using $upstream* variables inside map directive

[unoobee]

> And you are reporting that it does not ever write to "ssd_cache".
Yes, this is correct. I want to choose the cache location based on the size
of the cached file

I want to get the behavior described in the article, but only with the file
size in the map directive, I assume I need $sent_http_content_length or
$upstream_http_content_length.

https://www.nginx.com/blog/cache-placement-strategies-nginx-plus/

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,249880,289971#msg-289971