add support for image inspect with containerd-integration

This is a squashed version of various PRs (or related code-changes)
to implement image inspect with the containerd-integration;

- add support for image inspect
- introduce GetImageOpts to manage image inspect data in backend
- GetImage to return image tags with details
- list images matching digest to discover all tags
- Add ExposedPorts and Volumes to the image returned
- Refactor resolving/getting images
- Return the image ID on inspect
- consider digest and ignore tag when both are set
- docker run --platform

Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>
Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

api/server/router/image/image_routes.go

@@ -206,9 +206,8 @@ func (ir *imageRouter) getImagesByName(ctx context.Context, w http.ResponseWrite
 }
 
 func (ir *imageRouter) toImageInspect(img *image.Image) (*types.ImageInspect, error) {
-	refs := ir.referenceBackend.References(img.ID().Digest())
 	var repoTags, repoDigests []string
-	for _, ref := range refs {
+	for _, ref := range img.Details.References {
 		switch ref.(type) {
 		case reference.NamedTagged:
 			repoTags = append(repoTags, reference.FamiliarString(ref))

daemon/containerd/image.go

@@ -2,14 +2,219 @@ package containerd
 
 import (
 	"context"
-	"errors"
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"strconv"
+	"sync/atomic"
+	"time"
 
+	"github.com/containerd/containerd/content"
+	cerrdefs "github.com/containerd/containerd/errdefs"
+	containerdimages "github.com/containerd/containerd/images"
+	cplatforms "github.com/containerd/containerd/platforms"
+	"github.com/docker/distribution/reference"
+	containertypes "github.com/docker/docker/api/types/container"
 	imagetype "github.com/docker/docker/api/types/image"
+	"github.com/docker/docker/daemon/images"
 	"github.com/docker/docker/errdefs"
 	"github.com/docker/docker/image"
+	"github.com/docker/docker/layer"
+	"github.com/docker/docker/pkg/platforms"
+	"github.com/docker/go-connections/nat"
+	"github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+	"golang.org/x/sync/semaphore"
 )
 
