Vendor integration dependencies.

integration/vendor/github.com/docker/docker/image/fs.go

@@ -0,0 +1,175 @@
+package image
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/distribution/digest"
+	"github.com/docker/docker/pkg/ioutils"
+)
+
+// IDWalkFunc is function called by StoreBackend.Walk
+type IDWalkFunc func(id ID) error
+
+// StoreBackend provides interface for image.Store persistence
+type StoreBackend interface {
+	Walk(f IDWalkFunc) error
+	Get(id ID) ([]byte, error)
+	Set(data []byte) (ID, error)
+	Delete(id ID) error
+	SetMetadata(id ID, key string, data []byte) error
+	GetMetadata(id ID, key string) ([]byte, error)
+	DeleteMetadata(id ID, key string) error
+}
+
+// fs implements StoreBackend using the filesystem.
+type fs struct {
+	sync.RWMutex
+	root string
+}
+
+const (
+	contentDirName  = "content"
+	metadataDirName = "metadata"
+)
+
+// NewFSStoreBackend returns new filesystem based backend for image.Store
+func NewFSStoreBackend(root string) (StoreBackend, error) {
+	return newFSStore(root)
+}
+
+func newFSStore(root string) (*fs, error) {
+	s := &fs{
+		root: root,
+	}
+	if err := os.MkdirAll(filepath.Join(root, contentDirName, string(digest.Canonical)), 0700); err != nil {
+		return nil, err
+	}
+	if err := os.MkdirAll(filepath.Join(root, metadataDirName, string(digest.Canonical)), 0700); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *fs) contentFile(id ID) string {
+	dgst := digest.Digest(id)
+	return filepath.Join(s.root, contentDirName, string(dgst.Algorithm()), dgst.Hex())
+}
+
+func (s *fs) metadataDir(id ID) string {
+	dgst := digest.Digest(id)
+	return filepath.Join(s.root, metadataDirName, string(dgst.Algorithm()), dgst.Hex())
+}
+
+// Walk calls the supplied callback for each image ID in the storage backend.
+func (s *fs) Walk(f IDWalkFunc) error {
+	// Only Canonical digest (sha256) is currently supported
+	s.RLock()
+	dir, err := ioutil.ReadDir(filepath.Join(s.root, contentDirName, string(digest.Canonical)))
+	s.RUnlock()
+	if err != nil {
+		return err
+	}
+	for _, v := range dir {
+		dgst := digest.NewDigestFromHex(string(digest.Canonical), v.Name())
+		if err := dgst.Validate(); err != nil {
+			logrus.Debugf("Skipping invalid digest %s: %s", dgst, err)
+			continue
+		}
+		if err := f(ID(dgst)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Get returns the content stored under a given ID.
+func (s *fs) Get(id ID) ([]byte, error) {
+	s.RLock()
+	defer s.RUnlock()
+
+	return s.get(id)
+}
+
+func (s *fs) get(id ID) ([]byte, error) {
+	content, err := ioutil.ReadFile(s.contentFile(id))
+	if err != nil {
+		return nil, err
+	}
+
+	// todo: maybe optional
+	if ID(digest.FromBytes(content)) != id {
+		return nil, fmt.Errorf("failed to verify image: %v", id)
+	}
+
+	return content, nil
+}
+
+// Set stores content under a given ID.
+func (s *fs) Set(data []byte) (ID, error) {
+	s.Lock()
+	defer s.Unlock()
+
+	if len(data) == 0 {
+		return "", fmt.Errorf("Invalid empty data")
+	}
+
+	id := ID(digest.FromBytes(data))
+	if err := ioutils.AtomicWriteFile(s.contentFile(id), data, 0600); err != nil {
+		return "", err
+	}
+
+	return id, nil
+}
+
+// Delete removes content and metadata files associated with the ID.
+func (s *fs) Delete(id ID) error {
+	s.Lock()
+	defer s.Unlock()
+
+	if err := os.RemoveAll(s.metadataDir(id)); err != nil {
+		return err
+	}
+	if err := os.Remove(s.contentFile(id)); err != nil {
+		return err
+	}
+	return nil
+}
+
+// SetMetadata sets metadata for a given ID. It fails if there's no base file.
+func (s *fs) SetMetadata(id ID, key string, data []byte) error {
+	s.Lock()
+	defer s.Unlock()
+	if _, err := s.get(id); err != nil {
+		return err
+	}
+
+	baseDir := filepath.Join(s.metadataDir(id))
+	if err := os.MkdirAll(baseDir, 0700); err != nil {
+		return err
+	}
+	return ioutils.AtomicWriteFile(filepath.Join(s.metadataDir(id), key), data, 0600)
+}
+
+// GetMetadata returns metadata for a given ID.
+func (s *fs) GetMetadata(id ID, key string) ([]byte, error) {
+	s.RLock()
+	defer s.RUnlock()
+
+	if _, err := s.get(id); err != nil {
+		return nil, err
+	}
+	return ioutil.ReadFile(filepath.Join(s.metadataDir(id), key))
+}
+
+// DeleteMetadata removes the metadata associated with an ID.
+func (s *fs) DeleteMetadata(id ID, key string) error {
+	s.Lock()
+	defer s.Unlock()
+
+	return os.RemoveAll(filepath.Join(s.metadataDir(id), key))
+}

