Working config for auth_request with proxy_cache. (nginx 1.18.0)

nginx.conf

# Working config for auth_request with proxy_cache. (nginx 1.18.0)
# https://gist.github.com/jinto/f120e497db8d39d866db49ff2454b7b3
# ...
proxy_cache_path /tmp/cache_xx levels=1:2 keys_zone=auth_cache:10m max_size=128m inactive=10m use_temp_path=off;

server {
  location / {
    auth_request /_ml_proxy/auth;
    # ...
    proxy_pass http://backend_ip:7860/;
  }

  location ~ ^/_ml_proxy/auth { internal;
    include                 proxy_params;
    proxy_cache             auth_cache;
    proxy_cache_methods     GET HEAD POST;
    proxy_cache_key         $cookie_sessionid;   # for django
    proxy_cache_valid       200 1m;
    proxy_pass              http://backend_auth_ip;
    proxy_pass_request_body off;
    proxy_set_header        Content-Length "";
  }
}