replace resolveimageconfig with generic sourcemetaresolver

This is more versatile function that works for any source,
not just images.

It can be used together with a policy that switches
between input and output source as well as for adding
additional metadata for other sources in the future.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

client/build.go

@@ -84,6 +84,11 @@ func (g *gatewayClientForBuild) ResolveImageConfig(ctx context.Context, in *gate
 	return g.gateway.ResolveImageConfig(ctx, in, opts...)
 }
 
+func (g *gatewayClientForBuild) ResolveSourceMeta(ctx context.Context, in *gatewayapi.ResolveSourceMetaRequest, opts ...grpc.CallOption) (*gatewayapi.ResolveSourceMetaResponse, error) {
+	ctx = buildid.AppendToOutgoingContext(ctx, g.buildID)
+	return g.gateway.ResolveSourceMeta(ctx, in, opts...)
+}
+
 func (g *gatewayClientForBuild) Solve(ctx context.Context, in *gatewayapi.SolveRequest, opts ...grpc.CallOption) (*gatewayapi.SolveResponse, error) {
 	ctx = buildid.AppendToOutgoingContext(ctx, g.buildID)
 	return g.gateway.Solve(ctx, in, opts...)

client/client_test.go

@@ -41,6 +41,7 @@ import (
 	intoto "github.com/in-toto/in-toto-golang/in_toto"
 	controlapi "github.com/moby/buildkit/api/services/control"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	gateway "github.com/moby/buildkit/frontend/gateway/client"
 	gatewaypb "github.com/moby/buildkit/frontend/gateway/pb"
@@ -3061,7 +3062,7 @@ func testSourceDateEpochClamp(t *testing.T, sb integration.Sandbox) {
 
 	var bboxConfig []byte
 	_, err = c.Build(sb.Context(), SolveOpt{}, "", func(ctx context.Context, c gateway.Client) (*gateway.Result, error) {
-		_, _, bboxConfig, err = c.ResolveImageConfig(ctx, "docker.io/library/busybox:latest", llb.ResolveImageConfigOpt{})
+		_, _, bboxConfig, err = c.ResolveImageConfig(ctx, "docker.io/library/busybox:latest", sourceresolver.Opt{})
 		if err != nil {
 			return nil, err
 		}
@@ -10059,7 +10060,7 @@ func testSourcePolicy(t *testing.T, sb integration.Sandbox) {
 					},
 				}
 
-				ref, dgst, _, err := c.ResolveImageConfig(ctx, origRef, llb.ResolveImageConfigOpt{
+				ref, dgst, _, err := c.ResolveImageConfig(ctx, origRef, sourceresolver.Opt{
 					SourcePolicies: pol,
 				})
 				if err != nil {

client/llb/imagemetaresolver/resolver.go

@@ -9,6 +9,7 @@ import (
 	"github.com/containerd/containerd/remotes"
 	"github.com/containerd/containerd/remotes/docker"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/util/contentutil"
 	"github.com/moby/buildkit/util/imageutil"
 	"github.com/moby/buildkit/version"
@@ -70,32 +71,31 @@ type imageMetaResolver struct {
 }
 
 type resolveResult struct {
-	ref    string
 	config []byte
 	dgst   digest.Digest
 }
 
-func (imr *imageMetaResolver) ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt) (string, digest.Digest, []byte, error) {
+func (imr *imageMetaResolver) ResolveImageConfig(ctx context.Context, ref string, opt sourceresolver.Opt) (string, digest.Digest, []byte, error) {
 	imr.locker.Lock(ref)
 	defer imr.locker.Unlock(ref)
 
-	platform := opt.Platform
-	if platform == nil {
-		platform = imr.platform
+	platform := imr.platform
+	if opt.Platform != nil {
+		platform = opt.Platform
 	}
 
 	k := imr.key(ref, platform)
 
 	if res, ok := imr.cache[k]; ok {
-		return res.ref, res.dgst, res.config, nil
+		return ref, res.dgst, res.config, nil
 	}
 
-	ref, dgst, config, err := imageutil.Config(ctx, ref, imr.resolver, imr.buffer, nil, platform, opt.SourcePolicies)
+	dgst, config, err := imageutil.Config(ctx, ref, imr.resolver, imr.buffer, nil, platform)
 	if err != nil {
 		return "", "", nil, err
 	}
 
-	imr.cache[k] = resolveResult{dgst: dgst, config: config, ref: ref}
+	imr.cache[k] = resolveResult{dgst: dgst, config: config}
 	return ref, dgst, config, nil
 }
 

client/llb/resolver.go

@@ -1,11 +1,7 @@
 package llb
 
 import (
-	"context"
-
-	spb "github.com/moby/buildkit/sourcepolicy/pb"
-	digest "github.com/opencontainers/go-digest"
-	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 )
 
 // WithMetaResolver adds a metadata resolver to an image
@@ -31,30 +27,4 @@ func WithLayerLimit(l int) ImageOption {
 }
 
 // ImageMetaResolver can resolve image config metadata from a reference
-type ImageMetaResolver interface {
-	ResolveImageConfig(ctx context.Context, ref string, opt ResolveImageConfigOpt) (string, digest.Digest, []byte, error)
-}
-
-type ResolverType int
-
-const (
-	ResolverTypeRegistry ResolverType = iota
-	ResolverTypeOCILayout
-)
-
-type ResolveImageConfigOpt struct {
-	ResolverType
-
-	Platform    *ocispecs.Platform
-	ResolveMode string
-	LogName     string
-
-	Store ResolveImageConfigOptStore
-
-	SourcePolicies []*spb.Policy
-}
-
-type ResolveImageConfigOptStore struct {
-	SessionID string
-	StoreID   string
-}
+type ImageMetaResolver = sourceresolver.ImageMetaResolver

client/llb/resolver_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/containerd/containerd/platforms"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/solver/pb"
 	digest "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
@@ -74,7 +75,7 @@ type testResolver struct {
 	platform string
 }
 
-func (r *testResolver) ResolveImageConfig(ctx context.Context, ref string, opt ResolveImageConfigOpt) (string, digest.Digest, []byte, error) {
+func (r *testResolver) ResolveImageConfig(ctx context.Context, ref string, opt sourceresolver.Opt) (string, digest.Digest, []byte, error) {
 	var img struct {
 		Config struct {
 			Env        []string `json:"Env,omitempty"`

client/llb/source.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/distribution/reference"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/util/apicaps"
 	"github.com/moby/buildkit/util/gitutil"
@@ -136,10 +137,11 @@ func Image(ref string, opts ...ImageOption) State {
 				if p == nil {
 					p = c.Platform
 				}
-				_, _, dt, err := info.metaResolver.ResolveImageConfig(ctx, ref, ResolveImageConfigOpt{
+				_, _, dt, err := info.metaResolver.ResolveImageConfig(ctx, ref, sourceresolver.Opt{
 					Platform: p,
+					ImageOpt: &sourceresolver.ResolveImageOpt{
 						ResolveMode: info.resolveMode.String(),
-					ResolverType: ResolverTypeRegistry,
+					},
 				})
 				if err != nil {
 					return State{}, err
@@ -152,10 +154,11 @@ func Image(ref string, opts ...ImageOption) State {
 			if p == nil {
 				p = c.Platform
 			}
-			ref, dgst, dt, err := info.metaResolver.ResolveImageConfig(context.TODO(), ref, ResolveImageConfigOpt{
+			ref, dgst, dt, err := info.metaResolver.ResolveImageConfig(context.TODO(), ref, sourceresolver.Opt{
 				Platform: p,
+				ImageOpt: &sourceresolver.ResolveImageOpt{
 					ResolveMode: info.resolveMode.String(),
-				ResolverType: ResolverTypeRegistry,
+				},
 			})
 			if err != nil {
 				return State{}, err

