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libimage.ManifestList.Inspect(): show artifact types and file lists
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When listing instances in an image index, show their artifact types and
the names of any files that they're tracking.

Signed-off-by: Nalin Dahyabhai <[email protected]>
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nalind committed Jan 30, 2024
1 parent e8f9cdb commit 1ad13e9
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Showing 4 changed files with 171 additions and 12 deletions.
22 changes: 13 additions & 9 deletions libimage/define/manifests.go
Original file line number Diff line number Diff line change
Expand Up @@ -4,24 +4,28 @@ import (
"github.com/containers/image/v5/manifest"
)

// ManifestListDescriptor references a platform-specific manifest.
// Contains exclusive field like `annotations` which is only present in
// OCI spec and not in docker image spec.
// ManifestListDescriptor describes a manifest that is mentioned in an
// image index or manifest list.
// Contains a subset of the fields which are present in both the OCI spec and
// the Docker spec, along with some which are unique to one or the other.
type ManifestListDescriptor struct {
manifest.Schema2Descriptor
Platform manifest.Schema2PlatformSpec `json:"platform"`
// Annotations contains arbitrary metadata for the image index.
Annotations map[string]string `json:"annotations,omitempty"`
Platform manifest.Schema2PlatformSpec `json:"platform,omitempty"`
Annotations map[string]string `json:"annotations,omitempty"`
ArtifactType string `json:"artifactType,omitempty"`
Data []byte `json:"data,omitempty"`
Files []string `json:"files,omitempty"`
}

// ManifestListData is a list of platform-specific manifests, specifically used to
// generate output struct for `podman manifest inspect`. Reason for maintaining and
// having this type is to ensure we can have a common type which contains exclusive
// having this type is to ensure we can have a single type which contains exclusive
// fields from both Docker manifest format and OCI manifest format.
type ManifestListData struct {
SchemaVersion int `json:"schemaVersion"`
MediaType string `json:"mediaType"`
ArtifactType string `json:"artifactType,omitempty"`
Manifests []ManifestListDescriptor `json:"manifests"`
// Annotations contains arbitrary metadata for the image index.
Annotations map[string]string `json:"annotations,omitempty"`
Subject *ManifestListDescriptor `json:"subject,omitempty"`
Annotations map[string]string `json:"annotations,omitempty"`
}
55 changes: 53 additions & 2 deletions libimage/manifest_list.go
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ import (
"github.com/containers/storage"
structcopier "github.com/jinzhu/copier"
"github.com/opencontainers/go-digest"
imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1"
)

// NOTE: the abstractions and APIs here are a first step to further merge
Expand Down Expand Up @@ -221,17 +222,67 @@ func (i *Image) IsManifestList(ctx context.Context) (bool, error) {
// Inspect returns a dockerized version of the manifest list.
func (m *ManifestList) Inspect() (*define.ManifestListData, error) {
inspectList := define.ManifestListData{}
// Copy the fields from the Docker-format version of the list.
dockerFormat := m.list.Docker()
err := structcopier.Copy(&inspectList, &dockerFormat)
if err != nil {
return &inspectList, err
}
// Get missing annotation field from OCIv1 Spec
// and populate inspect data.
// Get OCI-specific fields from the OCIv1-format version of the list
// and copy them to the inspect data.
ociFormat := m.list.OCIv1()
inspectList.ArtifactType = ociFormat.ArtifactType
inspectList.Annotations = ociFormat.Annotations
for i, manifest := range ociFormat.Manifests {
inspectList.Manifests[i].Annotations = manifest.Annotations
inspectList.Manifests[i].ArtifactType = manifest.ArtifactType
inspectList.Manifests[i].URLs = append([]string{}, manifest.URLs...)
inspectList.Manifests[i].Data = manifest.Data
inspectList.Manifests[i].Files, err = m.list.Files(manifest.Digest)
if err != nil {
return &inspectList, err
}
}
if ociFormat.Subject != nil {
platform := ociFormat.Subject.Platform
if platform == nil {
platform = &imgspecv1.Platform{}
}
inspectList.Subject = &define.ManifestListDescriptor{
Platform: manifest.Schema2PlatformSpec{
OS: platform.OS,
Architecture: platform.Architecture,
OSVersion: platform.OSVersion,
Variant: platform.Variant,
OSFeatures: append([]string{}, platform.OSFeatures...),
},
Schema2Descriptor: manifest.Schema2Descriptor{
MediaType: ociFormat.Subject.MediaType,
Digest: ociFormat.Subject.Digest,
Size: ociFormat.Subject.Size,
URLs: ociFormat.Subject.URLs,
},
Annotations: ociFormat.Subject.Annotations,
ArtifactType: ociFormat.Subject.ArtifactType,
Data: ociFormat.Subject.Data,
}
}
// Set MediaType to mirror the value we'd use when saving the list
// using defaults, instead of forcing it to one or the other by
// using the value from one version or the other that we explicitly
// requested above.
serialized, err := m.list.Serialize("")
if err != nil {
return &inspectList, err
}
var typed struct {
MediaType string `json:"mediaType,omitempty"`
}
if err := json.Unmarshal(serialized, &typed); err != nil {
return &inspectList, err
}
if typed.MediaType != "" {
inspectList.MediaType = typed.MediaType
}
return &inspectList, nil
}
Expand Down
36 changes: 35 additions & 1 deletion libimage/manifests/manifests.go
Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,8 @@ type List interface {
Push(ctx context.Context, dest types.ImageReference, options PushOptions) (reference.Canonical, digest.Digest, error)
Add(ctx context.Context, sys *types.SystemContext, ref types.ImageReference, all bool) (digest.Digest, error)
AddArtifact(ctx context.Context, sys *types.SystemContext, options AddArtifactOptions, files ...string) (digest.Digest, error)
InstanceByFile(file string) (digest.Digest, error)
Files(instanceDigest digest.Digest) ([]string, error)
}

