diff --git a/scripts/lib/upyun_upload.lua b/scripts/lib/upyun_upload.lua
index d489f93..3515665 100644
--- a/scripts/lib/upyun_upload.lua
+++ b/scripts/lib/upyun_upload.lua
@@ -11,6 +11,10 @@ local Upyun = require('lib.upyun')
 
 function upyun_upload.upload(filepath, filename, retry)
 
+    if retry == nil then
+        retry = 1
+    end
+
     if retry > 3 then
         ngx.log(ngx.ERR, "failed to upload file : reach max retries")
     else