@@ -27,6 +27,7 @@ import (

 	pkgprogress "github.com/docker/docker/pkg/progress"

 	"github.com/docker/docker/reference"

 	"github.com/moby/buildkit/cache"

+	gw "github.com/moby/buildkit/frontend/gateway/client"

 	"github.com/moby/buildkit/session"

 	"github.com/moby/buildkit/session/auth"

 	"github.com/moby/buildkit/source"

@@ -113,7 +114,7 @@ func (is *imageSource) resolveLocal(refStr string) ([]byte, error) {

 	return img.RawJSON(), nil

 }

-func (is *imageSource) ResolveImageConfig(ctx context.Context, ref string, platform *ocispec.Platform) (digest.Digest, []byte, error) {

+func (is *imageSource) ResolveImageConfig(ctx context.Context, ref string, opt gw.ResolveImageConfigOpt) (digest.Digest, []byte, error) {

 	if preferLocal {

 		dt, err := is.resolveLocal(ref)

 		if err == nil {

@@ -126,7 +127,7 @@ func (is *imageSource) ResolveImageConfig(ctx context.Context, ref string, platf

 		dt   []byte

 	}

 	res, err := is.g.Do(ctx, ref, func(ctx context.Context) (interface{}, error) {

-		dgst, dt, err := imageutil.Config(ctx, ref, is.getResolver(ctx), is.ContentStore, platform)

+		dgst, dt, err := imageutil.Config(ctx, ref, is.getResolver(ctx), is.ContentStore, opt.Platform)

 		if err != nil {

 			return nil, err

 		}

@@ -257,7 +258,7 @@ func (p *puller) resolve(ctx context.Context) error {

 				return

 			}

-			_, dt, err := p.is.ResolveImageConfig(ctx, ref.String(), &p.platform)

+			_, dt, err := p.is.ResolveImageConfig(ctx, ref.String(), gw.ResolveImageConfigOpt{Platform: &p.platform})

 			if err != nil {

 				p.resolveErr = err

 				resolveProgressDone(err)

@@ -2,6 +2,7 @@ package containerimage

 import (

 	"context"

+	"encoding/json"

 	"fmt"

 	"strings"

@@ -9,15 +10,15 @@ import (

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/layer"

 	"github.com/docker/docker/reference"

-	"github.com/moby/buildkit/cache"

 	"github.com/moby/buildkit/exporter"

+	"github.com/moby/buildkit/exporter/containerimage/exptypes"

 	digest "github.com/opencontainers/go-digest"

+	"github.com/pkg/errors"

 	"github.com/sirupsen/logrus"

 )

 const (

-	keyImageName        = "name"

-	exporterImageConfig = "containerimage.config"

+	keyImageName = "name"

 )

 // Differ can make a moby layer from a snapshot

@@ -54,8 +55,11 @@ func (e *imageExporter) Resolve(ctx context.Context, opt map[string]string) (exp

 				}

 				i.targetNames = append(i.targetNames, ref)

 			}

-		case exporterImageConfig:

-			i.config = []byte(v)

+		case exptypes.ExporterImageConfigKey:

+			if i.meta == nil {

+				i.meta = make(map[string][]byte)

+			}

+			i.meta[k] = []byte(v)

 		default:

 			logrus.Warnf("image exporter: unknown option %s", k)

 		}

@@ -66,18 +70,47 @@ func (e *imageExporter) Resolve(ctx context.Context, opt map[string]string) (exp

 type imageExporterInstance struct {

 	*imageExporter

 	targetNames []distref.Named

-	config      []byte

+	meta        map[string][]byte

 }

 func (e *imageExporterInstance) Name() string {

 	return "exporting to image"

 }

-func (e *imageExporterInstance) Export(ctx context.Context, ref cache.ImmutableRef, opt map[string][]byte) (map[string]string, error) {

-	if config, ok := opt[exporterImageConfig]; ok {

-		e.config = config

+func (e *imageExporterInstance) Export(ctx context.Context, inp exporter.Source) (map[string]string, error) {

+

+	if len(inp.Refs) > 1 {

+		return nil, fmt.Errorf("exporting multiple references to image store is currently unsupported")

+	}

+

+	ref := inp.Ref

+	if ref != nil && len(inp.Refs) == 1 {

+		return nil, fmt.Errorf("invalid exporter input: Ref and Refs are mutually exclusive")

