Update dist pull to use client

Replaced pull unpacker with boolean to call unpack.
Added unpack and target to image type.
Updated progress logic for pull.
Added list images to client.
Updated rootfs unpacker to use client.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

client.go

@@ -2,7 +2,6 @@ package containerd
 
 import (
 	"context"
-	"encoding/json"
 	"io/ioutil"
 	"log"
 	"net/http"
@@ -21,7 +20,6 @@ import (
 	"github.com/containerd/containerd/images"
 	"github.com/containerd/containerd/remotes"
 	"github.com/containerd/containerd/remotes/docker"
-	"github.com/containerd/containerd/rootfs"
 	contentservice "github.com/containerd/containerd/services/content"
 	"github.com/containerd/containerd/services/diff"
 	diffservice "github.com/containerd/containerd/services/diff"
@@ -29,7 +27,6 @@ import (
 	snapshotservice "github.com/containerd/containerd/services/snapshot"
 	"github.com/containerd/containerd/snapshot"
 	"github.com/opencontainers/image-spec/identity"
-	"github.com/opencontainers/image-spec/specs-go/v1"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"google.golang.org/grpc"
@@ -205,10 +202,10 @@ type RemoteContext struct {
 	// If no resolver is provided, defaults to Docker registry resolver.
 	Resolver remotes.Resolver
 
-	// Unpacker is used after an image is pulled to extract into a registry.
+	// Unpack is done after an image is pulled to extract into a snapshotter.
 	// If an image is not unpacked on pull, it can be unpacked any time
 	// afterwards. Unpacking is required to run an image.
-	Unpacker Unpacker
+	Unpack bool
 
 	// PushWrapper allows hooking into the push method. This can be used
 	// track content that is being sent to the remote.
@@ -232,11 +229,7 @@ func defaultRemoteContext() *RemoteContext {
 // uses the snapshotter, content store, and diff service
 // configured for the client.
 func WithPullUnpack(client *Client, c *RemoteContext) error {
-	c.Unpacker = &snapshotUnpacker{
-		store:       client.ContentStore(),
-		diff:        client.DiffService(),
-		snapshotter: client.SnapshotService(),
-	}
+	c.Unpack = true
 	return nil
 }
 
@@ -265,55 +258,6 @@ func WithPushWrapper(w func(remotes.Pusher) remotes.Pusher) RemoteOpts {
 	}
 }
 
-type Unpacker interface {
-	Unpack(context.Context, images.Image) error
-}
-
-type snapshotUnpacker struct {
-	snapshotter snapshot.Snapshotter
-	store       content.Store
-	diff        diff.DiffService
-}
-
-func (s *snapshotUnpacker) Unpack(ctx context.Context, image images.Image) error {
-	layers, err := s.getLayers(ctx, image)
-	if err != nil {
-		return err
-	}
-	if _, err := rootfs.ApplyLayers(ctx, layers, s.snapshotter, s.diff); err != nil {
-		return err
-	}
-	return nil
-}
-
-func (s *snapshotUnpacker) getLayers(ctx context.Context, image images.Image) ([]rootfs.Layer, error) {
-	p, err := content.ReadBlob(ctx, s.store, image.Target.Digest)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to read manifest blob")
-	}
-	var manifest v1.Manifest
-	if err := json.Unmarshal(p, &manifest); err != nil {
-		return nil, errors.Wrap(err, "failed to unmarshal manifest")
-	}
-	diffIDs, err := image.RootFS(ctx, s.store)
-	if err != nil {
-		return nil, errors.Wrap(err, "failed to resolve rootfs")
-	}
-	if len(diffIDs) != len(manifest.Layers) {
-		return nil, errors.Errorf("mismatched image rootfs and manifest layers")
-	}
-	layers := make([]rootfs.Layer, len(diffIDs))
-	for i := range diffIDs {
-		layers[i].Diff = v1.Descriptor{
-			// TODO: derive media type from compressed type
-			MediaType: v1.MediaTypeImageLayer,
-			Digest:    diffIDs[i],
-		}
-		layers[i].Blob = manifest.Layers[i]
-	}
-	return layers, nil
-}
-
 func (c *Client) Pull(ctx context.Context, ref string, opts ...RemoteOpts) (Image, error) {
 	pullCtx := defaultRemoteContext()
 	for _, o := range opts {
@@ -347,27 +291,16 @@ func (c *Client) Pull(ctx context.Context, ref string, opts ...RemoteOpts) (Imag
 	if err != nil {
 		return nil, err
 	}
-	if pullCtx.Unpacker != nil {
-		if err := pullCtx.Unpacker.Unpack(ctx, i); err != nil {
+	img := &image{
+		client: c,
+		i:      i,
+	}
+	if pullCtx.Unpack {
+		if err := img.Unpack(ctx); err != nil {
 			return nil, err
 		}
 	}
-	return &image{
-		client: c,
-		i:      i,
-	}, nil
-}
-
-// GetImage returns an existing image
-func (c *Client) GetImage(ctx context.Context, ref string) (Image, error) {
-	i, err := c.ImageService().Get(ctx, ref)
-	if err != nil {
-		return nil, err
-	}
-	return &image{
-		client: c,
-		i:      i,
-	}, nil
+	return img, nil
 }
 
 func (c *Client) Push(ctx context.Context, ref string, desc ocispec.Descriptor, opts ...RemoteOpts) error {
@@ -426,6 +359,34 @@ func (c *Client) Push(ctx context.Context, ref string, desc ocispec.Descriptor,
 	return nil
 }
 
+// GetImage returns an existing image
+func (c *Client) GetImage(ctx context.Context, ref string) (Image, error) {
+	i, err := c.ImageService().Get(ctx, ref)
+	if err != nil {
+		return nil, err
+	}
+	return &image{
+		client: c,
+		i:      i,
+	}, nil
+}
+
+// ListImages returns all existing images
+func (c *Client) ListImages(ctx context.Context) ([]Image, error) {
+	imgs, err := c.ImageService().List(ctx)
+	if err != nil {
+		return nil, err
+	}
+	images := make([]Image, len(imgs))
+	for i, img := range imgs {
+		images[i] = &image{
+			client: c,
+			i:      img,
+		}
+	}
+	return images, nil
+}
+
 // Close closes the clients connection to containerd
 func (c *Client) Close() error {
 	return c.conn.Close()