mutate: add uncompressed blob size annotation

mutate/compress.go

@@ -22,6 +22,10 @@ type Compressor interface {
 	// indicate what compression type is used, e.g. "gzip", or "" for no
 	// compression.
 	MediaTypeSuffix() string
+
+	// BytesRead returns the number of bytes read from the uncompressed input
+	// stream at the current time, no guarantee of completion.
+	BytesRead() int64
 }
 
 type noopCompressor struct{}
@@ -34,28 +38,36 @@ func (nc noopCompressor) MediaTypeSuffix() string {
 	return ""
 }
 
+func (nc noopCompressor) BytesRead() int64 {
+	return -1
+}
+
 // NoopCompressor provides no compression.
 var NoopCompressor Compressor = noopCompressor{}
 
 // GzipCompressor provides gzip compression.
-var GzipCompressor Compressor = gzipCompressor{}
+var GzipCompressor Compressor = &gzipCompressor{}
 
-type gzipCompressor struct{}
+type gzipCompressor struct {
+	bytesRead int64
+}
 
-func (gz gzipCompressor) Compress(reader io.Reader) (io.ReadCloser, error) {
+func (gz *gzipCompressor) Compress(reader io.Reader) (io.ReadCloser, error) {
 	pipeReader, pipeWriter := io.Pipe()
 
 	gzw := gzip.NewWriter(pipeWriter)
 	if err := gzw.SetConcurrency(256<<10, 2*runtime.NumCPU()); err != nil {
 		return nil, errors.Wrapf(err, "set concurrency level to %v blocks", 2*runtime.NumCPU())
 	}
 	go func() {
-		if _, err := system.Copy(gzw, reader); err != nil {
+		bytesRead, err := system.Copy(gzw, reader)
+		if err != nil {
 			log.Warnf("gzip compress: could not compress layer: %v", err)
 			// #nosec G104
 			_ = pipeWriter.CloseWithError(errors.Wrap(err, "compressing layer"))
 			return
 		}
+		gz.bytesRead = bytesRead
 		if err := gzw.Close(); err != nil {
 			log.Warnf("gzip compress: could not close gzip writer: %v", err)
 			// #nosec G104
@@ -76,25 +88,33 @@ func (gz gzipCompressor) MediaTypeSuffix() string {
 	return "gzip"
 }
 
+func (gz gzipCompressor) BytesRead() int64 {
+	return gz.bytesRead
+}
+
 // ZstdCompressor provides zstd compression.
-var ZstdCompressor Compressor = zstdCompressor{}
+var ZstdCompressor Compressor = &zstdCompressor{}
 
-type zstdCompressor struct{}
+type zstdCompressor struct {
+	bytesRead int64
+}
 
-func (zs zstdCompressor) Compress(reader io.Reader) (io.ReadCloser, error) {
+func (zs *zstdCompressor) Compress(reader io.Reader) (io.ReadCloser, error) {
 
 	pipeReader, pipeWriter := io.Pipe()
 	zw, err := zstd.NewWriter(pipeWriter)
 	if err != nil {
 		return nil, err
 	}
 	go func() {
-		if _, err := system.Copy(zw, reader); err != nil {
+		bytesRead, err := system.Copy(zw, reader)
+		if err != nil {
 			log.Warnf("zstd compress: could not compress layer: %v", err)
 			// #nosec G104
 			_ = pipeWriter.CloseWithError(errors.Wrap(err, "compressing layer"))
 			return
 		}
+		zs.bytesRead = bytesRead
 		if err := zw.Close(); err != nil {
 			log.Warnf("zstd compress: could not close gzip writer: %v", err)
 			// #nosec G104
@@ -114,3 +134,7 @@ func (zs zstdCompressor) Compress(reader io.Reader) (io.ReadCloser, error) {
 func (zs zstdCompressor) MediaTypeSuffix() string {
 	return "zstd"
 }
+
+func (zs zstdCompressor) BytesRead() int64 {
+	return zs.bytesRead
+}

mutate/mutate.go

@@ -24,6 +24,7 @@ package mutate
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"reflect"
 	"time"
@@ -36,6 +37,8 @@ import (
 	"github.com/pkg/errors"
 )
 
