A Quest for the Ultimate Template Engine

Slides for MountainWest RubyConf 2015 talk "A Quest for the Ultimate Template Engine" http://mtnwestrubyconf.org/2015/sessions

Transcript

1. A Quest for the Ultimate Template Engine Akira Matsuda
2. Today's Talk My personal story About Ruby template engines
3. me from: Japan name: Akira Matsuda GitHub: amatsuda I Do: Ruby, Rails !
4. Template Engines Text Files + Ruby => HTML On Rails (ActionView) app/views/*.html.*
5. My first Ruby Template Engine Was Of course, ERB
6. ERB: The Default One Included in the Matz Ruby package as a stdlib Still a part of DHH's "omakase"
7. The Syntax <tbody> <% @users.each do |user| %> <tr> <td><%= user.name %></td> </tr> <% end %> </tbody>
8. The syntax looked familiar to me I used to be an ASP programmer I used to be a PHP programmer I used to be a JSP programmer
9. The ERB Syntax The spec is called eRuby
10. Crated By @shugo Copied ePerl syntax
11. Problem ERB sometimes sucks Because HTML sucks
12. We are humans <tbody> <% @users.each do |user| %> <tr> <td><%= user.name %></td> </tr> <% end %> </tbody>
13. We make mistakes <tbody> <% @users.each do |user| %> <tr> <td><%= user.name %></td> <% end %> </tr> </tbody>
14. Broken HTML Sometimes works Sometimes does not work
15. I Was Always Wondering Why doesn't the Framework validate the response HTML?
16. Then One Day, I met Haml
17. Haml
18. Haml Templating Haiku Beautiful DRY Well-indented Clear markup
19. Valid HTML! Parses the markup then compiles it into an HTML Ensures that the output is always valid HTML This was a revolution!
20. Syntax %tbody - @users.each do |user| %tr %td= user.name
21. I was fascinated No more broken HTML! Since then, I have never looked back on ERB
22. Then One Day, A Rails newbie came to me and said, "why is Haml so slow?" My app responds very quickly as an API server, but rendering the same set of data into an HTML is too slow
23. His Claim app/views/recipes/ index.???.json #=> fast app/views/recipes/ index.html.haml #=> slow
24. The Rails newbie's name was
25. @mineroaoki
26. @mineroaoki A Ruby committer The author of Net::HTTP, FileUtils, Ripper, Racc, TMail, etc. The author of legendary Ruby book "Ruby Hacking Guide"
27. History of Minero Aoki 1999: Became a Ruby Committer 2002: Wrote RHG while he was a student ..2013: Had been doing something else, wearing suit 2013: Came back to the Ruby world as a Rails programmer
28. RHG Even @ko1 learned Ruby implementation through this book English version is available online: http://ruby-hacking-guide.github.io/
29. I thought, Yeah, Haml might not be as fast as ERB Because of its syntax, parsing & compiling should be slow, but who cares?
30. He is a super hacker But a newbie Maybe his template is slow just because his Haml code sucks Or maybe what he meant was "ActionView is slow"?
31. Parsing & compiling Haml might be slow Because Haml is so complex But compiled code will be cached by ActionView
32. Parsing & compiling Haml might be slow But who cares?
33. A Rails tips If you feel like your view is slow, it might be because of url_for
34. Benchmark Let's quickly make sure that Haml is as fast as ERB in production
35. generate scaffold % rails g scaffold user name age:integer email phone
36. Preparing 1,000 Records (1..1000).each do |i| User.create! name: 'User %05d' % i, age: i, email: 'user%05d@example.com' % i, phone: "#{i}-#{i}" end
37. Run it in production mode Make the rst request from the browser
38. Make Requests With curl or ab or httperf or whatever
39. From the Log File I, [2015-03-09T18:34:26.780189 #57017] INFO -- : Completed 200 OK in 312ms (Views: 307.5ms | ActiveRecord: 3.9ms) I, [2015-03-09T18:34:27.103951 #57017] INFO -- : Completed 200 OK in 319ms (Views: 314.8ms | ActiveRecord: 3.9ms) I, [2015-03-09T18:34:27.366058 #57017] INFO -- : Completed 200 OK in 258ms (Views: 254.7ms | ActiveRecord: 2.9ms) I, [2015-03-09T18:34:27.658356 #57017] INFO -- : Completed 200 OK in 289ms (Views: 285.7ms | ActiveRecord: 2.5ms) I, [2015-03-09T18:34:27.953852 #57017] INFO -- : Completed 200 OK in 290ms (Views: 287.2ms | ActiveRecord: 2.4ms) I, [2015-03-09T18:34:28.216769 #57017] INFO -- : Completed 200 OK in 258ms (Views: 255.1ms | ActiveRecord: 2.6ms) I, [2015-03-09T18:34:28.560278 #57017] INFO -- : Completed 200 OK in 339ms (Views: 334.9ms | ActiveRecord: 3.6ms)
40. grep the View Rendering Time And Summarize
41. The Result (100 requests) ERB: 27135.9 msec Haml: 29116.8 msec
42. OMG
43. Haml is slow! It turned out that Haml is 7% slower in production runtime!
44. It's true that Haml is slow So what shall we do?
45. What shall we do? 1. Do Nothing
46. Do Nothing Let it be slow Who cares? We're Ruby programmers!
47. "Premature optimization is the root of all evil" There must be so many other reasons that make your Rails app slow DB network Business logic
48. While rendering is 7% slower Throughput from the client will be 1-2% difference
49. We're Ruby programmers If you really care about the app's performance, your app should've written in C What we should care is the balance
