Merge pull request #4039 from deitch/split-moby

move moby components that do not have runtime dependencies to own directory

src/cmd/linuxkit/build.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/moby"
+	mobybuild "github.com/linuxkit/linuxkit/src/cmd/linuxkit/moby/build"
 	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/spec"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -52,7 +53,7 @@ func buildCmd() *cobra.Command {
 		arch               string
 		cacheDir           flagOverEnvVarOverDefaultString
 		buildFormats       formatList
-		outputTypes        = moby.OutputTypes()
+		outputTypes        = mobybuild.OutputTypes()
 		noSbom             bool
 		sbomOutputFilename string
 		inputTar           string
@@ -94,13 +95,13 @@ The generated image can be in one of multiple formats which can be run on variou
 
 			if len(buildFormats) > 1 {
 				for _, o := range buildFormats {
-					if moby.Streamable(o) {
+					if mobybuild.Streamable(o) {
 						return fmt.Errorf("format type %s must be the only format specified", o)
 					}
 				}
 			}
 
-			if len(buildFormats) == 1 && moby.Streamable(buildFormats[0]) {
+			if len(buildFormats) == 1 && mobybuild.Streamable(buildFormats[0]) {
 				if outputFile == "" {
 					outputFile = filepath.Join(dir, name+"."+buildFormats[0])
 					// stop the errors in the validation below
@@ -108,7 +109,7 @@ The generated image can be in one of multiple formats which can be run on variou
 					dir = ""
 				}
 			} else {
-				err := moby.ValidateFormats(buildFormats, cacheDir.String())
+				err := mobybuild.ValidateFormats(buildFormats, cacheDir.String())
 				if err != nil {
 					return fmt.Errorf("error parsing formats: %v", err)
 				}
@@ -129,7 +130,7 @@ The generated image can be in one of multiple formats which can be run on variou
 				if dir != "" {
 					return fmt.Errorf("the -output option cannot be specified with -dir")
 				}
-				if !moby.Streamable(buildFormats[0]) {
+				if !mobybuild.Streamable(buildFormats[0]) {
 					return fmt.Errorf("the -output option cannot be specified for build type %s as it cannot be streamed", buildFormats[0])
 				}
 				if outputFile == "-" {
@@ -225,17 +226,17 @@ The generated image can be in one of multiple formats which can be run on variou
 			// this is a weird interface, but currently only streamable types can have additional files
 			// need to split up the base tarball outputs from the secondary stages
 			var tp string
-			if moby.Streamable(buildFormats[0]) {
+			if mobybuild.Streamable(buildFormats[0]) {
 				tp = buildFormats[0]
 			}
-			var sbomGenerator *moby.SbomGenerator
+			var sbomGenerator *mobybuild.SbomGenerator
 			if !noSbom {
-				sbomGenerator, err = moby.NewSbomGenerator(sbomOutputFilename, sbomCurrentTime)
+				sbomGenerator, err = mobybuild.NewSbomGenerator(sbomOutputFilename, sbomCurrentTime)
 				if err != nil {
 					return fmt.Errorf("error creating sbom generator: %v", err)
 				}
 			}
-			err = moby.Build(m, w, moby.BuildOpts{Pull: pull, BuilderType: tp, DecompressKernel: decompressKernel, CacheDir: cacheDir.String(), DockerCache: docker, Arch: arch, SbomGenerator: sbomGenerator, InputTar: inputTar})
+			err = mobybuild.Build(m, w, mobybuild.BuildOpts{Pull: pull, BuilderType: tp, DecompressKernel: decompressKernel, CacheDir: cacheDir.String(), DockerCache: docker, Arch: arch, SbomGenerator: sbomGenerator, InputTar: inputTar})
 			if err != nil {
 				return fmt.Errorf("%v", err)
 			}
@@ -247,7 +248,7 @@ The generated image can be in one of multiple formats which can be run on variou
 				}
 
 				log.Infof("Create outputs:")
-				err = moby.Formats(filepath.Join(dir, name), image, buildFormats, size, arch, cacheDir.String())
+				err = mobybuild.Formats(filepath.Join(dir, name), image, buildFormats, size, arch, cacheDir.String())
 				if err != nil {
 					return fmt.Errorf("error writing outputs: %v", err)
 				}