client/llb/sourceresolver/imageresolver.go

@@ -0,0 +1,59 @@
+package sourceresolver
+
+import (
+	"context"
+	"strings"
+
+	"github.com/distribution/reference"
+	"github.com/moby/buildkit/solver/pb"
+	"github.com/moby/buildkit/util/imageutil"
+	digest "github.com/opencontainers/go-digest"
+	"github.com/pkg/errors"
+)
+
+type ImageMetaResolver interface {
+	ResolveImageConfig(ctx context.Context, ref string, opt Opt) (string, digest.Digest, []byte, error)
+}
+
+type imageMetaResolver struct {
+	mr MetaResolver
+}
+
+var _ ImageMetaResolver = &imageMetaResolver{}
+
+func NewImageMetaResolver(mr MetaResolver) ImageMetaResolver {
+	return &imageMetaResolver{
+		mr: mr,
+	}
+}
+
+func (imr *imageMetaResolver) ResolveImageConfig(ctx context.Context, ref string, opt Opt) (string, digest.Digest, []byte, error) {
+	parsed, err := reference.ParseNormalizedNamed(ref)
+	if err != nil {
+		return "", "", nil, errors.Wrapf(err, "could not parse reference %q", ref)
+	}
+	ref = parsed.String()
+	op := &pb.SourceOp{
+		Identifier: "docker-image://" + ref,
+	}
+	if opt := opt.OCILayoutOpt; opt != nil {
+		op.Identifier = "oci-layout://" + ref
+		op.Attrs = map[string]string{}
+		if opt.Store.SessionID != "" {
+			op.Attrs[pb.AttrOCILayoutSessionID] = opt.Store.SessionID
+		}
+		if opt.Store.StoreID != "" {
+			op.Attrs[pb.AttrOCILayoutStoreID] = opt.Store.StoreID
+		}
+	}
+	res, err := imr.mr.ResolveSourceMetadata(ctx, op, opt)
+	if err != nil {
+		return "", "", nil, errors.Wrapf(err, "failed to resolve source metadata for %s", ref)
+	}
+	if res.Image == nil {
+		return "", "", nil, &imageutil.ResolveToNonImageError{Ref: ref, Updated: res.Op.Identifier}
+	}
+	ref = strings.TrimPrefix(res.Op.Identifier, "docker-image://")
+	ref = strings.TrimPrefix(ref, "oci-layout://")
+	return ref, res.Image.Digest, res.Image.Config, nil
+}

client/llb/sourceresolver/types.go

@@ -0,0 +1,54 @@
+package sourceresolver
+
+import (
+	"context"
+
+	"github.com/moby/buildkit/solver/pb"
+	spb "github.com/moby/buildkit/sourcepolicy/pb"
+	digest "github.com/opencontainers/go-digest"
+	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+type ResolverType int
+
+const (
+	ResolverTypeRegistry ResolverType = iota
+	ResolverTypeOCILayout
+)
+
+type MetaResolver interface {
+	ResolveSourceMetadata(ctx context.Context, op *pb.SourceOp, opt Opt) (*MetaResponse, error)
+}
+
+type Opt struct {
+	LogName        string
+	SourcePolicies []*spb.Policy
+	Platform       *ocispecs.Platform
+
+	ImageOpt     *ResolveImageOpt
+	OCILayoutOpt *ResolveOCILayoutOpt
+}
+
+type MetaResponse struct {
+	Op *pb.SourceOp
+
+	Image *ResolveImageResponse
+}
+
+type ResolveImageOpt struct {
+	ResolveMode string
+}
+
+type ResolveImageResponse struct {
+	Digest digest.Digest
+	Config []byte
+}
+
+type ResolveOCILayoutOpt struct {
+	Store ResolveImageConfigOptStore
+}
+
+type ResolveImageConfigOptStore struct {
+	SessionID string
+	StoreID   string
+}

control/gateway/gateway.go

@@ -96,6 +96,15 @@ func (gwf *GatewayForwarder) ResolveImageConfig(ctx context.Context, req *gwapi.
 	return fwd.ResolveImageConfig(ctx, req)
 }
 
+func (gwf *GatewayForwarder) ResolveSourceMeta(ctx context.Context, req *gwapi.ResolveSourceMetaRequest) (*gwapi.ResolveSourceMetaResponse, error) {
+	fwd, err := gwf.lookupForwarder(ctx)
+	if err != nil {
+		return nil, errors.Wrap(err, "forwarding ResolveSourceMeta")
+	}
+
+	return fwd.ResolveSourceMeta(ctx, req)
+}
+
 func (gwf *GatewayForwarder) Solve(ctx context.Context, req *gwapi.SolveRequest) (*gwapi.SolveResponse, error) {
 	fwd, err := gwf.lookupForwarder(ctx)
 	if err != nil {

frontend/attestations/sbom/sbom.go

@@ -9,6 +9,7 @@ import (
 
 	intoto "github.com/in-toto/in-toto-golang/in_toto"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	gatewaypb "github.com/moby/buildkit/frontend/gateway/pb"
 	"github.com/moby/buildkit/solver/result"
 	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
@@ -33,12 +34,13 @@ const (
 // attestation.
 type Scanner func(ctx context.Context, name string, ref llb.State, extras map[string]llb.State, opts ...llb.ConstraintsOpt) (result.Attestation[*llb.State], error)
 
-func CreateSBOMScanner(ctx context.Context, resolver llb.ImageMetaResolver, scanner string, resolveOpt llb.ResolveImageConfigOpt) (Scanner, error) {
+func CreateSBOMScanner(ctx context.Context, resolver sourceresolver.MetaResolver, scanner string, resolveOpt sourceresolver.Opt) (Scanner, error) {
 	if scanner == "" {
 		return nil, nil
 	}
 
-	scanner, _, dt, err := resolver.ResolveImageConfig(ctx, scanner, resolveOpt)
+	imr := sourceresolver.NewImageMetaResolver(resolver)
+	scanner, _, dt, err := imr.ResolveImageConfig(ctx, scanner, resolveOpt)
 	if err != nil {
 		return nil, err
 	}

frontend/dockerfile/builder/build.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/containerd/containerd/platforms"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/exporter/containerimage/image"
 	"github.com/moby/buildkit/frontend"
 	"github.com/moby/buildkit/frontend/attestations/sbom"
@@ -101,8 +102,11 @@ func Build(ctx context.Context, c client.Client) (_ *client.Result, err error) {
 
 	var scanner sbom.Scanner
 	if bc.SBOM != nil {
-		scanner, err = sbom.CreateSBOMScanner(ctx, c, bc.SBOM.Generator, llb.ResolveImageConfigOpt{
+		// TODO: scanner should pass policy
+		scanner, err = sbom.CreateSBOMScanner(ctx, c, bc.SBOM.Generator, sourceresolver.Opt{
+			ImageOpt: &sourceresolver.ResolveImageOpt{
 				ResolveMode: opts["image-resolve-mode"],
+			},
 		})
 		if err != nil {
 			return nil, err

frontend/dockerfile/dockerfile2llb/convert.go

@@ -20,6 +20,7 @@ import (
 	"github.com/docker/go-connections/nat"
 	"github.com/moby/buildkit/client/llb"
 	"github.com/moby/buildkit/client/llb/imagemetaresolver"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/exporter/containerimage/image"
 	"github.com/moby/buildkit/frontend/dockerfile/instructions"
 	"github.com/moby/buildkit/frontend/dockerfile/parser"
@@ -423,12 +424,12 @@ func toDispatchState(ctx context.Context, dt []byte, opt ConvertOpt) (*dispatchS
 							prefix += platforms.Format(*platform) + " "
 						}
 						prefix += "internal]"
-						mutRef, dgst, dt, err := metaResolver.ResolveImageConfig(ctx, d.stage.BaseName, llb.ResolveImageConfigOpt{
-							Platform:       platform,
-							ResolveMode:    opt.ImageResolveMode.String(),
+						mutRef, dgst, dt, err := metaResolver.ResolveImageConfig(ctx, d.stage.BaseName, sourceresolver.Opt{
 							LogName:  fmt.Sprintf("%s load metadata for %s", prefix, d.stage.BaseName),
-							ResolverType:   llb.ResolverTypeRegistry,
-							SourcePolicies: nil,
+							Platform: platform,
+							ImageOpt: &sourceresolver.ResolveImageOpt{
+								ResolveMode: opt.ImageResolveMode.String(),
+							},
 						})
 						if err != nil {
 							return suggest.WrapError(errors.Wrap(err, origName), origName, append(allStageNames, commonImageNames()...), true)

frontend/dockerfile/dockerfile_test.go

@@ -7046,7 +7046,7 @@ func testSourcePolicyWithNamedContext(t *testing.T, sb integration.Sandbox) {
 		FrontendAttrs: map[string]string{
 			"context:replace": "docker-image:docker.io/library/alpine:latest",
 		},
-		LocalDirs: map[string]string{
+		LocalMounts: map[string]fsutil.FS{
 			dockerui.DefaultLocalNameDockerfile: mainContext,
 			dockerui.DefaultLocalNameContext:    mainContext,
 			"test":                              replaceContext,

frontend/dockerui/namedcontext.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/distribution/reference"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	"github.com/moby/buildkit/exporter/containerimage/image"
 	"github.com/moby/buildkit/frontend/gateway/client"
@@ -72,11 +73,12 @@ func (bc *Client) namedContextRecursive(ctx context.Context, name string, nameWi
 
 		named = reference.TagNameOnly(named)
 
