Wrap every method with just one line

Feature Flag 基盤構築の一環として実装したサーバーサイドロジックの紹介です。
Ruby において include するだけですべての method をトラップして実装を差し込む手法を用いて、クライアントにサーバーサイドロジックの一部を確認/上書きできる用になります。

Transcript

1. ©2020 Wantedly, Inc. Wrap every method With just another line Meguro.rb#30 Jan 31, 2020 - Shimpei Otsubo
2. ©2020 Wantedly, Inc. Shimpei Otsubo @potsbo Developer Experience Squad, Wantedly, Inc. Kubernetes Dev Tools CI / CD AuthN / Z Productivity Dvorak
3. ©2020 Wantedly, Inc. AB ςετ͕೉͍͠໰୊ ςετ͕ͮ͠Β͘ͳΔ ࣗಈ΋खಈ΋ ޙΖଆͷϚΠΫϩαʔϏεͰߦ͏ͱ؅ཧෆೳ Ұ൪લͳΒ
   port-forward
   ͱ͔Ͱߦ͚Δ͕ʜ ˞αʔϏεϝογϡͰղܾ͍ͨ͠ϨΠϠͰ΋͋Δʜ $4
   ͕ࠞཚ ਓʹΑͬͯڍಈ͕ҟͳΔࣄ͕͋ͬͯ΋Կނ͔Θ͔Βͳ͍
4. ©2020 Wantedly, Inc. AB ςετΛ؆୯ʹτάϧͰ͖Δ
   extension
   ࡞ͬͨ ˞ը૾͸αϯϓϧͰ͢ ͲΜͳ
   flag
   Ͱࠓͷϖʔδ͕
   render
   ͞Ε͔ͨΘ͔Δ ͲΜͳ
   flag
   ͰࠓͷϖʔδΛ
   render
   ͯ͠΄͍͔͠ࢦఆͰ͖Δ
5. ©2020 Wantedly, Inc. Thread.current resp header middleware ͲΜͳ஋Λ࢖͔ͬͨʁΛ
   feedback ͲΜͳ஋Λ࢖ͬͯ΄͍͔͠ʁΛࢦఆ Thread.current req header Header Λհͯ͠ method
   ͷධՁ஋Λ read /write )FBEFS
   ͳͷͰ
   NJDSPTFSWJDF
   Ͱ఻ൖՄೳ call return
6. ©2020 Wantedly, Inc. ڵຯର৅ͷ
   NFUIPE
   ʹ͢΂ͯΛ
   IPPL
   ͢Δඞཁ͕͋Δ ͜ͷͨΊʹ͸
7. ©2020 Wantedly, Inc. class Experiment def self.enable?(name, target) # some consistent logic here end end Experiment.enable?(:show_new_button, current_user) # => true or false Wantedly ʹ͓͚Δ
   AB
   ςετͷํ๏ ಉҰͷ
   user
   ʹରͯ͠͸ৗʹಉҰͷ
   boolean
   ͕ฦΔ
   method
8. ©2020 Wantedly, Inc. Thread.current
   ͔Β
   user
   ͕ࢦఆͨ͠஋͕͋Ε͹ͦΕΛར༻ ͳ͚Ε͹
   Thread.current
   ʹར༻ͨ͠஋Λ٧ΊΔ class Experiment def self.enable?(name, target) # some consistent logic here end def self.wrapped_enable?(name, target) request_value = Thread.current[:request][name] return request_value unless request_value.nil? actual_value = enable?(name, target) Thread.current[:response][name] = actual_value end end ˞Thread.current
   ͱ
   header
   ͷؒΛͭͳ͙
   middleware
   Λผ్༻ҙ
9. ©2020 Wantedly, Inc. Rename
   ͯͦ͠ͷ··࢖͑ΔΑ͏ʹ͢Δ class Experiment def self.real_enable?(name, target) # some consistent logic here end def self.enable?(name, target) request_value = Thread.current[:request][name] return request_value unless request_value.nil? actual_value = real_enable?(name, target) Thread.current[:response][name] = actual_value end end
10. ©2020 Wantedly, Inc. ҰൠԽͯ͠ΈΔ class FeatureFlag def self.intercept(name) request_value = Thread.current[:request][name] return request_value unless request_value.nil? actual_value = yield Thread.current[:response][name] = actual_value end end class Experiment def self.real_enable?(name, target) # some consistent logic here end def self.enable?(name, target) FeatureFlag.intercept(name) do real_enable?(name, target) end end end ϒϩοΫͰғΈ͑͢͞Ε͹Ͳ͜Ͱ΋
    PWFSSJEF
    Մೳʂ
11. ©2020 Wantedly, Inc. ଞͷػೳͷग़͠෼͚ʹ΋࢖͑Δ͸ͣ
12. ©2020 Wantedly, Inc. Helper
    ͷ͍ΖΜͳ
    method ͰػೳΛग़͠෼͚͍ͯ͠Δ৔ॴ͕͋Δ module I18nHelper # the new landing page currently supports only Japanese!! def show_new_landing_page? I18n.locale == :ja end end
13. ©2020 Wantedly, Inc. ϒϩοΫͰғΉ͚ͩͰ
    XSBQ
    Ͱ͖Δ class FeatureFlag def self.intercept(name) ... end end module I18nHelper # the new landing page currently supports only Japanese!! def show_new_landing_page? FeatureFlag.intercept(:show_new_landing_page?) do I18n.locale == :ja end end end
14. ©2020 Wantedly, Inc. ϒϩοΫͰғΉ͚ͩͰ
