Migrate custom OCI types to ocispec in oci/skills package

Replace the dual type system where the packager used ocispec types
internally but the store, registry, and helpers used custom types
(ImageConfig, ImageIndex, IndexDescriptor, Platform). This eliminates
friction like needing JSON re-serialization between the packager's
ocispec.Image and the store's ImageConfig.

Removed 7 custom struct types and 5 redundant media type constants in
favor of their ocispec equivalents. Updated ParsePlatform to support
os/arch/variant format, and replaced Platform.String() method with
PlatformString() free function. Also fixed platform variant propagation
in packager config and index construction, and added -copyright_file
to mockgen directives so generated mocks include SPDX headers.

Closes #24

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: JAORMX

env/env.go

@@ -3,7 +3,7 @@
 
 package env
 
-//go:generate mockgen -source=env.go -destination=mocks/mock_reader.go -package=mocks Reader
+//go:generate mockgen -copyright_file=../.github/license-header.txt -source=env.go -destination=mocks/mock_reader.go -package=mocks Reader
 
 import "os"
 

env/mocks/mock_reader.go

@@ -3,13 +3,14 @@
 
 package skills
 
-//go:generate mockgen -source=interfaces.go -destination=mocks/mock_interfaces.go -package=mocks
+//go:generate mockgen -copyright_file=../../.github/license-header.txt -source=interfaces.go -destination=mocks/mock_interfaces.go -package=mocks
 
 import (
 	"context"
 	"time"
 
 	"github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 // RegistryClient provides remote OCI registry operations for skills.
@@ -34,7 +35,7 @@ type PackageOptions struct {
 
 	// Platforms specifies target platforms for the image index.
 	// If empty, defaults to DefaultPlatforms.
-	Platforms []Platform
+	Platforms []ocispec.Platform
 }
 
 // PackageResult contains the result of packaging a skill.
@@ -44,5 +45,5 @@ type PackageResult struct {
 	ConfigDigest   digest.Digest
 	LayerDigest    digest.Digest
 	Config         *SkillConfig
-	Platforms      []Platform
+	Platforms      []ocispec.Platform
 }

oci/skills/interfaces.go

@@ -7,6 +7,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"strings"
+
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 // Artifact type for skill identification.
@@ -15,29 +17,8 @@ const (
 	ArtifactTypeSkill = "dev.toolhive.skills.v1"
 )
 
-// OCI Image Index media type.
-const (
-	// MediaTypeImageIndex is the OCI image index media type.
-	MediaTypeImageIndex = "application/vnd.oci.image.index.v1+json"
-)
-
-// Standard OCI media types for Kubernetes image volume compatibility.
-const (
-	// MediaTypeImageManifest is the OCI image manifest media type.
-	MediaTypeImageManifest = "application/vnd.oci.image.manifest.v1+json"
-
-	// MediaTypeImageConfig is the standard OCI image config media type.
-	MediaTypeImageConfig = "application/vnd.oci.image.config.v1+json"
-
-	// MediaTypeImageLayer is the standard OCI image layer media type.
-	MediaTypeImageLayer = "application/vnd.oci.image.layer.v1.tar+gzip"
-)
-
 // Annotation keys for skill metadata in manifests.
 const (
-	// AnnotationCreated is the OCI standard annotation for creation time.
-	AnnotationCreated = "org.opencontainers.image.created"
-
 	// AnnotationSkillName is the annotation key for skill name.
 	AnnotationSkillName = "dev.toolhive.skills.name"
 
@@ -84,35 +65,8 @@ type SkillConfig struct {
 	Files         []string          `json:"files"`
 }
 
-// ImageConfig represents a standard OCI image configuration.
-// This structure is required for Kubernetes image volume compatibility.
-type ImageConfig struct {
-	Architecture string          `json:"architecture"`
-	OS           string          `json:"os"`
-	Config       ImageConfigData `json:"config,omitempty"`
-	RootFS       RootFS          `json:"rootfs"`
-	History      []HistoryEntry  `json:"history,omitempty"`
-}
-
-// ImageConfigData contains container configuration including labels.
-type ImageConfigData struct {
-	Labels map[string]string `json:"Labels,omitempty"`
-}
-
-// RootFS describes the rootfs of the image.
-type RootFS struct {
-	Type    string   `json:"type"`
-	DiffIDs []string `json:"diff_ids"`
-}
-
-// HistoryEntry describes a layer in the image history.
-type HistoryEntry struct {
-	Created   string `json:"created,omitempty"`
-	CreatedBy string `json:"created_by,omitempty"`
-}
-
 // SkillConfigFromImageConfig extracts SkillConfig from OCI image config labels.
-func SkillConfigFromImageConfig(imgConfig *ImageConfig) (*SkillConfig, error) {
+func SkillConfigFromImageConfig(imgConfig *ocispec.Image) (*SkillConfig, error) {
 	if imgConfig == nil {
 		return nil, fmt.Errorf("image config is nil")
 	}
@@ -149,56 +103,44 @@ func SkillConfigFromImageConfig(imgConfig *ImageConfig) (*SkillConfig, error) {
 	return config, nil
 }
 
