add optional check that snapshotter supports the image platform when unpacking

Signed-off-by: Kathryn Baldauf <kabaldau@microsoft.com>

client.go

@@ -39,6 +39,7 @@ import (
 	snapshotsapi "github.com/containerd/containerd/api/services/snapshots/v1"
 	"github.com/containerd/containerd/api/services/tasks/v1"
 	versionservice "github.com/containerd/containerd/api/services/version/v1"
+	apitypes "github.com/containerd/containerd/api/types"
 	"github.com/containerd/containerd/containers"
 	"github.com/containerd/containerd/content"
 	contentproxy "github.com/containerd/containerd/content/proxy"
@@ -782,3 +783,33 @@ func CheckRuntime(current, expected string) bool {
 	}
 	return true
 }
+
+func (c *Client) GetSnapshotterSupportedPlatforms(ctx context.Context, snapshotterName string) (platforms.MatchComparer, error) {
+	filters := []string{fmt.Sprintf("type==%s, id==%s", plugin.SnapshotPlugin, snapshotterName)}
+	in := c.IntrospectionService()
+
+	resp, err := in.Plugins(ctx, filters)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(resp.Plugins) <= 0 {
+		return nil, fmt.Errorf("inspection service could not find snapshotter %s plugin", snapshotterName)
+	}
+
+	sn := resp.Plugins[0]
+	snPlatforms := toPlatforms(sn.Platforms)
+	return platforms.Any(snPlatforms...), nil
+}
+
+func toPlatforms(pt []apitypes.Platform) []ocispec.Platform {
+	platforms := make([]ocispec.Platform, len(pt))
+	for i, p := range pt {
+		platforms[i] = ocispec.Platform{
+			Architecture: p.Architecture,
+			OS:           p.OS,
+			Variant:      p.Variant,
+		}
+	}
+	return platforms
+}

client_test.go

@@ -137,7 +137,7 @@ func TestMain(m *testing.M) {
 	}).Info("running tests against containerd")
 
 	// pull a seed image
-	log.G(ctx).Info("start to pull seed image")
+	log.G(ctx).WithField("image", testImage).Info("start to pull seed image")
 	if _, err = client.Pull(ctx, testImage, WithPullUnpack); err != nil {
 		fmt.Fprintf(os.Stderr, "%s: %s\n", err, buf.String())
 		ctrd.Kill()

image.go

@@ -18,6 +18,7 @@ package containerd
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"strings"
 	"sync/atomic"
@@ -281,11 +282,22 @@ type UnpackConfig struct {
 	ApplyOpts []diff.ApplyOpt
 	// SnapshotOpts for configuring a snapshotter
 	SnapshotOpts []snapshots.Opt
+	// CheckPlatformSupported is whether to validate that a snapshotter
+	// supports an image's platform before unpacking
+	CheckPlatformSupported bool
 }
 
 // UnpackOpt provides configuration for unpack
 type UnpackOpt func(context.Context, *UnpackConfig) error
 
+// WithSnapshotterPlatformCheck sets `CheckPlatformSupported` on the UnpackConfig
+func WithSnapshotterPlatformCheck() UnpackOpt {
+	return func(ctx context.Context, uc *UnpackConfig) error {
+		uc.CheckPlatformSupported = true
+		return nil
+	}
+}
+
 func (i *image) Unpack(ctx context.Context, snapshotterName string, opts ...UnpackOpt) error {
 	ctx, done, err := i.client.WithLease(ctx)
 	if err != nil {
@@ -300,7 +312,12 @@ func (i *image) Unpack(ctx context.Context, snapshotterName string, opts ...Unpa
 		}
 	}
 
-	layers, err := i.getLayers(ctx, i.platform)
+	manifest, err := i.getManifest(ctx, i.platform)
+	if err != nil {
+		return err
+	}
+
+	layers, err := i.getLayers(ctx, i.platform, manifest)
 	if err != nil {
 		return err
 	}
@@ -320,6 +337,12 @@ func (i *image) Unpack(ctx context.Context, snapshotterName string, opts ...Unpa
 	if err != nil {
 		return err
 	}
+	if config.CheckPlatformSupported {
+		if err := i.checkSnapshotterSupport(ctx, snapshotterName, manifest); err != nil {
+			return err
+		}
+	}
+
 	for _, layer := range layers {
 		unpacked, err = rootfs.ApplyLayerWithOpts(ctx, layer, chain, sn, a, config.SnapshotOpts, config.ApplyOpts)
 		if err != nil {
@@ -361,14 +384,17 @@ func (i *image) Unpack(ctx context.Context, snapshotterName string, opts ...Unpa
 	return err
 }
 
-func (i *image) getLayers(ctx context.Context, platform platforms.MatchComparer) ([]rootfs.Layer, error) {
-	cs := i.client.ContentStore()
-
+func (i *image) getManifest(ctx context.Context, platform platforms.MatchComparer) (ocispec.Manifest, error) {
+	cs := i.ContentStore()
 	manifest, err := images.Manifest(ctx, cs, i.i.Target, platform)
 	if err != nil {
-		return nil, err
+		return ocispec.Manifest{}, err
 	}
+	return manifest, nil
+}
 
+func (i *image) getLayers(ctx context.Context, platform platforms.MatchComparer, manifest ocispec.Manifest) ([]rootfs.Layer, error) {
+	cs := i.ContentStore()
 	diffIDs, err := i.i.RootFS(ctx, cs, platform)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to resolve rootfs")
@@ -388,6 +414,37 @@ func (i *image) getLayers(ctx context.Context, platform platforms.MatchComparer)
 	return layers, nil
 }
 