+	}

+

+	// only one loop

+	for _, v := range inp.Refs {

+		ref = v

+	}

+

+	var config []byte

+	switch len(inp.Refs) {

+	case 0:

+		config = inp.Metadata[exptypes.ExporterImageConfigKey]

+	case 1:

+		platformsBytes, ok := inp.Metadata[exptypes.ExporterPlatformsKey]

+		if !ok {

+			return nil, fmt.Errorf("cannot export image, missing platforms mapping")

+		}

+		var p exptypes.Platforms

+		if err := json.Unmarshal(platformsBytes, &p); err != nil {

+			return nil, errors.Wrapf(err, "failed to parse platforms passed to exporter")

+		}

+		if len(p.Platforms) != len(inp.Refs) {

+			return nil, errors.Errorf("number of platforms does not match references %d %d", len(p.Platforms), len(inp.Refs))

+		}

+		config = inp.Metadata[fmt.Sprintf("%s/%s", exptypes.ExporterImageConfigKey, p.Platforms[0].ID)]

 	}

-	config := e.config

 	var diffs []digest.Digest

 	if ref != nil {

@@ -24,6 +24,7 @@ import (

 	"github.com/moby/buildkit/executor"

 	"github.com/moby/buildkit/exporter"

 	"github.com/moby/buildkit/frontend"

+	gw "github.com/moby/buildkit/frontend/gateway/client"

 	"github.com/moby/buildkit/session"

 	"github.com/moby/buildkit/snapshot"

 	"github.com/moby/buildkit/solver"

@@ -141,7 +142,7 @@ func (w *Worker) ResolveOp(v solver.Vertex, s frontend.FrontendLLBBridge) (solve

 		case *pb.Op_Source:

 			return ops.NewSourceOp(v, op, baseOp.Platform, w.SourceManager, w)

 		case *pb.Op_Exec:

-			return ops.NewExecOp(v, op, w.CacheManager, w.MetadataStore, w.Executor, w)

+			return ops.NewExecOp(v, op, w.CacheManager, w.Opt.SessionManager, w.MetadataStore, w.Executor, w)

 		case *pb.Op_Build:

 			return ops.NewBuildOp(v, op, s, w)

 		}

@@ -150,13 +151,13 @@ func (w *Worker) ResolveOp(v solver.Vertex, s frontend.FrontendLLBBridge) (solve

 }

 // ResolveImageConfig returns image config for an image

-func (w *Worker) ResolveImageConfig(ctx context.Context, ref string, platform *ocispec.Platform) (digest.Digest, []byte, error) {

+func (w *Worker) ResolveImageConfig(ctx context.Context, ref string, opt gw.ResolveImageConfigOpt) (digest.Digest, []byte, error) {

 	// ImageSource is typically source/containerimage

 	resolveImageConfig, ok := w.ImageSource.(resolveImageConfig)

 	if !ok {

 		return "", nil, errors.Errorf("worker %q does not implement ResolveImageConfig", w.ID())

 	}

-	return resolveImageConfig.ResolveImageConfig(ctx, ref, platform)

+	return resolveImageConfig.ResolveImageConfig(ctx, ref, opt)

 }

 // Exec executes a process directly on a worker

@@ -175,8 +176,8 @@ func (w *Worker) DiskUsage(ctx context.Context, opt client.DiskUsageInfo) ([]*cl

 }

 // Prune deletes reclaimable build cache

-func (w *Worker) Prune(ctx context.Context, ch chan client.UsageInfo) error {

-	return w.CacheManager.Prune(ctx, ch)

+func (w *Worker) Prune(ctx context.Context, ch chan client.UsageInfo, info client.PruneInfo) error {

+	return w.CacheManager.Prune(ctx, ch, info)

 }

 // Exporter returns exporter by name

@@ -327,5 +328,5 @@ func oneOffProgress(ctx context.Context, id string) func(err error) error {

 }

 type resolveImageConfig interface {

-	ResolveImageConfig(ctx context.Context, ref string, platform *ocispec.Platform) (digest.Digest, []byte, error)

+	ResolveImageConfig(ctx context.Context, ref string, opt gw.ResolveImageConfigOpt) (digest.Digest, []byte, error)

 }