Rails Four For you and for me!

Transcription

1 Realtime Rails Four

2 Rails Four For you and for me!

3 Aaron

4 HI!! :-)

5 AT&T, AT&T logo and all AT&T related marks are trademarks of AT&T Intellectual Property and/or AT&T affiliated companies.

6 Rails Four For you and me!!!

7 The Web!

8 Ruby Rails Web

9 Thread Safety In Rails

10 Delete config.threadsafe!

11 Why delete?

12 Always be thread safe!

13 My Opinion! Always be thread safe!

14 Simplify

15 Is it safe to remove?

16 What did it do?

17 threadsafe! Preload frameworks (enable) Cache classes (enable) Depency loading (disable) Allow concurrency (enable)

18 Loading Code isn t Thread-safe*

19 ENABLED Preload Frameworks

20 Cache classes ENABLED

21 DISABLED Depency Loading

22 ENABLED Allow Concurrency

23 Rack::Lock Get Lock Read from Socket Process Stuff Write to Socket Release Lock

24 Rack::Lock Thread 2 Get Lock Read from Socket Thread 1 Process Stuff Write to Socket Release Lock

25 Rack::Lock Thread 2 Get Lock Read from Socket Process Stuff Write to Socket Release Lock

26 Rack::Lock Get Lock Read from Socket Process Stuff Write to Socket Thread 2 Release Lock

27 Rack::Lock with Processes

28 Rack::Lock with Threads

29 Best Case: Extra Overhead

30 Worst Case: 1 req at a time

31 IMPACT

32 Boot time increases (in prod)

33 Fewer middleware

34 Multi-Proc servers stay the same

35 Threaded servers Just Work

36 Bug Fixes

37 100% Caching

38 Locking = def = some_calculation

39 check then act Is nil? Calculate Set Return

40 check then act Thread 1 Is nil? Calculate Set Return

41 check then act Is nil? Thread 2 Thread 1 Calculate Set Return

42 check then act Is nil? Calculate Thread 2 Thread 1 Set Return

43 check then act Is nil? Calculate Set Return

44 Fix #1 (eager init) class Foo class << self = fib(34) p Foo.hard_calculation

45 Fix #2 (locking) class = Mutex.new class << self def = fib(34) p Foo.hard_calculation

46 Fix #2 (locking) class = Mutex.new class << self def = fib(34) p Foo.hard_calculation

47 Fix #2 (locking) class = Mutex.new class << self def = fib(34) p Foo.hard_calculation

48 Move methods to instances

49 Move to object class Foo def = fib(34) def Foo.new.hard_calculation

50 Lazy Object class Foo include Mutex_m def hard_calculation synchronize = fib(34) Foo.new.hard_calculation

51 Maintain API class Foo include Mutex_m def hard_calculation synchronize = fib(34) Instance = new def self.hard_calculation Instance.hard_calculation Foo.hard_calculation

52 Hash.new { } class Foo def = Hash.new { h,k h[k] = [] } def

53 Fix #1 (lock) class Foo include Mutex_m def initialize = Hash.new { h,k h[k] = [] } def some_value(key) synchronize }

54 Fix #2 thread_safe

55 What about the App Level?

56 Thread Safety In Web Apps

57 Avoid shared data

58 Most people don t type Thread.new

59 Look for things that are global.

60 Global Variables $so_global = {} $so_global[:foo] = bar

61 Constants SET_TWICE = 10 SET_TWICE = 10 Warning ALSO_GLOBAL = {} ALSO_GLOBAL[:foo] = bar No Warning

62 Class methods class MyModel def = fib(34)

63 Avoid global data

64 Add locks

65 Streaming

66 Template Rering Today

67 Templates Results are Buffered

68 Clients are blocked while Rails works

69 The entire page must fit in memory

70 Rack Encourages Buffering class MyApplication def call(env) [200, {}, [ my page ]]

71 We can do I/O and CPU in parallel.

72 So why buffer?

73 ActionController::Live

74 Example class BrowserController < ApplicationController include ActionController::Live def index 100.times do response.stream.write "hello!\n" response.stream.close

75 Example class BrowserController < ApplicationController include ActionController::Live Mix in def index 100.times do response.stream.write "hello!\n" response.stream.close Stream

76 response.stream acts like an I/O object

77 Everything Is a File

78 How does it work?

79 Our API def index response.status = 200 response.headers[ X-Whatever ] = <3 response.stream.write hello response.stream.write world response.stream.close

