imagetools inspect: add --format flag

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/moby/buildkit/util/imageutil/config.go

@@ -0,0 +1,222 @@
+package imageutil
+
+import (
+	"context"
+	"encoding/json"
+	"sync"
+	"time"
+
+	"github.com/containerd/containerd/content"
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/leases"
+	"github.com/containerd/containerd/platforms"
+	"github.com/containerd/containerd/reference"
+	"github.com/containerd/containerd/remotes"
+	"github.com/containerd/containerd/remotes/docker"
+	"github.com/moby/buildkit/util/leaseutil"
+	"github.com/moby/buildkit/util/resolver/limited"
+	"github.com/moby/buildkit/util/resolver/retryhandler"
+	digest "github.com/opencontainers/go-digest"
+	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+type ContentCache interface {
+	content.Ingester
+	content.Provider
+}
+
+var leasesMu sync.Mutex
+var leasesF []func(context.Context) error
+
+func CancelCacheLeases() {
+	leasesMu.Lock()
+	for _, f := range leasesF {
+		f(context.TODO())
+	}
+	leasesF = nil
+	leasesMu.Unlock()
+}
+
+func AddLease(f func(context.Context) error) {
+	leasesMu.Lock()
+	leasesF = append(leasesF, f)
+	leasesMu.Unlock()
+}
+
+func Config(ctx context.Context, str string, resolver remotes.Resolver, cache ContentCache, leaseManager leases.Manager, p *ocispecs.Platform) (digest.Digest, []byte, error) {
+	// TODO: fix buildkit to take interface instead of struct
+	var platform platforms.MatchComparer
+	if p != nil {
+		platform = platforms.Only(*p)
+	} else {
+		platform = platforms.Default()
+	}
+	ref, err := reference.Parse(str)
+	if err != nil {
+		return "", nil, errors.WithStack(err)
+	}
+
+	if leaseManager != nil {
+		ctx2, done, err := leaseutil.WithLease(ctx, leaseManager, leases.WithExpiration(5*time.Minute), leaseutil.MakeTemporary)
+		if err != nil {
+			return "", nil, errors.WithStack(err)
+		}
+		ctx = ctx2
+		defer func() {
+			// this lease is not deleted to allow other components to access manifest/config from cache. It will be deleted after 5 min deadline or on pruning inactive builder
+			AddLease(done)
+		}()
+	}
+
+	desc := ocispecs.Descriptor{
+		Digest: ref.Digest(),
+	}
+	if desc.Digest != "" {
+		ra, err := cache.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
+	}
+
+	if desc.MediaType == images.MediaTypeDockerSchema1Manifest {
+		return readSchema1Config(ctx, ref.String(), desc, fetcher, cache)
+	}
+
+	children := childrenConfigHandler(cache, platform)
+
+	handlers := []images.Handler{
+		retryhandler.New(limited.FetchHandler(cache, fetcher, str), func(_ []byte) {}),
+		children,
+	}
+	if err := images.Dispatch(ctx, images.Handlers(handlers...), nil, desc); err != nil {
+		return "", nil, err
+	}
+	config, err := images.Config(ctx, cache, desc, platform)
+	if err != nil {
+		return "", nil, err
+	}
+
+	dt, err := content.ReadBlob(ctx, cache, config)
+	if err != nil {
+		return "", nil, err
+	}
+
+	return desc.Digest, dt, nil
+}
+
+func childrenConfigHandler(provider content.Provider, platform platforms.MatchComparer) images.HandlerFunc {
+	return func(ctx context.Context, desc ocispecs.Descriptor) ([]ocispecs.Descriptor, error) {
+		var descs []ocispecs.Descriptor
+		switch desc.MediaType {
+		case images.MediaTypeDockerSchema2Manifest, ocispecs.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 ocispecs.Manifest
+			if err := json.Unmarshal(p, &manifest); err != nil {
+				return nil, err
+			}
+
+			descs = append(descs, manifest.Config)
+		case images.MediaTypeDockerSchema2ManifestList, ocispecs.MediaTypeImageIndex:
+			p, err := content.ReadBlob(ctx, provider, desc)
+			if err != nil {
+				return nil, err
+			}
+
+			var index ocispecs.Index
+			if err := json.Unmarshal(p, &index); err != nil {
+				return nil, err
+			}
+
+			if platform != nil {
+				for _, d := range index.Manifests {
+					if d.Platform == nil || platform.Match(*d.Platform) {
+						descs = append(descs, d)
+					}
+				}
+			} else {
+				descs = append(descs, index.Manifests...)
+			}
+		case images.MediaTypeDockerSchema2Config, ocispecs.MediaTypeImageConfig, docker.LegacyConfigMediaType:
+			// 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
+
+	dt := make([]byte, ra.Size())
+	if _, err := ra.ReadAt(dt, 0); err != nil {
+		return "", err
+	}
+
+	return DetectManifestBlobMediaType(dt)
+}
+
+func DetectManifestBlobMediaType(dt []byte) (string, error) {
+	var mfst struct {
+		MediaType *string         `json:"mediaType"`
+		Config    json.RawMessage `json:"config"`
+		Manifests json.RawMessage `json:"manifests"`
+		Layers    json.RawMessage `json:"layers"`
+	}
+
+	if err := json.Unmarshal(dt, &mfst); err != nil {
+		return "", err
+	}
+
+	mt := images.MediaTypeDockerSchema2ManifestList
+
+	if mfst.Config != nil || mfst.Layers != nil {
+		mt = images.MediaTypeDockerSchema2Manifest
+
+		if mfst.Manifests != nil {
+			return "", errors.Errorf("invalid ambiguous manifest and manifest list")
+		}
+	}
+
+	if mfst.MediaType != nil {
+		switch *mfst.MediaType {
+		case images.MediaTypeDockerSchema2ManifestList, ocispecs.MediaTypeImageIndex:
+			if mt != images.MediaTypeDockerSchema2ManifestList {
+				return "", errors.Errorf("mediaType in manifest does not match manifest contents")
+			}
+			mt = *mfst.MediaType
+		case images.MediaTypeDockerSchema2Manifest, ocispecs.MediaTypeImageManifest:
+			if mt != images.MediaTypeDockerSchema2Manifest {
+				return "", errors.Errorf("mediaType in manifest does not match manifest contents")
+			}
+			mt = *mfst.MediaType
+		}
+	}
+	return mt, nil
+}

