RubyFuZa 2012 - EventMachine

Lightning overview of EventMachine

Transcript

1. EventMachine Christopher Spring EM.run{ awesome_stuff! } Monday 05 March 12
2. @autonomous Monday 05 March 12
3. Monday 05 March 12
4. Monday 05 March 12
5. EventMachine Monday 05 March 12
6. EventMachine Monday 05 March 12
7. • Mostly IO bound • Handle thousands concurrent connections • Stream data • Real time data delivery • You’ve got Mad Ruby Skills Monday 05 March 12
8. What is EventMachine? • Toolkit for creating evented applications • Implementation of the Reactor Pattern • MRI, YARV, jRuby, Rubinius Monday 05 March 12
9. Evented? Monday 05 March 12
10. Evented? puts(1) puts(2) puts(3) Monday 05 March 12
11. Evented? puts(1) puts(2) puts(3) puts(1) work{ puts(3) } puts(2) Monday 05 March 12
12. Reactor pattern “Event handling pattern for handling service requests delivered concurrently to a service handler by one or more inputs. The service handler then demultiplexes the incoming requests and dispatches them synchronously to the associated request handlers.” http://en.wikipedia.org/wiki/Reactor_pattern Monday 05 March 12
13. Http Keyboard Udp etc Demultiplexer Event Handler A Event Handler B Event Handler C Event Handler D Service handler Event dispatcher Monday 05 March 12
14. Http Keyboard Udp etc Demultiplexer Event Handler A Event Handler B Event Handler C Event Handler D Service handler Event dispatcher Monday 05 March 12
15. Http Keyboard Udp etc Demultiplexer Event Handler A Event Handler B Event Handler C Event Handler D Service handler Event dispatcher Thread 1 Thread 2 Thread 20 ... Monday 05 March 12
16. Benefits • Application code separate from reactor • Non blocking IO • Single process • No threads! Monday 05 March 12
17. Limitations • Demultiplexing limits • Some others we’ll cover later... Monday 05 March 12
18. Teh Basics • EM.run • EM.connection • EM.next_tick • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
19. Teh Basics • EM.run • EM.connection • EM.next_tick • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
20. require "rubygems" require "eventmachine" EM.run do # ... EM.stop end Monday 05 March 12
21. ... don’t do this! • big ass loops • 1_000_000.times{} • while condition? • sleep • blocking IO Monday 05 March 12
22. Teh Basics • EM.run • EM.connection • EM.next_tick • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
23. class EchoServer < EM::Connection def post_init puts "New connection" end def unbind puts "Connection closed" end def receive_data(data) send_data ">> #{data}" end end EM.run do EM.start_server('127.0.0.1', 9000, EchoServer) puts "Started server at 127.0.0.1:9000" end Monday 05 March 12
24. class EchoServer < EM::Connection def post_init puts "New connection" end def unbind puts "Connection closed" end def receive_data(data) send_data ">> #{data}" end end EM.run do EM.start_server('127.0.0.1', 9000, EchoServer) puts "Started server at 127.0.0.1:9000" end # $ telnet localhost 9000 # Hello # >> Hello # Bye # >> Bye Monday 05 March 12
25. # TCP EM.run do EM.start_server('127.0.0.1', 9000, EchoServer) end # UDP EM.run do EM.open_datagram_socket('127.0.0.1', 9000, EchoServer) end # Unix-domain server EM.run do EM.start_unix_domain_server('/tmp/sock', nil, EchoServer) end Monday 05 March 12
26. class EchoClient < EM::Connection def post_init puts "Sending stuff to server" send_data("Why, hello there!") end def unbind puts "Connection closed" end def receive_data(data) puts ">> #{data}" end end EM.run do EM.connect('127.0.0.1', 9000, EchoClient) end Monday 05 March 12
27. class EchoClient < EM::Connection def post_init puts "Sending stuff to server" send_data("Why, hello there!") end def unbind puts "Connection closed" end def receive_data(data) puts ">> #{data}" end end EM.run do EM.connect('127.0.0.1', 9000, EchoClient) end Monday 05 March 12
28. Teh Basics • EM.run • EM.connection • EM.next_tick • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
29. EM.run do EM.next_tick do # ... awesome stuff end end Monday 05 March 12
30. Task 1 Task 2 Task 3 Monday 05 March 12
31. Task 1 Task 2 Task 3 EM.run{ } Monday 05 March 12
32. Task 1 Task 2 Task 3 EM.run{ } EM.next_tick{ } Monday 05 March 12
33. Teh Basics • EM.run • EM.connection • EM.next_tick • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
34. EM.run do EM.defer do send_email( user1 ) end EM.defer do send_email( user2 ) end EM.defer do send_email( user3 ) end end Monday 05 March 12
35. Email 1 Email 2 Email 3 Monday 05 March 12
36. Email 1 EM.defer{ } Email 2 Email 3 Monday 05 March 12
37. EM.run do get_stuff = Proc.new do # ... long_running_io() end use_stuff = Proc.new do |io_results| # ... end # ... EM.defer( get_stuff, use_stuff ) end Monday 05 March 12