// PushOptions includes various settings which are needed for pushing the
Expand Down Expand Up @@ -218,6 +220,38 @@ func (l *list) SaveToImage(store storage.Store, imageID string, names []string,
return img.ID, nil
}

// Files returns the list of files associated with a particular artifact
// instance in the image index, primarily for display purposes.
func (l *list) Files(instanceDigest digest.Digest) ([]string, error) {
filesList, ok := l.artifacts.Files[instanceDigest]
if ok {
return append([]string{}, filesList...), nil
}
return nil, nil
}

// instanceByFile returns the instanceDigest of the first manifest in the index
// which refers to the named file. The name will be passed to filepath.Abs()
// before searching for an instance which references it.
func (l *list) InstanceByFile(file string) (digest.Digest, error) {
if parsedDigest, err := digest.Parse(file); err == nil {
// nice try, but that's already a digest!
return parsedDigest, nil
}
abs, err := filepath.Abs(file)
if err != nil {
return "", err
}
for instanceDigest, files := range l.artifacts.Files {
for _, file := range files {
if file == abs {
return instanceDigest, nil
}
}
}
return "", os.ErrNotExist
}

// Reference returns an image reference for the composite image being built
// in the list, or an error if the list has never been saved to a local image.
func (l *list) Reference(store storage.Store, multiple cp.ImageListSelection, instances []digest.Digest) (types.ImageReference, error) {
Expand Down Expand Up @@ -255,7 +289,7 @@ func (l *list) Reference(store storage.Store, multiple cp.ImageListSelection, in
if err != nil {
return nil, fmt.Errorf("locating per-image directory for %s: %w", img.ID, err)
}
tmp, err := os.MkdirTemp(imgDirectory, pushArtifactsSubdirectory)
tmp, err := os.MkdirTemp(imgDirectory, pushingArtifactsSubdirectory)
if err != nil {
return nil, err
}
Expand Down
70 changes: 70 additions & 0 deletions libimage/manifests/manifests_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -644,3 +644,73 @@ func TestPushManifest(t *testing.T) {
_, _, err = list.Push(ctx, destRef, options)
assert.NoError(t, err, "list.Push(with ForceCompressionFormat: true)")
}

func TestInstanceByImageAndFiles(t *testing.T) {
if unshare.IsRootless() {
t.Skip("Test can only run as root")
}
ctx := context.Background()

dir := t.TempDir()
storeOptions := storage.StoreOptions{
GraphRoot: filepath.Join(dir, "root"),
RunRoot: filepath.Join(dir, "runroot"),
GraphDriverName: "vfs",
}
store, err := storage.GetStore(storeOptions)
assert.NoError(t, err, "error opening store")
if store == nil {
return
}
defer func() {
if _, err := store.Shutdown(true); err != nil {
assert.NoError(t, err, "error closing store")
}
}()

cconfig := filepath.Join("..", "testdata", "containers.conf")
absCconfig, err := filepath.Abs(cconfig)
assert.NoError(t, err)
gzipped := filepath.Join("..", "testdata", "oci-name-only.tar.gz")
absGzipped, err := filepath.Abs(gzipped)
assert.NoError(t, err)
pngfile := filepath.Join("..", "..", "logos", "containers.png")
absPngfile, err := filepath.Abs(pngfile)
assert.NoError(t, err)

list := Create()
options := AddArtifactOptions{}
firstInstanceDigest, err := list.AddArtifact(ctx, sys, options, cconfig, gzipped)
assert.NoError(t, err)
secondInstanceDigest, err := list.AddArtifact(ctx, sys, options, pngfile)
assert.NoError(t, err)

candidate, err := list.InstanceByFile(cconfig)
assert.NoError(t, err)
assert.Equal(t, firstInstanceDigest, candidate)
candidate, err = list.InstanceByFile(gzipped)
assert.NoError(t, err)
assert.Equal(t, firstInstanceDigest, candidate)

firstFiles, err := list.Files(firstInstanceDigest)
assert.NoError(t, err)
assert.ElementsMatch(t, []string{absCconfig, absGzipped}, firstFiles)

candidate, err = list.InstanceByFile(pngfile)
assert.NoError(t, err)
assert.Equal(t, secondInstanceDigest, candidate)

secondFiles, err := list.Files(secondInstanceDigest)
assert.NoError(t, err)
assert.ElementsMatch(t, []string{absPngfile}, secondFiles)

_, err = list.InstanceByFile("ha ha, fooled you")
assert.Error(t, err)
assert.ErrorIs(t, err, os.ErrNotExist)

otherDigest, err := digest.Parse(otherListDigest)
assert.NoError(t, err)
noFiles, err := list.Files(otherDigest)
assert.NoError(t, err)
assert.ElementsMatch(t, []string{}, noFiles)
}

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