integration/vendor/github.com/docker/docker/image/image.go

@@ -0,0 +1,140 @@
+package image
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"time"
+
+	"github.com/docker/distribution/digest"
+	"github.com/docker/engine-api/types/container"
+)
+
+// ID is the content-addressable ID of an image.
+type ID digest.Digest
+
+func (id ID) String() string {
+	return digest.Digest(id).String()
+}
+
+// V1Image stores the V1 image configuration.
+type V1Image struct {
+	// ID a unique 64 character identifier of the image
+	ID string `json:"id,omitempty"`
+	// Parent id of the image
+	Parent string `json:"parent,omitempty"`
+	// Comment user added comment
+	Comment string `json:"comment,omitempty"`
+	// Created timestamp when image was created
+	Created time.Time `json:"created"`
+	// Container is the id of the container used to commit
+	Container string `json:"container,omitempty"`
+	// ContainerConfig is the configuration of the container that is committed into the image
+	ContainerConfig container.Config `json:"container_config,omitempty"`
+	// DockerVersion specifies version on which image is built
+	DockerVersion string `json:"docker_version,omitempty"`
+	// Author of the image
+	Author string `json:"author,omitempty"`
+	// Config is the configuration of the container received from the client
+	Config *container.Config `json:"config,omitempty"`
+	// Architecture is the hardware that the image is build and runs on
+	Architecture string `json:"architecture,omitempty"`
+	// OS is the operating system used to build and run the image
+	OS string `json:"os,omitempty"`
+	// Size is the total size of the image including all layers it is composed of
+	Size int64 `json:",omitempty"`
+}
+
+// Image stores the image configuration
+type Image struct {
+	V1Image
+	Parent     ID        `json:"parent,omitempty"`
+	RootFS     *RootFS   `json:"rootfs,omitempty"`
+	History    []History `json:"history,omitempty"`
+	OSVersion  string    `json:"os.version,omitempty"`
+	OSFeatures []string  `json:"os.features,omitempty"`
+
+	// rawJSON caches the immutable JSON associated with this image.
+	rawJSON []byte
+
+	// computedID is the ID computed from the hash of the image config.
+	// Not to be confused with the legacy V1 ID in V1Image.
+	computedID ID
+}
+
+// RawJSON returns the immutable JSON associated with the image.
+func (img *Image) RawJSON() []byte {
+	return img.rawJSON
+}
+
+// ID returns the image's content-addressable ID.
+func (img *Image) ID() ID {
+	return img.computedID
+}
+
+// ImageID stringizes ID.
+func (img *Image) ImageID() string {
+	return string(img.ID())
+}
+
+// RunConfig returns the image's container config.
+func (img *Image) RunConfig() *container.Config {
+	return img.Config
+}
+
+// MarshalJSON serializes the image to JSON. It sorts the top-level keys so
+// that JSON that's been manipulated by a push/pull cycle with a legacy
+// registry won't end up with a different key order.
+func (img *Image) MarshalJSON() ([]byte, error) {
+	type MarshalImage Image
+
+	pass1, err := json.Marshal(MarshalImage(*img))
+	if err != nil {
+		return nil, err
+	}
+
+	var c map[string]*json.RawMessage
+	if err := json.Unmarshal(pass1, &c); err != nil {
+		return nil, err
+	}
+	return json.Marshal(c)
+}
+
+// History stores build commands that were used to create an image
+type History struct {
+	// Created timestamp for build point
+	Created time.Time `json:"created"`
+	// Author of the build point
+	Author string `json:"author,omitempty"`
+	// CreatedBy keeps the Dockerfile command used while building image.
+	CreatedBy string `json:"created_by,omitempty"`
+	// Comment is custom message set by the user when creating the image.
+	Comment string `json:"comment,omitempty"`
+	// EmptyLayer is set to true if this history item did not generate a
+	// layer. Otherwise, the history item is associated with the next
+	// layer in the RootFS section.
+	EmptyLayer bool `json:"empty_layer,omitempty"`
+}
+
+// Exporter provides interface for exporting and importing images
+type Exporter interface {
+	Load(io.ReadCloser, io.Writer, bool) error
+	// TODO: Load(net.Context, io.ReadCloser, <- chan StatusMessage) error
+	Save([]string, io.Writer) error
+}
+
+// NewFromJSON creates an Image configuration from json.
+func NewFromJSON(src []byte) (*Image, error) {
+	img := &Image{}
+
+	if err := json.Unmarshal(src, img); err != nil {
+		return nil, err
+	}
+	if img.RootFS == nil {
+		return nil, errors.New("Invalid image JSON, no RootFS key.")
+	}
+
+	img.rawJSON = src
+
+	return img, nil
+}

