Journey of Feature Flag development in LINE Android

Hidetsugu Tamaki
LINE App Dev Team3 Software Engineer
https://linedevday.linecorp.com/jp/2019/sessions/D2-4

Transcript

1. 2019 DevDay Journey of Feature Flag Development in LINE Android > Hidetsugu Tamaki > LINE App Dev Team3 Software Engineer
2. > LINE Android development Hidetsugu Tamaki Introduction > Apr. 2018 ~
3. Agenda > Pain Points of Feature Branches > Benefits of Feature Flags > History of Feature Flags in LINE Android
4. Agenda > Pain Points of Feature Branches > Benefits of Feature Flags > History of Feature Flags in LINE Android
5. Feature Branch Main branch
6. Feature Branch Main branch Feature branch
7. Feature Branch Main branch Feature branch Pull requests
8. Feature Branch Main branch Feature branch Pull requests
9. LINE Android Project Developers 100 Changes per week in LoC 20,000
10. Feature Branches in Large Applications Main branch Feature branches
11. Agenda > Pain Points of Feature Branches > Benefits of Feature Flags > History of Feature Flag in LINE Android
12. Feature Flag Strategy Main branch Sticker feature PRs
13. Feature Flag Strategy Main branch Sticker feature PRs
14. Feature Flag Strategy Main branch Sticker feature PRs
15. Feature Flag Usage > View visibility . .
16. Feature Flag Usage > Activity I B CG CG ) G E )B = .( . ((. L CG CG G F . = C G I GK B FF I BF L CG CG G F B: = C G I GK B FF I > View visibility FG A E GG C F F B ) G E )B = )( ( ,(
17. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
18. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
19. Conflict Minimization Main branch Sticker feature PRs
20. Conflict Minimization Main branch Sticker feature PRs Theme feature PRs
21. Conflict Minimization Main branch Sticker feature PRs Theme feature PRs Saved PRs Saved PRs
22. Conflict Minimization Main branch Sticker feature PRs Theme feature PRs Conflict Saved PRs Saved PRs
23. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
24. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
25. Smoother Release Schedule Management Main branch Sticker feature PRs
26. Smoother Release Schedule Management Main branch Release branches 1.0 Sticker feature PRs
27. Smoother Release Schedule Management Main branch Release branches 1.0 Sticker feature PRs
28. Smoother Release Schedule Management Main branch Release branches 1.0 2.0 Sticker feature PRs
29. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
30. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
31. Instant Toggling Main branch Release branch 1.0 Sticker feature PR
32. ✗ Instant Toggling Main branch Release branch 1.0 Critical issue Sticker feature PR
33. Instant Toggling Main branch Release branch 1.0 Critical issue Sticker feature PR Conflicting PR ✗
34. ✗ Instant Toggling Main branch Release branch 1.0 Critical issue Conflicting PR Sticker feature PR
35. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
36. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
37. Better Collaboration with Stakeholders Developer Planner Tester Designer Organization
38. Better Collaboration with Stakeholders Developer Planner Tester Designer Users Partners Organization
39. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
40. Feature Flags Achieve > Conflict minimization > Smoother release schedule management > Instant toggling > Better collaboration with stakeholders
41. Limitation of Feature Flags Not a “silver bullet” > Difficult to apply > Updating libraries > Overkill > Prototyping
42. Reference https://youtu.be/H81EEAZ4XAI Presented at DroidKaigi 2019 https://speakerdeck.com/line_developers/flag-based-feature-management
43. Agenda > Pain Points of Feature Branches > Benefits of Feature Flags > History of Feature Flags in LINE Android
44. Feature Flags in LINE Android > Started with a simple Gradle script (Dec. 2015) > Injects values into BuildConfig file > Loads values from a property file
45. Feature Flags in LINE Android > Started with a simple Gradle script (Dec. 2015) > Injects values into BuildConfig file A A A C= # . " A A A C= # " #. > Loads values from a property file
46. Feature Flags in LINE Android > Started with a simple Gradle script (Dec. 2015) > Injects values into BuildConfig file > Loads values from a property file
47. > Toggle flag by user name or app version > Toggle flag at runtime > Support Gradle submodule Growth of Feature Flags
48. > Toggle flag by user name or app version > Toggle flag at runtime > Support Gradle submodule Growth of Feature Flags
49. Module Structure of LINE Android line-android-app submodule-sticker Product Flavor Product Flavor 
    