src/cmd/linuxkit/moby/apk_tarwriter.go

@@ -19,7 +19,7 @@ type apkTarWriter struct {
 	location string
 }
 
-func newAPKTarWriter(w *tar.Writer, location string) *apkTarWriter {
+func NewAPKTarWriter(w *tar.Writer, location string) *apkTarWriter {
 	return &apkTarWriter{
 		Writer:   w,
 		location: location,

src/cmd/linuxkit/moby/build/build.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"archive/tar"
@@ -18,6 +18,7 @@ import (
 	"github.com/containerd/containerd/reference"
 	// drop-in 100% compatible replacement and 17% faster than compress/gzip.
 	gzip "github.com/klauspost/pgzip"
+	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/moby"
 	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/util"
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v2"
@@ -83,7 +84,7 @@ func OutputTypes() []string {
 	return ts
 }
 
-func outputImage(image *Image, section string, index int, prefix string, m Moby, idMap map[string]uint32, dupMap map[string]string, iw *tar.Writer, opts BuildOpts) error {
+func outputImage(image *moby.Image, section string, index int, prefix string, m moby.Moby, idMap map[string]uint32, dupMap map[string]string, iw *tar.Writer, opts BuildOpts) error {
 	log.Infof("  Create OCI config for %s", image.Image)
 	imageName := util.ReferenceExpand(image.Image)
 	ref, err := reference.Parse(imageName)
@@ -98,7 +99,7 @@ func outputImage(image *Image, section string, index int, prefix string, m Moby,
 	if err != nil {
 		return fmt.Errorf("failed to retrieve config for %s: %v", image.Image, err)
 	}
-	oci, runtime, err := ConfigToOCI(image, configRaw, idMap)
+	oci, runtime, err := moby.ConfigToOCI(image, configRaw, idMap)
 	if err != nil {
 		return fmt.Errorf("failed to create OCI spec for %s: %v", image.Image, err)
 	}
@@ -108,7 +109,7 @@ func outputImage(image *Image, section string, index int, prefix string, m Moby,
 	}
 	path := path.Join("containers", section, prefix+image.Name)
 	readonly := oci.Root.Readonly
-	err = ImageBundle(path, fmt.Sprintf("%s[%d]", section, index), image.ref, config, runtime, iw, readonly, dupMap, opts)
+	err = ImageBundle(path, fmt.Sprintf("%s[%d]", section, index), image.Ref(), config, runtime, iw, readonly, dupMap, opts)
 	if err != nil {
 		return fmt.Errorf("failed to extract root filesystem for %s: %v", image.Image, err)
 	}
@@ -117,7 +118,7 @@ func outputImage(image *Image, section string, index int, prefix string, m Moby,
 
 // Build performs the actual build process. The output is the filesystem
 // in a tar stream written to w.
-func Build(m Moby, w io.Writer, opts BuildOpts) error {
+func Build(m moby.Moby, w io.Writer, opts BuildOpts) error {
 	if MobyDir == "" {
 		MobyDir = defaultMobyConfigDir()
 	}
@@ -138,7 +139,7 @@ func Build(m Moby, w io.Writer, opts BuildOpts) error {
 		}
 	}
 	var (
-		oldConfig *Moby
+		oldConfig *moby.Moby
 		in        *os.File
 		err       error
 	)
@@ -167,7 +168,7 @@ func Build(m Moby, w io.Writer, opts BuildOpts) error {
 				if _, err := buf.ReadFrom(inputTarReader); err != nil {
 					return fmt.Errorf("failed to read metadata file from input tar: %w", err)
 				}
-				config, err := NewConfig(buf.Bytes(), nil)
+				config, err := moby.NewConfig(buf.Bytes(), nil)
 				if err != nil {
 					return fmt.Errorf("invalid config in existing tar file: %v", err)
 				}
@@ -202,18 +203,22 @@ func Build(m Moby, w io.Writer, opts BuildOpts) error {
 	// deduplicate containers with the same image
 	dupMap := map[string]string{}
 