-// Platform represents a target platform for OCI artifacts.
-type Platform struct {
-	Architecture string `json:"architecture"`
-	OS           string `json:"os"`
-}
-
-// String returns the platform in "os/arch" format.
-func (p Platform) String() string {
-	return p.OS + "/" + p.Architecture
+// PlatformString returns the platform in "os/arch" or "os/arch/variant" format.
+func PlatformString(p ocispec.Platform) string {
+	s := p.OS + "/" + p.Architecture
+	if p.Variant != "" {
+		s += "/" + p.Variant
+	}
+	return s
 }
 
-// ParsePlatform parses a platform string in "os/arch" format.
-func ParsePlatform(s string) (Platform, error) {
+// ParsePlatform parses a platform string in "os/arch" or "os/arch/variant" format.
+func ParsePlatform(s string) (ocispec.Platform, error) {
 	parts := strings.Split(s, "/")
-	if len(parts) != 2 {
-		return Platform{}, fmt.Errorf("invalid platform format: %q (expected os/arch)", s)
+	if len(parts) < 2 || len(parts) > 3 {
+		return ocispec.Platform{}, fmt.Errorf("invalid platform format: %q (expected os/arch or os/arch/variant)", s)
 	}
 	osName := strings.TrimSpace(parts[0])
 	arch := strings.TrimSpace(parts[1])
 	if osName == "" || arch == "" {
-		return Platform{}, fmt.Errorf("invalid platform format: %q (os and arch cannot be empty)", s)
+		return ocispec.Platform{}, fmt.Errorf("invalid platform format: %q (os and arch cannot be empty)", s)
 	}
-	return Platform{OS: osName, Architecture: arch}, nil
+	p := ocispec.Platform{OS: osName, Architecture: arch}
+	if len(parts) == 3 {
+		variant := strings.TrimSpace(parts[2])
+		if variant == "" {
+			return ocispec.Platform{}, fmt.Errorf("invalid platform format: %q (variant cannot be empty)", s)
+		}
+		p.Variant = variant
+	}
+	return p, nil
 }
 
 // DefaultPlatforms are the default platforms for skill artifacts.
 // These cover most Kubernetes clusters.
-var DefaultPlatforms = []Platform{
+var DefaultPlatforms = []ocispec.Platform{
 	{OS: "linux", Architecture: "amd64"},
 	{OS: "linux", Architecture: "arm64"},
 }
 
-// ImageIndex represents an OCI image index (multi-platform manifest list).
-type ImageIndex struct {
-	SchemaVersion int               `json:"schemaVersion"`
-	MediaType     string            `json:"mediaType"`
-	ArtifactType  string            `json:"artifactType,omitempty"`
-	Manifests     []IndexDescriptor `json:"manifests"`
-	Annotations   map[string]string `json:"annotations,omitempty"`
-}
-
-// IndexDescriptor describes a manifest in an image index.
-type IndexDescriptor struct {
-	MediaType   string            `json:"mediaType"`
-	Digest      string            `json:"digest"`
-	Size        int64             `json:"size"`
-	Platform    *Platform         `json:"platform,omitempty"`
-	Annotations map[string]string `json:"annotations,omitempty"`
-}
-
 // ParseRequiresAnnotation parses skill dependency references from manifest annotations.
 // Returns nil if the annotation is missing or invalid.
 func ParseRequiresAnnotation(annotations map[string]string) []string {

oci/skills/mediatypes.go

@@ -6,6 +6,7 @@ package skills
 import (
 	"testing"
 
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -15,16 +16,16 @@ func TestSkillConfigFromImageConfig(t *testing.T) {
 
