Add permission endpoint for extracting one permission from a set of roleIds

pkg/store/filesystem/permissions.go

@@ -19,14 +19,32 @@ func (s Store) ListPermissionsByResource(resource *proto.Resource, roleIDs []str
 	return records, nil
 }
 
+// ReadPermissionById finds the permission in the roles, specified by the provided roleIDs
+func (s Store) ReadPermissionByID(permissionID string, roleIDs []string) (*proto.Permission, error) {
+	for _, roleID := range roleIDs {
+		role, err := s.ReadBundle(roleID)
+		if err != nil {
+			s.Logger.Debug().Str("roleID", roleID).Msg("role not found, skipping")
+			continue
+		}
+		for _, permission := range role.Settings {
+			if permission.Id == permissionID {
+				if value, ok := permission.Value.(*proto.Setting_PermissionValue); ok {
+					return value.PermissionValue, nil
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
 // extractPermissionsByResource collects all permissions from the provided role that match the requested resource
 func extractPermissionsByResource(resource *proto.Resource, role *proto.Bundle) []*proto.Permission {
 	permissions := make([]*proto.Permission, 0)
 	for _, setting := range role.Settings {
-		if _, ok := setting.Value.(*proto.Setting_PermissionValue); ok {
-			value := setting.Value.(*proto.Setting_PermissionValue).PermissionValue
+		if value, ok := setting.Value.(*proto.Setting_PermissionValue); ok {
 			if util.IsResourceMatched(setting.Resource, resource) {
-				permissions = append(permissions, value)
+				permissions = append(permissions, value.PermissionValue)
 			}
 		}
 	}