Practical Modularisation for Android Developers

How can you use Gradle and an extremely opinionated module structure to reduce your build times?

Transcript

1. Practical modularisation for Android developers Jordan Terry 1
2. Agenda • Introduction • What is modularisation? • What is your codebase? • Cohesion, Coupling & Gradle • Build times • Reusability • Defining a strategy • Questions? 2
3. 3 Introduction 🇹 Then Now 2015 2018 2021 @JordNullable
4. What is modularisation? 4
5. 5 What is modularisation? Large system Modules
7. 7 Android modularisation Large System Modules Codebase Gradle Modules
8. Talking about modularisation 8
9. The benefits of modularisation 9 Build Times Reusability
10. What is your codebase? 10 • Define a way to measure modularisation • Apply that to your codebase
11. 11 Monolithic Modular What is your codebase? You are somewhere here…
12. 12 Monolithic Modular What is your codebase? = code base with a module that takes more time to compile than other modules = code base with no modules that take more time to compile than the sum of other modules
13. What is your codebase? 13 Monolithic Modular
14. 14 Monolithic Very Modular What is your codebase? Modular
16. Cohesion, Coupling & Gradle 16
17. High Cohesion Low Cohesion Cohesion 17 Low Cohesion High Cohesion
18. High Coupling Low Coupling Coupling 18 Low Coupling High Coupling
19. Gradle 19 • Module definition • Connecting Modules • Incremental Compilation
20. 20 import ':app' import ':login' import ':profile' import ':networking' import ':okhttp' settings.gradle.kts app/ -> login/ -> src/ -> build.gradle.kts -> profile/ -> src/ -> build.gradle.kts -> networking/ -> src/ -> build.gradle.kts -> okhttp/ -> src/ -> build.gradle.kts -> settings.gradle.kts app/ -> login/ -> src/ -> build.gradle.kts -> profile/ -> src/ -> build.gradle.kts -> networking/ -> src/ -> build.gradle.kts -> okhttp/ -> src/ -> build.gradle.kts -> settings.gradle.kts app/ -> login/ -> src/ -> build.gradle.kts -> profile/ -> src/ -> build.gradle.kts -> networking/ -> src/ -> build.gradle.kts -> okhttp/ -> src/ -> build.gradle.kts -> settings.gradle.kts app/ -> login/ -> src/ -> build.gradle.kts -> profile/ -> src/ -> build.gradle.kts -> networking/ -> src/ -> build.gradle.kts -> okhttp/ -> src/ -> build.gradle.kts -> settings.gradle.kts build.gradle.kts plugins { id("kotlin-android") } android { ... } dependencies { ... } Defining Modules
21. 21 :networking :login :profile :okhttp :app Defining modules
22. dependencies { implementation project(":login") implementation project(":profile") } 22 app/build.gradle.kts Connecting modules
23. 23 :networking :login :profile :okhttp :app Connecting Modules
24. :profile :profile 24 :profile Incremental compilation
25. :login :profile :profile :login :networking :networking 25 :okhttp :app Incremental compilation
26. The benefits of modularisation 26 Build Times Reusability
27. Incremental Build times 27 • How important are build times? • When incremental build times go wrong • Some tips on cohesion
28. XKCD 303 - https://xkcd.com/303/ 28 Build Times
29. @vRallev on Twitter - https://mobile.twitter.com/vRallev/status/1485430862850125824 29 Build Times
30. @softwarejameson on Twitter - https://twitter.com/softwarejameson/status/1455971162060697613?lang=en 30 Build Times
31. Build times 600 engineers * $1.42/minutes * 42 builds/week * 44 work weeks/year = $1,600,000/year 31 Gradle vs Maven: Performance Comparison - https://gradle.org/gradle-vs-maven-performance/ Money Saved Equation
32. :timelines :profile :login :network models 32 Build times - comparing structures :app :timelines :login :profile :networking :networking :network models
33. :timelines :login :login models :profile models :timeline models :profile :networking 33 Build times - comparing structures :app :timelines :login :profile :networking :login models :profile models :timeline models :json
34. Reusability 34 • What are reusable components • Reusable libraries • Reusable modules
35. Reusability 35 OkHttp Play Billing Toast API
36. :timelines :profile :okhttp-4 :login Reusability - Third Parties 36 :timelines :login :profile :okhttp-3 :okhttp-4 :networking :networking :okhttp-3
37. :navigation :navigation jetpack :navigation compose :login :timelines :timelines :login :profile :profile Reusability - APIs & Implementations 37 :navigation :api :navigation: impl compose :navigation: impl jetpack :navigation :impl
38. A modularisation strategy 38 • Training • Discipline ◦ Cohesion & Coupling
39. Coming up with a plan 39 :foundation :feature :feature :feature :feature High Cohesion Low Coupling
40. Where to find me? 40 • @JordNullable
41. Any questions? 41