fix: show relevant error messages in case of images which cannot be scanned by Trivy

errors/errors.go

@@ -83,7 +83,7 @@ var (
 	ErrConfigNotFound                   = errors.New("config with the given name does not exist")
 	ErrNoURLProvided                    = errors.New("no URL provided")
 	ErrIllegalConfigKey                 = errors.New("given config key is not allowed")
-	ErrScanNotSupported                 = errors.New("scanning is not supported for given image media type")
+	ErrScanNotSupported                 = errors.New("scanning is not supported for given media type")
 	ErrCLITimeout                       = errors.New("query timed out while waiting for results")
 	ErrDuplicateConfigName              = errors.New("cli config name already added")
 	ErrInvalidRoute                     = errors.New("invalid route prefix")

pkg/extensions/search/cve/trivy/scanner.go

@@ -282,7 +282,7 @@ func (scanner Scanner) isManifestScanable(digestStr string) (bool, error) {
 		case ispec.MediaTypeImageLayerGzip, ispec.MediaTypeImageLayer, string(regTypes.DockerLayer):
 			continue
 		default:
-			return false, zerr.ErrScanNotSupported
+			return false, fmt.Errorf("%w: layer media type '%s'", zerr.ErrScanNotSupported, imageLayer.MediaType)
 		}
 	}
 
@@ -299,7 +299,7 @@ func (scanner Scanner) isManifestDataScannable(manifestData mTypes.ManifestMeta)
 		case ispec.MediaTypeImageLayerGzip, ispec.MediaTypeImageLayer, string(regTypes.DockerLayer):
 			continue
 		default:
-			return false, zerr.ErrScanNotSupported
+			return false, fmt.Errorf("%w: layer media type '%s'", zerr.ErrScanNotSupported, imageLayer.MediaType)
 		}
 	}