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
2. None

3. @bkeepers I

4. opensoul.org I

5. None

6. group therapy

7. None
8. None

9. pride

10. craftsman

11. art

12. I

13. get.harmonyapp.com

14. get.gaug.es

15. speakerdeck.com

16. None

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. $

44. None

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

53. None

54. software is complex

55. rake stats

56. 2.5 million parts

57. None

58. software is immature

59. None

60. software is opaque

61. software is durable

62. None

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

69. None

70. DRY

71. None

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]
78. None

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

97. None

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/