Hack to allow rm to work with oras v2 until oras-project/oras-go#454

Signed-off-by: carabasdaniel <[email protected]>

Author: carabasdaniel

pkg/app/rm.go

@@ -1,9 +1,15 @@
 package app
 
 import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/opcr-io/policy/pkg/oci"
 	"github.com/opcr-io/policy/pkg/parser"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
-	"oras.land/oras-go/pkg/content"
 )
 
 func (c *PolicyApp) Rm(existingRef string, force bool) error {
@@ -30,35 +36,108 @@ func (c *PolicyApp) Rm(existingRef string, force bool) error {
 		return nil
 	}
 
-	ociStore, err := content.NewOCI(c.Configuration.PoliciesRoot())
+	ociClient, err := oci.NewOCI(c.Context, c.Logger, c.getHosts, c.Configuration.PoliciesRoot())
 	if err != nil {
 		return err
 	}
-	err = ociStore.LoadIndex()
+
+	existingRefs, err := ociClient.ListReferences()
 	if err != nil {
 		return err
 	}
 
-	existingRefs := ociStore.ListReferences()
-
-	_, ok := existingRefs[existingRefParsed]
+	ref, ok := existingRefs[existingRefParsed]
 	if !ok {
 		return errors.Errorf("ref [%s] not found in the local store", existingRef)
 	}
+	// attach ref name annotation for comparisson.
+	ref.Annotations = make(map[string]string)
+	ref.Annotations[ocispec.AnnotationRefName] = existingRefParsed
 
-	ociStore.DeleteReference(existingRefParsed)
+	err = c.removeFromIndex(ref)
+	if err != nil {
+		return err
+	}
+
+	// Reload ociClient with refreshed index to update reference list.
+	ociClient, err = oci.NewOCI(c.Context, c.Logger, c.getHosts, c.Configuration.PoliciesRoot())
+	if err != nil {
+		return err
+	}
 
-	// TODO: if there are no references left to the policy, perhaps delete the descriptor?
-	// or implement a cleanup command.
+	updatedRefs, err := ociClient.ListReferences()
+	if err != nil {
+		return err
+	}
+	// Check if existing images use same digest.
+	removeBlob := true
+	for _, v := range updatedRefs {
+		if v.Digest == ref.Digest {
+			removeBlob = false
+			break
+		}
+	}
+	// only remove the blob if not used by another reference.
+	if removeBlob {
+		// Hack to remove the existing digest until ocistore deleter is implemented
+		// https://github.com/oras-project/oras-go/issues/454
+		digestPath := filepath.Join(strings.Split(ref.Digest.String(), ":")...)
+		blob := filepath.Join(c.Configuration.PoliciesRoot(), "blobs", digestPath)
+		err = os.Remove(blob)
+		if err != nil {
+			return err
+		}
+	}
 
 	c.UI.Normal().
 		WithStringValue("reference", existingRef).
 		Msg("Removed reference.")
 
-	err = ociStore.SaveIndex()
+	return nil
+}
+
+func (c *PolicyApp) removeFromIndex(ref ocispec.Descriptor) error {
+
+	type index struct {
+		Version   int                  `json:"schemaVersion"`
+		Manifests []ocispec.Descriptor `json:"manifests"`
+	}
+
+	var localIndex index
+	indexPath := filepath.Join(c.Configuration.PoliciesRoot(), "index.json")
+	indexBytes, err := os.ReadFile(indexPath)
+	if err != nil {
+		return err
+	}
+
+	err = json.Unmarshal(indexBytes, &localIndex)
+	if err != nil {
+		return err
+	}
+
+	localIndex.Manifests = removeFromManifests(localIndex.Manifests, ref)
+
+	newIndexBytes, err := json.Marshal(localIndex)
 	if err != nil {
 		return err
 	}
 
+	err = os.WriteFile(indexPath, newIndexBytes, 0664)
+	if err != nil {
+		return err
+	}
 	return nil
 }
+
+func removeFromManifests(manifests []ocispec.Descriptor, ref ocispec.Descriptor) []ocispec.Descriptor {
+	newarray := make([]ocispec.Descriptor, len(manifests)-1)
+	k := 0
+	for i := 0; i < len(manifests); i++ {
+		if manifests[i].Digest == ref.Digest && manifests[i].Annotations[ocispec.AnnotationRefName] == ref.Annotations[ocispec.AnnotationRefName] {
+			continue
+		}
+		newarray[k] = manifests[i]
+		k++
+	}
+	return newarray
+}