new file mode 100644

@@ -0,0 +1,14 @@

+package distribution

+

+import (

+	"github.com/docker/distribution"

+	"github.com/docker/distribution/reference"

+	"github.com/docker/docker/api/types"

+	"golang.org/x/net/context"

+)

+

+// Backend is all the methods that need to be implemented

+// to provide image specific functionality.

+type Backend interface {

+	GetRepository(context.Context, reference.Named, *types.AuthConfig) (distribution.Repository, bool, error)

+}

new file mode 100644

@@ -0,0 +1,31 @@

+package distribution

+

+import "github.com/docker/docker/api/server/router"

+

+// distributionRouter is a router to talk with the registry

+type distributionRouter struct {

+	backend Backend

+	routes  []router.Route

+}

+

+// NewRouter initializes a new distribution router

+func NewRouter(backend Backend) router.Router {

+	r := &distributionRouter{

+		backend: backend,

+	}

+	r.initRoutes()

+	return r

+}

+

+// Routes returns the available routes

+func (r *distributionRouter) Routes() []router.Route {

+	return r.routes

+}

+

+// initRoutes initializes the routes in the distribution router

+func (r *distributionRouter) initRoutes() {

+	r.routes = []router.Route{

+		// GET

+		router.NewGetRoute("/distribution/{name:.*}/json", r.getDistributionInfo),

+	}

+}

new file mode 100644

@@ -0,0 +1,114 @@

+package distribution

+

+import (

+	"encoding/base64"

+	"encoding/json"

+	"net/http"

+	"strings"

+

+	"github.com/docker/distribution/manifest/manifestlist"

+	"github.com/docker/distribution/manifest/schema1"

+	"github.com/docker/distribution/manifest/schema2"

+	"github.com/docker/distribution/reference"

+	"github.com/docker/docker/api/server/httputils"

+	"github.com/docker/docker/api/types"

+	registrytypes "github.com/docker/docker/api/types/registry"

+	"github.com/pkg/errors"

+	"golang.org/x/net/context"

+)

+

+func (s *distributionRouter) getDistributionInfo(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

+	if err := httputils.ParseForm(r); err != nil {

+		return err

+	}

+

+	w.Header().Set("Content-Type", "application/json")

+

+	var (

+		config              = &types.AuthConfig{}

+		authEncoded         = r.Header.Get("X-Registry-Auth")

+		distributionInspect registrytypes.DistributionInspect

+	)

+

+	if authEncoded != "" {

+		authJSON := base64.NewDecoder(base64.URLEncoding, strings.NewReader(authEncoded))

+		if err := json.NewDecoder(authJSON).Decode(&config); err != nil {

+			// for a search it is not an error if no auth was given

+			// to increase compatibility with the existing api it is defaulting to be empty

+			config = &types.AuthConfig{}

+		}

+	}

+

+	image := vars["name"]

+

+	ref, err := reference.ParseAnyReference(image)

+	if err != nil {

+		return err

+	}

+	namedRef, ok := ref.(reference.Named)

+	if !ok {

+		if _, ok := ref.(reference.Digested); ok {

+			// full image ID

+			return errors.Errorf("no manifest found for full image ID")

+		}

+		return errors.Errorf("unknown image reference format: %s", image)

+	}

+

+	distrepo, _, err := s.backend.GetRepository(ctx, namedRef, config)

+	if err != nil {

+		return err

+	}

+

+	if canonicalRef, ok := namedRef.(reference.Canonical); !ok {

+		namedRef = reference.TagNameOnly(namedRef)

+

+		taggedRef, ok := namedRef.(reference.NamedTagged)

+		if !ok {

+			return errors.Errorf("image reference not tagged: %s", image)

+		}

+

+		dscrptr, err := distrepo.Tags(ctx).Get(ctx, taggedRef.Tag())

+		if err != nil {

+			return err

+		}

+		distributionInspect.Digest = dscrptr.Digest

+	} else {

+		distributionInspect.Digest = canonicalRef.Digest()

+	}

+	// at this point, we have a digest, so we can retrieve the manifest

+

+	mnfstsrvc, err := distrepo.Manifests(ctx)

+	if err != nil {

+		return err

+	}

+	mnfst, err := mnfstsrvc.Get(ctx, distributionInspect.Digest)