integration/vendor/github.com/docker/docker/image/rootfs.go

@@ -0,0 +1,16 @@
+package image
+
+import "github.com/docker/docker/layer"
+
+// TypeLayers is used for RootFS.Type for filesystems organized into layers.
+const TypeLayers = "layers"
+
+// NewRootFS returns empty RootFS struct
+func NewRootFS() *RootFS {
+	return &RootFS{Type: TypeLayers}
+}
+
+// Append appends a new diffID to rootfs
+func (r *RootFS) Append(id layer.DiffID) {
+	r.DiffIDs = append(r.DiffIDs, id)
+}

integration/vendor/github.com/docker/docker/image/rootfs_unix.go

@@ -0,0 +1,18 @@
+// +build !windows
+
+package image
+
+import "github.com/docker/docker/layer"
+
+// RootFS describes images root filesystem
+// This is currently a placeholder that only supports layers. In the future
+// this can be made into an interface that supports different implementations.
+type RootFS struct {
+	Type    string         `json:"type"`
+	DiffIDs []layer.DiffID `json:"diff_ids,omitempty"`
+}
+
+// ChainID returns the ChainID for the top layer in RootFS.
+func (r *RootFS) ChainID() layer.ChainID {
+	return layer.CreateChainID(r.DiffIDs)
+}

integration/vendor/github.com/docker/docker/image/rootfs_windows.go

@@ -0,0 +1,48 @@
+// +build windows
+
+package image
+
+import (
+	"crypto/sha512"
+	"fmt"
+
+	"github.com/docker/distribution/digest"
+	"github.com/docker/docker/layer"
+)
+
+// TypeLayersWithBase is used for RootFS.Type for Windows filesystems that have layers and a centrally-stored base layer.
+const TypeLayersWithBase = "layers+base"
+
+// RootFS describes images root filesystem
+// This is currently a placeholder that only supports layers. In the future
+// this can be made into an interface that supports different implementations.
+type RootFS struct {
+	Type      string         `json:"type"`
+	DiffIDs   []layer.DiffID `json:"diff_ids,omitempty"`
+	BaseLayer string         `json:"base_layer,omitempty"`
+}
+
+// BaseLayerID returns the 64 byte hex ID for the baselayer name.
+func (r *RootFS) BaseLayerID() string {
+	if r.Type != TypeLayersWithBase {
+		panic("tried to get base layer ID without a base layer")
+	}
+	baseID := sha512.Sum384([]byte(r.BaseLayer))
+	return fmt.Sprintf("%x", baseID[:32])
+}
+
+// ChainID returns the ChainID for the top layer in RootFS.
+func (r *RootFS) ChainID() layer.ChainID {
+	ids := r.DiffIDs
+	if r.Type == TypeLayersWithBase {
+		// Add an extra ID for the base.
+		baseDiffID := layer.DiffID(digest.FromBytes([]byte(r.BaseLayerID())))
+		ids = append([]layer.DiffID{baseDiffID}, ids...)
+	}
+	return layer.CreateChainID(ids)
+}
+
+// NewRootFSWithBaseLayer returns a RootFS struct with a base layer
+func NewRootFSWithBaseLayer(baseLayer string) *RootFS {
+	return &RootFS{Type: TypeLayersWithBase, BaseLayer: baseLayer}
+}

