working commit

2026-03-06 16:26:04 +02:00
parent 48a2d95f14
commit ef9a3f6b20
11 changed files with 242 additions and 503 deletions
@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
 	"os"
 	"path/filepath"
@@ -30,27 +31,124 @@ func NewEmptyImager(place string) *Imager {
 	return imager
 }

+func NewImagerFromPlace(place string) (*Imager, error) {
+	var err error
+	imager := &Imager{
+		index: ocispec.Index{
+			MediaType: MediaTypeOIIv1,
+			Manifests: make([]ocispec.Descriptor, 0),
+		},
+		place: place,
+	}
+	imager.index.SchemaVersion = 2
+
+	// Read and check layout version
+	lpath := filepath.Join(imager.place, ocispec.ImageLayoutFile)
+	lfile, err := os.OpenFile(lpath, os.O_RDONLY, 0)
+	if err != nil {
+		return imager, err
+	}
+	defer lfile.Close()
+	buffer := bytes.NewBuffer(nil)
+	if err != nil {
+		return imager, err
+	}
+	_, err = io.Copy(buffer, lfile)
+	if err != nil {
+		return imager, err
+	}
+	layout := ocispec.ImageLayout{}
+	err = json.Unmarshal(buffer.Bytes(), &layout)
+	if err != nil {
+		return imager, err
+	}
+	if layout.Version != ocispec.ImageLayoutVersion {
+		err = fmt.Errorf("Unknown layout version: %s", layout.Version)
+		return imager, err
+	}
+	// Read image
+	ipath := filepath.Join(imager.place, ocispec.ImageIndexFile)
+	ifile, err := os.OpenFile(ipath, os.O_RDONLY, 0)
+	if err != nil {
+		return imager, err
+	}
+	defer ifile.Close()
+	buffer = bytes.NewBuffer(nil)
+	_, err = io.Copy(buffer, ifile)
+	if err != nil {
+		return imager, err
+	}
+	err = json.Unmarshal(buffer.Bytes(), &imager.index)
+	if err != nil {
+		return imager, err
+	}
+	return imager, err
+}
+
+func (ima *Imager) ReadManifest(ctx context.Context, digstr string) (bool, string, []byte, error) {
+	var exist bool
+	var mime string
+	var man []byte
+	var err error
+
+	digobj, err := ocidigest.Parse(digstr)
+	if err != nil {
+		return exist, mime, man, err
+	}
+
+	var size int64
+	for _, descr := range ima.index.Manifests {
+		if digstr == descr.Digest.Encoded() {
+			size = descr.Size
+			mime = descr.MediaType
+			exist = true
+		}
+	}
+
+	subdir := string(digobj.Algorithm())
+	mpath := filepath.Join(ima.place, ocispec.ImageBlobsDir, subdir, digobj.Encoded())
+	mfile, err := os.OpenFile(mpath, os.O_RDONLY, 0)
+	if err != nil {
+		return exist, mime, man, err
+	}
+	defer mfile.Close()
+
+	buffer := bytes.NewBuffer(nil)
+	verifier := digobj.Verifier()
+	mwriter := io.MultiWriter(verifier, buffer)
+	readsize, err := io.Copy(mwriter, mfile)
+	man = buffer.Bytes()
+	if size != readsize {
+		err = errors.New("Mismatch manigest sizes")
+		return exist, mime, man, err
+	}
+	if !verifier.Verified() {
+		err = errors.New("Mismatch manifest digests")
+		return exist, mime, man, err
+	}
+	return exist, mime, man, err
+}
+
 func (ima *Imager) WriteManifest(ctx context.Context, digest, mime string, payload []byte) error {
 	var err error
-	digestobj, err := ocidigest.Parse(digest)
+	digobj, err := ocidigest.Parse(digest)
 	if err != nil {
 		return err
 	}
-	subdir := string(digestobj.Algorithm())
-	dir := filepath.Join(ima.place, subdir)
-	err = os.MkdirAll(dir, 0750)
+	subdir := string(digobj.Algorithm())
+	blobdir := filepath.Join(ima.place, ocispec.ImageBlobsDir, subdir)
+	err = os.MkdirAll(blobdir, 0750)
 	if err != nil {
 		return err
 	}
-	mpath := filepath.Join(dir, digestobj.Encoded())
+	mpath := filepath.Join(blobdir, digobj.Encoded())
 	mfile, err := os.OpenFile(mpath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0640)
 	if err != nil {
 		return err
 	}
 	defer mfile.Close()
 	reader := bytes.NewReader(payload)
-
-	verifier := digestobj.Verifier()
+	verifier := digobj.Verifier()
 	mwriter := io.MultiWriter(verifier, mfile)
 	recsize, err := io.Copy(mwriter, reader)
 	size := int64(len(payload))
@@ -64,23 +162,27 @@ func (ima *Imager) WriteManifest(ctx context.Context, digest, mime string, paylo
 	}
 	descr := ocispec.Descriptor{
 		MediaType: mime,
-		Digest:    digestobj,
+		Digest:    digobj,
 		Size:      size,
 	}
 	ima.index.Manifests = append(ima.index.Manifests, descr)
+	return err
+}
+
+func (ima *Imager) WriteIndex(ctx context.Context) error {
 	indexdat, err := json.Marshal(ima.index)
 	if err != nil {
 		return err
 	}
 	// Flush index
-	ipath := filepath.Join(dir, "index.json")
+	ipath := filepath.Join(ima.place, ocispec.ImageIndexFile)
 	ifile, err := os.OpenFile(ipath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0640)
 	if err != nil {
 		return err
 	}
 	defer ifile.Close()
-	reader = bytes.NewReader(indexdat)
-	recsize, err = io.Copy(ifile, reader)
+	reader := bytes.NewReader(indexdat)
+	recsize, err := io.Copy(ifile, reader)
 	if err != nil {
 		return err
 	}
@@ -88,27 +190,50 @@ func (ima *Imager) WriteManifest(ctx context.Context, digest, mime string, paylo
 		err = errors.New("Mismatch index sizes")
 		return err
 	}
+	// Flush layout
+	lpath := filepath.Join(ima.place, ocispec.ImageLayoutFile)
+	lfile, err := os.OpenFile(lpath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0640)
+	if err != nil {
+		return err
+	}
+	defer lfile.Close()
+	layout := ocispec.ImageLayout{
+		Version: ocispec.ImageLayoutVersion,
+	}
+	layoutdat, err := json.Marshal(layout)
+	reader = bytes.NewReader(layoutdat)
+	if err != nil {
+		return err
+	}
+	recsize, err = io.Copy(lfile, reader)
+	if err != nil {
+		return err
+	}
+	if recsize != int64(len(layoutdat)) {
+		err = errors.New("Mismatch layout sizes")
+		return err
+	}
 	return err
 }

