Nick Poorman nickpoorman

Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

	ruby '2.7.1'

	gem 'rails', github: 'rails/rails'
	gem 'tzinfo-data', '>= 1.2016.7' # Don't rely on OSX/Linux timezone data

	# Action Text
	gem 'actiontext', github: 'basecamp/actiontext', ref: 'okra'
	gem 'okra', github: 'basecamp/okra'

	# Drivers

	# frozen_string_literal: true
	class AssociationLoader < GraphQL::Batch::Loader
	attr_reader :klass, :association

	def initialize(klass, association)
	raise ArgumentError, "association to load must be a symbol (got #{association.inspect})" unless association.is_a?(Symbol)
	raise ArgumentError, "cannot load associations for class #{klass.name}" unless klass < ActiveRecord::Base
	raise TypeError, "association #{association} does not exist on #{klass.name}" unless klass.reflect_on_association(association)

	@klass = klass