Aloha Ruby Conference 2012

Transcript

1. Rails Four & The Future!
2. Rails Four For you and for me!
3. Aaron Patterson @tenderlove
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. Aloha Ruby Conference
7. SPAM!!!
8. Dog the Bounty Hunter
9. Magnum P.I.
10. Proof!
11. WWFMD
13. Gorbachev Puff-Puff Thunderhorse
20. @gorbypuff
21. Rails Four For you and me!!!
22. The Web!
23. Not a TV Psychic
24. Ruby Rails Web
25. Concurrency In Ruby
26. Parallelization
27. P56N (possibly misspelled)
28. GIL Global Interpreter Lock
29. Alternatives: JRuby / Rubinius
30. Good News!
31. GIL was removed! In Ruby 1.9
32. Bad News.
33. GIL was replaced with GVL
34. Is MRI useless? For P32N
35. def fib(n) if n < 3 1 else fib(n-1) + fib(n-2) end end 4.times { fib(34) } Recursive Fib()
36. [aaron@higgins git]$ time ruby test.rb real 0m5.727s user 0m5.706s sys 0m0.011s [aaron@higgins git]$
37. def fib(n) if n < 3 1 else fib(n-1) + fib(n-2) end end 4.times.map { Thread.new { fib(34) } }.each(&:join) Threaded Fib()
38. [aaron@higgins git]$ time ruby test.rb real 0m5.753s user 0m5.732s sys 0m0.014s [aaron@higgins git]$
39. ❤ Use JRuby or Rubinius ❤ Use multiple processes What do we do?
40. Slow Server server = WEBrick::GenericServer.new(:Port => 28561, :MaxClients => 4) server.start do |socket| { } until socket.gets == "\r\n" socket.print "HTTP/1.0 200 OK\r\n" socket.print "\r\n" sleep 0.5 socket.print "Hello World" socket.close end
41. Slow Server server = WEBrick::GenericServer.new(:Port => 28561, :MaxClients => 4) server.start do |socket| { } until socket.gets == "\r\n" socket.print "HTTP/1.0 200 OK\r\n" socket.print "\r\n" sleep 0.5 socket.print "Hello World" socket.close end
42. Client require 'net/http' uri = URI('http://localhost:28561') 4.times { puts Net::HTTP.get_response uri }
43. $ time ruby client.rb Hello World Hello World Hello World Hello World real 0m2.029s user 0m0.017s sys 0m0.012s $
44. $ time ruby client.rb Hello World Hello World Hello World Hello World real 0m2.029s user 0m0.017s sys 0m0.012s $ 4 * 0.5
45. require 'net/http' uri = URI('http://localhost:28561') 4.times.map { Thread.new { puts Net::HTTP.get_response(uri).body } }.each &:join Threaded Client
46. $ time ruby client.rb Hello World Hello World Hello World Hello World real 0m0.525s user 0m0.016s sys 0m0.009s $
47. $ time ruby client.rb Hello World Hello World Hello World Hello World real 0m0.525s user 0m0.016s sys 0m0.009s $ 0.525!