-		ref, dgst, data, err := bc.client.ResolveImageConfig(ctx, named.String(), llb.ResolveImageConfigOpt{
-			Platform:     opt.Platform,
-			ResolveMode:  opt.ResolveMode,
+		ref, dgst, data, err := bc.client.ResolveImageConfig(ctx, named.String(), sourceresolver.Opt{
 			LogName:  fmt.Sprintf("[context %s] load metadata for %s", nameWithPlatform, ref),
-			ResolverType: llb.ResolverTypeRegistry,
+			Platform: opt.Platform,
+			ImageOpt: &sourceresolver.ResolveImageOpt{
+				ResolveMode: opt.ResolveMode,
+			},
 		})
 		if err != nil {
 			e := &imageutil.ResolveToNonImageError{}
@@ -146,16 +148,15 @@ func (bc *Client) namedContextRecursive(ctx context.Context, name string, nameWi
 			return nil, nil, errors.Wrapf(err, "could not wrap %q with digest", name)
 		}
 
-		// TODO: How should source policy be handled here with a dummy ref?
-		_, dgst, data, err := bc.client.ResolveImageConfig(ctx, dummyRef.String(), llb.ResolveImageConfigOpt{
-			Platform:     opt.Platform,
-			ResolveMode:  opt.ResolveMode,
+		_, dgst, data, err := bc.client.ResolveImageConfig(ctx, dummyRef.String(), sourceresolver.Opt{
 			LogName:  fmt.Sprintf("[context %s] load metadata for %s", nameWithPlatform, dummyRef.String()),
-			ResolverType: llb.ResolverTypeOCILayout,
-			Store: llb.ResolveImageConfigOptStore{
+			Platform: opt.Platform,
+			OCILayoutOpt: &sourceresolver.ResolveOCILayoutOpt{
+				Store: sourceresolver.ResolveImageConfigOptStore{
 					SessionID: bc.bopts.SessionID,
 					StoreID:   named.Name(),
 				},
+			},
 		})
 		if err != nil {
 			return nil, nil, err

frontend/frontend.go

@@ -3,7 +3,7 @@ package frontend
 import (
 	"context"
 
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor"
 	gw "github.com/moby/buildkit/frontend/gateway/client"
 	"github.com/moby/buildkit/session"
@@ -22,8 +22,8 @@ type Frontend interface {
 }
 
 type FrontendLLBBridge interface {
+	sourceresolver.MetaResolver
 	Solve(ctx context.Context, req SolveRequest, sid string) (*Result, error)
-	ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt) (string, digest.Digest, []byte, error)
 	Warn(ctx context.Context, dgst digest.Digest, msg string, opts WarnOpts) error
 }
 

frontend/gateway/client/client.go

@@ -6,6 +6,7 @@ import (
 	"syscall"
 
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/solver/result"
 	spb "github.com/moby/buildkit/sourcepolicy/pb"
@@ -26,8 +27,9 @@ func NewResult() *Result {
 }
 
 type Client interface {
+	sourceresolver.MetaResolver
 	Solve(ctx context.Context, req SolveRequest) (*Result, error)
-	ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt) (string, digest.Digest, []byte, error)
+	ResolveImageConfig(ctx context.Context, ref string, opt sourceresolver.Opt) (string, digest.Digest, []byte, error)
 	BuildOpts() BuildOpts
 	Inputs(ctx context.Context) (map[string]llb.State, error)
 	NewContainer(ctx context.Context, req NewContainerRequest) (Container, error)

frontend/gateway/forwarder/forward.go

@@ -6,6 +6,7 @@ import (
 
 	cacheutil "github.com/moby/buildkit/cache/util"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor"
 	"github.com/moby/buildkit/frontend"
 	"github.com/moby/buildkit/frontend/gateway/client"
@@ -94,6 +95,12 @@ func (c *BridgeClient) Solve(ctx context.Context, req client.SolveRequest) (*cli
 
 	return cRes, nil
 }
+
+func (c *BridgeClient) ResolveImageConfig(ctx context.Context, ref string, opt sourceresolver.Opt) (string, digest.Digest, []byte, error) {
+	imr := sourceresolver.NewImageMetaResolver(c)
+	return imr.ResolveImageConfig(ctx, ref, opt)
+}
+
 func (c *BridgeClient) loadBuildOpts() client.BuildOpts {
 	wis := c.workers.WorkerInfos()
 	workers := make([]client.WorkerInfo, len(wis))

frontend/gateway/gateway.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	"net"
 	"os"
 	"path/filepath"
@@ -25,6 +26,7 @@ import (
 	cacheutil "github.com/moby/buildkit/cache/util"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	"github.com/moby/buildkit/exporter/containerimage/image"
@@ -164,7 +166,8 @@ func (gf *gatewayFrontend) Solve(ctx context.Context, llbBridge frontend.Fronten
 				return nil, err
 			}
 
-			ref, dgst, config, err := llbBridge.ResolveImageConfig(ctx, reference.TagNameOnly(sourceRef).String(), llb.ResolveImageConfigOpt{})
+			imr := sourceresolver.NewImageMetaResolver(llbBridge)
+			ref, dgst, config, err := imr.ResolveImageConfig(ctx, reference.TagNameOnly(sourceRef).String(), sourceresolver.Opt{})
 			if err != nil {
 				return nil, err
 			}
@@ -554,6 +557,49 @@ type llbBridgeForwarder struct {
 	ctrsMu sync.Mutex
 }
 