 func (ima *Imager) WriteLayer(ctx context.Context, digest string, size int64, reader io.Reader) error {
 	var err error
-	digestobj, err := ocidigest.Parse(digest)
+	digobj, err := ocidigest.Parse(digest)
 	if err != nil {
 		return err
 	}
-	subdir := string(digestobj.Algorithm())
-	dir := filepath.Join(ima.place, subdir)
-	err = os.MkdirAll(dir, 0750)
+	subdir := string(digobj.Algorithm())
+	blobdir := filepath.Join(ima.place, ocispec.ImageBlobsDir, subdir)
+	err = os.MkdirAll(blobdir, 0750)
 	if err != nil {
 		return err
 	}
-	fpath := filepath.Join(dir, digestobj.Encoded())
+	fpath := filepath.Join(blobdir, digobj.Encoded())
 	file, err := os.OpenFile(fpath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0640)
 	if err != nil {
 		return err
 	}
-	verifier := digestobj.Verifier()
+	verifier := digobj.Verifier()
 	mwriter := io.MultiWriter(verifier, file)
 	recsize, err := io.Copy(mwriter, reader)
 	if size != recsize {
@@ -121,3 +246,38 @@ func (ima *Imager) WriteLayer(ctx context.Context, digest string, size int64, re
 	}
 	return err
 }
+
+func (ima *Imager) ReadLayer(ctx context.Context, digstr string, writer io.Writer) (bool, error) {
+	var exist bool
+	var err error
+	digobj, err := ocidigest.Parse(digstr)
+	if err != nil {
+		return exist, err
+	}
+	subdir := string(digobj.Algorithm())
+	mpath := filepath.Join(ima.place, ocispec.ImageBlobsDir, subdir, digobj.Encoded())
+	stat, err := os.Stat(mpath)
+	if err != nil {
+		return exist, err
+	}
+	size := stat.Size()
+	mfile, err := os.OpenFile(mpath, os.O_RDONLY, 0)
+	if err != nil {
+		return exist, err
+	}
+	defer mfile.Close()
+
+	verifier := digobj.Verifier()
+	mwriter := io.MultiWriter(verifier, writer)
+	readsize, err := io.Copy(mwriter, mfile)
+	if size != readsize {
+		err = errors.New("Mismatch layer sizes")
+		return exist, err
+	}
+	if !verifier.Verified() {
+		err = errors.New("Mismatch layer digests")
+		return exist, err
+	}
+	exist = true
+	return exist, err
+}