48. ❤ Release GVL ❤ Wait until data is ready (select()) ❤ Acquire GVL IO#read
49. rb_thread_blocking_region() GVL Magic
50. What does it mean?
51. Fibonacci As A Service
52. FAAS (the next big thing)
53. A Blocked VM is a Blocked VM
54. Threads Matter Even with a GVL
55. Thread Safety In Rails
56. Delete config.threadsafe!
57. Why delete?
58. Always be thread safe!
59. Always be thread safe! My Opinion!
60. Simplify
61. Is it safe to remove?
62. What did it do?
63. threadsafe! ❤ Preload frameworks (enable) ❤ Cache classes (enable) ❤ Dependency loading (disable) ❤ Allow concurrency (enable)
64. Loading Code isn’t Thread-safe*
65. Preload Frameworks EN A B LED
66. Cache classes EN A B LED
67. Dependency Loading D ISA B LED
68. Allow Concurrency EN A B LED
69. Get Lock Read from Socket Process Stuff Write to Socket Release Lock Rack::Lock
70. Thread 2 Get Lock Read from Socket Process Stuff Write to Socket Release Lock Thread 1 Rack::Lock
71. Thread 2 Get Lock Read from Socket Process Stuff Write to Socket Release Lock Rack::Lock
72. Thread 2 Get Lock Read from Socket Process Stuff Write to Socket Release Lock Rack::Lock
73. Rack::Lock with Processes
74. Rack::Lock with Threads
75. Best Case: Extra Overhead
76. Worst Case: 1 req at a time
77. IMPACT
78. Boot time increases (in prod)
79. Fewer middleware
80. Multi-Proc servers stay the same
81. Threaded servers Just Work™
82. Bug Fixes
83. 100% Caching
84. Locking ||= def some_method @value ||= some_calculation end
85. check then act Is nil? Calculate Return Set
86. check then act Is nil? Calculate Return Thread 1 Set
87. check then act Is nil? Calculate Return Thread 1 Set Thread 2
88. check then act Is nil? Calculate Return Thread 1 Set Thread 2
89. check then act Is nil? Calculate Return Set
90. Fix #1 (eager init) class Foo class << self def hard_calculation @calc end end @calc = fib(34) end p Foo.hard_calculation
91. Fix #2 (locking) class Foo @lock = Mutex.new class << self def hard_calculation @lock.synchronize do @calc ||= fib(34) end end end end p Foo.hard_calculation
92. Fix #2 (locking) class Foo @lock = Mutex.new class << self def hard_calculation @lock.synchronize do @calc ||= fib(34) end end end end p Foo.hard_calculation
93. Fix #2 (locking) class Foo @lock = Mutex.new class << self def hard_calculation @lock.synchronize do @calc ||= fib(34) end end end end p Foo.hard_calculation
94. Move methods to instances
95. Move to object class Foo def initialize @calc = fib(34) end def hard_calculation @calc end end Foo.new.hard_calculation
96. Lazy Object class Foo include Mutex_m def hard_calculation synchronize do @calc ||= fib(34) end end end Foo.new.hard_calculation
97. Maintain API class Foo include Mutex_m def hard_calculation synchronize do @calc ||= fib(34) end end Instance = new def self.hard_calculation Instance.hard_calculation end end Foo.hard_calculation
98. Hash.new { } class Foo def initialize @cache = Hash.new { |h,k| h[k] = [] } end def some_value(key) @cache[key] end end
99. Fix #1 (lock) class Foo include Mutex_m def initialize super @cache = Hash.new { |h,k| h[k] = [] } end def some_value(key) synchronize { @cache[key] } end end