+func (lbf *llbBridgeForwarder) ResolveSourceMeta(ctx context.Context, req *pb.ResolveSourceMetaRequest) (*pb.ResolveSourceMetaResponse, error) {
+	if req.Source == nil {
+		return nil, status.Error(codes.InvalidArgument, "source is required")
+	}
+	log.Printf("bridge.ResolveSourceMeta: %v", req.Source)
+
+	ctx = tracing.ContextWithSpanFromContext(ctx, lbf.callCtx)
+	var platform *ocispecs.Platform
+	if p := req.Platform; p != nil {
+		platform = &ocispecs.Platform{
+			OS:           p.OS,
+			Architecture: p.Architecture,
+			Variant:      p.Variant,
+			OSVersion:    p.OSVersion,
+			OSFeatures:   p.OSFeatures,
+		}
+	}
+	resolveopt := sourceresolver.Opt{
+		LogName:        req.LogName,
+		SourcePolicies: req.SourcePolicies,
+		Platform:       platform,
+	}
+	resolveopt.ImageOpt = &sourceresolver.ResolveImageOpt{
+		ResolveMode: req.ResolveMode,
+	}
+	resp, err := lbf.llbBridge.ResolveSourceMetadata(ctx, req.Source, resolveopt)
+	if err != nil {
+		return nil, err
+	}
+
+	r := &pb.ResolveSourceMetaResponse{
+		Source: resp.Op,
+	}
+
+	if resp.Image != nil {
+		r.Image = &pb.ResolveSourceImageResponse{
+			Digest: resp.Image.Digest,
+			Config: resp.Image.Config,
+		}
+	}
+	return r, nil
+}
+
 func (lbf *llbBridgeForwarder) ResolveImageConfig(ctx context.Context, req *pb.ResolveImageConfigRequest) (*pb.ResolveImageConfigResponse, error) {
 	ctx = tracing.ContextWithSpanFromContext(ctx, lbf.callCtx)
 	var platform *ocispecs.Platform
@@ -566,17 +612,27 @@ func (lbf *llbBridgeForwarder) ResolveImageConfig(ctx context.Context, req *pb.R
 			OSFeatures:   p.OSFeatures,
 		}
 	}
-	ref, dgst, dt, err := lbf.llbBridge.ResolveImageConfig(ctx, req.Ref, llb.ResolveImageConfigOpt{
-		ResolverType: llb.ResolverType(req.ResolverType),
-		Platform:     platform,
-		ResolveMode:  req.ResolveMode,
+	log.Printf("bridge.ResolveImageConfig: %v", req.Ref)
+	imr := sourceresolver.NewImageMetaResolver(lbf.llbBridge)
+	resolveopt := sourceresolver.Opt{
 		LogName:        req.LogName,
-		Store: llb.ResolveImageConfigOptStore{
+		SourcePolicies: req.SourcePolicies,
+		Platform:       platform,
+	}
+	if sourceresolver.ResolverType(req.ResolverType) == sourceresolver.ResolverTypeRegistry {
+		resolveopt.ImageOpt = &sourceresolver.ResolveImageOpt{
+			ResolveMode: req.ResolveMode,
+		}
+	} else if sourceresolver.ResolverType(req.ResolverType) == sourceresolver.ResolverTypeOCILayout {
+		resolveopt.OCILayoutOpt = &sourceresolver.ResolveOCILayoutOpt{
+			Store: sourceresolver.ResolveImageConfigOptStore{
 				SessionID: req.SessionID,
 				StoreID:   req.StoreID,
 			},
-		SourcePolicies: req.SourcePolicies,
-	})
+		}
+	}
+
+	ref, dgst, dt, err := imr.ResolveImageConfig(ctx, req.Ref, resolveopt)
 	if err != nil {
 		return nil, err
 	}

frontend/gateway/grpcclient/client.go

@@ -12,10 +12,12 @@ import (
 	"syscall"
 	"time"
 
+	distreference "github.com/distribution/reference"
 	"github.com/gogo/googleapis/google/rpc"
 	gogotypes "github.com/gogo/protobuf/types"
 	"github.com/golang/protobuf/ptypes/any"
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/frontend/gateway/client"
 	pb "github.com/moby/buildkit/frontend/gateway/pb"
 	"github.com/moby/buildkit/identity"
@@ -23,6 +25,7 @@ import (
 	"github.com/moby/buildkit/util/apicaps"
 	"github.com/moby/buildkit/util/bklog"
 	"github.com/moby/buildkit/util/grpcerrors"
+	"github.com/moby/buildkit/util/imageutil"
 	"github.com/moby/sys/signal"
 	digest "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
@@ -479,7 +482,11 @@ func (c *grpcClient) Solve(ctx context.Context, creq client.SolveRequest) (res *
 	return res, nil
 }
 
-func (c *grpcClient) ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt) (string, digest.Digest, []byte, error) {
+func (c *grpcClient) ResolveSourceMetadata(ctx context.Context, op *opspb.SourceOp, opt sourceresolver.Opt) (*sourceresolver.MetaResponse, error) {
+	if c.caps.Supports(pb.CapSourceMetaResolver) != nil {
+		return nil, errors.Errorf("fallback not implemented")
+	}
+
 	var p *opspb.Platform
 	if platform := opt.Platform; platform != nil {
 		p = &opspb.Platform{
@@ -491,16 +498,97 @@ func (c *grpcClient) ResolveImageConfig(ctx context.Context, ref string, opt llb
 		}
 	}
 
-	resp, err := c.client.ResolveImageConfig(ctx, &pb.ResolveImageConfigRequest{
-		ResolverType:   int32(opt.ResolverType),
-		Ref:            ref,
+	req := &pb.ResolveSourceMetaRequest{
+		Source:         op,
 		Platform:       p,
-		ResolveMode:    opt.ResolveMode,
 		LogName:        opt.LogName,
-		SessionID:      opt.Store.SessionID,
-		StoreID:        opt.Store.StoreID,
 		SourcePolicies: opt.SourcePolicies,
-	})
+	}
+	resp, err := c.client.ResolveSourceMeta(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	r := &sourceresolver.MetaResponse{
+		Op: resp.Source,
+	}
+	if resp.Image != nil {
+		r.Image = &sourceresolver.ResolveImageResponse{
+			Digest: resp.Image.Digest,
+			Config: resp.Image.Config,
+		}
+	}
+	return r, nil
+}
+
+func (c *grpcClient) resolveImageConfigViaSourceMetadata(ctx context.Context, ref string, opt sourceresolver.Opt, p *opspb.Platform) (string, digest.Digest, []byte, error) {
+	op := &opspb.SourceOp{
+		Identifier: "docker-image://" + ref,
+	}
+	if opt.OCILayoutOpt != nil {
+		named, err := distreference.ParseNormalizedNamed(ref)
+		if err != nil {
+			return "", "", nil, err
+		}
+		op.Identifier = "oci-layout://" + named.String()
+		op.Attrs = map[string]string{
+			opspb.AttrOCILayoutSessionID: opt.OCILayoutOpt.Store.SessionID,
+			opspb.AttrOCILayoutStoreID:   opt.OCILayoutOpt.Store.StoreID,
+		}
+	}
+
+	req := &pb.ResolveSourceMetaRequest{
+		Source:         op,
+		Platform:       p,
+		LogName:        opt.LogName,
+		SourcePolicies: opt.SourcePolicies,
+	}
+	resp, err := c.client.ResolveSourceMeta(ctx, req)
+	if err != nil {
+		return "", "", nil, err
+	}
+	if resp.Image == nil {
+		return "", "", nil, &imageutil.ResolveToNonImageError{Ref: ref, Updated: resp.Source.Identifier}
+	}
+	ref = strings.TrimPrefix(resp.Source.Identifier, "docker-image://")
+	ref = strings.TrimPrefix(ref, "oci-layout://")
+	return ref, resp.Image.Digest, resp.Image.Config, nil
+}
+
+func (c *grpcClient) ResolveImageConfig(ctx context.Context, ref string, opt sourceresolver.Opt) (string, digest.Digest, []byte, error) {
+	var p *opspb.Platform
+	if platform := opt.Platform; platform != nil {
+		p = &opspb.Platform{
+			OS:           platform.OS,
+			Architecture: platform.Architecture,
+			Variant:      platform.Variant,
+			OSVersion:    platform.OSVersion,
+			OSFeatures:   platform.OSFeatures,
+		}
+	}
+
+	if c.caps.Supports(pb.CapSourceMetaResolver) == nil {
+		return c.resolveImageConfigViaSourceMetadata(ctx, ref, opt, p)
+	}
+
+	req := &pb.ResolveImageConfigRequest{
+		Ref:            ref,
+		LogName:        opt.LogName,
+		SourcePolicies: opt.SourcePolicies,
+		Platform:       p,
+	}
+	if iopt := opt.ImageOpt; iopt != nil {
+		req.ResolveMode = iopt.ResolveMode
+		req.ResolverType = int32(sourceresolver.ResolverTypeRegistry)
+	}
+
+	if iopt := opt.OCILayoutOpt; iopt != nil {
+		req.ResolverType = int32(sourceresolver.ResolverTypeOCILayout)
+		req.StoreID = iopt.Store.StoreID
+		req.SessionID = iopt.Store.SessionID
+	}
+
+	resp, err := c.client.ResolveImageConfig(ctx, req)
 	if err != nil {
 		return "", "", nil, err
 	}

frontend/gateway/pb/caps.go

@@ -68,6 +68,10 @@ const (
 	// CapAttestations is the capability to indicate that attestation
 	// references will be attached to results
 	CapAttestations apicaps.CapID = "reference.attestations"
+
+	// CapSourceMetaResolver is the capability to indicates support for ResolveSourceMetadata
+	// function in gateway API
+	CapSourceMetaResolver apicaps.CapID = "source.metaresolver"
 )
 