50. The Balance Between Performance And Productivity Maintainability Developers' Sanity
51. The Recipe for the ...
52. Our Recipe If your application is not fast enough, just add more servers.
53. What shall we do? 1. Do Nothing 2. Switch Back to ERB
54. 2. Switch back to ERB
55. Seriously Syntax matters
56. The Balance User Experience: Developer Happiness: 㽉
57. What shall we do? 1. Do Nothing 2. Switch Back to ERB 3. Find Something Else
58. 3. Find Something Else
59. What would you do to find something?
60. We do this.
61. google: haml slow
62. Google says, "I heard that Slim is faster than Haml, so it must be a good one" "I read someone's blog that shows Slim is faster than Haml, so I switched to Slim"
63. Slim? Similar to Haml Built on top of Temple
64. Syntax
65. Hello, World! | Hello, World!
66. Hello, World! h1 Hello, World!
67. To Me, Syntax matters And the syntax looks weird
68. "Faster than Haml" Seems like a good marketing Some people may choose Python over Ruby Some people may choose JRuby over CRuby because b() runs faster on JRuby
69. You can choose Slim If you're OK with the syntax
70. What shall we do? 1. Do Nothing 2. Switch Back to ERB 3. Find Something Else 4. Improve Haml
71. 4. Improve Haml
72. Faster Is Better, Of Course Even if speed is not a critical problem
73. I don't know why but I had a commit bit When I PRed one line of code
75. The diff
76. I Had to Do This Because, Our super large legacy Rails app was still on Ruby 1.8 at that moment...
77. Maybe They Didn't Want to Work on 1.8.7 Anymore So they gave me the commit right
78. Then I got a mail
79. Looks like I'm responsible
80. So, I started reading Haml
81. Pushed some nitpicks
82. The real problem Compiled ruby code
83. Hello! in ERB ERB.new("<% 'Hello!' %>").src
84. Hello! in ERB #=> "#coding:UTF-8\n_erbout = ''; 'Hello!' ; _erbout.force_encoding(__EN CODING__)"
85. Hello! in Haml Haml::Engine.new("= 'Hello!'").compiler.precompile d_with_ambles([])
86. Hello! in Haml begin;extend Haml::Helpers;_hamlout = @haml_buffer = Haml::Buffer.new(haml_buffer, {:autoclose=>["area", "base", "basefont", "br", "col", "command", "embed", "frame", "hr", "img", "input", "isindex", "keygen", "link", "menuitem", "meta", "param", "source", "track", "wbr"], :preserve=>["textarea", "pre", "code"], :attr_wrapper=>"'", :ugly=>false, :format=>:html5, :encoding=>"UTF-8", :escape_html=>false, :escape_attrs=>true, :hyphenate_data_attrs=>true, :cdata=>false});_erbout = _hamlout.buffer;@output_buffer = output_buffer ||= ActionView::OutputBuffer.new rescue nil;;_hamlout.push_text("#{_hamlout.format_script_false_false_ false_false_false_true_false(( 'Hello!' ));}\n", 0, false);_erbout;ensure;@haml_buffer = @haml_buffer.upper if @haml_buffer;end;
87. Lovely Haiku!
88. Let's see how we can improve this the Ruby code
89. What shall we do? 1. Do Nothing 2. Switch Back to ERB 3. Find Something Else 4. Improve Haml 5. Fork Haml
90. 5. Fork Haml
91. We need to care about compatibility
92. I concluded that I can not make Haml as fast as ERB without breaking compatibility
93. So, I made a fork
94. HamlX As I announced at RubyConf 2014
95. Current Status of HamlX Still not done
96. Benchmark
97. The Result (100 requests) ERB: 27135.9 msec Haml: 29116.8 msec HamlX: 27407.7 msec
98. What shall we do? 1. Do Nothing 2. Switch Back to ERB 3. Find Something Else 4. Improve Haml 5. Fork Haml 6. Create a New Haml Implementation
99. 6. Create a new Haml implementation
100. My co-worker at Cookpad
101. @eagletmt
102. @eagletmt eagle? tomato?
103. After my presentation at RubyConf
104. He started creating his own version
105. My Approach Haml minus slow parts
106. His Approach From the bottom up!
107. His Concept Slim is faster than Haml because Slim is built on Temple Slim and Haml's syntax is similar Why don't we make a Haml compiler on top of Temple?
108. The Creator of Temple Says, Nathan Weizenbaum (the maintainer of Haml) told me targeting Haml could be difficult, but I’m quite optimistic. It’s better to try, fail and learn, than not try at all. http://timelessrepo.com/temple#another_abstraction_haml_and_html
109. I actually tried! But gave up.
110. But @egletmt did it. Because he is a better hacker than me Or maybe because he is young and brave
111. eagletmt/fast_haml
112. Already gemified % gem i fast_haml
113. Benchmark
114. The Result (100 requests) ERB: 27135.9 msec Haml: 29116.8 msec HamlX: 27407.7 msec FastHaml: 23769.8 msec
115. Possibly Faster Than Slim
116. Still an Experimental Project Nobody uses this in production, I guess
117. I know that the name is terrible "Naming matters."
118. Worth Trying This If you're really sure that your system's bottleneck lies in the template engine If you want to experience the world's fastest Template engine
119. A Quest for the Ultimate Template Engine
120. The Ultimate Template Engine Developer Experience Sane Syntax End User Experience Runtime Performance
121. We're getting close! Stay tuned!
122. Or, YOU can do it, of course.
123. YOU can do it! YOU can patch YOU can create your own engine Rather than just sitting and waiting and complaining