Observing throttle usage

[derekargueta]

Is there a way to instrument how much of the throttle quotas get used? As some kind of histogram, i.e. what the 50th percentile usage was, to inform whether the limits could use a little tightening. I'd imagine this getting captured when the period resets.

[santib]

Hi @derekargueta, I moved the issue to a discussion if that's fine.

how much of the throttle quotas get used?

Let me see if I understand your question. Given a throttle setup, you want to know for each discriminator how close it was to getting throttled?

For example if you have

Rack::Attack.throttle("requests by ip", limit: 5, period: 2) do |request|
  request.ip
end

You want to know for each period (2 secs) and each discriminator (IP) how many requests were made so to know how close they were to the limit (5 reqs) ?

I don't think there is any kind of instrumentation for that, only when a request if matched we notify it.

That said, you might be able to achieve your goal in some other ways. For example:

1. Using the Tracks feature?
2. Maybe writing a custom cache store that decorates the one you are using, with logic to track every increment to the cache store?