John Nunemaker jnunemaker

Internet Scale Services Checklist

A checklist for designing and developing internet scale services, inspired by James Hamilton's 2007 paper "On Desgining and Deploying Internet-Scale Services."

http://mvdirona.com/jrh/talksandpapers/jamesrh_lisa.pdf

Basic tenets

Does the design expect failures to happen regularly and handle them gracefully?
Have we kept things as simple as possible?

Prepare your RDS instance and [authorize access to it][1] (basically make it public).
Put your app in maintenance mode:
```
heroku maintenance:on
```
Save the latest SQL dump of the DB:

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.

	package main

	import (
	"fmt"
	"log"
	"net/http"

	"html/template"

	"github.com/gorilla/sessions"

	require "net/http"

	def start_server
	# Remove the X to enable the parameters for tuning.
	# These are the default values as of Ruby 2.2.0.
	@child = spawn(<<-EOC.split.join(" "))
	XRUBY_GC_HEAP_FREE_SLOTS=4096
	XRUBY_GC_HEAP_INIT_SLOTS=10000
	XRUBY_GC_HEAP_GROWTH_FACTOR=1.8
	XRUBY_GC_HEAP_GROWTH_MAX_SLOTS=0

	require 'active_support/all'
	require 'active_record'
	require 'logger'

	ActiveRecord::Base.logger = Logger.new(STDOUT)

	spec = { 'test' => {adapter: 'sqlite3', database: ':memory:'},
	'test_readonly' => {adapter: 'sqlite3', database: ':memory:'},
	'shared_test' => {adapter: 'sqlite3', database: ':memory:'},
	'shared_test_readonly' => {adapter: 'sqlite3', database: ':memory:'}

	begin
	require "bundler/inline"
	rescue LoadError => e
	$stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
	raise e
	end

	gemfile(true) do
	source "https://rubygems.org"

	require 'parallel'
	require 'rtesseract'
	require 'mini_magick'

	source = "/MyDirectory/my.pdf"
	doc = {}
	pdf = MiniMagick::Image.open(source)
	Parallel.map(pdf.pages.each_with_index, in_threads: 8) do \|page, idx\|
	tmpfile = Tempfile.new(['', '.tif'])
	MiniMagick::Tool::Convert.new do \|convert\|

	#!/usr/bin/env ruby

	# gem install active_support
	require 'active_support/inflector'
	require 'active_support/core_ext/string'

	# gem install webrick (only ruby3)
	require 'webrick'

	# gem install mechanize

	FROM ruby:3.0-alpine

	RUN apk add --no-cache --update \
	ack \
	bash \
	build-base \
	curl \
	git \
	htop \
	less \