Fixup attestation platforms for the local exporter

client/build.go

@@ -4,7 +4,6 @@ import (
 	"context"
 
 	"github.com/moby/buildkit/client/buildid"
-	"github.com/moby/buildkit/frontend/attestations"
 	gateway "github.com/moby/buildkit/frontend/gateway/client"
 	"github.com/moby/buildkit/frontend/gateway/grpcclient"
 	gatewayapi "github.com/moby/buildkit/frontend/gateway/pb"
@@ -24,7 +23,6 @@ func (c *Client) Build(ctx context.Context, opt SolveOpt, product string, buildF
 	feOpts := opt.FrontendAttrs
 
 	opt.Frontend = ""
-	opt.FrontendAttrs = attestations.Filter(opt.FrontendAttrs)
 
 	if product == "" {
 		product = apicaps.ExportedProduct

client/solve.go

@@ -210,11 +210,12 @@ func (c *Client) solve(ctx context.Context, def *llb.Definition, runGateway runG
 		})
 	}
 
+	frontendAttrs := map[string]string{}
+	for k, v := range opt.FrontendAttrs {
+		frontendAttrs[k] = v
+	}
 	for k, v := range cacheOpt.frontendAttrs {
-		if opt.FrontendAttrs == nil {
-			opt.FrontendAttrs = map[string]string{}
-		}
-		opt.FrontendAttrs[k] = v
+		frontendAttrs[k] = v
 	}
 
 	solveCtx, cancelSolve := context.WithCancel(ctx)
@@ -254,7 +255,7 @@ func (c *Client) solve(ctx context.Context, def *llb.Definition, runGateway runG
 			ExporterAttrs:  ex.Attrs,
 			Session:        s.ID(),
 			Frontend:       opt.Frontend,
-			FrontendAttrs:  opt.FrontendAttrs,
+			FrontendAttrs:  frontendAttrs,
 			FrontendInputs: frontendInputs,
 			Cache:          cacheOpt.options,
 			Entitlements:   opt.AllowedEntitlements,
@@ -270,7 +271,7 @@ func (c *Client) solve(ctx context.Context, def *llb.Definition, runGateway runG
 
 	if runGateway != nil {
 		eg.Go(func() error {
-			err := runGateway(ref, s, opt.FrontendAttrs)
+			err := runGateway(ref, s, frontendAttrs)
 			if err == nil {
 				return nil
 			}

control/control.go

@@ -17,6 +17,7 @@ import (
 	controlgateway "github.com/moby/buildkit/control/gateway"
 	"github.com/moby/buildkit/exporter"
 	"github.com/moby/buildkit/exporter/util/epoch"
+	"github.com/moby/buildkit/exporter/util/multiplatform"
 	"github.com/moby/buildkit/frontend"
 	"github.com/moby/buildkit/frontend/attestations"
 	"github.com/moby/buildkit/session"
@@ -295,12 +296,22 @@ func (c *Controller) Solve(ctx context.Context, req *controlapi.SolveRequest) (*
 	}
 
 	// if SOURCE_DATE_EPOCH is set, enable it for the exporter
-	if epochVal, ok := req.FrontendAttrs["build-arg:SOURCE_DATE_EPOCH"]; ok {
+	if v, ok := epoch.ParseBuildArgs(req.FrontendAttrs); ok {
 		if _, ok := req.ExporterAttrs[epoch.KeySourceDateEpoch]; !ok {
 			if req.ExporterAttrs == nil {
 				req.ExporterAttrs = make(map[string]string)
 			}
-			req.ExporterAttrs[epoch.KeySourceDateEpoch] = epochVal
+			req.ExporterAttrs[epoch.KeySourceDateEpoch] = v
+		}
+	}
+
+	// if multi-platform is set, enable it for the exporter
+	if v, ok := multiplatform.ParseBuildArgs(req.FrontendAttrs); ok {
+		if _, ok := req.ExporterAttrs[multiplatform.KeyMultiPlatform]; !ok {
+			if req.ExporterAttrs == nil {
+				req.ExporterAttrs = make(map[string]string)
+			}
+			req.ExporterAttrs[multiplatform.KeyMultiPlatform] = v
 		}
 	}
 

