oci/client: relax annotation parser

This is in order to allow `flux pull artifact` to retrieve any kind
of OCI artifact, e.g. a Helm chart for debugging.

Signed-off-by: Ilya Dmitrichenko <errordeveloper@gmail.com>

oci/client/list.go

@@ -104,11 +104,10 @@ func (c *Client) List(ctx context.Context, url string, opts ListOptions) ([]Meta
 			return nil, fmt.Errorf("parsing manifest failed: %w", err)
 		}
 
-		if m, err := MetadataFromAnnotations(manifest.Annotations); err == nil {
-			meta.Revision = m.Revision
-			meta.Source = m.Source
-			meta.Created = m.Created
-		}
+		manifestMetadata := MetadataFromAnnotations(manifest.Annotations)
+		meta.Revision = manifestMetadata.Revision
+		meta.Source = manifestMetadata.Source
+		meta.Created = manifestMetadata.Created
 
 		digest, err := crane.Digest(meta.URL, c.optionsWithContext(ctx)...)
 		if err != nil {

oci/client/meta.go

@@ -17,17 +17,15 @@ limitations under the License.
 package client
 
 import (
-	"fmt"
-
 	"github.com/fluxcd/pkg/oci"
 )
 
 // Metadata holds the upstream information about on artifact's source.
 // https://github.com/opencontainers/image-spec/blob/main/annotations.md
 type Metadata struct {
-	Created     string            `json:"created"`
-	Source      string            `json:"source_url"`
-	Revision    string            `json:"source_revision"`
+	Created     string            `json:"created,omitempty"`
+	Source      string            `json:"source_url,omitempty"`
+	Revision    string            `json:"source_revision,omitempty"`
 	Digest      string            `json:"digest"`
 	URL         string            `json:"url"`
 	Annotations map[string]string `json:"annotations,omitempty"`
@@ -49,28 +47,11 @@ func (m *Metadata) ToAnnotations() map[string]string {
 }
 
 // MetadataFromAnnotations parses the OpenContainers annotations and returns a Metadata object.
-func MetadataFromAnnotations(annotations map[string]string) (*Metadata, error) {
-	created, ok := annotations[oci.CreatedAnnotation]
-	if !ok {
-		return nil, fmt.Errorf("'%s' annotation not found", oci.CreatedAnnotation)
-	}
-
-	source, ok := annotations[oci.SourceAnnotation]
-	if !ok {
-		return nil, fmt.Errorf("'%s' annotation not found", oci.SourceAnnotation)
-	}
-
-	revision, ok := annotations[oci.RevisionAnnotation]
-	if !ok {
-		return nil, fmt.Errorf("'%s' annotation not found", oci.RevisionAnnotation)
-	}
-
-	m := Metadata{
-		Created:     created,
-		Source:      source,
-		Revision:    revision,
+func MetadataFromAnnotations(annotations map[string]string) *Metadata {
+	return &Metadata{
+		Created:     annotations[oci.CreatedAnnotation],
+		Source:      annotations[oci.SourceAnnotation],
+		Revision:    annotations[oci.RevisionAnnotation],
 		Annotations: annotations,
 	}
-
-	return &m, nil
 }

oci/client/pull.go

@@ -47,10 +47,7 @@ func (c *Client) Pull(ctx context.Context, url, outDir string) (*Metadata, error
 		return nil, fmt.Errorf("parsing manifest failed: %w", err)
 	}
 
-	meta, err := MetadataFromAnnotations(manifest.Annotations)
-	if err != nil {
-		return nil, err
-	}
+	meta := MetadataFromAnnotations(manifest.Annotations)
 	meta.Digest = ref.Context().Digest(digest.String()).String()
 
 	layers, err := img.Layers()

oci/client/pull_test.go

@@ -0,0 +1,78 @@
+/*
+Copyright 2023 The Flux authors
+
+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 client
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+	"testing"
+
+	"github.com/fluxcd/pkg/oci"
+	"github.com/google/go-containerregistry/pkg/crane"
+	"github.com/google/go-containerregistry/pkg/v1/empty"
+	"github.com/google/go-containerregistry/pkg/v1/mutate"
+	"github.com/google/go-containerregistry/pkg/v1/tarball"
+	"github.com/google/go-containerregistry/pkg/v1/types"
+	. "github.com/onsi/gomega"
+)
+
+func Test_PullAnyTarball(t *testing.T) {
+	g := NewWithT(t)
+	ctx := context.Background()
+	c := NewClient(DefaultOptions())
+	testDir := "testdata/artifact"
+
+	tag := "latest"
+	repo := "test-no-annotations" + randStringRunes(5)
+
+	dst := fmt.Sprintf("%s/%s:%s", dockerReg, repo, tag)
+
+	artifact := filepath.Join(t.TempDir(), "artifact.tgz")
+	g.Expect(c.Build(artifact, testDir, nil)).To(Succeed())
+
+	img := mutate.MediaType(empty.Image, types.OCIManifestSchema1)
+	img = mutate.ConfigMediaType(img, oci.CanonicalConfigMediaType)
+
+	layer, err := tarball.LayerFromFile(artifact, tarball.WithMediaType(oci.CanonicalContentMediaType))
+	g.Expect(err).ToNot(HaveOccurred())
+
+	img, err = mutate.Append(img, mutate.Addendum{Layer: layer})
+	g.Expect(err).ToNot(HaveOccurred())
+
+	g.Expect(crane.Push(img, dst, c.optionsWithContext(ctx)...)).ToNot(HaveOccurred())
+
+	extractTo := filepath.Join(t.TempDir(), "artifact")
+	m, err := c.Pull(ctx, dst, extractTo)
+	g.Expect(err).ToNot(HaveOccurred())
+	g.Expect(m).ToNot(BeNil())
+	g.Expect(extractTo).To(BeADirectory())
+
+	for _, entry := range []string{
+		"deploy",
+		"deploy/repo.yaml",
+		"deployment.yaml",
+		"ignore-dir",
+		"ignore-dir/deployment.yaml",
+		"ignore.txt",
+		"somedir",
+		"somedir/repo.yaml",
+		"somedir/git/repo.yaml",
+	} {
+		g.Expect(extractTo + "/" + entry).To(Or(BeAnExistingFile(), BeADirectory()))
+	}
+}