How to build a distributed throttling system with Nginx, Lua, and Redis

For daylong limits the single interval count may be less than ideal if a burst of activity happens to cross the reset threshold, the allowed rate will be double the expected limit.

Also, I think a trivial optimization would be to remove the GET call and just call INCR.

Or is there a k8s native alternative to this somewhere?

Curious over what time period, and if the 200 accesses included any asset, or only the main HTML of a page.

Edit: Your link shows a limit of 100 accesses per day.

One thing I've been doing recently is to deploy oauth2_proxy in proxy mode, protecting an authorization endpoint. The authorization endpoint can be custom code in any langauge - it can have logic for rate limiting or anything else. Together oauth2_proxy handles authentication, and the authorization endpoint might do an LDAP lookup and limit access based on a group or something else. If you want to return something other than a 401 or a 403 you have to do a little more work.

Something along the lines of this:

     location / {
        auth_request /auth;
        auth_request_set $backend_status $upstream_status;
     }

     location = /auth {
          proxy_pass http://oauth2-proxy:8080/authz;
          proxy_pass_request_body off;
          proxy_set_header Content-Length "";
          proxy_set_header X-Original-URI $request_uri;
      }

     location @process_backend_error {
         return $backend_status;
     }

However, this does not appear to work in a cluster.