-	if m.Kernel.ref != nil {
+	kernelRef := m.Kernel.Ref()
+	var oldKernelRef *reference.Spec
+	if oldConfig != nil {
+		oldKernelRef = oldConfig.Kernel.Ref()
+	}
+	if kernelRef != nil {
 		// first check if the existing one had it
-		//if config != nil && len(oldConfig.initRefs) > index+1 && oldConfig.initRefs[index].String() == image {
+		if oldKernelRef != nil && oldKernelRef.String() == kernelRef.String() {
-		if oldConfig != nil && oldConfig.Kernel.ref != nil && oldConfig.Kernel.ref.String() == m.Kernel.ref.String() {
+			if err := extractPackageFilesFromTar(in, iw, kernelRef.String(), "kernel"); err != nil {
-			if err := extractPackageFilesFromTar(in, iw, m.Kernel.ref.String(), "kernel"); err != nil {
 				return err
 			}
 		} else {
 			// get kernel and initrd tarball and ucode cpio archive from container
-			log.Infof("Extract kernel image: %s", m.Kernel.ref)
+			log.Infof("Extract kernel image: %s", m.Kernel.Ref())
-			kf := newKernelFilter(m.Kernel.ref, iw, m.Kernel.Cmdline, m.Kernel.Binary, m.Kernel.Tar, m.Kernel.UCode, opts.DecompressKernel)
+			kf := newKernelFilter(kernelRef, iw, m.Kernel.Cmdline, m.Kernel.Binary, m.Kernel.Tar, m.Kernel.UCode, opts.DecompressKernel)
-			err := ImageTar("kernel", m.Kernel.ref, "", kf, "", opts)
+			err := ImageTar("kernel", kernelRef, "", kf, "", opts)
 			if err != nil {
 				return fmt.Errorf("failed to extract kernel image and tarball: %v", err)
 			}
@@ -228,9 +233,14 @@ func Build(m Moby, w io.Writer, opts BuildOpts) error {
 	if len(m.Init) != 0 {
 		log.Infof("Add init containers:")
 	}
-	apkTar := newAPKTarWriter(iw, "init")
+	apkTar := moby.NewAPKTarWriter(iw, "init")
-	for i, ii := range m.initRefs {
+	initRefs := m.InitRefs()
-		if oldConfig != nil && len(oldConfig.initRefs) > i && oldConfig.initRefs[i].String() == ii.String() {
+	var oldInitRefs []*reference.Spec
+	if oldConfig != nil {
+		oldInitRefs = oldConfig.InitRefs()
+	}
+	for i, ii := range initRefs {
+		if len(oldInitRefs) > i && oldInitRefs[i].String() == ii.String() {
 			if err := extractPackageFilesFromTar(in, apkTar, ii.String(), fmt.Sprintf("init[%d]", i)); err != nil {
 				return err
 			}
@@ -521,8 +531,8 @@ func tarAppend(ref *reference.Spec, iw *tar.Writer, tr *tar.Reader) error {
 		if hdr.PAXRecords == nil {
 			hdr.PAXRecords = make(map[string]string)
 		}
-		hdr.PAXRecords[PaxRecordLinuxkitSource] = ref.String()
+		hdr.PAXRecords[moby.PaxRecordLinuxkitSource] = ref.String()
-		hdr.PAXRecords[PaxRecordLinuxkitLocation] = "kernel"
+		hdr.PAXRecords[moby.PaxRecordLinuxkitLocation] = "kernel"
 		err = iw.WriteHeader(hdr)
 		if err != nil {
 			return err
@@ -615,9 +625,9 @@ func gunzip(src *bytes.Buffer) (*bytes.Buffer, error) {
 }
 
 // this allows inserting metadata into a file in the image
-func metadata(m Moby, md string) ([]byte, error) {
+func metadata(m moby.Moby, md string) ([]byte, error) {
 	// Make sure the Image strings are update to date with the refs
-	updateImages(&m)
+	moby.UpdateImages(&m)
 	switch md {
 	case "json":
 		return json.MarshalIndent(m, "", "    ")
@@ -628,7 +638,7 @@ func metadata(m Moby, md string) ([]byte, error) {
 	}
 }
 
-func filesystem(m Moby, tw *tar.Writer, idMap map[string]uint32) error {
+func filesystem(m moby.Moby, tw *tar.Writer, idMap map[string]uint32) error {
 	// TODO also include the files added in other parts of the build
 	var addedFiles = map[string]bool{}
 
@@ -666,11 +676,11 @@ func filesystem(m Moby, tw *tar.Writer, idMap map[string]uint32) error {
 			dirMode |= 0001
 		}
 