38. Teh Basics • EM.run • EM.connection • next_tick; add_timer; add_periodic_timer • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
39. EM.run do queue = EM::Queue.new # ... queue.push( data1, data2 ) # ... queue.pop { |data| puts data } # >> data1 end Monday 05 March 12
40. EM.run do queue = EM::Queue.new EM.defer do sleep( 2 ) queue.push( 'some@email.com' ) sleep( 3 ) queue.push( 'some@one.com') end welcomer = Proc.new do |email| send_welcome( email ) EM.next_tick( queue.pop(&welcomer) ) end queue.pop(&welcomer); end Monday 05 March 12
41. Teh Basics • EM.run • EM.connection • EM.next_tick • EM.defer • EM::Queue • EM::Channel Monday 05 March 12
42. EM.run do channel = EM::Channel.new EM.defer do channel.subscribe do |msg| puts "Received #{msg}" end end EM.add_periodic_timer(1) do channel << Time.now end end Monday 05 March 12
43. Deferrable • Light weight concurrency • Delayed execution with triggers • :succeeded • :failed • nil • callback and errback Monday 05 March 12
44. class LoanRequest include EM::Deferrable def initialize( name ) @name = name callback do |who| puts "Approved #{who}!" end errback do |who| puts "Denied #{who}!" end end def approved! # succeed( *args ) set_deferred_status(:succeeded, @name) end def denied! # fail( *args ) set_deferred_status(:failed, @name) end end Monday 05 March 12
45. class LoanRequest include EM::Deferrable def initialize( name ) @name = name callback do |who| puts "Approved #{who}!" end errback do |who| puts "Denied #{who}!" end end def approved! # succeed( *args ) set_deferred_status(:succeeded, @name) end def denied! # fail( *args ) set_deferred_status(:failed, @name) end end EM.run do s1 = LoanRequest.new('Marc') s1.approved! s2 = LoanRequest.new('Chris') EM.add_timer(2){ s2.denied! } end Monday 05 March 12
46. class LoanRequest include EM::Deferrable def initialize( name ) @name = name callback do |who| puts "Approved #{who}!" end errback do |who| puts "Denied #{who}!" end end def approved! # succeed( *args ) set_deferred_status(:succeeded, @name) end def denied! # fail( *args ) set_deferred_status(:failed, @name) end end EM.run do s1 = LoanRequest.new('Marc') s1.approved! s2 = LoanRequest.new('Chris') EM.add_timer(2){ s2.denied! } end # :00 Approved Marc! # :02 Denied Chris! Monday 05 March 12
47. state: nil Monday 05 March 12
48. state: nil callback{} callback{} callback{} Monday 05 March 12
49. state: nil callback{} callback{} callback{} errback{} errback{} Monday 05 March 12
50. state: succeeded callback{} callback{} callback{} errback{} errback{} Monday 05 March 12
51. state: succeeded callback{} callback{} callback{} Monday 05 March 12
52. state: succeeded Monday 05 March 12
53. state: failed callback{} callback{} callback{} errback{} errback{} Monday 05 March 12
54. state: failed errback{} errback{} Monday 05 March 12
55. state: failed Monday 05 March 12
56. class Mailer include EM::Deferrable def add_mailing(val) callback do sleep 1 puts "Sent #{val}" end end def connection_open! puts 'Open connection' succeed end def connection_lost! puts 'Lost connection' set_deferred_status nil end end Monday 05 March 12
57. class Mailer include EM::Deferrable def add_mailing(val) callback do sleep 1 puts "Sent #{val}" end end def connection_open! puts 'Open connection' succeed end def connection_lost! puts 'Lost connection' set_deferred_status nil end end EM.run do m = Mailer.new m.add_mailing(1) m.add_mailing(2) m.connection_open! EM.add_timer(1) do m.connection_lost! EM.add_timer(2) do m.add_mailing(3) m.add_mailing(4) m.connection_open! end end end Monday 05 March 12
58. class Mailer include EM::Deferrable def add_mailing(val) callback do sleep 1 puts "Sent #{val}" end end def connection_open! puts 'Open connection' succeed end def connection_lost! puts 'Lost connection' set_deferred_status nil end end EM.run do m = Mailer.new m.add_mailing(1) m.add_mailing(2) m.connection_open! EM.add_timer(1) do m.connection_lost! EM.add_timer(2) do m.add_mailing(3) m.add_mailing(4) m.connection_open! end end end # Open connection # Sent 1 # Sent 2 # Lost connection # Open connection # Sent 3 # Sent 4 Monday 05 March 12
59. Gotchas • Inverted flow of control can make debugging difficult • Synchronous code will slow it down • Use/Write libraries for EM Monday 05 March 12
60. Worth checking out • EM-Synchrony: https://github.com/igrigorik/em-synchrony • Goliath: https://github.com/postrank-labs/goliath • Async_Sinatra: https://github.com/raggi/async_sinatra Monday 05 March 12
61. Monday 05 March 12
62. Baie Dankie! Monday 05 March 12
63. Questions? Monday 05 March 12