Boris Farber & Nikita Kozlov - The_Build_Side_of_Android_App

1. The Build Side of an Android App Nikita Kozlov Zalando SE @Nikita_E_Kozlov Boris Farber Google @borisfarber
2. Background • Build improvement is the most requested feature from developers • Worked with a few companies to speed up their builds • Share best practices and patterns
3. Problem • You add new features, libraries and frameworks. • You refactor your code to smaller classes, add tests • Somehow, the build times add up
4. We don’t think about our build as a design component
5. Build challenge • Analysing build takes time • Difficult to estimate and prioritize • Build improvement might be ambiguous
6. Focus on following • Build Tools versions • Hardware • Modularization
7. Our process Create a test project Implement suggestion Test & Measure Implement within a real project Android Studio Poet Gradle Profiler*
8. Incremental build change a Java/Kotlin file assembleDebug
9. Build Tools versions
10. Versions we tested • Gradle: 4.3.1 to 4.8 • Android Gradle Plugin: from 3.0.1 to 3.1.2 • Kotlin: from 1.1.60 to 1.2.50
11. What about Build Tools versions? 2x speed up just from the build tools
12. Another easy win From the build scan: • Compilation - 35% • Dexing - 55%
13. Dexing is a limiting step .CLASS .CLASS .CLASS .DEX .DEX .DEX Will be faster if min SDK is 21 .CLASS
14. Incremental build with min SDK 21 Set min SDK to 21 during development to increase your build speed
15. Better Hardware
16. Hardware MacBook Pro 2015 • 13-inch • 2.7 GHz Intel Core i5 • 16 GB 1867 MHz DDR3 MacBook Pro 2017 • 15-inch • 2,8 GHz Intel Core i7 • 16 GB 2133 MHz LPDDR3 vs
17. Hardware • Better hardware reduces build time significantly • Sometimes even more than modularization
18. Background processes matters • Background processes reduces build time • Antivirus made build speed 3 times slower
19. Modularization
20. Modularization - theory Module 2 Module 3 Module 1 App Module App Module Key principles: 1. Parallelization 2. Caching 3. Compile avoidance
21. Compile Avoidance App Feature Incremental build after a change of method’s body in Feature: 8s Incremental build after a adding a public method to Feature: 10s
22. Extracting rarely-changed code reduces build time App Incremental build with a change in App: 55s Incremental build with a change in App: 39s App Utils
23. Work against tests whenever you can App Incremental build of App with a change in App: 55s Incremental build of Utils module: 26s App Utils
24. Change in the library module vs application module App Utils Incremental build of App module: 39s Incremental build of Utils module: 26s
25. Intermodule dependencies increase build time Incremental build with change in Feature 3: 1m 5s Incremental build with change in Feature 3: 1m 11s Feature 1 Feature 3 Feature 2 App Feature 2 Feature 3 Feature 1 App
26. Start simple if you don’t have time App Tracking Utils Core UI Networking App Feature Feature Feature Common code
27. Use a topology that works for you App App Monolith Incremental build with change in App: 81s Incremental build with change in Main: 92s
28. Use a topology that works for you App Feature App Monolith Feature Incremental build with change in Feature: 10s Incremental build with change in Feature: 7s
29. Modularization rules of thumb • Extract utils and other rarely-changed code • Keep in mind the intermodule dependencies • Developing library modules in TDD way helps • Measure on a test project first
30. Our process Create a test project Implement suggestion Test & Measure Implement within a real project Android Studio Poet Gradle Profiler
31. • Tool to generate large self contained Android projects • https://github.com/android/android-studio-poet • Accepts JSON config file for the parameters Android Studio Poet
32. Features Java Butterknife Kotlin External Libraries Gradle Plugins Flavours Build Types Intermodule dependencies Build Tools versioning String resources Images Layouts Activities Data Binding External repositories Dependency visualization Packages Classes Methods Fields
33. Two input formats Compact Full
34. Demo
35. Learn more • Extend Android Studio Poet - https://github.com/android/android-studio-poet/blob/master/exten d/Extending.md • For this talk we made about 50 configs and more then 500 builds • Our configs, we used for this presentation https://github.com/android/android-studio-poet/tree/master/config s
36. Thanks ! And to Sergio Murguia, Google and Stefan Oehme, Gradle
37. Questions ? Nikita Kozlov Zalando SE @Nikita_E_Kozlov Boris Farber Google @borisfarber