Faster builds on Android - from 2 minutes to 2 seconds

What does a developer do when a build takes 2 minutes? He gets bored and his mind starts to wander. Maybe he opens Reddit, Twitter orMedium or checks his emails. Switching context and multitasking kills productivity. Every developer needs fast feedback, so he can get jump into the flow state. Therefore, fast builds are essential for productive development.

First, we take a look into Gradle Build Scans. There is no sense in accelerating your build without measuring and comparing the different outcomes. Gradle Build Scans help you to understand what happens during your build and which parts consume the most time.

Then we continue with basic tips to tweak your build with Gradle. Most of those tips are quick wins, because they only require a simple change in the Gradle build settings.

Finally, we take a look into how modularisation influences the build speed by an example. Doing it right you can change your business logic and run your tests in 2 seconds instead of 2 minutes.

Transcript

1. Faster Builds on Android From 2 Minutes to 2 Seconds @muffls Philipp Hofmann
2. @muffls Philipp Hofmann
3. Make diabetes suck less
4. Why is build speed important? Photo by Chris Liverani on Unsplash
5. How often do you hit compile?
6. 10 - 100 times per day?
7. From 2 minutes to 2 seconds.
8. We save 118 seconds.
9. Around 20 minutes to 2 hours per day.
10. Around 1,6 to 10 hours per week.
11. Reduce by 5 seconds.
12. 20 builds * 5s * 10 devs * 5 days = 1,4 hours / week
13. 100 builds * 5s * 10 devs * 5 days = 9,6 hours / week
14. What do you do when you have to wait 2 minutes? Photo by NordWood Themes on Unsplash
15. Or just 20 seconds? Photo by NordWood Themes on Unsplash
17. Photo by Stefan Cosma on Unsplash
18. Multitasking is killing your brain.
19. Multitasking lets your IQ drop significantly.
20. Like skipping whole night sleep.
21. Or smoking weed. Image Source
22. Knowing there is an unread email can reduce your IQ by 10 points!
23. Multitasking is especially bad for men.
24. It can reduce the IQ up to 15 points.
25. Turning you into a cognitive equivalent of an 8-year-old.
26. Multitasking Is Killing Your Brain CREDIT: Getty Images
27. Slow Builds = Slow Tests Test automation is a pain.
28. Faster Builds
29. Faster Builds = More Frequent Feedback
30. Faster Builds = More Frequent Feedback = Faster Development
31. • Measure Your Builds • Quick Wins to Fasten Your Builds • Modularisation and Build Speed • Some additional information about the topic on the chart • Maybe some numbers or a background information about some insights • Here is just another placeholder text to visualise the look of a filled info box INFO BOX Topics
32. Measure Your Builds Photo by Annie Spratt on Unsplash
33. $ ./gradlew clean cleanBuildCache
34. $ ./gradlew assembleDebug --scan
35. $ ./gradlew assembleDebug --scan BUILD SUCCESSFUL in 1s 84 actionable tasks: 84 up-to-date Publishing a build scan to scans.gradle.com requires accepting the Gradle Terms of Service defined at https:// gradle.com/terms-of-service. Do you accept these terms? [yes, no]
36. $ ./gradlew assembleDebug --scan BUILD SUCCESSFUL in 1s 84 actionable tasks: 84 up-to-date Publishing a build scan to scans.gradle.com requires accepting the Gradle Terms of Service defined at https:// gradle.com/terms-of-service. Do you accept these terms? [yes, no] yes
37. $ ./gradlew assembleDebug --scan BUILD SUCCESSFUL in 1s 84 actionable tasks: 84 up-to-date Publishing a build scan to scans.gradle.com requires accepting the Gradle Terms of Service defined at https:// gradle.com/terms-of-service. Do you accept these terms? [yes, no] yes Gradle Terms of Service accepted.
38. $ ./gradlew assembleDebug --scan BUILD SUCCESSFUL in 1s 84 actionable tasks: 84 up-to-date Publishing a build scan to scans.gradle.com requires accepting the Gradle Terms of Service defined at https:// gradle.com/terms-of-service. Do you accept these terms? [yes, no] yes Gradle Terms of Service accepted. Publishing build scan...
39. $ ./gradlew assembleDebug --scan BUILD SUCCESSFUL in 1s 84 actionable tasks: 84 up-to-date Publishing a build scan to scans.gradle.com requires accepting the Gradle Terms of Service defined at https:// gradle.com/terms-of-service. Do you accept these terms? [yes, no] yes Gradle Terms of Service accepted. Publishing build scan... https://gradle.com/s/glklref6wdxr6
44. Create Build Scans https://guides.gradle.org/creating-build-scans/
45. Profile Your Build https://developer.android.com/studio/build/optimize-your-build#profile
46. $ ./gradlew assembleDebug --profile
49. Gradle Profiler https://github.com/gradle/gradle-profiler
50. Talaiot https://github.com/cdsap/Talaiot
52. Measure Optimise
53. Quick Wins to Fasten Your Builds Photo by Richard R Schünemann on Unsplash
54. Update your Tools Photo by Todd Quackenbush on Unsplash
55. Update Gradle
58. Improving build speed in Android Studio https://medium.com/androiddevelopers/improving-build-speed-in-android- studio-3e1425274837
59. Update JVM
60. Update Android Studio and SDK Tools
61. Update Android Plugin for Gradle
62. • Gradle • JVM • Android Studio and SDK Tools • Android Plugin for Gradle Update
63. Use Apply Changes
64. For devices and emulators running on Android 8.0 or newer.
