For those working in a Java JAX-RS environment and looking for an additional rate filter on the app server itself, here is a similar Redis+Lua rate limiter implemented as a Jersey/JAX-RS filter [1].
It supports multiple limits, for example max 100 requests/minute and 10000/day, etc. The lua magic is here [2].
This isn’t using the same rate limiting approach as OP which follows the CloudFlare suggestion of a simplified sliding window which counts lastInterval/thisInterval instead of just a current interval counter that will reset in a single instant.
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.
We did a very similar implementation (although not distributed) for a similar problem, using Redis and Laravel.
We had MANY people crawling our website, and we would prefer that they use our API for that. Using Redis we block IPs who accessed our website more than X times not logged-in (200 URLs right now).
We also had the requirement that all good bots(Bing, Baidu, Google) should pass-thru without blocks or any slowdown.
Another requirement, was that those good bots should be verified(Reverse & Forward DNS Lookup) before entering out good bot list.
Not to say they did anything wrong, great work! But if facing the same problem, but for inhouse solution I'd consider using auth_requrest in the first place.
To me, advantage is archtectural, that I would not have specify which parameters of request are considered or how are they processed. Disadvantage is semantic, returning 403 instead of 429. But original article states returning 403 anyway.
And also, regarding rate limiting by IP, I think it should be done for 10x-100x of single user limit, just as first line of defense. Also nginx rate limiting has notion of burst which helps filter out "smart" crawlers, which unlike users, send requests for hours.
You can change a 403 to a 429 easily in conjunction with auth_request using a named location.
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.
It supports multiple limits, for example max 100 requests/minute and 10000/day, etc. The lua magic is here [2].
[1] https://github.com/cobbzilla/cobbzilla-wizard/blob/master/wi...
[2] https://github.com/cobbzilla/cobbzilla-wizard/blob/master/wi...