 func init() {
@@ -231,4 +235,11 @@ func init() {
 		Enabled: true,
 		Status:  apicaps.CapStatusExperimental,
 	})
+
+	Caps.Init(apicaps.Cap{
+		ID:      CapSourceMetaResolver,
+		Name:    "source meta resolver",
+		Enabled: true,
+		Status:  apicaps.CapStatusExperimental,
+	})
 }

frontend/gateway/pb/gateway.proto

@@ -17,6 +17,8 @@ option (gogoproto.unmarshaler_all) = true;
 service LLBBridge {
 	// apicaps:CapResolveImage
 	rpc ResolveImageConfig(ResolveImageConfigRequest) returns (ResolveImageConfigResponse);
+	// apicaps:CapSourceMetaResolver
+	rpc ResolveSourceMeta(ResolveSourceMetaRequest) returns (ResolveSourceMetaResponse);
 	// apicaps:CapSolveBase
 	rpc Solve(SolveRequest) returns (SolveResponse);
 	// apicaps:CapReadFile
@@ -132,6 +134,24 @@ message ResolveImageConfigResponse {
 	string Ref = 3;
 }
 
+message ResolveSourceMetaRequest {
+	pb.SourceOp Source = 1;
+	pb.Platform Platform = 2;
+	string LogName = 3;
+	string ResolveMode = 4;
+	repeated moby.buildkit.v1.sourcepolicy.Policy SourcePolicies = 8;
+}
+
+message ResolveSourceMetaResponse {
+	pb.SourceOp Source = 1;
+	ResolveSourceImageResponse Image = 2;
+}
+
+message ResolveSourceImageResponse {
+	string Digest = 1 [(gogoproto.customtype) = "github.com/opencontainers/go-digest.Digest", (gogoproto.nullable) = false];
+	bytes Config = 2;
+}
+
 message SolveRequest {
 	pb.Definition Definition = 1;
 	string Frontend = 2;

solver/llbsolver/bridge.go

@@ -10,7 +10,7 @@ import (
 	"github.com/mitchellh/hashstructure/v2"
 	"github.com/moby/buildkit/cache/remotecache"
 	"github.com/moby/buildkit/client"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor"
 	resourcestypes "github.com/moby/buildkit/executor/resources/types"
 	"github.com/moby/buildkit/frontend"
@@ -351,32 +351,44 @@ func (rp *resultProxy) Result(ctx context.Context) (res solver.CachedResult, err
 	})
 }
 
-func (b *llbBridge) ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt) (resolvedRef string, dgst digest.Digest, config []byte, err error) {
+func (b *llbBridge) ResolveSourceMetadata(ctx context.Context, op *pb.SourceOp, opt sourceresolver.Opt) (resp *sourceresolver.MetaResponse, err error) {
 	w, err := b.resolveWorker()
 	if err != nil {
-		return "", "", nil, err
+		return nil, err
 	}
 	if opt.LogName == "" {
-		opt.LogName = fmt.Sprintf("resolve image config for %s", ref)
+		// TODO: better name
+		opt.LogName = fmt.Sprintf("resolve image config for %s", op.Identifier)
 	}
-	id := ref // make a deterministic ID for avoiding duplicates
-	if platform := opt.Platform; platform == nil {
-		id += platforms.Format(platforms.DefaultSpec())
+	id := op.Identifier
+	if opt.Platform != nil {
+		id += platforms.Format(*opt.Platform)
 	} else {
-		id += platforms.Format(*platform)
+		id += platforms.Format(platforms.DefaultSpec())
 	}
 	pol, err := loadSourcePolicy(b.builder)
 	if err != nil {
-		return "", "", nil, err
+		return nil, err
 	}
 	if pol != nil {
 		opt.SourcePolicies = append(opt.SourcePolicies, pol)
 	}
+
+	if _, err := sourcepolicy.NewEngine(opt.SourcePolicies).Evaluate(ctx, op); err != nil {
+		return nil, errors.Wrap(err, "could not resolve image due to policy")
+	}
+
+	// policy is evaluated, so we can remove it from the options
+	opt.SourcePolicies = nil
+
 	err = inBuilderContext(ctx, b.builder, opt.LogName, id, func(ctx context.Context, g session.Group) error {
-		resolvedRef, dgst, config, err = w.ResolveImageConfig(ctx, ref, opt, b.sm, g)
+		resp, err = w.ResolveSourceMetadata(ctx, op, opt, b.sm, g)
 		return err
 	})
-	return resolvedRef, dgst, config, err
+	if err != nil {
+		return nil, err
+	}
+	return resp, nil
 }
 
 type lazyCacheManager struct {

solver/llbsolver/proc/sbom.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor/resources"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	"github.com/moby/buildkit/frontend"
@@ -26,8 +27,10 @@ func SBOMProcessor(scannerRef string, useCache bool, resolveMode string) llbsolv
 			return nil, err
 		}
 
-		scanner, err := sbom.CreateSBOMScanner(ctx, s.Bridge(j), scannerRef, llb.ResolveImageConfigOpt{
+		scanner, err := sbom.CreateSBOMScanner(ctx, s.Bridge(j), scannerRef, sourceresolver.Opt{
+			ImageOpt: &sourceresolver.ResolveImageOpt{
 				ResolveMode: resolveMode,
+			},
 		})
 		if err != nil {
 			return nil, err

solver/llbsolver/provenance.go

@@ -3,6 +3,7 @@ package llbsolver
 import (
 	"context"
 	"fmt"
+	"log"
 	"strconv"
 	"strings"
 	"sync"
@@ -11,7 +12,7 @@ import (
 	"github.com/containerd/containerd/platforms"
 	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/cache/config"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor/resources"
 	"github.com/moby/buildkit/exporter/containerimage"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
@@ -133,21 +134,26 @@ func (b *provenanceBridge) findByResult(rp solver.ResultProxy) (*resultWithBridg
 	return nil, false
 }
 
-func (b *provenanceBridge) ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt) (resolvedRef string, dgst digest.Digest, config []byte, err error) {
-	ref, dgst, config, err = b.llbBridge.ResolveImageConfig(ctx, ref, opt)
+func (b *provenanceBridge) ResolveSourceMetadata(ctx context.Context, op *pb.SourceOp, opt sourceresolver.Opt) (*sourceresolver.MetaResponse, error) {
+	log.Printf("prov.ResolveSourceMetadata: %#v %#v", op, opt)
+	resp, err := b.llbBridge.ResolveSourceMetadata(ctx, op, opt)
 	if err != nil {
-		return "", "", nil, err
+		return nil, err
 	}
-
+	if img := resp.Image; img != nil {
+		local := !strings.HasPrefix(resp.Op.Identifier, "docker-image://")
+		ref := strings.TrimPrefix(resp.Op.Identifier, "docker-image://")
+		ref = strings.TrimPrefix(ref, "oci-layout://")
 		b.mu.Lock()
 		b.images = append(b.images, provenance.ImageSource{
 			Ref:      ref,
 			Platform: opt.Platform,
-		Digest:   dgst,
-		Local:    opt.ResolverType == llb.ResolverTypeOCILayout,
+			Digest:   img.Digest,
+			Local:    local,
 		})
 		b.mu.Unlock()
-	return ref, dgst, config, nil
+	}
+	return resp, nil
 }
 
 func (b *provenanceBridge) Solve(ctx context.Context, req frontend.SolveRequest, sid string) (res *frontend.Result, err error) {

solver/llbsolver/sourcepolicy.go

@@ -7,5 +7,5 @@ import (
 )
 
 type SourcePolicyEvaluator interface {
-	Evaluate(ctx context.Context, op *pb.Op) (bool, error)
+	Evaluate(ctx context.Context, op *pb.SourceOp) (bool, error)
 }

solver/llbsolver/vertex.go

@@ -253,7 +253,7 @@ func loadLLB(ctx context.Context, def *pb.Definition, polEngine SourcePolicyEval
 		}
 		dgst := digest.FromBytes(dt)
 		if polEngine != nil {
-			mutated, err := polEngine.Evaluate(ctx, &op)
+			mutated, err := polEngine.Evaluate(ctx, op.GetSource())
 			if err != nil {
 				return solver.Edge{}, errors.Wrap(err, "error evaluating the source policy")
 			}

source/containerimage/ocilayout.go

@@ -8,7 +8,7 @@ import (
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/reference"
 	"github.com/containerd/containerd/remotes"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/session"
 	sessioncontent "github.com/moby/buildkit/session/content"
 	"github.com/moby/buildkit/util/imageutil"
@@ -21,7 +21,7 @@ const (
 )
 