vendor/github.com/moby/buildkit/util/imageutil/schema1.go

@@ -0,0 +1,87 @@
+package imageutil
+
+import (
+	"context"
+	"encoding/json"
+	"io/ioutil"
+	"strings"
+	"time"
+
+	"github.com/containerd/containerd/remotes"
+	digest "github.com/opencontainers/go-digest"
+	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+func readSchema1Config(ctx context.Context, ref string, desc ocispecs.Descriptor, fetcher remotes.Fetcher, cache ContentCache) (digest.Digest, []byte, error) {
+	rc, err := fetcher.Fetch(ctx, desc)
+	if err != nil {
+		return "", nil, err
+	}
+	defer rc.Close()
+	dt, err := ioutil.ReadAll(rc)
+	if err != nil {
+		return "", nil, errors.Wrap(err, "failed to fetch schema1 manifest")
+	}
+	dt, err = convertSchema1ConfigMeta(dt)
+	if err != nil {
+		return "", nil, err
+	}
+	return desc.Digest, dt, nil
+}
+
+func convertSchema1ConfigMeta(in []byte) ([]byte, error) {
+	type history struct {
+		V1Compatibility string `json:"v1Compatibility"`
+	}
+	var m struct {
+		History []history `json:"history"`
+	}
+	if err := json.Unmarshal(in, &m); err != nil {
+		return nil, errors.Wrap(err, "failed to unmarshal schema1 manifest")
+	}
+	if len(m.History) == 0 {
+		return nil, errors.Errorf("invalid schema1 manifest")
+	}
+
+	var img ocispecs.Image
+	if err := json.Unmarshal([]byte(m.History[0].V1Compatibility), &img); err != nil {
+		return nil, errors.Wrap(err, "failed to unmarshal image from schema 1 history")
+	}
+
+	img.RootFS = ocispecs.RootFS{
+		Type: "layers", // filled in by exporter
+	}
+	img.History = make([]ocispecs.History, len(m.History))
+
+	for i := range m.History {
+		var h v1History
+		if err := json.Unmarshal([]byte(m.History[i].V1Compatibility), &h); err != nil {
+			return nil, errors.Wrap(err, "failed to unmarshal history")
+		}
+		img.History[len(m.History)-i-1] = ocispecs.History{
+			Author:     h.Author,
+			Comment:    h.Comment,
+			Created:    &h.Created,
+			CreatedBy:  strings.Join(h.ContainerConfig.Cmd, " "),
+			EmptyLayer: (h.ThrowAway != nil && *h.ThrowAway) || (h.Size != nil && *h.Size == 0),
+		}
+	}
+
+	dt, err := json.MarshalIndent(img, "", "   ")
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to marshal schema1 config")
+	}
+	return dt, nil
+}
+
+type v1History struct {
+	Author          string    `json:"author,omitempty"`
+	Created         time.Time `json:"created"`
+	Comment         string    `json:"comment,omitempty"`
+	ThrowAway       *bool     `json:"throwaway,omitempty"`
+	Size            *int      `json:"Size,omitempty"` // used before ThrowAway field
+	ContainerConfig struct {
+		Cmd []string `json:"Cmd,omitempty"`
+	} `json:"container_config,omitempty"`
+}