80 Rack API def call(env) return [200, { X-Whatever => <3 }, [ hello world ]]

81 Wrapped Request class Response attr_accessor :status attr_reader :headers, :stream def = = = StringIO.new def call(env) res = Response.new controller.response = res controller.index [res.status, res.headers, res.stream]

82 Threaded action def call(env) res = Response.new controller.response = res Thread.new { controller.index } [res.status, res.headers, res.stream]

83 Block until write def call(env) res = Response.new controller.response = res Thread.new { controller.index } res.stream.await [res.status, res.headers, res.stream]

84 Block until write def call(env) res = Response.new controller.response = res Thread.new { controller.index } res.stream.await Block [res.status, res.headers, res.stream]

85 Blocking Buffer class Buffer def = = Queue.new def await # wait for << str

86 Blocking Buffer class Buffer def = = Queue.new def await # wait for `call` blocks here << str

87 Blocking Buffer class Buffer def = = Queue.new def await # wait for << str `write` unblocks

88 What can we do?

89 Rails Internals

90 Streaming ERB

91 View Source # encoding: utf-8 require 'erb' doc = ERB.new '<%= hello %> world' puts doc.src

92 Source #coding:utf-8 _erbout = ''; _erbout.concat(( hello ).to_s); _erbout.concat " world"; _erbout.force_encoding( ENCODING )

93 Control Output class MyERB < ERB def set_eoutvar(compiler, eoutvar = '_erbout') compiler.put_cmd = "#{eoutvar}.write" compiler.insert_cmd = "#{eoutvar}.write" compiler.pre_cmd = [] compiler.post_cmd = [] doc = MyERB.new '<%= hello %> world', nil, nil, '$stdout' puts doc.src

94 Source #coding:utf-8 $stdout.write(( hello ).to_s); $stdout.write " world"

95 $ ruby test.rb hello world $

96 Web Apps

97 Infinite Streams

98 Server Sent Events

99 SSE Response HTTP/ OK X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Content-Type: text/event-stream Transfer-Encoding: chunked event: ping data: {"ping":" t21:44:41-07:00"} event: reload data: {"changed":["/users/aaron/git/lolwut/app/views/ users/"]}

100 SSE Response HTTP/ OK X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Content-Type: text/event-stream Transfer-Encoding: chunked event: ping data: {"ping":" t21:44:41-07:00"} event: reload data: {"changed":["/users/aaron/git/lolwut/app/views/ users/"]}

101 SSE Response HTTP/ OK X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Content-Type: text/event-stream Transfer-Encoding: chunked event: ping data: {"ping":" t21:44:41-07:00"} event: reload data: {"changed":["/users/aaron/git/lolwut/app/views/ users/"]}

102 SSE Response HTTP/ OK X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Content-Type: text/event-stream Transfer-Encoding: chunked event: ping data: {"ping":" t21:44:41-07:00"} event: reload data: {"changed":["/users/aaron/git/lolwut/app/views/ users/"]}

103 Client Side jquery(document).ready(function() { settimeout(function() { var source = new EventSource('/control'); // if we get a reload command, reload the page source.addeventlistener('reload', function(e) { window.location.reload(); }); }, 1); });

104 Client Side jquery(document).ready(function() { settimeout(function() { var source = new EventSource('/control'); // if we get a reload command, reload the page source.addeventlistener('reload', function(e) { window.location.reload(); }); }, 1); });

105 Client Side jquery(document).ready(function() { settimeout(function() { var source = new EventSource('/control'); // if we get a reload command, reload the page source.addeventlistener('reload', function(e) { window.location.reload(); }); }, 1); });

106 Client Side jquery(document).ready(function() { settimeout(function() { var source = new EventSource('/control'); // if we get a reload command, reload the page source.addeventlistener('reload', function(e) { window.location.reload(); }); }, 1); });

107 Real-Time Browser Communication

108

109 FS Events Puma FS-Events Browser

110 FS Events Puma FS-Events Browser

111 FS Events Puma FS-Events Browser

112 FS Events Puma FS-Events Browser

113 DB Events DRB Puma Console Browser

114 Socket DB Events DRB Puma Console Browser

115 Other Input Sources Embedded systems (sausage box) Telephony (twilio) Other users (chat systems)

116 Thread Safety Streaming P72N

117 Cores are increasing.

118 We need to utilize the entire machine

119 High latency clients are increasing.

120 Patience is decreasing.

121 Lie. Using cached data

122 Cheat. Updating partial parts of the page

123 Steal. Move computations to client side via JS

124 Lie. Cheat. Steal.

125 Be Good Engineers

126 THANK YOU

127 Questions?