如何在thumbor、s3设置中添加清漆?

客户端需要原始s3图像或缩略图

没有清漆的基本设置如下所示:

client => s3 image
client => thumbor => s3 image (thumbor gets s3 image and creates thumbnail for the client)

我想给缓存图像添加清漆。我应该在服务器之间的哪里放置清漆?

1. client => s3 image becomse: client => varnish => s3 image
2. client => thumbor => s3 becomes any of the following I think

  1) client => varnish => thumbor => s3 image 
  2) client => thumbor => varnish => s3 image
  3) client => varnish => thumbor => varnish => s3 image

我想如果我能把它设置好就最好了。。但我想很难安排 1)对2)我应该选择哪一个?