Fixes: Distribution API #17726

Signed-off-by: Kan Cheung <[email protected]>

Author: kanlac

pkg/api/handlers/compat/distribution.go

@@ -0,0 +1,135 @@
+//go:build !remote
+
+package compat
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/containers/image/v5/docker"
+	"github.com/containers/image/v5/docker/reference"
+	"github.com/containers/image/v5/image"
+	"github.com/containers/image/v5/manifest"
+	"github.com/containers/image/v5/types"
+	"github.com/containers/podman/v5/libpod"
+	"github.com/containers/podman/v5/pkg/api/handlers/utils"
+	api "github.com/containers/podman/v5/pkg/api/types"
+	registrytypes "github.com/docker/docker/api/types/registry"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+func InspectDistribution(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+
+	runtime := r.Context().Value(api.RuntimeKey).(*libpod.Runtime)
+
+	name := utils.GetName(r)
+
+	_, imgRef, err := parseImageReference(name)
+	if err != nil {
+		utils.Error(w, http.StatusUnauthorized, err)
+		return
+	}
+
+	imgSrc, err := imgRef.NewImageSource(r.Context(), nil)
+	if err != nil {
+		var unauthErr docker.ErrUnauthorizedForCredentials
+		if errors.As(err, &unauthErr) {
+			utils.Error(w, http.StatusUnauthorized, errors.New("401 Unauthorized"))
+		} else {
+			utils.Error(w, http.StatusUnauthorized, fmt.Errorf("image not found: %w", err))
+		}
+		return
+	}
+	defer imgSrc.Close()
+
+	unparsedImage := image.UnparsedInstance(imgSrc, nil)
+	manBlob, manType, err := unparsedImage.Manifest(r.Context())
+	if err != nil {
+		utils.Error(w, http.StatusInternalServerError, fmt.Errorf("error getting manifest: %w", err))
+		return
+	}
+	img, err := image.FromUnparsedImage(r.Context(), runtime.SystemContext(), unparsedImage)
+	if err != nil {
+		utils.Error(w, http.StatusInternalServerError, fmt.Errorf("error getting manifest: %w", err))
+		return
+	}
+
+	digest, err := manifest.Digest(manBlob)
+	if err != nil {
+		utils.Error(w, http.StatusInternalServerError, fmt.Errorf("error getting manifest digest: %w", err))
+		return
+	}
+
+	distributionInspect := registrytypes.DistributionInspect{
+		Descriptor: ocispec.Descriptor{
+			Digest:    digest,
+			Size:      int64(len(manBlob)),
+			MediaType: manType,
+		},
+	}
+
+	platforms, err := getPlatformsFromManifest(r.Context(), img, manBlob, manType)
+	if err != nil {
+		utils.Error(w, http.StatusInternalServerError, err)
+		return
+	}
+	distributionInspect.Platforms = platforms
+
+	utils.WriteResponse(w, http.StatusOK, distributionInspect)
+}
+
+func parseImageReference(name string) (reference.Named, types.ImageReference, error) {
+	namedRef, err := reference.ParseNormalizedNamed(name)
+	if err != nil {
+		return nil, nil, fmt.Errorf("not a valid image reference: %q", name)
+	}
+
+	namedRef = reference.TagNameOnly(namedRef)
+
+	imgRef, err := docker.NewReference(namedRef)
+	if err != nil {
+		return nil, nil, fmt.Errorf("error creating image reference: %w", err)
+	}
+
+	return namedRef, imgRef, nil
+}
+
+func getPlatformsFromManifest(ctx context.Context, img types.Image, manBlob []byte, manType string) ([]ocispec.Platform, error) {
+	if manType == "" {
+		manType = manifest.GuessMIMEType(manBlob)
+	}
+
+	if manifest.MIMETypeIsMultiImage(manType) {
+		manifestList, err := manifest.ListFromBlob(manBlob, manType)
+		if err != nil {
+			return nil, fmt.Errorf("error parsing manifest list: %w", err)
+		}
+
+		instanceDigests := manifestList.Instances()
+		platforms := make([]ocispec.Platform, 0, len(instanceDigests))
+		for _, digest := range instanceDigests {
+			instance, err := manifestList.Instance(digest)
+			if err != nil {
+				return nil, fmt.Errorf("error getting manifest list instance: %w", err)
+			}
+			if instance.ReadOnly.Platform == nil {
+				continue
+			}
+			platforms = append(platforms, *instance.ReadOnly.Platform)
+		}
+		return platforms, nil
+	}
+
+	switch manType {
+	case ocispec.MediaTypeImageManifest, manifest.DockerV2Schema2MediaType:
+		config, err := img.OCIConfig(ctx)
+		if err != nil {
+			return nil, fmt.Errorf("error getting OCI config: %w", err)
+		}
+		return []ocispec.Platform{config.Platform}, nil
+	}
+	return []ocispec.Platform{}, nil
+}

pkg/api/server/register_distribution.go

@@ -3,13 +3,16 @@
 package server
 
 import (
+	"net/http"
+
 	"github.com/containers/podman/v5/pkg/api/handlers/compat"
 	"github.com/gorilla/mux"
 )
 
 func (s *APIServer) registerDistributionHandlers(r *mux.Router) error {
-	r.HandleFunc(VersionedPath("/distribution/{name}/json"), compat.UnsupportedHandler)
+	r.HandleFunc(VersionedPath("/distribution/{name:.*}/json"), s.APIHandler(compat.InspectDistribution)).Methods(http.MethodGet)
+	r.HandleFunc(VersionedPath("/libpod/distribution/{name:.*}/json"), s.APIHandler(compat.InspectDistribution)).Methods(http.MethodGet)
 	// Added non version path to URI to support docker non versioned paths
-	r.HandleFunc("/distribution/{name}/json", compat.UnsupportedHandler)
+	r.HandleFunc("/distribution/{name:.*}/json", s.APIHandler(compat.InspectDistribution)).Methods(http.MethodGet)
 	return nil
 }

test/apiv2/python/rest_api/test_v2_0_0_distribution.py

@@ -0,0 +1,34 @@
+import unittest
+
+import requests
+from .fixtures import APITestCase
+
+
+class DistributionTestCase(APITestCase):
+    def test_distribution_inspect(self):
+        # Make sure the image exists
+        r = requests.post(self.uri("/images/pull?reference=alpine:latest"), timeout=15)
+        self.assertEqual(r.status_code, 200, r.text)
+
+        r = requests.get(self.podman_url + "/v1.40/distribution/alpine/json")
+        self.assertEqual(r.status_code, 200, r.text)
+
+        result = r.json()
+        self.assertIn("Descriptor", result)
+        self.assertIn("Platforms", result)
+
+        descriptor = result["Descriptor"]
+        self.assertIn("mediaType", descriptor)
+        self.assertIn("digest", descriptor)
+        self.assertIn("size", descriptor)
+
+        for platform in result["Platforms"]:
+            self.assertIn("architecture", platform)
+            self.assertIn("os", platform)
+
+    def test_distribution_inspect_invalid_image(self):
+        r = requests.get(self.podman_url + "/v1.40/distribution/nonexistentimage/json")
+        self.assertEqual(r.status_code, 401, r.text)
+
+if __name__ == "__main__":
+    unittest.main()