+	if err != nil {

+		return err

+	}

+

+	// retrieve platform information depending on the type of manifest

+	switch mnfstObj := mnfst.(type) {

+	case *manifestlist.DeserializedManifestList:

+		for _, m := range mnfstObj.Manifests {

+			distributionInspect.Platforms = append(distributionInspect.Platforms, m.Platform)

+		}

+	case *schema2.DeserializedManifest:

+		blobsrvc := distrepo.Blobs(ctx)

+		configJSON, err := blobsrvc.Get(ctx, mnfstObj.Config.Digest)

+		var platform manifestlist.PlatformSpec

+		if err == nil {

+			err := json.Unmarshal(configJSON, &platform)

+			if err == nil {

+				distributionInspect.Platforms = append(distributionInspect.Platforms, platform)

+			}

+		}

+	case *schema1.SignedManifest:

+		platform := manifestlist.PlatformSpec{

+			Architecture: mnfstObj.Architecture,

+			OS:           "linux",

+		}

+		distributionInspect.Platforms = append(distributionInspect.Platforms, platform)

+	}

+

+	return httputils.WriteJSON(w, http.StatusOK, distributionInspect)

+}

@@ -8274,3 +8274,60 @@ paths:

           format: "int64"

           required: true

       tags: ["Secret"]

+  /distribution/{name}/json:

+    get:

+      summary: "Get image information from the registry"

+      description: "Return image digest and platform information by contacting the registry."

+      operationId: "DistributionInspect"

+      produces:

+        - "application/json"

+      responses:

+        200:

+          description: "digest and platform information"

+          schema:

+            type: "object"

+            x-go-name: DistributionInspect

+            required: [Digest, ID, Platforms]

+            properties:

+              Digest:

+                type: "string"

+                x-nullable: false

+              Platforms:

+                type: "array"

+                items:

+                  type: "object"

+                  properties:

+                    Architecture:

+                      type: "string"

+                    OS:

+                      type: "string"

+                    OSVersion:

+                      type: "string"

+                    OSFeatures:

+                      type: "array"

+                      items:

+                        type: "string"

+                    Variant:

+                      type: "string"

+                    Features:

+                      type: "array"

+                      items:

+                        type: "string"

+        401:

+          description: "Failed authentication or no image found"

+          schema:

+            $ref: "#/definitions/ErrorResponse"

+          examples:

+            application/json:

+              message: "No such image: someimage (tag: latest)"

+        500:

+          description: "Server error"

+          schema:

+            $ref: "#/definitions/ErrorResponse"

+      parameters:

+        - name: "name"

+          in: "path"

+          description: "Image name or id"

+          type: "string"

+          required: true

+      tags: ["Distribution"]

@@ -3,6 +3,9 @@ package registry

 import (

 	"encoding/json"

 	"net"

+

+	"github.com/docker/distribution/manifest/manifestlist"

+	digest "github.com/opencontainers/go-digest"

 )

 // ServiceConfig stores daemon registry services configuration.

@@ -102,3 +105,13 @@ type SearchResults struct {

 	// Results is a slice containing the actual results for the search

 	Results []SearchResult `json:"results"`

 }

+

+// DistributionInspect describes the result obtained from contacting the

+// registry to retrieve image metadata

+type DistributionInspect struct {

+	// Digest is the content addressable digest for the image on the registry

+	Digest digest.Digest

+	// Platforms contains the list of platforms supported by the image,

+	// obtained by parsing the manifest

+	Platforms []manifestlist.PlatformSpec

+}

@@ -20,6 +20,7 @@ import (

 	"github.com/docker/docker/api/server/router/build"

 	checkpointrouter "github.com/docker/docker/api/server/router/checkpoint"

 	"github.com/docker/docker/api/server/router/container"

+	distributionrouter "github.com/docker/docker/api/server/router/distribution"

 	"github.com/docker/docker/api/server/router/image"

 	"github.com/docker/docker/api/server/router/network"

 	pluginrouter "github.com/docker/docker/api/server/router/plugin"

@@ -487,6 +488,7 @@ func initRouter(s *apiserver.Server, d *daemon.Daemon, c *cluster.Cluster) {

 		build.NewRouter(buildbackend.NewBackend(d, d), d),

 		swarmrouter.NewRouter(c),

 		pluginrouter.NewRouter(d.PluginManager()),

+		distributionrouter.NewRouter(d),

 	}

 	if d.NetworkControllerEnabled() {