65. gradle.properties
66. Caching org.gradle.caching=true
67. If neither a task’s inputs nor its output have changed since the last time it was run, Gradle will not run it again.
68. Enabled by default. Since Android Plugin 2.3.0 https://developer.android.com/studio/build/build-cache
70. Gradle Build Cache https://docs.gradle.org/current/userguide/build_cache.html
71. Incremental Compilation kotlin.incremental=true
72. Incremental annotation processor kapt.incremental.apt=true
73. Parallel Builds org.gradle.parallel=true
74. Create a build variant for development
75. flavorDimensions "mode" productFlavors { dev { dimension "mode" resConfigs "en", "xxhdpi" buildConfigField "long", "TIMESTAMP", "0L" } full { dimension "mode" } }
76. Quick wins 1. Update your Tools 2. Use Apply Changes 3. Caching 4. Incremental Compilation 5. Parallel Builds 6. Build Variant for Develop Photo by Richard R Schünemann on Unsplash
77. More Stuff
78. Scope annotation processing
79. Apply only needed plugins
80. apply plugin: 'com.android.application' apply plugin: 'kotlin-android' apply plugin: 'kotlin-android-extensions' apply plugin: 'maven-publish' apply plugin: 'kotlin-kapt' apply plugin: 'talaiot' apply plugin: 'io.gitlab.arturbosch.detekt' apply plugin: 'org.jlleitschuh.gradle.ktlint'
81. Optimize your build speed https://developer.android.com/studio/build/optimize-your-build
82. Improving the Performance of Gradle Builds https://guides.gradle.org/performance/
83. Check your memory settings org.gradle.jvmargs= -Xmx3g -XX:MaxPermSize=2048m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
84. Java Performance Tuning https://dzone.com/articles/java-performance-tuning
85. 19 tips for Gradle in Android projects — 2019 Edition https://medium.com/google-developer-experts/19-tips-for-gradle-in-android- projects-2019-edition-11af704eb06e
86. Modularisation and Build Speed
87. Modules can speed up your build, but can also slow down your build.
88. 1. Build modules in parallel
93. Example
94. Small app with one module.
98. Optimise • Update gradle and gradle plugin • Update Kotlin • Enable parallel builds and incremental compilation • Split up code into multiple modules
100. Reduced build time for around 25%.
101. 2. Compilation avoidance
104. A taste of bluetooth.
105. Change Run
108. 18 seconds when in layout
109. 7 seconds when in Fragment
110. Change Run
113. 6 seconds when in layout
114. 3 seconds when in Fragment
115. Change Run
116. 65 seconds
117. Change Run
118. Change Run
119. 65 seconds
120. 9 seconds
121. Build just what you need • Build only the code you want to check. • Let you iterate faster on your feature modules.
122. api implementation vs
123. api implementation Module A Module B
124. Module A Module B Module C Foo api
125. Module A Module B Module C Foo api
126. Module A Module B Module C Foo api
127. Module A Module B Module C Foo implementation Module A Module B Module C Foo api
128. Module A Module B Module C Foo implementation Module A Module B Module C Foo api
129. Module A Module B Module C implementation Foo Module A Module B Module C Foo api
130. Module A Module B Module C Foo implementation Module A Module B Module C Foo api
131. Module A Module B Module C implementation Foo Module A Module B Module C Foo api
132. Module A Module B Module C Foo implementation Module A Module B Module C Foo api ModuleB is part of my Public API ModuleB is my Implementation Detail
133. Module A Module B Module C Foo implementation Module A Module B Module C Foo api ModuleB is part of my Public API ModuleB is my Implementation Detail
134. Module A Module B Module C Foo implementation Module A Module B Module C Foo api ModuleB is part of my Public API ModuleB is my Implementation Detail
135. @FMuntenescu Florina Muntenescu
136. 3. Faster Tests
137. Run tests 15 seconds
138. Run tests 4 seconds
139. I promised 2 seconds.
140. Plain Kotlin or Java No Android dependencies
142. https://medium.com/google-developer-experts/19-tips-for-gradle-in-android-projects-2019-edition-11af704eb06e :libjava:assemble of the base java plugin
143. https://medium.com/google-developer-experts/19-tips-for-gradle-in-android-projects-2019-edition-11af704eb06e :lib1:assembleDebug of the com.android.library
144. Create pure Java Kotlin / Libraries
145. Advantages of Multiple Modules
146. Advantages of Multiple Modules 1. Build modules in parallel 2. Compilation avoidance 3. Faster tests 4. And all the other advantages … (Reusability, Maintainability, SOLID, …)
147. Spotify has over 600 modules.
148. Modularisation - How hard can it be? (Droidcon London 2018)
149. Sum it up
150. Faster Builds = Faster Development Photo by Andrea Leopardi on Unsplash
151. Photo by Richard R Schünemann on Unsplash Quick wins 1. Update your tools 2. Use Apply Changes 3. Use Gradle caching 4. Incremental compilation 5. Parallel builds 6. Build variant for develop
152. Modules can speed up your build, but can also slow down your build.
153. Advantages of multiple modules 1. Build modules in parallel 2. Compilation avoidance 3. Faster tests
154. Create pure Java Kotlin / Libraries
155. I optimise the build speed!
156. Measure Optimise
157. @muffls Philipp Hofmann
158. Droidcon Turin 2019
159. @muffls Philipp Hofmann Questions?