podman/pkg/machine/ocipull/source.go

121 lines
3.4 KiB
Go

package ocipull
import (
"context"
"encoding/json"
"errors"
"fmt"
"strings"
"github.com/containers/image/v5/docker"
"github.com/containers/image/v5/oci/layout"
"github.com/containers/image/v5/types"
"github.com/opencontainers/go-digest"
specV1 "github.com/opencontainers/image-spec/specs-go/v1"
)
// readManifestFromImageSource reads the manifest from the specified image
// source. Note that the manifest is expected to be an OCI v1 manifest.
func readManifestFromImageSource(ctx context.Context, src types.ImageSource) (*specV1.Manifest, *digest.Digest, int64, error) {
rawData, mimeType, err := src.GetManifest(ctx, nil)
if err != nil {
return nil, nil, -1, err
}
if mimeType != specV1.MediaTypeImageManifest {
return nil, nil, -1, fmt.Errorf("image %q is of type %q (expected: %q)", strings.TrimPrefix(src.Reference().StringWithinTransport(), "//"), mimeType, specV1.MediaTypeImageManifest)
}
manifest := specV1.Manifest{}
if err := json.Unmarshal(rawData, &manifest); err != nil {
return nil, nil, -1, fmt.Errorf("reading manifest: %w", err)
}
manifestDigest := digest.FromBytes(rawData)
return &manifest, &manifestDigest, int64(len(rawData)), nil
}
// readManifestFromOCIPath returns the manifest of the specified source image
// at `sourcePath` along with its digest. The digest can later on be used to
// locate the manifest on the file system.
func readManifestFromOCIPath(ctx context.Context, sourcePath string) (*specV1.Manifest, *digest.Digest, int64, error) {
ociRef, err := layout.ParseReference(sourcePath)
if err != nil {
return nil, nil, -1, err
}
ociSource, err := ociRef.NewImageSource(ctx, &types.SystemContext{})
if err != nil {
return nil, nil, -1, err
}
defer ociSource.Close()
return readManifestFromImageSource(ctx, ociSource)
}
func GetLocalBlob(ctx context.Context, path string) (*types.BlobInfo, error) {
ociRef, err := layout.ParseReference(path)
if err != nil {
return nil, err
}
img, err := ociRef.NewImage(ctx, &types.SystemContext{})
if err != nil {
return nil, err
}
b, _, err := img.Manifest(ctx)
if err != nil {
return nil, err
}
localManifest := specV1.Manifest{}
if err := json.Unmarshal(b, &localManifest); err != nil {
return nil, err
}
blobs := img.LayerInfos()
if err != nil {
return nil, err
}
if len(blobs) != 1 {
return nil, errors.New("invalid disk image")
}
fmt.Println(blobs[0].Digest.Hex())
return &blobs[0], nil
}
func GetRemoteManifest(ctx context.Context, dest string) (*specV1.Manifest, error) {
ref, err := docker.ParseReference(fmt.Sprintf("//%s", dest))
if err != nil {
return nil, err
}
imgSrc, err := ref.NewImage(ctx, &types.SystemContext{})
if err != nil {
return nil, err
}
b, _, err := imgSrc.Manifest(ctx)
if err != nil {
return nil, err
}
remoteManifest := specV1.Manifest{}
err = json.Unmarshal(b, &remoteManifest)
return &remoteManifest, err
}
func GetRemoteDescriptor(ctx context.Context, dest string) (*specV1.Descriptor, error) {
remoteManifest, err := GetRemoteManifest(ctx, dest)
if err != nil {
return nil, err
}
if len(remoteManifest.Layers) != 1 {
return nil, errors.New("invalid remote disk image")
}
return &remoteManifest.Layers[0], nil
}
func ReadImageManifestFromOCIPath(ctx context.Context, ociImagePath string) (*specV1.Manifest, error) {
imageManifest, _, _, err := readManifestFromOCIPath(ctx, ociImagePath)
return imageManifest, err
}