-		uid, err := idNumeric(f.UID, idMap)
+		uid, err := moby.IDNumeric(f.UID, idMap)
 		if err != nil {
 			return err
 		}
-		gid, err := idNumeric(f.GID, idMap)
+		gid, err := moby.IDNumeric(f.GID, idMap)
 		if err != nil {
 			return err
 		}
@@ -740,8 +750,8 @@ func filesystem(m Moby, tw *tar.Writer, idMap map[string]uint32) error {
 					Gid:      int(gid),
 					Format:   tar.FormatPAX,
 					PAXRecords: map[string]string{
-						PaxRecordLinuxkitSource:   "linuxkit.files",
+						moby.PaxRecordLinuxkitSource:   "linuxkit.files",
-						PaxRecordLinuxkitLocation: fmt.Sprintf("files[%d]", filecount),
+						moby.PaxRecordLinuxkitLocation: fmt.Sprintf("files[%d]", filecount),
 					},
 				}
 				err := tw.WriteHeader(hdr)
@@ -760,8 +770,8 @@ func filesystem(m Moby, tw *tar.Writer, idMap map[string]uint32) error {
 			Gid:     int(gid),
 			Format:  tar.FormatPAX,
 			PAXRecords: map[string]string{
-				PaxRecordLinuxkitSource:   "linuxkit.files",
+				moby.PaxRecordLinuxkitSource:   "linuxkit.files",
-				PaxRecordLinuxkitLocation: fmt.Sprintf("files[%d]", filecount),
+				moby.PaxRecordLinuxkitLocation: fmt.Sprintf("files[%d]", filecount),
 			},
 		}
 		if f.Directory {
@@ -815,7 +825,7 @@ func extractPackageFilesFromTar(inTar *os.File, tw tarWriter, image, section str
 		if hdr.PAXRecords == nil {
 			continue
 		}
-		if hdr.PAXRecords[PaxRecordLinuxkitSource] == image && hdr.PAXRecords[PaxRecordLinuxkitLocation] == section {
+		if hdr.PAXRecords[moby.PaxRecordLinuxkitSource] == image && hdr.PAXRecords[moby.PaxRecordLinuxkitLocation] == section {
 			if err := tw.WriteHeader(hdr); err != nil {
 				return fmt.Errorf("failed to write header: %w", err)
 			}

src/cmd/linuxkit/moby/build/dir.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"path/filepath"

src/cmd/linuxkit/moby/build/docker.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 // We want to replace much of this with use of containerd tools
 // and also using the Docker API not shelling out

src/cmd/linuxkit/moby/build/image.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"archive/tar"
@@ -10,18 +10,11 @@ import (
 	"strings"
 
 	"github.com/containerd/containerd/reference"
+	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/moby"
 	"github.com/opencontainers/runtime-spec/specs-go"
 	log "github.com/sirupsen/logrus"
 )
 
-const (
-	// PaxRecordLinuxkitSource report the package source for a specific file
-	PaxRecordLinuxkitSource = "LINUXKIT.source"
-	// PaxRecordLinuxkitLocation report the location of the file in the linuxkit.yaml
-	// that led to this file being in this location
-	PaxRecordLinuxkitLocation = "LINUXKIT.location"
-)
-
 type tarWriter interface {
 	Close() error
 	Flush() error
@@ -170,8 +163,8 @@ func tarPrefix(path, location string, ref *reference.Spec, tw tarWriter) error {
 			Typeflag: tar.TypeDir,
 			Format:   tar.FormatPAX,
 			PAXRecords: map[string]string{
-				PaxRecordLinuxkitSource:   ref.String(),
+				moby.PaxRecordLinuxkitSource:   ref.String(),
-				PaxRecordLinuxkitLocation: location,
+				moby.PaxRecordLinuxkitLocation: location,
 			},
 		}
 		if err := tw.WriteHeader(hdr); err != nil {
@@ -232,8 +225,8 @@ func ImageTar(location string, ref *reference.Spec, prefix string, tw tarWriter,
 		if hdr.PAXRecords == nil {
 			hdr.PAXRecords = make(map[string]string)
 		}
-		hdr.PAXRecords[PaxRecordLinuxkitSource] = ref.String()
+		hdr.PAXRecords[moby.PaxRecordLinuxkitSource] = ref.String()
-		hdr.PAXRecords[PaxRecordLinuxkitLocation] = location
+		hdr.PAXRecords[moby.PaxRecordLinuxkitLocation] = location
 		if exclude[hdr.Name] {
 			log.Debugf("image tar: %s %s exclude %s", ref, prefix, hdr.Name)
 			_, err = io.Copy(io.Discard, tr)
@@ -310,8 +303,8 @@ func ImageTar(location string, ref *reference.Spec, prefix string, tw tarWriter,
 		if hdr.PAXRecords == nil {
 			hdr.PAXRecords = make(map[string]string)
 		}
-		hdr.PAXRecords[PaxRecordLinuxkitSource] = ref.String()
+		hdr.PAXRecords[moby.PaxRecordLinuxkitSource] = ref.String()
-		hdr.PAXRecords[PaxRecordLinuxkitLocation] = location
+		hdr.PAXRecords[moby.PaxRecordLinuxkitLocation] = location
 		origName := hdr.Name
 		hdr.Name = prefix + origName
 		hdr.Format = tar.FormatPAX
@@ -355,7 +348,7 @@ func ImageTar(location string, ref *reference.Spec, prefix string, tw tarWriter,
 }
 