exporter/containerimage/opts.go

@@ -6,6 +6,7 @@ import (
 
 	cacheconfig "github.com/moby/buildkit/cache/config"
 	"github.com/moby/buildkit/exporter/util/epoch"
+	"github.com/moby/buildkit/exporter/util/multiplatform"
 	"github.com/moby/buildkit/util/compression"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -34,6 +35,7 @@ type ImageCommitOpts struct {
 	BuildInfoAttrs bool
 	Annotations    AnnotationsGroup
 	Epoch          *time.Time
+	MultiPlatform  *bool
 }
 
 func (c *ImageCommitOpts) Load(opt map[string]string) (map[string]string, error) {
@@ -45,7 +47,12 @@ func (c *ImageCommitOpts) Load(opt map[string]string) (map[string]string, error)
 	}
 	opt = toStringMap(optb)
 
-	c.Epoch, opt, err = epoch.ParseAttr(opt)
+	c.Epoch, opt, err = epoch.ParseExporterAttrs(opt)
+	if err != nil {
+		return nil, err
+	}
+
+	c.MultiPlatform, opt, err = multiplatform.ParseExporterAttrs(opt)
 	if err != nil {
 		return nil, err
 	}

exporter/containerimage/writer.go

@@ -63,11 +63,20 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 		return nil, errors.Errorf("unable to export multiple refs, missing platforms mapping")
 	}
 
+	multiPlatform := len(inp.Refs) > 0
+
 	var p exptypes.Platforms
 	if ok && len(platformsBytes) > 0 {
 		if err := json.Unmarshal(platformsBytes, &p); err != nil {
 			return nil, errors.Wrapf(err, "failed to parse platforms passed to exporter")
 		}
+		if len(p.Platforms) > 1 {
+			multiPlatform = true
+		}
+	}
+
+	if opts.MultiPlatform != nil {
+		multiPlatform = *opts.MultiPlatform
 	}
 
 	if opts.Epoch == nil {
@@ -92,8 +101,26 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 		}
 	}
 
-	if len(inp.Refs) == 0 {
-		remotes, err := ic.exportLayers(ctx, opts.RefCfg, session.NewGroup(sessionID), inp.Ref)
+	if !multiPlatform {
+		if len(p.Platforms) > 1 {
+			return nil, errors.Errorf("cannot export multiple platforms without multi-platform enabled")
+		}
+
+		var ref cache.ImmutableRef
+		if inp.Ref != nil {
+			ref = inp.Ref
+		} else if len(p.Platforms) > 0 {
+			p := p.Platforms[0]
+			if _, ok := inp.Attestations[p.ID]; ok {
+				return nil, errors.Errorf("cannot export attestations without multi-platform enabled")
+			}
+			ref = inp.Refs[p.ID]
+		} else if len(inp.Refs) == 1 {
+			for _, ref = range inp.Refs {
+			}
+		}
+
+		remotes, err := ic.exportLayers(ctx, opts.RefCfg, session.NewGroup(sessionID), ref)
 		if err != nil {
 			return nil, err
 		}
@@ -112,7 +139,7 @@ func (ic *ImageWriter) Commit(ctx context.Context, inp *exporter.Source, session
 			return nil, errors.Errorf("index annotations not supported for single platform export")
 		}
 
