Making the registry backend able to handle V1 manifest responses

lib/backend/registrybackend/tagclient.go

@@ -21,6 +21,9 @@
 	"strconv"
 	"strings"
 
+	// import schema1 to have it register its unmarshalling functions with github.com/docker/distribution.RegisterManifestSchema()
+	_ "github.com/docker/distribution/manifest/schema1"
+	"github.com/docker/distribution/manifest/schema2"
 	"github.com/uber/kraken/core"
 	"github.com/uber/kraken/lib/backend"
 	"github.com/uber/kraken/lib/backend/backenderrors"
@@ -141,9 +144,14 @@
 		return backenderrors.ErrBlobNotFound
 	}
 
-	_, digest, err := dockerutil.ParseManifestV2(resp.Body)
+	contentType := resp.Header.Get("Content-Type")
+	if !strings.Contains(contentType, "application/vnd.docker.distribution.manifest") {
+		contentType = schema2.MediaTypeManifest
+	}
+
+	_, digest, err := dockerutil.ParseManifest(contentType, resp.Body)
 	if err != nil {
-		return fmt.Errorf("parse manifest v2: %s", err)
+		return fmt.Errorf("parse manifest: %s", err)
 	}
 	if _, err := io.Copy(dst, strings.NewReader(digest.String())); err != nil {
 		return fmt.Errorf("copy: %s", err)

lib/backend/registrybackend/tagclient_test.go

@@ -15,6 +15,7 @@ package registrybackend
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -70,6 +71,74 @@ func TestTagDownloadSuccess(t *testing.T) {
 	require.Equal(digest.String(), string(b.Bytes()))
 }
 
+func TestTagDownloadV1Manifest(t *testing.T) {
+	require := require.New(t)
+
+	// signed V1 manifest obtained from Docker hub for busybox:1.32.0
+	manifest := `{
+   "schemaVersion": 1,
+   "name": "library/busybox",
+   "tag": "1.32.0",
+   "architecture": "amd64",
+   "fsLayers": [
+      {
+         "blobSum": "sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4"
+      },
+      {
+         "blobSum": "sha256:9758c28807f21c13d05c704821fdd56c0b9574912f9b916c65e1df3e6b8bc572"
+      }
+   ],
+   "history": [
+      {
+         "v1Compatibility": "{\"architecture\":\"amd64\",\"config\":{\"Hostname\":\"\",\"Domainname\":\"\",\"User\":\"\",\"AttachStdin\":false,\"AttachStdout\":false,\"AttachStderr\":false,\"Tty\":false,\"OpenStdin\":false,\"StdinOnce\":false,\"Env\":[\"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"],\"Cmd\":[\"sh\"],\"ArgsEscaped\":true,\"Image\":\"sha256:11565868e68267a053372359046e1e70ce095538e95ff8398defd49bb66ddfce\",\"Volumes\":null,\"WorkingDir\":\"\",\"Entrypoint\":null,\"OnBuild\":null,\"Labels\":null},\"container\":\"6f1f5d35fed541933daae185eac73e333818ccec0b0760eb4cc8e30ce8d69de6\",\"container_config\":{\"Hostname\":\"6f1f5d35fed5\",\"Domainname\":\"\",\"User\":\"\",\"AttachStdin\":false,\"AttachStdout\":false,\"AttachStderr\":false,\"Tty\":false,\"OpenStdin\":false,\"StdinOnce\":false,\"Env\":[\"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"],\"Cmd\":[\"/bin/sh\",\"-c\",\"#(nop) \",\"CMD [\\\"sh\\\"]\"],\"ArgsEscaped\":true,\"Image\":\"sha256:11565868e68267a053372359046e1e70ce095538e95ff8398defd49bb66ddfce\",\"Volumes\":null,\"WorkingDir\":\"\",\"Entrypoint\":null,\"OnBuild\":null,\"Labels\":{}},\"created\":\"2020-10-14T10:07:34.124876277Z\",\"docker_version\":\"18.09.7\",\"id\":\"6ed978c75173f577f023843ea61461568332f466c963e1b088d81fe676e8816c\",\"os\":\"linux\",\"parent\":\"bf938fec00b8d83c6d28a66dd6aa1cf76384aec8e63c7771648007b0dfce6fd8\",\"throwaway\":true}"
+      },
+      {
+         "v1Compatibility": "{\"id\":\"bf938fec00b8d83c6d28a66dd6aa1cf76384aec8e63c7771648007b0dfce6fd8\",\"created\":\"2020-10-14T10:07:33.97009658Z\",\"container_config\":{\"Cmd\":[\"/bin/sh -c #(nop) ADD file:6098f054f12a3651c41038294c56d4a8c5c5d477259386e75ae2af763e84e683 in / \"]}}"
+      }
+   ],
+   "signatures": [
+      {
+         "header": {
+            "jwk": {
+               "crv": "P-256",
+               "kid": "JOJV:JUGG:HTN3:ABNG:FF4D:KCTY:FESP:BHX7:45NZ:YTDE:NWEF:CK7F",
+               "kty": "EC",
+               "x": "xPD2kMN77NdX9MlaZcaIVv1MX-89ChYWgVJ_3MFAmVM",
+               "y": "I5Qpk8KPtmGJLd77qlpvSEtJ4cKb9MjMqbD2Dp-FR7c"
+            },
+            "alg": "ES256"
+         },
+         "signature": "dLme4aiKt0EMdtRcCDox4Q5ntnBL5310_CyROeznc16cygwj6hWWXoUREo25423mWv19d8LtxEubXZcKIQBQRQ",
+         "protected": "eyJmb3JtYXRMZW5ndGgiOjIxMjgsImZvcm1hdFRhaWwiOiJDbjAiLCJ0aW1lIjoiMjAyMC0xMC0yOFQxNToxMDo0OFoifQ"
+      }
+   ]
+}`
+
+	var deserializedManifest map[string]interface{}
+	require.NoError(json.Unmarshal([]byte(manifest), &deserializedManifest))
+	name := deserializedManifest["name"]
+	tag := deserializedManifest["tag"]
+
+	r := chi.NewRouter()
+	r.Get(fmt.Sprintf("/v2/%s/manifests/{tag}", name), func(w http.ResponseWriter, req *http.Request) {
+		w.Header().Set("Content-Length", fmt.Sprintf("%d", len(manifest)))
+		w.Header().Set("Content-Type", "application/vnd.docker.distribution.manifest.v1+prettyjws")
+		_, err := io.WriteString(w, manifest)
+		require.NoError(err)
+	})
+	addr, stop := testutil.StartServer(r)
+	defer stop()
+
+	config := newTestConfig(addr)
+	client, err := NewTagClient(config)
+	require.NoError(err)
+
+	var b bytes.Buffer
+	imageName := fmt.Sprintf("%s:%s", name, tag)
+	require.NoError(client.Download(imageName, imageName, &b))
+	require.Equal("sha256:ab2a79aa5da153ea944a10532c529579449afa693c668adcf034602b12eeb675", string(b.Bytes()))
+}
+
 func TestTagDownloadFileNotFound(t *testing.T) {
 	require := require.New(t)
 