+var truncatedID = regexp.MustCompile(`^([a-f0-9]{4,64})$`)
+
 // GetImage returns an image corresponding to the image referred to by refOrID.
-func (i *ImageService) GetImage(ctx context.Context, refOrID string, options imagetype.GetImageOpts) (retImg *image.Image, retErr error) {
-	return nil, errdefs.NotImplemented(errors.New("not implemented"))
+func (i *ImageService) GetImage(ctx context.Context, refOrID string, options imagetype.GetImageOpts) (*image.Image, error) {
+	desc, err := i.resolveDescriptor(ctx, refOrID)
+	if err != nil {
+		return nil, err
+	}
+
+	platform := platforms.AllPlatformsWithPreference(cplatforms.Default())
+	if options.Platform != nil {
+		platform = cplatforms.OnlyStrict(*options.Platform)
+	}
+
+	cs := i.client.ContentStore()
+	conf, err := containerdimages.Config(ctx, cs, desc, platform)
+	if err != nil {
+		return nil, err
+	}
+
+	imageConfigBytes, err := content.ReadBlob(ctx, cs, conf)
+	if err != nil {
+		return nil, err
+	}
+
+	var ociimage ocispec.Image
+	if err := json.Unmarshal(imageConfigBytes, &ociimage); err != nil {
+		return nil, err
+	}
+
+	rootfs := image.NewRootFS()
+	for _, id := range ociimage.RootFS.DiffIDs {
+		rootfs.Append(layer.DiffID(id))
+	}
+	exposedPorts := make(nat.PortSet, len(ociimage.Config.ExposedPorts))
+	for k, v := range ociimage.Config.ExposedPorts {
+		exposedPorts[nat.Port(k)] = v
+	}
+
+	img := image.NewImage(image.ID(desc.Digest))
+	img.V1Image = image.V1Image{
+		ID:           string(desc.Digest),
+		OS:           ociimage.OS,
+		Architecture: ociimage.Architecture,
+		Config: &containertypes.Config{
+			Entrypoint:   ociimage.Config.Entrypoint,
+			Env:          ociimage.Config.Env,
+			Cmd:          ociimage.Config.Cmd,
+			User:         ociimage.Config.User,
+			WorkingDir:   ociimage.Config.WorkingDir,
+			ExposedPorts: exposedPorts,
+			Volumes:      ociimage.Config.Volumes,
+			Labels:       ociimage.Config.Labels,
+			StopSignal:   ociimage.Config.StopSignal,
+		},
+	}
+
+	img.RootFS = rootfs
+
+	if options.Details {
+		lastUpdated := time.Unix(0, 0)
+		size, err := i.size(ctx, desc, platform)
+		if err != nil {
+			return nil, err
+		}
+
+		tagged, err := i.client.ImageService().List(ctx, "target.digest=="+desc.Digest.String())
+		if err != nil {
+			return nil, err
+		}
+		tags := make([]reference.Named, 0, len(tagged))
+		for _, i := range tagged {
+			if i.UpdatedAt.After(lastUpdated) {
+				lastUpdated = i.UpdatedAt
+			}
+			name, err := reference.ParseNamed(i.Name)
+			if err != nil {
+				return nil, err
+			}
+			tags = append(tags, name)
+		}
+
+		img.Details = &image.Details{
+			References:  tags,
+			Size:        size,
+			Metadata:    nil,
+			Driver:      i.snapshotter,
+			LastUpdated: lastUpdated,
+		}
+	}
+
+	return img, nil
+}
+
+// size returns the total size of the image's packed resources.
+func (i *ImageService) size(ctx context.Context, desc ocispec.Descriptor, platform cplatforms.MatchComparer) (int64, error) {
+	var size int64
+
+	cs := i.client.ContentStore()
+	handler := containerdimages.LimitManifests(containerdimages.ChildrenHandler(cs), platform, 1)
+
+	var wh containerdimages.HandlerFunc = func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
+		children, err := handler(ctx, desc)
+		if err != nil {
+			if !cerrdefs.IsNotFound(err) {
+				return nil, err
+			}
+		}
+
+		atomic.AddInt64(&size, desc.Size)
+
+		return children, nil
+	}
+
+	l := semaphore.NewWeighted(3)
+	if err := containerdimages.Dispatch(ctx, wh, l, desc); err != nil {
+		return 0, err
+	}
+
+	return size, nil
+}
+
+// resolveDescriptor searches for a descriptor based on the given
+// reference or identifier. Returns the descriptor of
+// the image, which could be a manifest list, manifest, or config.
+func (i *ImageService) resolveDescriptor(ctx context.Context, refOrID string) (ocispec.Descriptor, error) {
+	parsed, err := reference.ParseAnyReference(refOrID)
+	if err != nil {
+		return ocispec.Descriptor{}, errdefs.InvalidParameter(err)
+	}
+
+	is := i.client.ImageService()
+
+	digested, ok := parsed.(reference.Digested)
+	if ok {
+		imgs, err := is.List(ctx, "target.digest=="+digested.Digest().String())
+		if err != nil {
+			return ocispec.Descriptor{}, errors.Wrap(err, "failed to lookup digest")
+		}
+		if len(imgs) == 0 {
+			return ocispec.Descriptor{}, images.ErrImageDoesNotExist{Ref: parsed}
+		}
+
+		return imgs[0].Target, nil
+	}
+
+	ref := reference.TagNameOnly(parsed.(reference.Named)).String()
+
+	// If the identifier could be a short ID, attempt to match
+	if truncatedID.MatchString(refOrID) {
+		filters := []string{
+			fmt.Sprintf("name==%q", ref), // Or it could just look like one.
+			"target.digest~=" + strconv.Quote(fmt.Sprintf(`sha256:^%s[0-9a-fA-F]{%d}$`, regexp.QuoteMeta(refOrID), 64-len(refOrID))),
+		}
+		imgs, err := is.List(ctx, filters...)
+		if err != nil {
+			return ocispec.Descriptor{}, err
+		}
+
+		if len(imgs) == 0 {
+			return ocispec.Descriptor{}, images.ErrImageDoesNotExist{Ref: parsed}
+		}
+		if len(imgs) > 1 {
+			digests := map[digest.Digest]struct{}{}
+			for _, img := range imgs {
+				if img.Name == ref {
+					return img.Target, nil
+				}
+				digests[img.Target.Digest] = struct{}{}
+			}
+
+			if len(digests) > 1 {
+				return ocispec.Descriptor{}, errdefs.NotFound(errors.New("ambiguous reference"))
+			}
+		}
+
+		return imgs[0].Target, nil
+	}
+
+	img, err := is.Get(ctx, ref)
+	if err != nil {
+		// TODO(containerd): error translation can use common function
+		if !cerrdefs.IsNotFound(err) {
+			return ocispec.Descriptor{}, err
+		}
+		return ocispec.Descriptor{}, images.ErrImageDoesNotExist{Ref: parsed}
+	}
+
+	return img.Target, nil
 }