    XSBQ
    Ͱ͖Δ class FeatureFlag def self.intercept(name) ... end end module I18nHelper # the new landing page currently supports only Japanese!! def show_new_landing_page? FeatureFlag.intercept(:show_new_landing_page?) do I18n.locale == :ja end end end ຖճॻ͘ͷ͸ྲྀੴʹ໘౗
15. ©2020 Wantedly, Inc. class FeatureFlag def self.intercept(name) ... end end module I18nHelper # the new landing page currently supports only Japanese!! def show_new_landing_page? FeatureFlag.intercept(:show_new_landing_page?) do I18n.locale == :ja end end end खಈͰίʔυΛ͍͡ΔͷͰ͸ͳ͘
16. ©2020 Wantedly, Inc. class FeatureFlag def self.intercept(name) ... end end module I18nHelper include FeatureFlag def show_new_landing_page? I18n.locale == :ja end end *ODMVEF
    ͚ͩͰղܾͰ͖ͨΒ޾ͤ Ұߦ௥Ճ͢Δ͚ͩʂʂ
17. ©2020 Wantedly, Inc. Ͱ͖ΔΑ͏ʹͨ͠ module FeatureFlag def self.included(base) base.class_eval do extend ClassMethods @_already_patched = [] @_patch_target = base end end module ClassMethods def intercept(name) ... end def method_added(name) if !@_already_patched.include?(name) && self == @_patch_target orig_method_name = "_#{base}_orig".to_sym @_already_patched << name @_already_patched << orig_method_name alias_method orig_method_name, name
18. ©2020 Wantedly, Inc. ॳظԽ module FeatureFlag def self.included(base) base.class_eval do extend ClassMethods @_already_patched = [] @_patch_target = base end end module ClassMethods def intercept(name) ... end def method_added(name) if !@_already_patched.include?(name) && self == @_patch_target orig_method_name = "_#{base}_orig".to_sym @_already_patched << name @_already_patched << orig_method_name alias_method orig_method_name, name Ͳͷ
    NPEVMF
    Ͱ
    JODMVEF
    ͨ͠ͷ͔͓֮͑ͯ͘
19. ©2020 Wantedly, Inc. module ClassMethods def intercept(name) ... end def method_added(name) if !@_already_patched.include?(name) && self == @_patch_target orig_method_name = "_#{base}_orig".to_sym @_already_patched << name @_already_patched << orig_method_name alias_method orig_method_name, name private orig_method_name define_method(name) do |*args| intercept(name) do send(old_name, *args) end end end super end end end ͢Ͱʹ
    XSBQ
    ͍ͯ͠ͳ͍͔ͷ֬ೝ
20. ©2020 Wantedly, Inc. module ClassMethods def intercept(name) ... end def method_added(name) if !@_already_patched.include?(name) && self == @_patch_target orig_method_name = "_#{base}_orig".to_sym @_already_patched << name @_already_patched << orig_method_name alias_method orig_method_name, name private orig_method_name define_method(name) do |*args| intercept(name) do send(old_name, *args) end end end super end end end طଘ࣮૷ͷୀආ
21. ©2020 Wantedly, Inc. module ClassMethods def intercept(name) ... end def method_added(name) if !@_already_patched.include?(name) && self == @_patch_target orig_method_name = "_#{base}_orig".to_sym @_already_patched << name @_already_patched << orig_method_name alias_method orig_method_name, name private orig_method_name define_method(name) do |*args| intercept(name) do send(old_name, *args) end end end super end end end 8SBQ
    ࣮૷
22. ©2020 Wantedly, Inc. αʔόʔͷڍಈ͕ݟ͑Δม͑ΒΕΔͱָ *ODMVEF
    ͚ͩͰ͢΂ͯͷ
    NFUIPE
    XSBQ
    ͸Մೳ ଞʹ΋͍Ζ͍Ζͳ֦ு͕Ͱ͖Δ ςετ΋σόοά΋ NFUIPE@BEEFE
    Ͱ௥Ճ͞Εͨ
    NFUIPE
    Λ͍͡Ε͹ྑ͍ XSBQ@POMZ
    GPP
    CBS
    ͱ͔΋࡞ΕΔ