feat: PoC for multi arch image create/update

cmd/oras/root/manifest/cmd.go

@@ -17,6 +17,7 @@ package manifest
 
 import (
 	"github.com/spf13/cobra"
+	"oras.land/oras/cmd/oras/root/manifest/index"
 )
 
 func Cmd() *cobra.Command {
@@ -30,6 +31,7 @@ func Cmd() *cobra.Command {
 		fetchCmd(),
 		fetchConfigCmd(),
 		pushCmd(),
+		index.Cmd(),
 	)
 	return cmd
 }

cmd/oras/root/manifest/index/cmd.go

@@ -0,0 +1,33 @@
+/*
+Copyright The ORAS Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package index
+
+import (
+	"github.com/spf13/cobra"
+)
+
+func Cmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "index [command]",
+		Short: "Index operations",
+	}
+
+	cmd.AddCommand(
+		createCmd(),
+		updateCmd(),
+	)
+	return cmd
+}

cmd/oras/root/manifest/index/create.go

@@ -0,0 +1,174 @@
+/*
+Copyright The ORAS Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package index
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/opencontainers/image-spec/specs-go"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/spf13/cobra"
+	"oras.land/oras-go/v2"
+	"oras.land/oras-go/v2/content"
+	"oras.land/oras/cmd/oras/internal/command"
+	oerrors "oras.land/oras/cmd/oras/internal/errors"
+	"oras.land/oras/cmd/oras/internal/option"
+	"oras.land/oras/internal/descriptor"
+)
+
+type createOptions struct {
+	option.Common
+	option.Target
+
+	sources   []string
+	extraRefs []string
+}
+
+func createCmd() *cobra.Command {
+	var opts createOptions
+	cmd := &cobra.Command{
+		Use:   "create [flags] <name>[:<tag[,<tag>][...]] [{<tag>|<digest>}...]",
+		Short: "Create and push an index from provided manifests",
+		Long: `Create and push an index to a repository or an OCI image layout
+
+Example - create an index from source manifests tagged amd64, arm64, darwin in the repository
+ localhost:5000/hello, and push the index without tagging it:
+  oras manifest index create localhost:5000/hello amd64 arm64 darwin
+
+Example - create an index from source manifests tagged amd64, arm64, darwin in the repository
+ localhost:5000/hello, and push the index with tag 'latest':
+  oras manifest index create localhost:5000/hello:latest amd64 arm64 darwin
+
+Example - create an index from source manifests using both tags and digests, 
+ and push the index with tag 'latest':
+  oras manifest index create localhost:5000/hello latest amd64 sha256:xxx darwin
+
+Example - create an index and push it with multiple tags:
+  oras manifest index create localhost:5000/tag1, tag2, tag3 amd64 arm64 sha256:xxx
+`,
+		Args: cobra.MinimumNArgs(1),
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			refs := strings.Split(args[0], ",")
+			opts.RawReference = refs[0]
+			opts.extraRefs = refs[1:]
+			opts.sources = args[1:]
+			return option.Parse(cmd, &opts)
+			// todo: add EnsureReferenceNotEmpty somewhere
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return createIndex(cmd, opts)
+		},
+	}
+
+	option.ApplyFlags(&opts, cmd.Flags())
+	return oerrors.Command(cmd, &opts.Target)
+}
+
+func createIndex(cmd *cobra.Command, opts createOptions) error {
+	ctx, logger := command.GetLogger(cmd, &opts.Common)
+	target, err := opts.NewTarget(opts.Common, logger)
+	if err != nil {
+		return err
+	}
+	// we assume that the sources and the to be created index are all in the same
+	// repository, so no copy is needed
+	manifests, err := resolveSourceManifests(ctx, target, opts.sources)
+	if err != nil {
+		return err
+	}
+	desc, content, err := packIndex(&ocispec.Index{}, manifests)
+	if err != nil {
+		return err
+	}
+	return pushIndex(ctx, target, desc, content, opts.Reference, opts.extraRefs)
+}
+
+func resolveSourceManifests(ctx context.Context, target oras.ReadOnlyTarget, sources []string) ([]ocispec.Descriptor, error) {
+	var resolved []ocispec.Descriptor
+	for _, source := range sources {
+		desc, content, err := oras.FetchBytes(ctx, target, source, oras.DefaultFetchBytesOptions)
+		if err != nil {
+			return nil, err
+		}
+		if descriptor.IsImageManifest(desc) {
+			desc.Platform, err = getPlatform(ctx, target, content)
+			if err != nil {
+				return nil, err
+			}
+		}
+		resolved = append(resolved, desc)
+	}
+	return resolved, nil
+}
+
+func getPlatform(ctx context.Context, target oras.ReadOnlyTarget, manifestBytes []byte) (*ocispec.Platform, error) {
+	// extract config descriptor
+	var manifest ocispec.Manifest
+	if err := json.Unmarshal(manifestBytes, &manifest); err != nil {
+		return nil, err
+	}
+	// fetch config content
+	contentBytes, err := content.FetchAll(ctx, target, manifest.Config)
+	if err != nil {
+		return nil, err
+	}
+	var platform ocispec.Platform
+	if err := json.Unmarshal(contentBytes, &platform); err != nil {
+		return nil, err
+	}
+	return &platform, nil
+}
+
+func packIndex(oldIndex *ocispec.Index, manifests []ocispec.Descriptor) (ocispec.Descriptor, []byte, error) {
+	index := ocispec.Index{
+		Versioned: specs.Versioned{
+			SchemaVersion: 2,
+		},
+		MediaType:    ocispec.MediaTypeImageIndex,
+		ArtifactType: oldIndex.ArtifactType,
+		Manifests:    manifests,
+		Subject:      oldIndex.Subject,
+		Annotations:  oldIndex.Annotations,
+	}
+	indexBytes, err := json.Marshal(index)
+	if err != nil {
+		return ocispec.Descriptor{}, nil, err
+	}
+	desc := content.NewDescriptorFromBytes(ocispec.MediaTypeImageIndex, indexBytes)
+	return desc, indexBytes, nil
+}
+
+func pushIndex(ctx context.Context, target oras.Target, desc ocispec.Descriptor, content []byte, ref string, extraRefs []string) error {
+	var err error
+	// need to refine the variable names of ref, extra ref
+	if ref != "" {
+		extraRefs = append(extraRefs, ref)
+	}
+	if len(extraRefs) == 0 {
+		err = target.Push(ctx, desc, bytes.NewReader(content))
+	} else {
+		desc, err = oras.TagBytesN(ctx, target, desc.MediaType, content, extraRefs, oras.DefaultTagBytesNOptions)
+	}
+	if err != nil {
+		return err
+	}
+	fmt.Println("Created and pushed index:", desc.Digest)
+	return nil
+}