Secret in ingress snippet

Has anyone setup an ingress yml file to use a secret? I authenticate using a client cert but then I need to authenticate to Kibana using basic authentication. (fyi - i send the client cert info as run_user_as in a different header). So instead of hard coding the Authorization part i’d like to grab the username and password from a cert. Has anyone been able to make this work?

Specifically i’m sending to Kibana the Authentication header: |
   proxy_set_header Authorization 'Basic @#$@$@#$@#@#';

What i’d like is: |
   proxy_set_header Authentication <some value from a secret>

Please check

Thanks for the suggestion but I believe this is if I want basic authentication with nginx. I already have a setup for authentication using client certificates. What I need is to pass basic authentication to Kibana and that username password won’t be passed in from the user - it must be configured somewhere. And the only way I see configuring that is hardcoding it in a snippet.