+func (i *image) getManifestPlatform(ctx context.Context, manifest ocispec.Manifest) (ocispec.Platform, error) {
+	cs := i.ContentStore()
+	p, err := content.ReadBlob(ctx, cs, manifest.Config)
+	if err != nil {
+		return ocispec.Platform{}, err
+	}
+
+	var image ocispec.Image
+	if err := json.Unmarshal(p, &image); err != nil {
+		return ocispec.Platform{}, err
+	}
+	return platforms.Normalize(ocispec.Platform{OS: image.OS, Architecture: image.Architecture}), nil
+}
+
+func (i *image) checkSnapshotterSupport(ctx context.Context, snapshotterName string, manifest ocispec.Manifest) error {
+	snapshotterPlatformMatcher, err := i.client.GetSnapshotterSupportedPlatforms(ctx, snapshotterName)
+	if err != nil {
+		return err
+	}
+
+	manifestPlatform, err := i.getManifestPlatform(ctx, manifest)
+	if err != nil {
+		return err
+	}
+
+	if snapshotterPlatformMatcher.Match(manifestPlatform) {
+		return nil
+	}
+	return fmt.Errorf("snapshotter %s does not support platform %s for image %s", snapshotterName, manifestPlatform, manifest.Config.Digest)
+}
+
 func (i *image) ContentStore() content.Store {
 	return i.client.ContentStore()
 }

image_test.go

@@ -81,6 +81,9 @@ func TestImageIsUnpacked(t *testing.T) {
 }
 
 func TestImagePullWithDistSourceLabel(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip()
+	}
 	var (
 		source   = "docker.io"
 		repoName = "library/busybox"
@@ -233,3 +236,39 @@ func TestImageUsage(t *testing.T) {
 		t.Fatalf("Expected actual usage with snapshots to be greater: %d <= %d", s, s3)
 	}
 }
+
+func TestImageSupportedBySnapshotter_Error(t *testing.T) {
+	var unsupportedImage string
+	if runtime.GOOS == "windows" {
+		unsupportedImage = "docker.io/library/busybox:latest"
+	} else {
+		unsupportedImage = "mcr.microsoft.com/windows/nanoserver:1809"
+	}
+
+	ctx, cancel := testContext(t)
+	defer cancel()
+
+	client, err := newClient(t, address)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer client.Close()
+
+	// Cleanup
+	err = client.ImageService().Delete(ctx, unsupportedImage)
+	if err != nil && !errdefs.IsNotFound(err) {
+		t.Fatal(err)
+	}
+
+	_, err = client.Pull(ctx, unsupportedImage,
+		WithSchema1Conversion,
+		WithPlatform(platforms.DefaultString()),
+		WithPullSnapshotter(DefaultSnapshotter),
+		WithPullUnpack,
+		WithUnpackOpts([]UnpackOpt{WithSnapshotterPlatformCheck()}),
+	)
+
+	if err == nil {
+		t.Fatalf("expected unpacking %s for snapshotter %s to fail", unsupportedImage, DefaultSnapshotter)
+	}
+}

services/introspection/introspection.go

@@ -21,6 +21,7 @@ import (
 
 	api "github.com/containerd/containerd/api/services/introspection/v1"
 	"github.com/containerd/containerd/errdefs"
+	"github.com/containerd/containerd/log"
 	ptypes "github.com/gogo/protobuf/types"
 )
 
@@ -40,6 +41,7 @@ func NewIntrospectionServiceFromClient(c api.IntrospectionClient) Service {
 }
 
 func (i *introspectionRemote) Plugins(ctx context.Context, filters []string) (*api.PluginsResponse, error) {
+	log.G(ctx).WithField("filters", filters).Info("remote introspection plugin filters")
 	resp, err := i.client.Plugins(ctx, &api.PluginsRequest{
 		Filters: filters,
 	})

snapshots/windows/windows.go

@@ -32,10 +32,12 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/log"
 	"github.com/containerd/containerd/mount"
+	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/containerd/snapshots/storage"
 	"github.com/containerd/continuity/fs"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 )
 
@@ -44,6 +46,7 @@ func init() {
 		Type: plugin.SnapshotPlugin,
 		ID:   "windows",
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
+			ic.Meta.Platforms = []ocispec.Platform{platforms.DefaultSpec()}
 			return NewSnapshotter(ic.Root)
 		},
 	})

unpacker.go

@@ -31,6 +31,7 @@ import (
 	"github.com/containerd/containerd/images"
 	"github.com/containerd/containerd/log"
 	"github.com/containerd/containerd/mount"
+	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/opencontainers/go-digest"
 	"github.com/opencontainers/image-spec/identity"
@@ -93,6 +94,17 @@ func (u *unpacker) unpack(
 		return errors.Errorf("number of layers and diffIDs don't match: %d != %d", len(layers), len(diffIDs))
 	}
 
+	if u.config.CheckPlatformSupported {
+		imgPlatform := platforms.Normalize(ocispec.Platform{OS: i.OS, Architecture: i.Architecture})
+		snapshotterPlatformMatcher, err := u.c.GetSnapshotterSupportedPlatforms(ctx, u.snapshotter)
+		if err != nil {
+			return errors.Wrapf(err, "failed to find supported platforms for snapshotter %s", u.snapshotter)
+		}
+		if !snapshotterPlatformMatcher.Match(imgPlatform) {
+			return fmt.Errorf("snapshotter %s does not support platform %s for image %s", u.snapshotter, imgPlatform, config.Digest)
+		}
+	}
+
 	var (
 		sn = u.c.SnapshotService(u.snapshotter)
 		a  = u.c.DiffService()