-		mfstDesc, configDesc, err := ic.commitDistributionManifest(ctx, opts, inp.Ref, inp.Metadata[exptypes.ExporterImageConfigKey], &remotes[0], annotations, inp.Metadata[exptypes.ExporterInlineCache], dtbi, opts.Epoch, session.NewGroup(sessionID))
+		mfstDesc, configDesc, err := ic.commitDistributionManifest(ctx, opts, ref, inp.Metadata[exptypes.ExporterImageConfigKey], &remotes[0], annotations, inp.Metadata[exptypes.ExporterInlineCache], dtbi, opts.Epoch, session.NewGroup(sessionID))
 		if err != nil {
 			return nil, err
 		}

exporter/local/export.go

@@ -11,6 +11,7 @@ import (
 	"github.com/moby/buildkit/exporter"
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	"github.com/moby/buildkit/exporter/util/epoch"
+	"github.com/moby/buildkit/exporter/util/multiplatform"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/session/filesync"
 	"github.com/moby/buildkit/solver/result"
@@ -41,15 +42,21 @@ func New(opt Opt) (exporter.Exporter, error) {
 }
 
 func (e *localExporter) Resolve(ctx context.Context, opt map[string]string) (exporter.ExporterInstance, error) {
-	tm, _, err := epoch.ParseAttr(opt)
+	tm, _, err := epoch.ParseExporterAttrs(opt)
+	if err != nil {
+		return nil, err
+	}
+
+	multiPlatform, _, err := multiplatform.ParseExporterAttrs(opt)
 	if err != nil {
 		return nil, err
 	}
 
 	i := &localExporterInstance{
 		localExporter: e,
 		opts: CreateFSOpts{
-			Epoch: tm,
+			Epoch:         tm,
+			MultiPlatform: multiPlatform,
 		},
 	}
 
@@ -93,6 +100,8 @@ func (e *localExporterInstance) Export(ctx context.Context, inp *exporter.Source
 		return nil, err
 	}
 
+	isMap := len(inp.Refs) > 0
+
 	platformsBytes, ok := inp.Metadata[exptypes.ExporterPlatformsKey]
 	if len(inp.Refs) > 0 && !ok {
 		return nil, errors.Errorf("unable to export multiple refs, missing platforms mapping")
@@ -103,8 +112,17 @@ func (e *localExporterInstance) Export(ctx context.Context, inp *exporter.Source
 		if err := json.Unmarshal(platformsBytes, &p); err != nil {
 			return nil, errors.Wrapf(err, "failed to parse platforms passed to exporter")
 		}
+		if len(p.Platforms) > 1 {
+			isMap = true
+		}
+	}
+
+	if e.opts.MultiPlatform != nil {
+		isMap = *e.opts.MultiPlatform
+	}
+	if !isMap && len(p.Platforms) > 1 {
+		return nil, errors.Errorf("unable to export multiple platforms without map")
 	}
-	isMap := len(p.Platforms) > 1
 
 	now := time.Now().Truncate(time.Second)
 

exporter/local/fs.go

@@ -27,6 +27,7 @@ import (
 type CreateFSOpts struct {
 	Epoch             *time.Time
 	AttestationPrefix string
+	MultiPlatform     *bool
 }
 
 func CreateFS(ctx context.Context, sessionID string, k string, ref cache.ImmutableRef, refs map[string]cache.ImmutableRef, attestations []result.Attestation, defaultTime time.Time, opt CreateFSOpts) (fsutil.FS, func() error, error) {

exporter/tar/export.go

@@ -13,6 +13,7 @@ import (
 	"github.com/moby/buildkit/exporter/containerimage/exptypes"
 	"github.com/moby/buildkit/exporter/local"
 	"github.com/moby/buildkit/exporter/util/epoch"
+	"github.com/moby/buildkit/exporter/util/multiplatform"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/session/filesync"
 	"github.com/moby/buildkit/solver/result"
@@ -48,12 +49,18 @@ func New(opt Opt) (exporter.Exporter, error) {
 func (e *localExporter) Resolve(ctx context.Context, opt map[string]string) (exporter.ExporterInstance, error) {
 	li := &localExporterInstance{localExporter: e}
 
-	tm, _, err := epoch.ParseAttr(opt)
+	tm, opt, err := epoch.ParseExporterAttrs(opt)
 	if err != nil {
 		return nil, err
 	}
 	li.opts.Epoch = tm
 
