| package imageutil |
| |
| import ( |
| "context" |
| "encoding/json" |
| |
| "github.com/containerd/containerd/content" |
| "github.com/containerd/containerd/images" |
| "github.com/containerd/containerd/platforms" |
| "github.com/containerd/containerd/reference" |
| "github.com/containerd/containerd/remotes" |
| digest "github.com/opencontainers/go-digest" |
| specs "github.com/opencontainers/image-spec/specs-go/v1" |
| "github.com/pkg/errors" |
| ) |
| |
| type IngesterProvider interface { |
| content.Ingester |
| content.Provider |
| } |
| |
| func Config(ctx context.Context, str string, resolver remotes.Resolver, ingester IngesterProvider, platform *specs.Platform) (digest.Digest, []byte, error) { |
| // TODO: fix containerd to take struct instead of string |
| platformStr := platforms.Default() |
| if platform != nil { |
| platformStr = platforms.Format(*platform) |
| } |
| ref, err := reference.Parse(str) |
| if err != nil { |
| return "", nil, errors.WithStack(err) |
| } |
| |
| desc := specs.Descriptor{ |
| Digest: ref.Digest(), |
| } |
| if desc.Digest != "" { |
| ra, err := ingester.ReaderAt(ctx, desc) |
| if err == nil { |
| desc.Size = ra.Size() |
| mt, err := DetectManifestMediaType(ra) |
| if err == nil { |
| desc.MediaType = mt |
| } |
| } |
| } |
| // use resolver if desc is incomplete |
| if desc.MediaType == "" { |
| _, desc, err = resolver.Resolve(ctx, ref.String()) |
| if err != nil { |
| return "", nil, err |
| } |
| } |
| |
| fetcher, err := resolver.Fetcher(ctx, ref.String()) |
| if err != nil { |
| return "", nil, err |
| } |
| |
| handlers := []images.Handler{ |
| remotes.FetchHandler(ingester, fetcher), |
| childrenConfigHandler(ingester, platformStr), |
| } |
| if err := images.Dispatch(ctx, images.Handlers(handlers...), desc); err != nil { |
| return "", nil, err |
| } |
| config, err := images.Config(ctx, ingester, desc, platformStr) |
| if err != nil { |
| return "", nil, err |
| } |
| |
| dt, err := content.ReadBlob(ctx, ingester, config) |
| if err != nil { |
| return "", nil, err |
| } |
| |
| return desc.Digest, dt, nil |
| } |
| |
| func childrenConfigHandler(provider content.Provider, platform string) images.HandlerFunc { |
| return func(ctx context.Context, desc specs.Descriptor) ([]specs.Descriptor, error) { |
| var descs []specs.Descriptor |
| switch desc.MediaType { |
| case images.MediaTypeDockerSchema2Manifest, specs.MediaTypeImageManifest: |
| p, err := content.ReadBlob(ctx, provider, desc) |
| if err != nil { |
| return nil, err |
| } |
| |
| // TODO(stevvooe): We just assume oci manifest, for now. There may be |
| // subtle differences from the docker version. |
| var manifest specs.Manifest |
| if err := json.Unmarshal(p, &manifest); err != nil { |
| return nil, err |
| } |
| |
| descs = append(descs, manifest.Config) |
| case images.MediaTypeDockerSchema2ManifestList, specs.MediaTypeImageIndex: |
| p, err := content.ReadBlob(ctx, provider, desc) |
| if err != nil { |
| return nil, err |
| } |
| |
| var index specs.Index |
| if err := json.Unmarshal(p, &index); err != nil { |
| return nil, err |
| } |
| |
| if platform != "" { |
| pf, err := platforms.Parse(platform) |
| if err != nil { |
| return nil, err |
| } |
| matcher := platforms.NewMatcher(pf) |
| |
| for _, d := range index.Manifests { |
| if d.Platform == nil || matcher.Match(*d.Platform) { |
| descs = append(descs, d) |
| } |
| } |
| } else { |
| descs = append(descs, index.Manifests...) |
| } |
| case images.MediaTypeDockerSchema2Config, specs.MediaTypeImageConfig: |
| // childless data types. |
| return nil, nil |
| default: |
| return nil, errors.Errorf("encountered unknown type %v; children may not be fetched", desc.MediaType) |
| } |
| |
| return descs, nil |
| } |
| } |
| |
| // specs.MediaTypeImageManifest, // TODO: detect schema1/manifest-list |
| func DetectManifestMediaType(ra content.ReaderAt) (string, error) { |
| // TODO: schema1 |
| |
| p := make([]byte, ra.Size()) |
| if _, err := ra.ReadAt(p, 0); err != nil { |
| return "", err |
| } |
| |
| var mfst struct { |
| Config json.RawMessage `json:"config"` |
| } |
| |
| if err := json.Unmarshal(p, &mfst); err != nil { |
| return "", err |
| } |
| |
| if mfst.Config != nil { |
| return images.MediaTypeDockerSchema2Manifest, nil |
| } |
| return images.MediaTypeDockerSchema2ManifestList, nil |
| } |