 // getOCILayoutResolver gets a resolver to an OCI layout for a specified store from the client using the given session.
-func getOCILayoutResolver(store llb.ResolveImageConfigOptStore, sm *session.Manager, g session.Group) *ociLayoutResolver {
+func getOCILayoutResolver(store sourceresolver.ResolveImageConfigOptStore, sm *session.Manager, g session.Group) *ociLayoutResolver {
 	r := &ociLayoutResolver{
 		store: store,
 		sm:    sm,
@@ -32,7 +32,7 @@ func getOCILayoutResolver(store llb.ResolveImageConfigOptStore, sm *session.Mana
 
 type ociLayoutResolver struct {
 	remotes.Resolver
-	store llb.ResolveImageConfigOptStore
+	store sourceresolver.ResolveImageConfigOptStore
 	sm    *session.Manager
 	g     session.Group
 }

source/containerimage/pull.go

@@ -15,7 +15,7 @@ import (
 	"github.com/containerd/containerd/snapshots"
 	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/client"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/solver"
 	"github.com/moby/buildkit/solver/errdefs"
@@ -45,7 +45,7 @@ type puller struct {
 	layerLimit     *int
 	vtx            solver.Vertex
 	ResolverType
-	store llb.ResolveImageConfigOptStore
+	store sourceresolver.ResolveImageConfigOptStore
 
 	g                flightcontrol.Group[struct{}]
 	cacheKeyErr      error

source/containerimage/source.go

@@ -14,7 +14,7 @@ import (
 	"github.com/containerd/containerd/remotes/docker"
 	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/client"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/snapshot"
 	"github.com/moby/buildkit/solver"
@@ -89,7 +89,7 @@ func (is *Source) Resolve(ctx context.Context, id source.Identifier, sm *session
 		mode       resolver.ResolveMode
 		recordType client.UsageRecordType
 		ref        reference.Spec
-		store      llb.ResolveImageConfigOptStore
+		store      sourceresolver.ResolveImageConfigOptStore
 		layerLimit *int
 	)
 	switch is.ResolverType {
@@ -116,7 +116,7 @@ func (is *Source) Resolve(ctx context.Context, id source.Identifier, sm *session
 			platform = *ociIdentifier.Platform
 		}
 		mode = resolver.ResolveModeForcePull // with OCI layout, we always just "pull"
-		store = llb.ResolveImageConfigOptStore{
+		store = sourceresolver.ResolveImageConfigOptStore{
 			SessionID: ociIdentifier.SessionID,
 			StoreID:   ociIdentifier.StoreID,
 		}
@@ -148,44 +148,51 @@ func (is *Source) Resolve(ctx context.Context, id source.Identifier, sm *session
 	return p, nil
 }
 
-func (is *Source) ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt, sm *session.Manager, g session.Group) (string, digest.Digest, []byte, error) {
+func (is *Source) ResolveImageConfig(ctx context.Context, ref string, opt sourceresolver.Opt, sm *session.Manager, g session.Group) (digest.Digest, []byte, error) {
 	key := ref
-	if platform := opt.Platform; platform != nil {
-		key += platforms.Format(*platform)
-	}
 	var (
 		rm    resolver.ResolveMode
 		rslvr remotes.Resolver
 		err   error
 	)
+	if platform := opt.Platform; platform != nil {
+		key += platforms.Format(*platform)
+	}
 
 	switch is.ResolverType {
 	case ResolverTypeRegistry:
-		rm, err = resolver.ParseImageResolveMode(opt.ResolveMode)
+		iopt := opt.ImageOpt
+		if iopt == nil {
+			return "", nil, errors.Errorf("missing imageopt for resolve")
+		}
+		rm, err = resolver.ParseImageResolveMode(iopt.ResolveMode)
 		if err != nil {
-			return "", "", nil, err
+			return "", nil, err
 		}
 		rslvr = resolver.DefaultPool.GetResolver(is.RegistryHosts, ref, "pull", sm, g).WithImageStore(is.ImageStore, rm)
 	case ResolverTypeOCILayout:
+		iopt := opt.OCILayoutOpt
+		if iopt == nil {
+			return "", nil, errors.Errorf("missing ocilayoutopt for resolve")
+		}
 		rm = resolver.ResolveModeForcePull
-		rslvr = getOCILayoutResolver(opt.Store, sm, g)
+		rslvr = getOCILayoutResolver(iopt.Store, sm, g)
 	}
 	key += rm.String()
 	res, err := is.g.Do(ctx, key, func(ctx context.Context) (*resolveImageResult, error) {
-		newRef, dgst, dt, err := imageutil.Config(ctx, ref, rslvr, is.ContentStore, is.LeaseManager, opt.Platform, opt.SourcePolicies)
+		dgst, dt, err := imageutil.Config(ctx, ref, rslvr, is.ContentStore, is.LeaseManager, opt.Platform)
 		if err != nil {
 			return nil, err
 		}
-		return &resolveImageResult{dgst: dgst, dt: dt, ref: newRef}, nil
+		return &resolveImageResult{dgst: dgst, dt: dt}, nil
 	})
 	if err != nil {
-		return "", "", nil, err
+		return "", nil, err
 	}
-	return res.ref, res.dgst, res.dt, nil
+	return res.dgst, res.dt, nil
 }
 
 type resolveImageResult struct {
-	ref  string
 	dgst digest.Digest
 	dt   []byte
 }

sourcepolicy/engine.go

@@ -61,8 +61,8 @@ func (e *Engine) selectorCache(src *spb.Selector) *selectorCache {
 // This function may error out even if the op was mutated, in which case `true` will be returned along with the error.
 //
 // An error is returned when the source is denied by the policy.
-func (e *Engine) Evaluate(ctx context.Context, op *pb.Op) (bool, error) {
-	if len(e.pol) == 0 {
+func (e *Engine) Evaluate(ctx context.Context, op *pb.SourceOp) (bool, error) {
+	if len(e.pol) == 0 || op == nil {
 		return false, nil
 	}
 
@@ -74,15 +74,13 @@ func (e *Engine) Evaluate(ctx context.Context, op *pb.Op) (bool, error) {
 			return mutated, errors.Wrapf(ErrTooManyOps, "too many mutations on a single source")
 		}
 
-		srcOp := op.GetSource()
-		if srcOp == nil {
-			return false, nil
-		}
 		if i == 0 {
-			ctx = bklog.WithLogger(ctx, bklog.G(ctx).WithField("orig", *srcOp).WithField("updated", op.GetSource()))
+			ctx = bklog.WithLogger(ctx, bklog.G(ctx).WithField("orig", *op))
+		} else {
+			ctx = bklog.WithLogger(ctx, bklog.G(ctx).WithField("updated", *op))
 		}
 
