1 files changed, 116 insertions, 0 deletions
diff --git a/pkg/v1/random/image.go b/pkg/v1/random/image.go
new file mode 100644
index 0000000..4b28913
--- /dev/null
+++ b/pkg/v1/random/image.go
@@ -0,0 +1,116 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package random
+
+import (
+	"archive/tar"
+	"bytes"
+	"crypto"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"io"
+	mrand "math/rand"
+	"time"
+
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/empty"
+	"github.com/google/go-containerregistry/pkg/v1/mutate"
+	"github.com/google/go-containerregistry/pkg/v1/partial"
+	"github.com/google/go-containerregistry/pkg/v1/types"
+)
+
+// uncompressedLayer implements partial.UncompressedLayer from raw bytes.
+type uncompressedLayer struct {
+	diffID    v1.Hash
+	mediaType types.MediaType
+	content   []byte
+}
+
+// DiffID implements partial.UncompressedLayer
+func (ul *uncompressedLayer) DiffID() (v1.Hash, error) {
+	return ul.diffID, nil
+}
+
+// Uncompressed implements partial.UncompressedLayer
+func (ul *uncompressedLayer) Uncompressed() (io.ReadCloser, error) {
+	return io.NopCloser(bytes.NewBuffer(ul.content)), nil
+}
+
+// MediaType returns the media type of the layer
+func (ul *uncompressedLayer) MediaType() (types.MediaType, error) {
+	return ul.mediaType, nil
+}
+
+var _ partial.UncompressedLayer = (*uncompressedLayer)(nil)
+
+// Image returns a pseudo-randomly generated Image.
+func Image(byteSize, layers int64) (v1.Image, error) {
+	adds := make([]mutate.Addendum, 0, 5)
+	for i := int64(0); i < layers; i++ {
+		layer, err := Layer(byteSize, types.DockerLayer)
+		if err != nil {
+			return nil, err
+		}
+		adds = append(adds, mutate.Addendum{
+			Layer: layer,
+			History: v1.History{
+				Author:    "random.Image",
+				Comment:   fmt.Sprintf("this is a random history %d of %d", i, layers),
+				CreatedBy: "random",
+				Created:   v1.Time{Time: time.Now()},
+			},
+		})
+	}
+
+	return mutate.Append(empty.Image, adds...)
+}
+
+// Layer returns a layer with pseudo-randomly generated content.
+func Layer(byteSize int64, mt types.MediaType) (v1.Layer, error) {
+	fileName := fmt.Sprintf("random_file_%d.txt", mrand.Int()) //nolint: gosec
+
+	// Hash the contents as we write it out to the buffer.
+	var b bytes.Buffer
+	hasher := crypto.SHA256.New()
+	mw := io.MultiWriter(&b, hasher)
+
+	// Write a single file with a random name and random contents.
+	tw := tar.NewWriter(mw)
+	if err := tw.WriteHeader(&tar.Header{
+		Name:     fileName,
+		Size:     byteSize,
+		Typeflag: tar.TypeReg,
+	}); err != nil {
+		return nil, err
+	}
+	if _, err := io.CopyN(tw, rand.Reader, byteSize); err != nil {
+		return nil, err
+	}
+	if err := tw.Close(); err != nil {
+		return nil, err
+	}
+
+	h := v1.Hash{
+		Algorithm: "sha256",
+		Hex:       hex.EncodeToString(hasher.Sum(make([]byte, 0, hasher.Size()))),
+	}
+
+	return partial.UncompressedToLayer(&uncompressedLayer{
+		diffID:    h,
+		mediaType: mt,
+		content:   b.Bytes(),
+	})
+}