A #devops question: is there a way to set up a "rolling cache" with nginx?

I want it to handle each request like so:

1. Immediately respond with the cached version
2. Start rebuilding the cache for that request in the background, so the next request for this URI gets a newer cached version

Cc @rysiek

@kuba @rysiek

I've never used that feature, but http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache_background_update claims to be a part of what you want.