integration/vendor/github.com/docker/docker/image/store.go

@@ -0,0 +1,295 @@
+package image
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/distribution/digest"
+	"github.com/docker/docker/layer"
+)
+
+// Store is an interface for creating and accessing images
+type Store interface {
+	Create(config []byte) (ID, error)
+	Get(id ID) (*Image, error)
+	Delete(id ID) ([]layer.Metadata, error)
+	Search(partialID string) (ID, error)
+	SetParent(id ID, parent ID) error
+	GetParent(id ID) (ID, error)
+	Children(id ID) []ID
+	Map() map[ID]*Image
+	Heads() map[ID]*Image
+}
+
+// LayerGetReleaser is a minimal interface for getting and releasing images.
+type LayerGetReleaser interface {
+	Get(layer.ChainID) (layer.Layer, error)
+	Release(layer.Layer) ([]layer.Metadata, error)
+}
+
+type imageMeta struct {
+	layer    layer.Layer
+	children map[ID]struct{}
+}
+
+type store struct {
+	sync.Mutex
+	ls        LayerGetReleaser
+	images    map[ID]*imageMeta
+	fs        StoreBackend
+	digestSet *digest.Set
+}
+
+// NewImageStore returns new store object for given layer store
+func NewImageStore(fs StoreBackend, ls LayerGetReleaser) (Store, error) {
+	is := &store{
+		ls:        ls,
+		images:    make(map[ID]*imageMeta),
+		fs:        fs,
+		digestSet: digest.NewSet(),
+	}
+
+	// load all current images and retain layers
+	if err := is.restore(); err != nil {
+		return nil, err
+	}
+
+	return is, nil
+}
+
+func (is *store) restore() error {
+	err := is.fs.Walk(func(id ID) error {
+		img, err := is.Get(id)
+		if err != nil {
+			logrus.Errorf("invalid image %v, %v", id, err)
+			return nil
+		}
+		var l layer.Layer
+		if chainID := img.RootFS.ChainID(); chainID != "" {
+			l, err = is.ls.Get(chainID)
+			if err != nil {
+				return err
+			}
+		}
+		if err := is.digestSet.Add(digest.Digest(id)); err != nil {
+			return err
+		}
+
+		imageMeta := &imageMeta{
+			layer:    l,
+			children: make(map[ID]struct{}),
+		}
+
+		is.images[ID(id)] = imageMeta
+
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	// Second pass to fill in children maps
+	for id := range is.images {
+		if parent, err := is.GetParent(id); err == nil {
+			if parentMeta := is.images[parent]; parentMeta != nil {
+				parentMeta.children[id] = struct{}{}
+			}
+		}
+	}
+
+	return nil
+}
+
+func (is *store) Create(config []byte) (ID, error) {
+	var img Image
+	err := json.Unmarshal(config, &img)
+	if err != nil {
+		return "", err
+	}
+
+	// Must reject any config that references diffIDs from the history
+	// which aren't among the rootfs layers.
+	rootFSLayers := make(map[layer.DiffID]struct{})
+	for _, diffID := range img.RootFS.DiffIDs {
+		rootFSLayers[diffID] = struct{}{}
+	}
+
+	layerCounter := 0
+	for _, h := range img.History {
+		if !h.EmptyLayer {
+			layerCounter++
+		}
+	}
+	if layerCounter > len(img.RootFS.DiffIDs) {
+		return "", errors.New("too many non-empty layers in History section")
+	}
+
+	dgst, err := is.fs.Set(config)
+	if err != nil {
+		return "", err
+	}
+	imageID := ID(dgst)
+
+	is.Lock()
+	defer is.Unlock()
+
+	if _, exists := is.images[imageID]; exists {
+		return imageID, nil
+	}
+
+	layerID := img.RootFS.ChainID()
+
+	var l layer.Layer
+	if layerID != "" {