+const UmociUncompressedBlobSizeAnnotation = "ci.umo.uncompressed_blob_size"
+
 func configPtr(c ispec.Image) *ispec.Image         { return &c }
 func manifestPtr(m ispec.Manifest) *ispec.Manifest { return &m }
 func timePtr(t time.Time) *time.Time               { return &t }
@@ -295,6 +298,13 @@ func (m *Mutator) Add(ctx context.Context, mediaType string, r io.Reader, histor
 		compressedMediaType = compressedMediaType + "+" + compressor.MediaTypeSuffix()
 	}
 
+	if annotations == nil {
+		annotations = make(map[string]string)
+	}
+	if compressor.BytesRead() >= 0 {
+		annotations[UmociUncompressedBlobSizeAnnotation] = fmt.Sprintf("%d", compressor.BytesRead())
+	}
+
 	// Append to layers.
 	desc = ispec.Descriptor{
 		MediaType:   compressedMediaType,

mutate/mutate_test.go

@@ -214,6 +214,7 @@ func TestMutateAdd(t *testing.T) {
 
 	// This isn't a valid image, but whatever.
 	buffer := bytes.NewBufferString("contents")
+	bufferSize := buffer.Len()
 
 	// Add a new layer.
 	annotations := map[string]string{"hello": "world"}
@@ -253,10 +254,18 @@ func TestMutateAdd(t *testing.T) {
 	if mutator.manifest.Layers[1].Digest == expectedLayerDigest {
 		t.Errorf("manifest.Layers[1].Digest is not the same!")
 	}
-	if len(mutator.manifest.Layers[1].Annotations) != 1 || mutator.manifest.Layers[1].Annotations["hello"] != "world" {
-		t.Errorf("manifest.Layers[1].Annotations was not set correctly!")
+	if len(mutator.manifest.Layers[1].Annotations) != 2 {
+		t.Errorf("manifest.Layers[1].Annotations was not set correctly!: %+v", mutator.manifest.Layers[1].Annotations)
+	}
+	if mutator.manifest.Layers[1].Annotations["hello"] != "world" {
+		t.Errorf("manifest.Layers[1].Annotations['hello'] was not set correctly!: %+v", mutator.manifest.Layers[1].Annotations)
+	}
+	if mutator.manifest.Layers[1].Annotations[UmociUncompressedBlobSizeAnnotation] != fmt.Sprintf("%d", bufferSize) {
+		t.Errorf("manifest.Layers[1].Annotations['%s'] was not set correctly!: %q, expected %d",
+			UmociUncompressedBlobSizeAnnotation,
+			mutator.manifest.Layers[1].Annotations[UmociUncompressedBlobSizeAnnotation],
+			bufferSize)
 	}
-
 	if mutator.manifest.Layers[1].Digest != newLayerDesc.Digest {
 		t.Fatalf("unexpected digest for new layer: %v %v", mutator.manifest.Layers[1].Digest, newLayerDesc.Digest)
 	}

test/create.bats

@@ -277,8 +277,8 @@ function teardown() {
 	# Verify that the hashes of the blobs and index match (blobs are
 	# content-addressable so using hashes is a bit silly, but whatever).
 	known_hashes=(
-		"6f3716b8ae2bb4b3fd0a851f5a553946ea351ed5fdda0bd708d325363c0487f7  $IMAGE/index.json"
-		"73ecb862d0ebee78acdf8553d34d1ae5c13df509030ac262e561d096bb480dfc  $IMAGE/blobs/sha256/73ecb862d0ebee78acdf8553d34d1ae5c13df509030ac262e561d096bb480dfc"
+		"b780d08bfed4850ab807b7c308682fae6868ed9c09c0c842063c418ebe2a19fb  $IMAGE/index.json"
+		"27bcd3b4f31740cc087346382aaba3fe1c01872d75ead1bd2b9f7053d2bb3231  $IMAGE/blobs/sha256/27bcd3b4f31740cc087346382aaba3fe1c01872d75ead1bd2b9f7053d2bb3231"
 		"e7013826daf8b5d68f82c5b790ca5e9de222a834f2cb3fe3532030161bd72083  $IMAGE/blobs/sha256/e7013826daf8b5d68f82c5b790ca5e9de222a834f2cb3fe3532030161bd72083"
 		"f4a39a97d97aa834da7ad2d92940f9636a57e3d9b3cc7c53242451b02a6cea89  $IMAGE/blobs/sha256/f4a39a97d97aa834da7ad2d92940f9636a57e3d9b3cc7c53242451b02a6cea89"
 	)