-		mut, err := e.evaluatePolicies(ctx, srcOp)
+		mut, err := e.evaluatePolicies(ctx, op)
 		if mut {
 			mutated = true
 		}

sourcepolicy/engine_test.go

@@ -53,12 +53,8 @@ func testLastRuleWins(t *testing.T) {
 	}
 
 	e := NewEngine(pol)
-	mut, err := e.Evaluate(context.Background(), &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	mut, err := e.Evaluate(context.Background(), &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	})
 	require.NoError(t, err)
 	require.False(t, mut)
@@ -89,12 +85,8 @@ func testMultiplePolicies(t *testing.T) {
 	}
 
 	e := NewEngine(pol)
-	mut, err := e.Evaluate(context.Background(), &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	mut, err := e.Evaluate(context.Background(), &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	})
 	require.ErrorIs(t, err, ErrSourceDenied)
 	require.False(t, mut)
@@ -135,12 +127,8 @@ func testConvertMultiple(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -169,12 +157,8 @@ func testConvertWildcard(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/golang:1.19",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -183,7 +167,7 @@ func testConvertWildcard(t *testing.T) {
 	mutated, err := e.Evaluate(ctx, op)
 	require.True(t, mutated)
 	require.NoError(t, err)
-	require.Equal(t, "docker-image://fakereg.io/library/golang:1.19", op.GetSource().Identifier)
+	require.Equal(t, "docker-image://fakereg.io/library/golang:1.19", op.Identifier)
 }
 
 func testConvertRegex(t *testing.T) {
@@ -202,12 +186,8 @@ func testConvertRegex(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/golang:1.19",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -216,7 +196,7 @@ func testConvertRegex(t *testing.T) {
 	mutated, err := e.Evaluate(ctx, op)
 	require.True(t, mutated)
 	require.NoError(t, err)
-	require.Equal(t, "docker-image://fakereg.io/library/golang:1.19", op.GetSource().Identifier)
+	require.Equal(t, "docker-image://fakereg.io/library/golang:1.19", op.Identifier)
 }
 
 func testConvertHTTP(t *testing.T) {
@@ -234,12 +214,8 @@ func testConvertHTTP(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "https://example.com/foo",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -248,7 +224,7 @@ func testConvertHTTP(t *testing.T) {
 	mutated, err := e.Evaluate(ctx, op)
 	require.True(t, mutated)
 	require.NoError(t, err)
-	require.Equal(t, "https://example.com/foo", op.GetSource().Identifier)
+	require.Equal(t, "https://example.com/foo", op.Identifier)
 }
 
 func testConvertLoop(t *testing.T) {
@@ -275,12 +251,8 @@ func testConvertLoop(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -324,12 +296,8 @@ func testAllowConvertDeny(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -338,7 +306,7 @@ func testAllowConvertDeny(t *testing.T) {
 	mutated, err := e.Evaluate(ctx, op)
 	require.True(t, mutated)
 	require.ErrorIs(t, err, ErrSourceDenied)
-	require.Equal(t, op.GetSource().Identifier, "docker-image://docker.io/library/alpine:latest")
+	require.Equal(t, op.Identifier, "docker-image://docker.io/library/alpine:latest")
 }
 
 func testConvertDeny(t *testing.T) {
@@ -362,12 +330,8 @@ func testConvertDeny(t *testing.T) {
 		},
 	}
 
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	}
 
 	ctx := context.Background()
@@ -376,7 +340,7 @@ func testConvertDeny(t *testing.T) {
 	mutated, err := e.Evaluate(ctx, op)
 	require.True(t, mutated)
 	require.ErrorIs(t, err, ErrSourceDenied)
-	require.Equal(t, op.GetSource().Identifier, "docker-image://docker.io/library/alpine:latest")
+	require.Equal(t, op.Identifier, "docker-image://docker.io/library/alpine:latest")
 }
 
 func testConvert(t *testing.T) {
@@ -388,12 +352,8 @@ func testConvert(t *testing.T) {
 
 	for src, dst := range cases {
 		t.Run(src+"=>"+dst, func(t *testing.T) {
-			op := &pb.Op{
-				Op: &pb.Op_Source{
-					Source: &pb.SourceOp{
+			op := &pb.SourceOp{
 				Identifier: src,
-					},
-				},
 			}
 
 			pol := &spb.Policy{
@@ -416,18 +376,14 @@ func testConvert(t *testing.T) {
 			mutated, err := e.Evaluate(ctx, op)
 			require.True(t, mutated)
 			require.NoError(t, err)
-			require.Equal(t, dst, op.GetSource().Identifier)
+			require.Equal(t, dst, op.Identifier)
 		})
 	}
 }
 
 func testAllowDeny(t *testing.T) {
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op := &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/alpine:latest",
-			},
-		},
 	}
 	pol := &spb.Policy{
 		Rules: []*spb.Rule{
@@ -453,12 +409,8 @@ func testAllowDeny(t *testing.T) {
 	require.False(t, mutated)
 	require.ErrorIs(t, err, ErrSourceDenied)
 
-	op = &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
+	op = &pb.SourceOp{
 		Identifier: "docker-image://docker.io/library/busybox:latest",
-			},
-		},
 	}
 
 	mutated, err = e.Evaluate(ctx, op)
@@ -489,12 +441,8 @@ func testDenyAll(t *testing.T) {
 			e := NewEngine([]*spb.Policy{pol})
 			ctx := context.Background()
 
-			op := &pb.Op{
-				Op: &pb.Op_Source{
-					Source: &pb.SourceOp{
+			op := &pb.SourceOp{
 				Identifier: ref,
-					},
-				},
 			}
 
 			mutated, err := e.Evaluate(ctx, op)

util/imageutil/config.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"strings"
 	"sync"
 	"time"
 
@@ -16,10 +15,7 @@ import (
 	"github.com/containerd/containerd/remotes"
 	"github.com/containerd/containerd/remotes/docker"
 	intoto "github.com/in-toto/in-toto-golang/in_toto"
-	"github.com/moby/buildkit/solver/pb"
 	srctypes "github.com/moby/buildkit/source/types"
-	"github.com/moby/buildkit/sourcepolicy"
-	spb "github.com/moby/buildkit/sourcepolicy/pb"
 	"github.com/moby/buildkit/util/contentutil"
 	"github.com/moby/buildkit/util/leaseutil"
 	"github.com/moby/buildkit/util/resolver/limited"
@@ -63,8 +59,7 @@ func (e ResolveToNonImageError) Error() string {
 	return fmt.Sprintf("ref mutated by policy to non-image: %s://%s -> %s", srctypes.DockerImageScheme, e.Ref, e.Updated)
 }
 
-func Config(ctx context.Context, str string, resolver remotes.Resolver, cache ContentCache, leaseManager leases.Manager, p *ocispecs.Platform, spls []*spb.Policy) (string, digest.Digest, []byte, error) {
-	// TODO: fix buildkit to take interface instead of struct
+func Config(ctx context.Context, str string, resolver remotes.Resolver, cache ContentCache, leaseManager leases.Manager, p *ocispecs.Platform) (digest.Digest, []byte, error) {
 	var platform platforms.MatchComparer
 	if p != nil {
 		platform = platforms.Only(*p)
@@ -73,46 +68,13 @@ func Config(ctx context.Context, str string, resolver remotes.Resolver, cache Co
 	}
 	ref, err := reference.Parse(str)
 	if err != nil {
-		return "", "", nil, errors.WithStack(err)
-	}
-
-	op := &pb.Op{
-		Op: &pb.Op_Source{
-			Source: &pb.SourceOp{
-				Identifier: srctypes.DockerImageScheme + "://" + ref.String(),
-			},
-		},
-	}
-
-	mut, err := sourcepolicy.NewEngine(spls).Evaluate(ctx, op)
-	if err != nil {
-		return "", "", nil, errors.Wrap(err, "could not resolve image due to policy")
-	}
-
-	if mut {
-		var (
-			t  string
-			ok bool
-		)
-
-		sid := op.GetSource().GetIdentifier()
-		t, newRef, ok := strings.Cut(sid, "://")
-		if !ok {
-			return "", "", nil, errors.Errorf("could not parse ref: %s", sid)
-		}
-		if ok && t != srctypes.DockerImageScheme {
-			return "", "", nil, &ResolveToNonImageError{Ref: str, Updated: sid}
-		}
-		ref, err = reference.Parse(newRef)
-		if err != nil {
-			return "", "", nil, errors.WithStack(err)
-		}
+		return "", nil, errors.WithStack(err)
 	}
 
 	if leaseManager != nil {
 		ctx2, done, err := leaseutil.WithLease(ctx, leaseManager, leases.WithExpiration(5*time.Minute), leaseutil.MakeTemporary)
 		if err != nil {
-			return "", "", nil, errors.WithStack(err)
+			return "", nil, errors.WithStack(err)
 		}
 		ctx = ctx2
 		defer func() {
@@ -143,18 +105,18 @@ func Config(ctx context.Context, str string, resolver remotes.Resolver, cache Co
 	if desc.MediaType == "" {
 		_, desc, err = resolver.Resolve(ctx, ref.String())
 		if err != nil {
-			return "", "", nil, err
+			return "", nil, err
 		}
 	}
 