+	multiPlatform, opt, err := multiplatform.ParseExporterAttrs(opt)
+	if err != nil {
+		return nil, err
+	}
+	li.opts.MultiPlatform = multiPlatform
+
 	for k, v := range opt {
 		switch k {
 		case preferNondistLayersKey:
@@ -126,6 +133,8 @@ func (e *localExporterInstance) Export(ctx context.Context, inp *exporter.Source
 		}, nil
 	}
 
+	isMap := len(inp.Refs) > 0
+
 	platformsBytes, ok := inp.Metadata[exptypes.ExporterPlatformsKey]
 	if len(inp.Refs) > 0 && !ok {
 		return nil, errors.Errorf("unable to export multiple refs, missing platforms mapping")
@@ -136,8 +145,17 @@ func (e *localExporterInstance) Export(ctx context.Context, inp *exporter.Source
 		if err := json.Unmarshal(platformsBytes, &p); err != nil {
 			return nil, errors.Wrapf(err, "failed to parse platforms passed to exporter")
 		}
+		if len(p.Platforms) > 1 {
+			isMap = true
+		}
+	}
+
+	if e.opts.MultiPlatform != nil {
+		isMap = *e.opts.MultiPlatform
+	}
+	if !isMap && len(p.Platforms) > 1 {
+		return nil, errors.Errorf("unable to export multiple platforms without map")
 	}
-	isMap := len(p.Platforms) > 1
 
 	var fs fsutil.FS
 

exporter/util/epoch/parse.go

@@ -10,10 +10,17 @@ import (
 )
 
 const (
+	frontendSourceDateEpochArg = "build-arg:SOURCE_DATE_EPOCH"
+
 	KeySourceDateEpoch = "source-date-epoch"
 )
 
-func ParseAttr(opt map[string]string) (*time.Time, map[string]string, error) {
+func ParseBuildArgs(opt map[string]string) (string, bool) {
+	v, ok := opt[frontendSourceDateEpochArg]
+	return v, ok
+}
+
+func ParseExporterAttrs(opt map[string]string) (*time.Time, map[string]string, error) {
 	rest := make(map[string]string, len(opt))
 
 	var tm *time.Time

exporter/util/multiplatform/parse.go

@@ -0,0 +1,45 @@
+package multiplatform
+
+import (
+	"strconv"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	frontendMultiPlatform    = "multi-platform"
+	frontendMultiPlatformArg = "build-arg:BUILDKIT_MULTI_PLATFORM"
+
+	KeyMultiPlatform = "multi-platform"
+)
+
+func ParseBuildArgs(opt map[string]string) (string, bool) {
+	if v, ok := opt[frontendMultiPlatform]; ok {
+		return v, true
+	}
+	if v, ok := opt[frontendMultiPlatformArg]; ok {
+		return v, true
+	}
+	return "", false
+}
+
+func ParseExporterAttrs(opt map[string]string) (*bool, map[string]string, error) {
+	rest := make(map[string]string, len(opt))
+
+	var multiPlatform *bool
+
+	for k, v := range opt {
+		switch k {
+		case KeyMultiPlatform:
+			b, err := strconv.ParseBool(v)
+			if err != nil {
+				return nil, nil, errors.Errorf("invalid boolean value %s", v)
+			}
+			multiPlatform = &b
+		default:
+			rest[k] = v
+		}
+	}
+
+	return multiPlatform, rest, nil
+}

frontend/dockerfile/builder/build.go

@@ -414,7 +414,7 @@ func Build(ctx context.Context, c client.Client) (_ *client.Result, err error) {
 			return nil, errors.Errorf("invalid boolean value %s", v)
 		}
 		if !b && exportMap {
-			return nil, errors.Errorf("returning multiple target plaforms is not allowed")
+			return nil, errors.Errorf("returning multiple target platforms is not allowed")
 		}
 		exportMap = b
 	}