Alexander Emelin FZambia

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.

	// Chi-like syntactic sugar layer on top of stdlib http.ServeMux.
	package main

	import (
	"net/http"
	"slices"
	)

	type (
	middleware func(http.Handler) http.Handler

	package gpool

	import "context"

	// Job represents function to be executed in worker.
	type Job func()

	type worker struct {
	jobs chan Job
	stop chan struct{}

	package main

	import (
	"context"
	"crypto/tls"
	"encoding/binary"
	"errors"
	"io"
	"log"
	"net/url"

	<!DOCTYPE html>
	<html lang="en">
	<head>
	<script type="text/javascript" src="https://rawgit.com/centrifugal/centrifuge-js/master/dist/centrifuge.min.js"></script>
	</head>
	<body>
	<script type="text/javascript">
	const centrifuge = new Centrifuge('ws://localhost:8000/websocket');
	function drawText(text) {
	const div = document.createElement('div');

	{
	"swagger": "2.0",
	"info": {
	"title": "api.proto",
	"version": "version not set"
	},
	"consumes": [
	"application/json"
	],
	"produces": [

	(function() {
	'use strict';
	window.addEventListener('load', function() {
	var canvas = document.getElementById('canvas');

	if (!canvas \|\| !canvas.getContext) {
	return false;
	}

	function rand(min, max) {

	$ gorelease -base=v0.7.0 -version=v0.8.0
	github.com/centrifugal/centrifuge
	---------------------------------
	Incompatible changes:
	- (*Client).Send: changed from func(github.com/centrifugal/protocol.Raw) error to func([]byte) error
	- (MemoryEngine).AddHistory: changed from func(string, github.com/centrifugal/protocol.Publication, ChannelOptions) (github.com/centrifugal/protocol.Publication, error) to func(string, github.com/centrifugal/protocol.Publication, ChannelOptions) (StreamPosition, bool, error)
	- (*Node).Disconnect: changed from func(string, bool) error to func(string, ...DisconnectOption) error
	- (Node).History: changed from func(string) ([]github.com/centrifugal/protocol.Publication, error) to func(string, ...HistoryOption) (HistoryResult, error)
	- (*Node).Publish: changed from func(string, []byte, ...PublishOption) error to func(string, []byte, ...PublishOption) (PublishResult, error)
	- (*Node).Unsubscribe: changed from func(string, string) error to func(string, string, ...UnsubscribeOption

	module.exports = { subscribe };

	var items = [
	{
	token: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiI5YmRhNWNlYy02MzRiLTQ2NWItOTNmMC00MTc5MWNmNTAyYzgifQ.DSJ1n4Zrf7CGSX15em3FWrL_4hbJXUFr_lebSQvU7go',
	channel: 'notifications#9bda5cec-634b-465b-93f0-41791cf502c8'
	},
	{
	token: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJiYWU3MTQxNy05MmVhLTRjMjMtODNkZi1mMDJlNTA2NTY0NmQifQ.lmfVqgTrGxX3Wy8nPC30852AbWnVUD9iJrWR209Qvw0',
	channel: 'notifications#bae71417-92ea-4c23-83df-f02e5065646d'

	package main

	import (
	"encoding/json"
	"fmt"
	"log"
	"math/rand"
	"net/http"
	"os"
	"os/signal"