 // ImageBundle produces an OCI bundle at the given path in a tarball, given an image and a config.json
-func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, runtime Runtime, tw tarWriter, readonly bool, dupMap map[string]string, opts BuildOpts) error { // nolint: lll
+func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, runtime moby.Runtime, tw tarWriter, readonly bool, dupMap map[string]string, opts BuildOpts) error { // nolint: lll
 	// if read only, just unpack in rootfs/ but otherwise set up for overlay
 	rootExtract := "rootfs"
 	if !readonly {
@@ -384,8 +377,8 @@ func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, ru
 		ModTime: defaultModTime,
 		Format:  tar.FormatPAX,
 		PAXRecords: map[string]string{
-			PaxRecordLinuxkitSource:   ref.String(),
+			moby.PaxRecordLinuxkitSource:   ref.String(),
-			PaxRecordLinuxkitLocation: location,
+			moby.PaxRecordLinuxkitLocation: location,
 		},
 	}
 	if err := tw.WriteHeader(hdr); err != nil {
@@ -406,8 +399,8 @@ func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, ru
 			ModTime:  defaultModTime,
 			Format:   tar.FormatPAX,
 			PAXRecords: map[string]string{
-				PaxRecordLinuxkitSource:   ref.String(),
+				moby.PaxRecordLinuxkitSource:   ref.String(),
-				PaxRecordLinuxkitLocation: location,
+				moby.PaxRecordLinuxkitLocation: location,
 			},
 		}
 		if err := tw.WriteHeader(hdr); err != nil {
@@ -421,8 +414,8 @@ func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, ru
 			ModTime:  defaultModTime,
 			Format:   tar.FormatPAX,
 			PAXRecords: map[string]string{
-				PaxRecordLinuxkitSource:   ref.String(),
+				moby.PaxRecordLinuxkitSource:   ref.String(),
-				PaxRecordLinuxkitLocation: location,
+				moby.PaxRecordLinuxkitLocation: location,
 			},
 		}
 		if err := tw.WriteHeader(hdr); err != nil {
@@ -445,8 +438,8 @@ func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, ru
 				ModTime:  defaultModTime,
 				Format:   tar.FormatPAX,
 				PAXRecords: map[string]string{
-					PaxRecordLinuxkitSource:   ref.String(),
+					moby.PaxRecordLinuxkitSource:   ref.String(),
-					PaxRecordLinuxkitLocation: location,
+					moby.PaxRecordLinuxkitLocation: location,
 				},
 			}
 			if err := tw.WriteHeader(hdr); err != nil {
@@ -476,8 +469,8 @@ func ImageBundle(prefix, location string, ref *reference.Spec, config []byte, ru
 		ModTime: defaultModTime,
 		Format:  tar.FormatPAX,
 		PAXRecords: map[string]string{
-			PaxRecordLinuxkitSource:   ref.String(),
+			moby.PaxRecordLinuxkitSource:   ref.String(),
-			PaxRecordLinuxkitLocation: location,
+			moby.PaxRecordLinuxkitLocation: location,
 		},
 	}
 	if err := tw.WriteHeader(hdr); err != nil {

src/cmd/linuxkit/moby/build/images.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"github.com/containerd/containerd/reference"

src/cmd/linuxkit/moby/build/linuxkit.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"crypto/sha256"
@@ -13,6 +13,7 @@ import (
 	"path/filepath"
 	"runtime"
 
