Allow using image id when on policy tag (#177)

oci/oci.go

@@ -6,6 +6,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -287,7 +288,15 @@ func (o *Oci) Tag(existingRef, newRef string) error {
 
 	descriptor, ok := refs[existingRef]
 	if !ok {
-		return errors.Errorf("policy [%s] not found in the local store", existingRef)
+		for _, v := range refs {
+			if strings.HasPrefix(v.Digest.String(), fmt.Sprintf("sha256:%s", existingRef)) {
+				descriptor = v
+				break
+			}
+		}
+		if descriptor.Size == 0 {
+			return errors.Errorf("policy [%s] not found in the local store", existingRef)
+		}
 	}
 
 	_, err = cloneDescriptor(&descriptor)

pkg/app/tag.go

@@ -1,6 +1,8 @@
 package app
 
 import (
+	"strings"
+
 	"github.com/opcr-io/policy/oci"
 	"github.com/opcr-io/policy/parser"
 	"github.com/pkg/errors"
@@ -13,10 +15,12 @@ func (c *PolicyApp) Tag(existingRef, newRef string) error {
 	if err != nil {
 		return err
 	}
-
-	existingRefParsed, err := parser.CalculatePolicyRef(existingRef, c.Configuration.DefaultDomain)
-	if err != nil {
-		return err
+	existingRefParsed := existingRef
+	if strings.Contains(existingRef, ":") {
+		existingRefParsed, err = parser.CalculatePolicyRef(existingRef, c.Configuration.DefaultDomain)
+		if err != nil {
+			return err
+		}
 	}
 
 	parsed, err := parser.CalculatePolicyRef(newRef, c.Configuration.DefaultDomain)