Evented Sinatra

slide1.rb

## Eventmachine
# Non-blocking I/O event loop in Ruby
# Lots of extensions that support MySQL, AMPQ, Redis, Memcache, etc.
# Suffers from callback hell (like node.js)
# Easy to start with

require 'eventmachine'
require 'em-http-request'

EventMachine.run {
  http = EventMachine::HttpRequest.new('http://google.com/').get :query => {'keyname' => 'value'}

  http.errback { p 'Uh oh'; EM.stop }
  http.callback {
    p http.response_header.status
    p http.response_header
    p http.response

    EventMachine.stop
  }
}

slide2.rb

## Ruby Fibers
# Allow a piece of code to yield execution at a later time (continuations)

fiber = Fiber.new do
  print "1 "
  Fiber.yield
  print "2 "
end

fiber.resume
print "3 "
fiber.resume

# prints out "1 3 2"

slide3.rb

## Eventmachine + Fibers = <3
# Supports a synchronous looking syntax
# Works well for a model that has a request / fiber

# Simple Example
EventMachine.run {
  http = EventMachine::HttpRequest.new('http://google.com/').aget :query => {'keyname' => 'value'}
  p http.response_header.status
  p http.response_header
  p http.response

  EventMachine.stop
}

slide4.rb

# Sinatra proxying requests to Google

require 'sinatra'
require 'rest-client'
require 'faraday'

get '/' do
  Faraday.get 'http://google.com'
end

# Benchmark
# ab -c 100 -n 1000 http://127.0.0.1:4567/
# Requests per second:    39.23 [#/sec] (mean)

slide5.rb

# Let's add Sinatra::Synchrony (https://github.com/kyledrake/sinatra-synchrony)

require 'sinatra'
require 'sinatra/synchrony'
require 'faraday'
Faraday.default_adapter = :em_synchrony #Tell Faraday to use correct EM adapter

get '/' do
  Faraday.get 'http://google.com'
end

# Benchmark
# ab -c 100 -n 1000 http://127.0.0.1:4567/
# Requests per second:    732.61 [#/sec] (mean)

# Each request becomes a Fiber using Rack::FiberPool
# There are AR DB adapters for MySQL and PostgreSQL