utils/dockerutil/dockerutil.go

@@ -19,21 +19,18 @@ import (
 	"io"
 	"io/ioutil"
 
-	"github.com/uber/kraken/core"
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/manifest/schema2"
+	"github.com/uber/kraken/core"
 )
 
 // ParseManifestV2 returns a parsed v2 manifest and its digest
-func ParseManifestV2(r io.Reader) (distribution.Manifest, core.Digest, error) {
-	b, err := ioutil.ReadAll(r)
+func ParseManifestV2(r io.Reader) (manifest distribution.Manifest, digest core.Digest, err error) {
+	manifest, digest, err = ParseManifest(schema2.MediaTypeManifest, r)
 	if err != nil {
-		return nil, core.Digest{}, fmt.Errorf("read: %s", err)
-	}
-	manifest, desc, err := distribution.UnmarshalManifest(schema2.MediaTypeManifest, b)
-	if err != nil {
-		return nil, core.Digest{}, fmt.Errorf("unmarshal manifest: %s", err)
+		return
 	}
+
 	deserializedManifest, ok := manifest.(*schema2.DeserializedManifest)
 	if !ok {
 		return nil, core.Digest{}, errors.New("expected schema2.DeserializedManifest")
@@ -42,6 +39,20 @@ func ParseManifestV2(r io.Reader) (distribution.Manifest, core.Digest, error) {
 	if version != 2 {
 		return nil, core.Digest{}, fmt.Errorf("unsupported manifest version: %d", version)
 	}
+
+	return
+}
+
+// ParseManifest returns a parsed manifest and its digest
+func ParseManifest(contentType string, r io.Reader) (distribution.Manifest, core.Digest, error) {
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, core.Digest{}, fmt.Errorf("read: %s", err)
+	}
+	manifest, desc, err := distribution.UnmarshalManifest(contentType, b)
+	if err != nil {
+		return nil, core.Digest{}, fmt.Errorf("unmarshal manifest: %s", err)
+	}
 	d, err := core.ParseSHA256Digest(string(desc.Digest))
 	if err != nil {
 		return nil, core.Digest{}, fmt.Errorf("parse digest: %s", err)