+	"github.com/linuxkit/linuxkit/src/cmd/linuxkit/moby"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -43,7 +44,7 @@ func ensureLinuxkitImage(name, cache string) error {
 
 	yaml := linuxkitYaml[name]
 
-	m, err := NewConfig([]byte(yaml), nil)
+	m, err := moby.NewConfig([]byte(yaml), nil)
 	if err != nil {
 		return err
 	}

src/cmd/linuxkit/moby/build/opts.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 // BuildOpts options that control the linuxkit build process
 type BuildOpts struct {

src/cmd/linuxkit/moby/build/output.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"archive/tar"

src/cmd/linuxkit/moby/build/sbom.go

@@ -1,4 +1,4 @@
-package moby
+package build
 
 import (
 	"archive/tar"

src/cmd/linuxkit/moby/config.go

@@ -31,6 +31,10 @@ type Moby struct {
 	initRefs []*reference.Spec
 }
 
+func (m Moby) InitRefs() []*reference.Spec {
+	return m.initRefs
+}
+
 // KernelConfig is the type of the config for a kernel
 type KernelConfig struct {
 	Image   string  `yaml:"image" json:"image"`
@@ -42,6 +46,10 @@ type KernelConfig struct {
 	ref *reference.Spec
 }
 
+func (k KernelConfig) Ref() *reference.Spec {
+	return k.ref
+}
+
 // File is the type of a file specification
 type File struct {
 	Path      string      `yaml:"path" json:"path"`
@@ -127,6 +135,10 @@ type ImageConfig struct {
 	ref *reference.Spec
 }
 
+func (i ImageConfig) Ref() *reference.Spec {
+	return i.ref
+}
+
 // Device specifies a device to be exposed to the container.
 type Device struct {
 	Path  string `yaml:"path" json:"path"`
@@ -237,7 +249,7 @@ func extractReferences(m *Moby) error {
 	return nil
 }
 
-func updateImages(m *Moby) {
+func UpdateImages(m *Moby) {
 	if m.Kernel.ref != nil {
 		m.Kernel.Image = m.Kernel.ref.String()
 	}
@@ -689,7 +701,7 @@ func getAllCapabilities() []string {
 
 var allCaps = getAllCapabilities()
 
-func idNumeric(v interface{}, idMap map[string]uint32) (uint32, error) {
+func IDNumeric(v interface{}, idMap map[string]uint32) (uint32, error) {
 	switch id := v.(type) {
 	case nil:
 		return uint32(0), nil
@@ -984,17 +996,17 @@ func ConfigToOCI(yaml *Image, config imagespec.ImageConfig, idMap map[string]uin
 	uidIf := assignInterface(label.UID, yaml.UID)
 	gidIf := assignInterface(label.GID, yaml.GID)
 	agIf := assignInterfaceArray(label.AdditionalGids, yaml.AdditionalGids)
-	uid, err := idNumeric(uidIf, idMap)
+	uid, err := IDNumeric(uidIf, idMap)
 	if err != nil {
 		return oci, runtime, err
 	}
-	gid, err := idNumeric(gidIf, idMap)
+	gid, err := IDNumeric(gidIf, idMap)
 	if err != nil {
 		return oci, runtime, err
 	}
 	var additionalGroups []uint32
 	for _, id := range agIf {
-		ag, err := idNumeric(id, idMap)
+		ag, err := IDNumeric(id, idMap)
 		if err != nil {
 			return oci, runtime, err
 		}

src/cmd/linuxkit/moby/const.go

@@ -0,0 +1,9 @@
+package moby
+
+const (
+	// PaxRecordLinuxkitSource report the package source for a specific file
+	PaxRecordLinuxkitSource = "LINUXKIT.source"
+	// PaxRecordLinuxkitLocation report the location of the file in the linuxkit.yaml
+	// that led to this file being in this location
+	PaxRecordLinuxkitLocation = "LINUXKIT.location"
+)