100. Fix #2 thread_safe https://github.com/headius/thread_safe
101. What about the App Level?
102. Thread Safety In Web Apps
103. Avoid shared data
104. Most people don’t type “Thread.new”
105. Look for things that are global.
106. Global Variables $so_global = {} $so_global[:foo] ||= “bar”
107. Constants SET_TWICE = 10 SET_TWICE = 10 ALSO_GLOBAL = {} ALSO_GLOBAL[:foo] ||= “bar” Warning No Warning
108. Class methods class MyModel def self.some_cache @foo ||= fib(34) end end
109. Avoid global data
110. Add locks
111. Streaming
112. Template Rendering Today
113. Templates Results are Buffered
114. Clients are blocked while Rails works
115. The entire page must fit in memory
116. Rack Encourages Buffering class MyApplication def call(env) [200, {}, [‘my page’]] end end
117. We can do I/O and CPU in parallel.
118. So why buffer?
119. ActionController::Live
120. Example class BrowserController < ApplicationController include ActionController::Live def index 100.times do response.stream.write "hello!\n" end response.stream.close end end
121. Example class BrowserController < ApplicationController include ActionController::Live def index 100.times do response.stream.write "hello!\n" end response.stream.close end end Mix in Stream
122. response.stream acts like an I/O object
123. Everything Is a File
124. How does it work?
125. Our API def index response.status = 200 response.headers[‘X-Whatever’] = ‘<3’ response.stream.write ‘hello’ response.stream.write ‘ world’ response.stream.close end
126. Rack API def call(env) return [200, {‘X-Whatever’ => ‘<3’}, [‘hello world’]] end
127. Wrapped Request class Response attr_accessor :status attr_reader :headers, :stream def initialize @status = 200 @headers = {} @stream = StringIO.new end end def call(env) res = Response.new controller.response = res controller.index [res.status, res.headers, res.stream] end
128. Threaded action def call(env) res = Response.new controller.response = res Thread.new { controller.index } [res.status, res.headers, res.stream] end
129. 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] end
130. 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] end Block
131. Blocking Buffer class Buffer def initialize @latch = Latch.new @buffer = Queue.new end def await # wait for write @latch.await end def write(str) @latch.release @buffer << str end end
132. Blocking Buffer class Buffer def initialize @latch = Latch.new @buffer = Queue.new end def await # wait for write @latch.await end def write(str) @latch.release @buffer << str end end `call` blocks here
133. Blocking Buffer class Buffer def initialize @latch = Latch.new @buffer = Queue.new end def await # wait for write @latch.await end def write(str) @latch.release @buffer << str end end `write` unblocks
134. What can we do?
135. Rails Internals
136. Streaming ERB
137. View Source # encoding: utf-8 require 'erb' doc = ERB.new '<%= hello %> world' puts doc.src
138. Source #coding:UTF-8 _erbout = ''; _erbout.concat(( hello ).to_s); _erbout.concat " world"; _erbout.force_encoding(__ENCODING__)
139. 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 = [] end end doc = MyERB.new '<%= hello %> world', nil, nil, '$stdout' puts doc.src
140. Source #coding:UTF-8 $stdout.write(( hello ).to_s); $stdout.write " world"
141. $ ruby test.rb hello world $
142. Web Apps
143. Infinite Streams
144. Server Sent Events
145. SSE Response HTTP/1.1 200 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":"2012-10-06T21:44:41-07:00"} event: reload data: {"changed":["/Users/aaron/git/lolwut/app/views/ users/"]}
146. SSE Response HTTP/1.1 200 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":"2012-10-06T21:44:41-07:00"} event: reload data: {"changed":["/Users/aaron/git/lolwut/app/views/ users/"]}
147. SSE Response HTTP/1.1 200 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":"2012-10-06T21:44:41-07:00"} event: reload data: {"changed":["/Users/aaron/git/lolwut/app/views/ users/"]}
148. SSE Response HTTP/1.1 200 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":"2012-10-06T21:44:41-07:00"} event: reload data: {"changed":["/Users/aaron/git/lolwut/app/views/ users/"]}
149. 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); });
150. 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); });
151. 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); });
152. 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); });
153. Real-Time Browser Communication
155. Puma Browser FS-Events FS Events
156. Puma Browser FS-Events FS Events
157. Puma Browser FS-Events FS Events
158. Puma Browser FS-Events FS Events
159. Puma Browser Console DRB DB Events
160. Puma Browser Console DRB DB Events Socket
161. Other Input Sources ❤ Embedded systems (sausage box) ❤ Telephony (twilio) ❤ Other users (chat systems)
162. Thread Safety P72N Streaming
163. Cores are increasing.
164. We need to utilize the entire machine
165. High latency clients are increasing.
166. Patience is decreasing.
167. Lie. Using cached data
168. Cheat. Updating partial parts of the page
169. Steal. Move computations to client side via JS
170. Lie. Cheat. Steal.
171. Be Good Engineers
172. THANK YOU
173. Questions?