daemon/images/image.go

@@ -24,11 +24,11 @@ import (
 
 // ErrImageDoesNotExist is error returned when no image can be found for a reference.
 type ErrImageDoesNotExist struct {
-	ref reference.Reference
+	Ref reference.Reference
 }
 
 func (e ErrImageDoesNotExist) Error() string {
-	ref := e.ref
+	ref := e.Ref
 	if named, ok := ref.(reference.Named); ok {
 		ref = reference.TagNameOnly(named)
 	}
@@ -176,6 +176,7 @@ func (i *ImageService) GetImage(ctx context.Context, refOrID string, options ima
 			return nil, err
 		}
 		img.Details = &image.Details{
+			References:  i.referenceStore.References(img.ID().Digest()),
 			Size:        size,
 			Metadata:    layerMetadata,
 			Driver:      i.layerStore.DriverName(),

image/image.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/docker/distribution/reference"
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/dockerversion"
 	"github.com/docker/docker/layer"
@@ -119,6 +120,7 @@ type Image struct {
 
 // Details provides additional image data
 type Details struct {
+	References  []reference.Named
 	Size        int64
 	Metadata    map[string]string
 	Driver      string
@@ -199,6 +201,13 @@ type ChildConfig struct {
 	Config          *container.Config
 }
 
+// NewImage creates a new image with the given ID
+func NewImage(id ID) *Image {
+	return &Image{
+		computedID: id,
+	}
+}
+
 // NewChildImage creates a new Image as a child of this image.
 func NewChildImage(img *Image, child ChildConfig, os string) *Image {
 	isEmptyLayer := layer.IsEmpty(child.DiffID)

pkg/platforms/platforms.go

@@ -0,0 +1,26 @@
+package platforms
+
+import (
+	cplatforms "github.com/containerd/containerd/platforms"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+type allPlatformsWithPreferenceMatcher struct {
+	preferred cplatforms.MatchComparer
+}
+
+// AllPlatformsWithPreference will return a platform matcher that matches all
+// platforms but will order platforms matching the preferred matcher first.
+func AllPlatformsWithPreference(preferred cplatforms.MatchComparer) cplatforms.MatchComparer {
+	return allPlatformsWithPreferenceMatcher{
+		preferred: preferred,
+	}
+}
+
+func (c allPlatformsWithPreferenceMatcher) Match(_ ocispec.Platform) bool {
+	return true
+}
+
+func (c allPlatformsWithPreferenceMatcher) Less(p1, p2 ocispec.Platform) bool {
+	return c.preferred.Less(p1, p2)
+}