+		l, err = is.ls.Get(layerID)
+		if err != nil {
+			return "", err
+		}
+	}
+
+	imageMeta := &imageMeta{
+		layer:    l,
+		children: make(map[ID]struct{}),
+	}
+
+	is.images[imageID] = imageMeta
+	if err := is.digestSet.Add(digest.Digest(imageID)); err != nil {
+		delete(is.images, imageID)
+		return "", err
+	}
+
+	return imageID, nil
+}
+
+func (is *store) Search(term string) (ID, error) {
+	is.Lock()
+	defer is.Unlock()
+
+	dgst, err := is.digestSet.Lookup(term)
+	if err != nil {
+		if err == digest.ErrDigestNotFound {
+			err = fmt.Errorf("No such image: %s", term)
+		}
+		return "", err
+	}
+	return ID(dgst), nil
+}
+
+func (is *store) Get(id ID) (*Image, error) {
+	// todo: Check if image is in images
+	// todo: Detect manual insertions and start using them
+	config, err := is.fs.Get(id)
+	if err != nil {
+		return nil, err
+	}
+
+	img, err := NewFromJSON(config)
+	if err != nil {
+		return nil, err
+	}
+	img.computedID = id
+
+	img.Parent, err = is.GetParent(id)
+	if err != nil {
+		img.Parent = ""
+	}
+
+	return img, nil
+}
+
+func (is *store) Delete(id ID) ([]layer.Metadata, error) {
+	is.Lock()
+	defer is.Unlock()
+
+	imageMeta := is.images[id]
+	if imageMeta == nil {
+		return nil, fmt.Errorf("unrecognized image ID %s", id.String())
+	}
+	for id := range imageMeta.children {
+		is.fs.DeleteMetadata(id, "parent")
+	}
+	if parent, err := is.GetParent(id); err == nil && is.images[parent] != nil {
+		delete(is.images[parent].children, id)
+	}
+
+	if err := is.digestSet.Remove(digest.Digest(id)); err != nil {
+		logrus.Errorf("error removing %s from digest set: %q", id, err)
+	}
+	delete(is.images, id)
+	is.fs.Delete(id)
+
+	if imageMeta.layer != nil {
+		return is.ls.Release(imageMeta.layer)
+	}
+	return nil, nil
+}
+
+func (is *store) SetParent(id, parent ID) error {
+	is.Lock()
+	defer is.Unlock()
+	parentMeta := is.images[parent]
+	if parentMeta == nil {
+		return fmt.Errorf("unknown parent image ID %s", parent.String())
+	}
+	if parent, err := is.GetParent(id); err == nil && is.images[parent] != nil {
+		delete(is.images[parent].children, id)
+	}
+	parentMeta.children[id] = struct{}{}
+	return is.fs.SetMetadata(id, "parent", []byte(parent))
+}
+
+func (is *store) GetParent(id ID) (ID, error) {
+	d, err := is.fs.GetMetadata(id, "parent")
+	if err != nil {
+		return "", err
+	}
+	return ID(d), nil // todo: validate?
+}
+
+func (is *store) Children(id ID) []ID {
+	is.Lock()
+	defer is.Unlock()
+
+	return is.children(id)
+}
+
+func (is *store) children(id ID) []ID {
+	var ids []ID
+	if is.images[id] != nil {
+		for id := range is.images[id].children {
+			ids = append(ids, id)
+		}
+	}
+	return ids
+}
+
+func (is *store) Heads() map[ID]*Image {
+	return is.imagesMap(false)
+}
+
+func (is *store) Map() map[ID]*Image {
+	return is.imagesMap(true)
+}
+
+func (is *store) imagesMap(all bool) map[ID]*Image {
+	is.Lock()
+	defer is.Unlock()
+
+	images := make(map[ID]*Image)
+
+	for id := range is.images {
+		if !all && len(is.children(id)) > 0 {
+			continue
+		}
+		img, err := is.Get(id)
+		if err != nil {
+			logrus.Errorf("invalid image access: %q, error: %q", id, err)
+			continue
+		}
+		images[id] = img
+	}
+	return images
+}

