Issue a custom token from NGINX - nginx

Question

I am new to NGINX. I'm wondering if it is possible to, with a single request to NGINX, make two proxy calls that affect the outcome of the response.
Specifically, I'm wanting to add a token to the response of an NGINX request where the token is given as a response header from a separate service.
Theoretically, it might look something like...
location / {
# Call to token service and set the response to a variable, maybe?
# proxy_pass Make the actual call
# Add token from step one to response headers
}
I don't know if this is supported by NGINX, if I need to delve into a custom module, or if this is just a bad idea.
Thanks.

Answer 1

Got it!
location / {
if ($http_x_entry_id = "") {
return 302 /entry;
}
auth_request /token/test-token;
auth_request_set $token $upstream_http_x_test_token;
set $test_ui test-ui;
proxy_pass http://$test_ui;
add_header X-My-Token "$token";
}
location /token/test-token {
internal;
set $token_api token-api;
error_page 500 =401 /error/401;
error_page 400 =401 /error/401;
proxy_method POST;
proxy_pass_request_body off;
proxy_set_header Content-Length "";
proxy_set_header X-Original-URI $request_uri;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
rewrite /token/(.*) "/$1/$http_x_entry_id" break;
proxy_pass http://$token_api:8080;
}