50. Module Structure of LINE Android line-android-app submodule-sticker Product Flavor Product Flavor 
     dev, beta, rc, release debug, release
51. Initial Feature Flags Implementation line-android-app FeatureFlag script Flag Property File Product Flavor Refers to Product Flavor submodule-sticker 
    
52. Initial Feature Flags Implementation line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java Injects values into Product Flavor submodule-sticker Refers to 
    
53. Misused Feature Flags in Submodules line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script Product Flavor BuildConfig.java submodule-sticker Refers to Injects values into Refers to Injects values into 
    
54. Misused Feature Flags in Submodules line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script Product Flavor BuildConfig.java submodule-sticker Back reference 
     Refers to Injects values into Refers to Injects values into
55. Misused Feature Flags in Submodules line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script Product Flavor BuildConfig.java dev, beta, rc, release debug, release submodule-sticker Back reference 
     Refers to Injects values into Refers to Injects values into
56. Misused Feature Flags in Submodules line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script Product Flavor BuildConfig.java dev, beta, rc, release debug, release submodule-sticker Back reference 
     Refers to Injects values into Refers to Injects values into
57. Misused Feature Flags in Submodules line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script Product Flavor BuildConfig.java package com.linecorp.line package com.linecorp.sticker dev, beta, rc, release debug, release submodule-sticker Back reference 
     Refers to Injects values into Refers to Injects values into
58. Problems of Misuse > Caused by BuildConfig.java and product flavors > Generated wrong values > Caused by back reference > Submodules were no longer standalone
59. Problems of Misuse > Caused by BuildConfig.java and product flavors > Generated wrong values > Caused by back reference > Submodules were no longer standalone
60. Workaround for Wrong Flag Values Simplified references by extracting Feature Flags into a module
61. Workaround for Wrong Flag Values line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script Product Flavor BuildConfig.java submodule-sticker Back reference 
     Refers to Injects values into Refers to Injects values into
62. Workaround for Wrong Flag Values line-android-app FeatureFlag script Flag Property File Product Flavor BuildConfig.java FeatureFlag script feature-flag BuildConfig.java Refers to submodule-sticker 
     Refers to Injects values into Injects values into
63. Workaround for Wrong Flag Values BuildConfig.java BuildConfig.java Injects values into Injects values into package com.linecorp.line package com.linecorp.sticker
64. Workaround for Wrong Flag Values FeatureFlag.java FeatureFlag.java Creates Creates package com.linecorp.line package com.linecorp.line
65. Workaround for Wrong Flag Values line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java FeatureFlag script feature-flag FeatureFlag.java Refers to submodule-sticker 
     Refers to Creates Creates
66.   
     Workaround for Wrong Flag Values line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java FeatureFlag script feature-flag FeatureFlag.java Refers to submodule-sticker      Refers to Creates Creates
67. Workaround for Wrong Flag Values line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java submodule-sticker 
     Refers to Creates
68. Things Got Worse > Tricky usage of `  
      > Wrong dependencies still remain > Poor compatibility with automated testing
69. Things Got Worse > Tricky usage of `  
      > Wrong dependencies still remain > Poor compatibility with automated testing
70. Things Got Worse > Tricky usage of `  
      > Wrong dependencies still remain > Poor compatibility with automated testing
71. Things Got Worse > Tricky usage of `  
      > Wrong dependencies still remain > Poor compatibility with automated testing
72. Things Got Worse > Tricky usage of `  
