The World Runs on Bad Software

Transcript

1. Brandon Keepers Lone Star Ruby Conference V August 12, 2011 BAD the world runs on software Ordered List
3. @bkeepers I
4. opensoul.org I
6. group therapy
9. pride
10. craftsman
11. art
12. I
13. get.harmonyapp.com
14. get.gaug.es
15. speakerdeck.com
17. I — GOOD CODE!
18. not perfect
19. :(
20. HAS NOT IMPLODED
21. HAS NOT IMPLODED yet ^
22. RUNS
23. in spite of
24. because of
25. bad software
26. pragmatism perfection
27. What is good software? How does it go bad? How do we build better software?
28. good software
29. “ Good software meets the present objective at an acceptable cost without incurring an unacceptable amount of future risk.
30. adequacy
31. !mediocrity
32. objective
33. software != code
34. “ Zach Dennis Mutually Human Software People fail to realize that quality is merely a property of the code that exists, not the reason for its existence.
35. users don’t care
36. “ Scott Berkun We’re frustrated most in life by things that come close to our deepest needs, but don’t deliver.
37. cost
38. “ Ray Yeargin Virtually all of the cost of software development is, directly and indirectly, the cost of design.
39. Production almost zero of
40. $$$$
41. $$$
42. $$
43. $
45. risk
46. !science
47. ‑Risk ‐Cost
48. What is good software? How does it go bad? How do we build better software?
49. entropy
50. “ The Pragmatic Programmer While software development is immune from almost all physical laws, entropy hits us hard.
51. why?
52. software is malleable
54. software is complex
55. rake stats
56. 2.5 million parts
58. software is immature
60. software is opaque
61. software is durable
63. What is good software? How does it go bad? How do we build better software?
64. better software? how do we build
65. talk to your users
66. automated testing
67. insurance policy
68. automation computers are good at
70. DRY
72. refactoring small, incremental
73. What is good software? How does it go bad? How do we build better software?
74. Examples
75. method_missing
76. class NilClass def method_missing(method, *args) nil end end
77. >> nil.foo.bar => nil >> nil + 5 => nil >> 5 + nil TypeError: coerce must return [x, y]
79. performance maintenance
80. def to_xml(options={}) root_tag = options.fetch(:root, 'game') instruct = options[:skip_instruct] ? '' : XML_INSTRUCT # … # gather up a bunch of variables # … <<-EOF #{instruct} <#{root_tag}> <id>#{id}</id> <current-move-user-id>#{current_move_user_id}</ current-move-user-id> <created-by-user-id>#{created_by_user_id}</ created-by-user-id> <chat_session_id>0</chat_session_id> <is-matchmaking>#{is_matchmaking}</is-matchmaking> <was-matchmaking>#{was_matchmaking}</was- matchmaking> <moves-count>#{moves_count}</moves-count> <random-seed>#{random_seed}</random-seed>
81. #{instruct} <#{root_tag}> <id>#{id}</id> <current-move-user-id>#{current_move_user_id}</ current-move-user-id> <created-by-user-id>#{created_by_user_id}</ created-by-user-id> <chat_session_id>0</chat_session_id> <is-matchmaking>#{is_matchmaking}</is-matchmaking> <was-matchmaking>#{was_matchmaking}</was- matchmaking> <moves-count>#{moves_count}</moves-count> <random-seed>#{random_seed}</random-seed> <client-version>#{client_version}</client-version> <created-at>#{created_at.try(:xmlschema)}</ created-at> <users type="array">#{users_xml}</users> #{current_user_xml} #{moves_xml} #{chats_xml} </#{root_tag}> EOF end
82. commit fa779d9c2d1214e43ff497f386b51ebf3708346e Author: Brandon Keepers <brandon@collectiveidea.com> Date: Wed Sep 22 17:08:38 2010 -0400 First attempt at getting embedded callbacks working
83. def create_or_update run_callbacks(:before_save) if result = super run_callbacks(:after_save) end result end Rails 2
84. def create_or_update run_callbacks(:save) { super } end Rails 3
85. def run_callbacks(kind, options={}, &block) self.embedded_associations.each do |association| self.send(association.name).run_callbacks( kind, options, &block ) end end
86. def run_callbacks(callback, &block) embedded_docs = [] embedded_associations.each do |association| embedded_docs += association.target end block = embedded_docs.inject(block) do |chain, doc| if doc.class.respond_to?("_#{callback}_callbacks") lambda { doc.run_callbacks(callback, &chain) } else chain end end super callback, &block end
87. SystemStackError: stack level too deep from mongo_mapper/plugins/embedded_callbacks.rb:23:in `run_callbacks' from activesupport-3.0.9/lib/active_support/callbacks.rb:414:in `_run_create_callbacks' from activesupport-3.0.9/lib/active_support/callbacks.rb:94:in `send' from activesupport-3.0.9/lib/active_support/callbacks.rb:94:in `run_callbacks' from mongo_mapper/plugins/embedded_callbacks.rb:28:in `run_callbacks' from mongo_mapper/plugins/embedded_callbacks.rb:23:in `run_callbacks'
88. now what?
89. pragmatic
90. software is design
91. embrace constraints
92. engineering is design
93. craftsmanship is design
94. “ Glen Vanderburg Sometimes you have to move ahead with weak evidence and weak conclusions because you don't have time to prove them.
95. opportunity costs
96. be pragmatic
98. “ Ed Yourdon You can discipline yourself to write software that's good enough—good enough for your users, for future maintainers, for your own peace of mind. You'll find that you are more productive and your users are happier.
99. Ordered List Thank you! brandon@orderedlist.com Brandon Keepers Lone Star Ruby Conference V August 12, 2011 @bkeepers http://spkr8.com/t/7829
100. Credits Power lines - http://www.flickr.com/photos/viamoi/3339707547/ House of cards - http://www.flickr.com/photos/gibbons/2294374741/ Dentists office - http://www.flickr.com/photos/cmdrcord/4996672560/ Broken chair - http://www.flickr.com/photos/gorbould/3004789912/ Schematics - http://www.flickr.com/photos/nicklockey/4547935355/ Engineers - http://www.flickr.com/photos/seattlemunicipalarchives/4818952324/ Black box - http://goldberg.berkeley.edu/art/big-images/