Modify the automatic determination of the Config type

Signed-off-by: zhouhao <[email protected]>

Author: zhouhao

image/autodetect.go

@@ -15,7 +15,6 @@
 package image
 
 import (
-	"encoding/json"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -79,8 +78,8 @@ func Autodetect(path string) (string, error) {
 
 	header := struct {
 		SchemaVersion int         `json:"schemaVersion"`
-		MediaType     string      `json:"mediaType"`
 		Config        interface{} `json:"config"`
+		Manifests     interface{} `json:"manifests"`
 	}{}
 
 	if err := json.NewDecoder(f).Decode(&header); err != nil {
@@ -97,16 +96,17 @@ func Autodetect(path string) (string, error) {
 	}
 
 	switch {
-	case header.MediaType == string(schema.MediaTypeManifest):
+	case header.SchemaVersion == 2 && header.Config != nil:
 		return TypeManifest, nil
 
-	case header.MediaType == string(schema.MediaTypeManifestList):
+	case header.Manifests != nil:
 		return TypeManifestList, nil
 
-	case header.MediaType == "" && header.SchemaVersion == 0 && header.Config != nil:
+	case header.SchemaVersion == 0 && header.Config != nil:
 		// config files don't have mediaType/schemaVersion header
 		return TypeConfig, nil
 	}
 
 	return "", errors.New("unknown media type")
+
 }