integration/vendor/github.com/docker/docker/image/v1/imagev1.go

@@ -0,0 +1,156 @@
+package v1
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"regexp"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/distribution/digest"
+	"github.com/docker/docker/image"
+	"github.com/docker/docker/layer"
+	"github.com/docker/engine-api/types/versions"
+)
+
+var validHex = regexp.MustCompile(`^([a-f0-9]{64})$`)
+
+// noFallbackMinVersion is the minimum version for which v1compatibility
+// information will not be marshaled through the Image struct to remove
+// blank fields.
+var noFallbackMinVersion = "1.8.3"
+
+// HistoryFromConfig creates a History struct from v1 configuration JSON
+func HistoryFromConfig(imageJSON []byte, emptyLayer bool) (image.History, error) {
+	h := image.History{}
+	var v1Image image.V1Image
+	if err := json.Unmarshal(imageJSON, &v1Image); err != nil {
+		return h, err
+	}
+
+	return image.History{
+		Author:     v1Image.Author,
+		Created:    v1Image.Created,
+		CreatedBy:  strings.Join(v1Image.ContainerConfig.Cmd, " "),
+		Comment:    v1Image.Comment,
+		EmptyLayer: emptyLayer,
+	}, nil
+}
+
+// CreateID creates an ID from v1 image, layerID and parent ID.
+// Used for backwards compatibility with old clients.
+func CreateID(v1Image image.V1Image, layerID layer.ChainID, parent digest.Digest) (digest.Digest, error) {
+	v1Image.ID = ""
+	v1JSON, err := json.Marshal(v1Image)
+	if err != nil {
+		return "", err
+	}
+
+	var config map[string]*json.RawMessage
+	if err := json.Unmarshal(v1JSON, &config); err != nil {
+		return "", err
+	}
+
+	// FIXME: note that this is slightly incompatible with RootFS logic
+	config["layer_id"] = rawJSON(layerID)
+	if parent != "" {
+		config["parent"] = rawJSON(parent)
+	}
+
+	configJSON, err := json.Marshal(config)
+	if err != nil {
+		return "", err
+	}
+	logrus.Debugf("CreateV1ID %s", configJSON)
+
+	return digest.FromBytes(configJSON), nil
+}
+
+// MakeConfigFromV1Config creates an image config from the legacy V1 config format.
+func MakeConfigFromV1Config(imageJSON []byte, rootfs *image.RootFS, history []image.History) ([]byte, error) {
+	var dver struct {
+		DockerVersion string `json:"docker_version"`
+	}
+
+	if err := json.Unmarshal(imageJSON, &dver); err != nil {
+		return nil, err
+	}
+
+	useFallback := versions.LessThan(dver.DockerVersion, noFallbackMinVersion)
+
+	if useFallback {
+		var v1Image image.V1Image
+		err := json.Unmarshal(imageJSON, &v1Image)
+		if err != nil {
+			return nil, err
+		}
+		imageJSON, err = json.Marshal(v1Image)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var c map[string]*json.RawMessage
+	if err := json.Unmarshal(imageJSON, &c); err != nil {
+		return nil, err
+	}
+
+	delete(c, "id")
+	delete(c, "parent")
+	delete(c, "Size") // Size is calculated from data on disk and is inconsistent
+	delete(c, "parent_id")
+	delete(c, "layer_id")
+	delete(c, "throwaway")
+
+	c["rootfs"] = rawJSON(rootfs)
+	c["history"] = rawJSON(history)
+
+	return json.Marshal(c)
+}
+
+// MakeV1ConfigFromConfig creates an legacy V1 image config from an Image struct
+func MakeV1ConfigFromConfig(img *image.Image, v1ID, parentV1ID string, throwaway bool) ([]byte, error) {
+	// Top-level v1compatibility string should be a modified version of the
+	// image config.
+	var configAsMap map[string]*json.RawMessage
+	if err := json.Unmarshal(img.RawJSON(), &configAsMap); err != nil {
+		return nil, err
+	}
+
+	// Delete fields that didn't exist in old manifest
+	imageType := reflect.TypeOf(img).Elem()
+	for i := 0; i < imageType.NumField(); i++ {
+		f := imageType.Field(i)
+		jsonName := strings.Split(f.Tag.Get("json"), ",")[0]
+		// Parent is handled specially below.
+		if jsonName != "" && jsonName != "parent" {
+			delete(configAsMap, jsonName)
+		}
+	}
+	configAsMap["id"] = rawJSON(v1ID)
+	if parentV1ID != "" {
+		configAsMap["parent"] = rawJSON(parentV1ID)
+	}
+	if throwaway {
+		configAsMap["throwaway"] = rawJSON(true)
+	}
+
+	return json.Marshal(configAsMap)
+}
+
+func rawJSON(value interface{}) *json.RawMessage {
+	jsonval, err := json.Marshal(value)
+	if err != nil {
+		return nil
+	}
+	return (*json.RawMessage)(&jsonval)
+}
+
+// ValidateID checks whether an ID string is a valid image ID.
+func ValidateID(id string) error {
+	if ok := validHex.MatchString(id); !ok {
+		return fmt.Errorf("image ID %q is invalid", id)
+	}
+	return nil
+}