 	fetcher, err := resolver.Fetcher(ctx, ref.String())
 	if err != nil {
-		return "", "", nil, err
+		return "", nil, err
 	}
 
 	if desc.MediaType == images.MediaTypeDockerSchema1Manifest {
 		dgst, dt, err := readSchema1Config(ctx, ref.String(), desc, fetcher, cache)
-		return ref.String(), dgst, dt, err
+		return dgst, dt, err
 	}
 
 	children := childrenConfigHandler(cache, platform)
@@ -162,7 +124,7 @@ func Config(ctx context.Context, str string, resolver remotes.Resolver, cache Co
 
 	dslHandler, err := docker.AppendDistributionSourceLabel(cache, ref.String())
 	if err != nil {
-		return "", "", nil, err
+		return "", nil, err
 	}
 
 	handlers := []images.Handler{
@@ -171,19 +133,19 @@ func Config(ctx context.Context, str string, resolver remotes.Resolver, cache Co
 		children,
 	}
 	if err := images.Dispatch(ctx, images.Handlers(handlers...), nil, desc); err != nil {
-		return "", "", nil, err
+		return "", nil, err
 	}
 	config, err := images.Config(ctx, cache, desc, platform)
 	if err != nil {
-		return "", "", nil, err
+		return "", nil, err
 	}
 
 	dt, err := content.ReadBlob(ctx, cache, config)
 	if err != nil {
-		return "", "", nil, err
+		return "", nil, err
 	}
 
-	return ref.String(), desc.Digest, dt, nil
+	return desc.Digest, dt, nil
 }
 
 func childrenConfigHandler(provider content.Provider, platform platforms.MatchComparer) images.HandlerFunc {

util/imageutil/config_test.go

@@ -57,7 +57,7 @@ func TestConfigMultiplatform(t *testing.T) {
 		// Now we should be able to get the amd64 config without fetching anything from the remote
 		// If it tries to fetch from the remote this will error out.
 		const ref = "example.com/test:latest"
-		_, _, dt, err := Config(ctx, ref, r, cc, nil, &pAmd64, nil)
+		_, dt, err := Config(ctx, ref, r, cc, nil, &pAmd64)
 		require.NoError(t, err)
 
 		var cfg ocispecs.Image
@@ -67,7 +67,7 @@ func TestConfigMultiplatform(t *testing.T) {
 
 		// Make sure it doesn't select a non-matching platform
 		pArmv7 := platforms.MustParse("linux/arm/v7")
-		_, _, _, err = Config(ctx, ref, r, cc, nil, &pArmv7, nil)
+		_, _, err = Config(ctx, ref, r, cc, nil, &pArmv7)
 		require.ErrorIs(t, err, errdefs.ErrNotFound)
 	}
 

worker/base/worker.go

@@ -18,7 +18,7 @@ import (
 	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/cache/metadata"
 	"github.com/moby/buildkit/client"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor"
 	"github.com/moby/buildkit/executor/resources"
 	"github.com/moby/buildkit/exporter"
@@ -365,16 +365,65 @@ func (w *Worker) PruneCacheMounts(ctx context.Context, ids []string) error {
 	return nil
 }
 
-func (w *Worker) ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt, sm *session.Manager, g session.Group) (string, digest.Digest, []byte, error) {
-	// is this an registry source? Or an OCI layout source?
-	switch opt.ResolverType {
-	case llb.ResolverTypeOCILayout:
-		return w.OCILayoutSource.ResolveImageConfig(ctx, ref, opt, sm, g)
-		// we probably should put an explicit case llb.ResolverTypeRegistry and default here,
-		// but then go complains that we do not have a return statement,
-		// so we just add it after
+func (w *Worker) ResolveSourceMetadata(ctx context.Context, op *pb.SourceOp, opt sourceresolver.Opt, sm *session.Manager, g session.Group) (*sourceresolver.MetaResponse, error) {
+	if opt.SourcePolicies != nil {
+		return nil, errors.New("source policies can not be set for worker")
 	}
-	return w.ImageSource.ResolveImageConfig(ctx, ref, opt, sm, g)
+
+	var platform *pb.Platform
+	if p := opt.Platform; p != nil {
+		platform = &pb.Platform{
+			Architecture: p.Architecture,
+			OS:           p.OS,
+			Variant:      p.Variant,
+			OSVersion:    p.OSVersion,
+		}
+	}
+
+	id, err := w.SourceManager.Identifier(&pb.Op_Source{Source: op}, platform)
+	if err != nil {
+		return nil, err
+	}
+
+	switch idt := id.(type) {
+	case *containerimage.ImageIdentifier:
+		if opt.ImageOpt == nil {
+			opt.ImageOpt = &sourceresolver.ResolveImageOpt{}
+		}
+		dgst, config, err := w.ImageSource.ResolveImageConfig(ctx, idt.Reference.String(), opt, sm, g)
+		if err != nil {
+			return nil, err
+		}
+		return &sourceresolver.MetaResponse{
+			Op: op,
+			Image: &sourceresolver.ResolveImageResponse{
+				Digest: dgst,
+				Config: config,
+			},
+		}, nil
+	case *containerimage.OCIIdentifier:
+		opt.OCILayoutOpt = &sourceresolver.ResolveOCILayoutOpt{
+			Store: sourceresolver.ResolveImageConfigOptStore{
+				StoreID:   idt.StoreID,
+				SessionID: idt.SessionID,
+			},
+		}
+		dgst, config, err := w.OCILayoutSource.ResolveImageConfig(ctx, idt.Reference.String(), opt, sm, g)
+		if err != nil {
+			return nil, err
+		}
+		return &sourceresolver.MetaResponse{
+			Op: op,
+			Image: &sourceresolver.ResolveImageResponse{
+				Digest: dgst,
+				Config: config,
+			},
+		}, nil
+	}
+
+	return &sourceresolver.MetaResponse{
+		Op: op,
+	}, nil
 }
 
 func (w *Worker) DiskUsage(ctx context.Context, opt client.DiskUsageInfo) ([]*client.UsageInfo, error) {

worker/worker.go

@@ -6,15 +6,15 @@ import (
 
 	"github.com/moby/buildkit/cache"
 	"github.com/moby/buildkit/client"
-	"github.com/moby/buildkit/client/llb"
+	"github.com/moby/buildkit/client/llb/sourceresolver"
 	"github.com/moby/buildkit/executor"
 	"github.com/moby/buildkit/exporter"
 	"github.com/moby/buildkit/frontend"
 	"github.com/moby/buildkit/session"
 	containerdsnapshot "github.com/moby/buildkit/snapshot/containerd"
 	"github.com/moby/buildkit/solver"
+	"github.com/moby/buildkit/solver/pb"
 	"github.com/moby/buildkit/util/leaseutil"
-	digest "github.com/opencontainers/go-digest"
 	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
@@ -30,7 +30,7 @@ type Worker interface {
 	LoadRef(ctx context.Context, id string, hidden bool) (cache.ImmutableRef, error)
 	// ResolveOp resolves Vertex.Sys() to Op implementation.
 	ResolveOp(v solver.Vertex, s frontend.FrontendLLBBridge, sm *session.Manager) (solver.Op, error)
-	ResolveImageConfig(ctx context.Context, ref string, opt llb.ResolveImageConfigOpt, sm *session.Manager, g session.Group) (string, digest.Digest, []byte, error)
+	ResolveSourceMetadata(ctx context.Context, op *pb.SourceOp, opt sourceresolver.Opt, sm *session.Manager, g session.Group) (*sourceresolver.MetaResponse, error)
 	DiskUsage(ctx context.Context, opt client.DiskUsageInfo) ([]*client.UsageInfo, error)
 	Exporter(name string, sm *session.Manager) (exporter.Exporter, error)
 	Prune(ctx context.Context, ch chan client.UsageInfo, opt ...client.PruneInfo) error