feat(oci): oci helm support [r8s-361] (#787)

pkg/liboras/repository.go

@@ -0,0 +1,126 @@
+package liboras
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"sort"
+
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	portainer "github.com/portainer/portainer/api"
+	"github.com/portainer/portainer/api/concurrent"
+	"github.com/segmentio/encoding/json"
+	"golang.org/x/mod/semver"
+	"oras.land/oras-go/v2/registry"
+	"oras.land/oras-go/v2/registry/remote"
+)
+
+// ListRepositories retrieves all repositories from a registry using specialized repository listing clients
+// Each registry type has different repository listing implementations that require specific API calls
+func ListRepositories(ctx context.Context, registry *portainer.Registry, registryClient *remote.Registry) ([]string, error) {
+	factory := NewRepositoryListClientFactory()
+	listClient, err := factory.CreateListClientWithRegistry(registry, registryClient)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create repository list client: %w", err)
+	}
+
+	return listClient.ListRepositories(ctx)
+}
+
+// FilterRepositoriesByMediaType filters repositories to only include those with the expected media type
+func FilterRepositoriesByMediaType(ctx context.Context, repositoryNames []string, registryClient *remote.Registry, expectedMediaType string) ([]string, error) {
+	// Run concurrently as this can take 10s+ to complete in serial
+	var tasks []concurrent.Func
+	for _, repoName := range repositoryNames {
+		name := repoName
+		task := func(ctx context.Context) (any, error) {
+			repository, err := registryClient.Repository(ctx, name)
+			if err != nil {
+				return nil, err
+			}
+
+			if HasMediaType(ctx, repository, expectedMediaType) {
+				return name, nil
+			}
+			return nil, nil // not a repository with the expected media type
+		}
+		tasks = append(tasks, task)
+	}
+
+	// 10 is a reasonable max concurrency limit
+	results, err := concurrent.Run(ctx, 10, tasks...)
+	if err != nil {
+		return nil, err
+	}
+
+	// Collect repository names
+	var repositories []string
+	for _, result := range results {
+		if result.Result != nil {
+			if repoName, ok := result.Result.(string); ok {
+				repositories = append(repositories, repoName)
+			}
+		}
+	}
+
+	return repositories, nil
+}
+
+// HasMediaType checks if a repository has artifacts with the specified media type
+func HasMediaType(ctx context.Context, repository registry.Repository, expectedMediaType string) bool {
+	// Check the first available tag
+	// Reasonable limitation - it won't work for repos where the latest tag is missing the expected media type but other tags have it
+	// This tradeoff is worth it for the performance benefits
+	var latestTag string
+	err := repository.Tags(ctx, "", func(tagList []string) error {
+		if len(tagList) > 0 {
+			// Order the taglist by latest semver, then get the latest tag
+			// e.g. ["1.0", "1.1"] -> ["1.1", "1.0"] -> "1.1"
+			sort.Slice(tagList, func(i, j int) bool {
+				return semver.Compare(tagList[i], tagList[j]) > 0
+			})
+			latestTag = tagList[0]
+		}
+		return nil
+	})
+
+	if err != nil {
+		return false
+	}
+
+	if latestTag == "" {
+		return false
+	}
+
+	descriptor, err := repository.Resolve(ctx, latestTag)
+	if err != nil {
+		return false
+	}
+
+	return descriptorHasMediaType(ctx, repository, descriptor, expectedMediaType)
+}
+
+// descriptorHasMediaType checks if a descriptor or its manifest contains the expected media type
+func descriptorHasMediaType(ctx context.Context, repository registry.Repository, descriptor ocispec.Descriptor, expectedMediaType string) bool {
+	// Check if the descriptor indicates the expected media type
+	if descriptor.MediaType == expectedMediaType {
+		return true
+	}
+
+	// Otherwise, look for the expected media type in the entire manifest content
+	manifestReader, err := repository.Manifests().Fetch(ctx, descriptor)
+	if err != nil {
+		return false
+	}
+	defer manifestReader.Close()
+
+	content, err := io.ReadAll(manifestReader)
+	if err != nil {
+		return false
+	}
+	var manifest ocispec.Manifest
+	if err := json.Unmarshal(content, &manifest); err != nil {
+		return false
+	}
+	return manifest.Config.MediaType == expectedMediaType
+}