k8s.io/kind/pkg/errors"
 )
 
@@ -36,6 +37,7 @@ import (
 // https://github.com/moby/moby/blob/master/image/spec/v1.md
 // https://github.com/moby/moby/blob/master/image/spec/v1.1.md
 // https://github.com/moby/moby/blob/master/image/spec/v1.2.md
+// https://github.com/opencontainers/image-spec/blob/v1.0.0/spec.md
 func GetArchiveTags(path string) ([]string, error) {
 	// open the archive and find the repositories entry
 	f, err := os.Open(path)
@@ -44,7 +46,12 @@ func GetArchiveTags(path string) ([]string, error) {
 	}
 	defer f.Close()
 	tr := tar.NewReader(f)
-	var hdr *tar.Header
+	var (
+		hdr        *tar.Header
+		ociLayout  ocispec.ImageLayout
+		indexBytes []byte
+		repoTags   archiveRepositories
+	)
 	for {
 		hdr, err = tr.Next()
 		if err == io.EOF {
@@ -54,19 +61,49 @@ func GetArchiveTags(path string) ([]string, error) {
 			return nil, err
 		}
 		if hdr.Name == "repositories" {
+			if err := untarJSON(tr, &repoTags); err != nil {
+				return nil, err
+			}
+			break
+		} else if hdr.Name == ocispec.ImageLayoutFile {
+			if err := untarJSON(tr, &ociLayout); err != nil {
+				return nil, err
+			}
+		} else if hdr.Name == "index.json" {
+			indexBytes, err = ioutil.ReadAll(tr)
+			if err != nil {
+				return nil, err
+			}
+		}
+		if ociLayout.Version != "" && len(indexBytes) > 0 {
 			break
 		}
 	}
-	// read and parse the tags
-	b, err := ioutil.ReadAll(tr)
-	if err != nil {
-		return nil, err
-	}
-	// parse
-	repoTags, err := parseRepositories(b)
-	if err != nil {
-		return nil, err
+
+	if ociLayout.Version != "" {
+		if ociLayout.Version != ocispec.ImageLayoutVersion {
+			return nil, fmt.Errorf("unsupported OCI Version: %s", ociLayout.Version)
+		}
+
+		var imageIndex ocispec.Index
+		if err := json.Unmarshal(indexBytes, &imageIndex); err != nil {
+			return nil, err
+		}
+
+		res := []string{}
+		for _, manifest := range imageIndex.Manifests {
+			if imageName, ok := manifest.Annotations["io.containerd.image.name"]; ok {
+				res = append(res, imageName)
+			}
+		}
+
+		if len(res) == 0 {
+			return nil, errors.New("could not find image tags in image metadata")
+		}
+
+		return res, nil
 	}
+
 	// convert to tags in the docker CLI sense
 	res := []string{}
 	for repo, tags := range repoTags {
@@ -215,3 +252,12 @@ func parseRepositories(data []byte) (archiveRepositories, error) {
 	}
 	return repoTags, nil
 }
+
+func untarJSON(reader io.Reader, i interface{}) error {
+	b, err := ioutil.ReadAll(reader)
+	if err != nil {
+		return err
+	}
+
+	return json.Unmarshal(b, i)
+}