      > Wrong dependencies still remain > Poor compatibility with automated testing
73. Proper Solution Isolated dependencies by processing flags within modules
74. Proper Solution line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java submodule-sticker 
     Refers to Creates
75. Proper Solution line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java submodule-sticker 
     Refers to FeatureFlag script Flag Property File Product Flavor FeatureFlag.java Refers to Creates Creates
76. Flag Property File Product Flavor Proper Solution debug, release
77. FeatureFlag.java FeatureFlag.java Proper Solution package com.linecorp.line package com.linecorp.sticker
78. Proper Solution line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java submodule-sticker 
     Refers to FeatureFlag script Flag Property File Product Flavor FeatureFlag.java Refers to Links to Creates Creates
79. Proper Solution line-android-app FeatureFlag script Flag Property File Product Flavor FeatureFlag.java submodule-sticker 
     Refers to FeatureFlag script Flag Property File Product Flavor FeatureFlag.java Refers to Links to Refers to Creates Creates
80. Link to Submodule Flag Values &, - B = B A: &, - &, - line-android-app submodule-sticker
81. )& ) ,) () CC )-)& ) = A: )& ) ,) -& ) Property Parsing: Format )& ) ,) () )-)& ) = A: )& ) ,) -& ) > Written with “disjunctive normal form” style property
82. Property Parsing: Phase > Enabled if build variant is 
     Phase
     Phase > Enabled if build variant is   
83. Property Parsing: Value Calculation : E variant )( ( & ( ( ( ( ( CE A E : CD= : )( ( & ( - ( )( ( & ( D E: C: CE A E : CD= : )( ( & ( - ( F )( ( & ( D E: Optimization Phase resolution
84. Property Parsing: Value Calculation : E variant )( ( & ( ( ( ( ( CE A E : CD= : )( ( & ( - ( )( ( & ( D E: C: CE A E : CD= : )( ( & ( - ( F )( ( & ( D E: Optimization Phase resolution
85. Property Parsing: Value Calculation : E variant )( ( & ( ( ( ( ( CE A E : CD= : )( ( & ( - ( )( ( & ( D E: C: CE A E : CD= : )( ( & ( - ( F )( ( & ( D E: Optimization Phase resolution
86. Property Parsing: Value Calculation : E variant )( ( & ( ( ( ( ( CE A E : CD= : )( ( & ( - ( )( ( & ( D E: C: CE A E : CD= : )( ( & ( - ( F )( ( & ( D E: Optimization Phase resolution
87. Property Parsing: Value Calculation )& ) ) () )-)& ) F AC: F E )& ) ) .-& ) )& ) ) F E F AC: F E )& ) ) .-& ) )& ) ) F AC: F E )& ) ) Optimization Variant resolution E F variant Package name extraction I )& ) ) CA CED F E E = )& ) )
88. Property Parsing: Value Calculation )& ) ) () )-)& ) F AC: F E )& ) ) .-& ) )& ) ) F E F AC: F E )& ) ) .-& ) )& ) ) F AC: F E )& ) ) Optimization Variant resolution E F variant Package name extraction I )& ) ) CA CED F E E = )& ) )
89. Property Parsing: Value Calculation )& ) ) () )-)& ) F AC: F E )& ) ) .-& ) )& ) ) F E F AC: F E )& ) ) .-& ) )& ) ) F AC: F E )& ) ) Optimization Variant resolution E F variant Package name extraction I )& ) ) CA CED F E E = )& ) )
90. Property Parsing: Value Calculation )& ) ) () )-)& ) F AC: F E )& ) ) .-& ) )& ) ) F E F AC: F E )& ) ) .-& ) )& ) ) F AC: F E )& ) ) Optimization Variant resolution E F variant Package name extraction I )& ) ) CA CED F E E = )& ) )
91. Property Parsing: Value Calculation )& ) ) () )-)& ) F AC: F E )& ) ) .-& ) )& ) ) F E F AC: F E )& ) ) .-& ) )& ) ) F AC: F E )& ) ) Optimization Variant resolution E F variant Package name extraction I )& ) ) CA CED F E E = )& ) )
92. Results > Gradle plugin instead of script > Simplified dependencies > Correct feature flag values in submodules
93. Results > Gradle plugin instead of script > Simplified dependencies > Correct feature flag values in submodules
94. Results > Gradle plugin instead of script > Simplified dependencies > Correct feature flag values in submodules
95. Results > Gradle plugin instead of script > Simplified dependencies > Correct feature flag values in submodules
96. Available Today > https://github.com/line/feature-flag-android
97. Summary > Solved pain points of feature branches with feature flags > Gradle plugin for Android is now available
98. Thank You