 	tests := []struct {
 		name      string
-		config    *ImageConfig
+		config    *ocispec.Image
 		wantName  string
 		wantErr   bool
 		wantTools []string
 		wantFiles []string
 	}{
 		{
 			name: "all fields populated",
-			config: &ImageConfig{
-				Config: ImageConfigData{
+			config: &ocispec.Image{
+				Config: ocispec.ImageConfig{
 					Labels: map[string]string{
 						LabelSkillName:         "my-skill",
 						LabelSkillDescription:  "A test skill",
@@ -41,8 +42,8 @@ func TestSkillConfigFromImageConfig(t *testing.T) {
 		},
 		{
 			name: "minimal config",
-			config: &ImageConfig{
-				Config: ImageConfigData{
+			config: &ocispec.Image{
+				Config: ocispec.ImageConfig{
 					Labels: map[string]string{
 						LabelSkillName: "minimal-skill",
 					},
@@ -57,15 +58,15 @@ func TestSkillConfigFromImageConfig(t *testing.T) {
 		},
 		{
 			name: "nil labels",
-			config: &ImageConfig{
-				Config: ImageConfigData{Labels: nil},
+			config: &ocispec.Image{
+				Config: ocispec.ImageConfig{Labels: nil},
 			},
 			wantErr: true,
 		},
 		{
 			name: "missing name",
-			config: &ImageConfig{
-				Config: ImageConfigData{
+			config: &ocispec.Image{
+				Config: ocispec.ImageConfig{
 					Labels: map[string]string{
 						LabelSkillDescription: "no name",
 					},
@@ -75,8 +76,8 @@ func TestSkillConfigFromImageConfig(t *testing.T) {
 		},
 		{
 			name: "invalid allowed tools JSON",
-			config: &ImageConfig{
-				Config: ImageConfigData{
+			config: &ocispec.Image{
+				Config: ocispec.ImageConfig{
 					Labels: map[string]string{
 						LabelSkillName:         "bad-tools",
 						LabelSkillAllowedTools: "not-json",
@@ -87,8 +88,8 @@ func TestSkillConfigFromImageConfig(t *testing.T) {
 		},
 		{
 			name: "invalid files JSON",
-			config: &ImageConfig{
-				Config: ImageConfigData{
+			config: &ocispec.Image{
+				Config: ocispec.ImageConfig{
 					Labels: map[string]string{
 						LabelSkillName:  "bad-files",
 						LabelSkillFiles: "not-json",
@@ -126,18 +127,23 @@ func TestParsePlatform(t *testing.T) {
 	tests := []struct {
 		name    string
 		input   string
-		want    Platform
+		want    ocispec.Platform
 		wantErr bool
 	}{
 		{
 			name:  "linux/amd64",
 			input: "linux/amd64",
-			want:  Platform{OS: "linux", Architecture: "amd64"},
+			want:  ocispec.Platform{OS: "linux", Architecture: "amd64"},
 		},
 		{
 			name:  "linux/arm64",
 			input: "linux/arm64",
-			want:  Platform{OS: "linux", Architecture: "arm64"},
+			want:  ocispec.Platform{OS: "linux", Architecture: "arm64"},
+		},
+		{
+			name:  "linux/arm/v7",
+			input: "linux/arm/v7",
+			want:  ocispec.Platform{OS: "linux", Architecture: "arm", Variant: "v7"},
 		},
 		{
 			name:    "no slash",
@@ -146,7 +152,7 @@ func TestParsePlatform(t *testing.T) {
 		},
 		{
 			name:    "too many parts",
-			input:   "linux/amd64/v8",
+			input:   "linux/amd64/v8/extra",
 			wantErr: true,
 		},
 		{
@@ -159,6 +165,11 @@ func TestParsePlatform(t *testing.T) {
 			input:   "linux/",
 			wantErr: true,
 		},
+		{
+			name:    "empty variant",
+			input:   "linux/arm/",
+			wantErr: true,
+		},
 	}
 
 	for _, tt := range tests {
@@ -179,8 +190,45 @@ func TestParsePlatform(t *testing.T) {
 func TestPlatformString(t *testing.T) {
 	t.Parallel()
 
-	p := Platform{OS: "linux", Architecture: "amd64"}
-	assert.Equal(t, "linux/amd64", p.String())
+	tests := []struct {
+		name     string
+		platform ocispec.Platform
+		want     string
+	}{
+		{
+			name:     "os/arch",
+			platform: ocispec.Platform{OS: "linux", Architecture: "amd64"},
+			want:     "linux/amd64",
+		},
+		{
+			name:     "os/arch/variant",
+			platform: ocispec.Platform{OS: "linux", Architecture: "arm", Variant: "v7"},
+			want:     "linux/arm/v7",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			assert.Equal(t, tt.want, PlatformString(tt.platform))
+		})
+	}
+}
+
+func TestParsePlatform_PlatformString_Roundtrip(t *testing.T) {
+	t.Parallel()
+
+	platforms := []ocispec.Platform{
+		{OS: "linux", Architecture: "amd64"},
+		{OS: "linux", Architecture: "arm64"},
+		{OS: "linux", Architecture: "arm", Variant: "v7"},
+	}
+
+	for _, p := range platforms {
+		parsed, err := ParsePlatform(PlatformString(p))
+		require.NoError(t, err)
+		assert.Equal(t, p, parsed)
+	}
 }
 
 func TestParseRequiresAnnotation(t *testing.T) {
@@ -238,6 +286,6 @@ func TestDefaultPlatforms(t *testing.T) {
 	t.Parallel()
 
 	require.Len(t, DefaultPlatforms, 2)
-	assert.Equal(t, Platform{OS: "linux", Architecture: "amd64"}, DefaultPlatforms[0])
-	assert.Equal(t, Platform{OS: "linux", Architecture: "arm64"}, DefaultPlatforms[1])
+	assert.Equal(t, ocispec.Platform{OS: "linux", Architecture: "amd64"}, DefaultPlatforms[0])
+	assert.Equal(t, ocispec.Platform{OS: "linux", Architecture: "arm64"}, DefaultPlatforms[1])
 }