Rack

• Ruby Web Server Interface
• HTTP Response code
• Hash of headers
• response body

#my_rack_app.rb
require 'rack'

app = Proc.new do |env|
  ['200', { 'Content-Type' => 'text/html' }, 
  ['Hello World']]
end

Rack::Handler::WEBRick.run app

#config.ru
run Proc.new { |env| ['200', { 'Content-Type' => 'text/html' }, 
                     ['Hello World']] }

Other Web Framework?

Web Framework

• Sinatra
• Padrino
• Lotus
• Volt
• Grape

Tool

• Rails Generator
• Rails Console
• db migration
• asset pipeline
• Thor
• Spring
• Guard
• xip.io
• better erros
• pry

Etc Tool

• Pow
• Foreman

Which Server do we have to use?

• webrick
• thin
• unicorn
• puma
• passenger

Ruby Process Model

It depends on implementation!

Ruby Implementation

• MRI CRuby
• JRuby
• Rubinius
• RubyMotion
• MacRuby

MRI CRuby

• Most popular ruby implementation
• MultiThread ( since 2.x ~)
• JIT
• But, still GIL limitation
• multithread for I/O

JRuby

• Based on jvm
• JRuby9000 released(support ruby2.2)
• true multithreaded implementation
• invoke dynamic

Rubinius

• ruby implementation based on LLVM
• multithead implementation
• performance penalty

Unicorn

• Master and worker process model
• slow client problem
• nginx with unicorn
• unix domain socket

Puma

• multithread web server
• recommended in the heroku
• rails supports thread safe
• hybrid model - multi process and multithread

Phusion Passenger

• apache / nginx module
• support hybrid - multi process and multithread

unicorn

worker_processes Integer(ENV["WEB_CONCURRENCY"] || 3)
timeout 15
preload_app true

before_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!
end

after_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.establish_connection
end

puma

workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['MAX_THREADS'] || 5)
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup
port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'

on_worker_boot do
  # Worker specific setup for Rails 4.1+
  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
  ActiveRecord::Base.establish_connection
end

view

• ERB
• Haml
• Slim

slim

• more simple than Haml
• It's like Jade
• Fast

ERB

• useful for custom view (json, yaml, config)

API

• response json
• RailsAPI
• Grape
• Rails5

JSON View

• Active Model Serializer
• Rabl
• Jbuilder

presenter / decorator

• Draper

Background Job

• Sidekiq
• Resque
• Delayed Job

Resque

• Process fork
• heavy rather than sidekiq

Sidekiq

• multithread background job
• Redis is used for queue
• open source / commercial
• based on celluloid
• provide job monitoring page
• easy to use
• best performance in the JRuby

Sidekiq

# config/initializers/sidekiq.rb
Sidekiq.configure_server do |config|
  database_url = ENV['DATABASE_URL']
  if database_url
    ENV['DATABASE_URL'] = "#{database_url}?pool=25"
    ActiveRecord::Base.establish_connection
  end
end

Resque

Resque.before_fork do
    defined?(ActiveRecord::Base) and
      ActiveRecord::Base.connection.disconnect!
  end

  Resque.after_fork do
    defined?(ActiveRecord::Base) and
      ActiveRecord::Base.establish_connection
  end

deploy

• Git
• Heroku
• Jenkins
• AWS Opsworks (chef solo)

AWS OPSWORKS

• Based on Chef Solo
• opsworks cookbook
• attributes / receipe
• pros and cons

Docker

Immutable Infrastructure

docker

• slow build
• fast deployment
• docker registry sucks
• AWS ECS
• versioning - rollback is easy
• docker image
• log management (host option)
• network (native mapping, dhcp)
• cluster management