How to make a non-blocking subrequest in nginx after serving content?

Question

Nginx

The bottom line is that there are a lot of pictures requested from the server. You need to follow up with them. Each has a unique setting. Now there is an application on nodejs, which now tracks everything and gives pictures. The application is not entirely stable.
The idea is this - to transfer the return of images to nginx, because. it is very reliable and somehow set it up so that it makes a subrequest to the node, but completely ignores what is happening inside it. Roughly speaking, I asked and forgot about it.
Even if there is no connection, then do nothing at all. Just submit a picture. Those. first give the picture, and then the subquery to the node.
Maybe there are other ways to solve this problem.

Answer 1

A bunch of options come to mind, from fast redis & redis_nginx_module types, and you already read anything from radish, to simple LUA sockets inside nginx-a. We gave the picture to nginx, he himself launched your lua script, which asynchronously sent a request to the node and immediately returned it.

Answer 2

Maybe just read the Nginx logs?

Answer 3

Do you just need to get request counters for each picture, or do you need a more cunning stat?