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 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 through an example. By 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. Measure Optimise
50. Quick Wins to Fasten Your Builds Photo by Richard R Schünemann on Unsplash
51. Update your Tools Photo by Todd Quackenbush on Unsplash
52. Update Gradle
55. Improving build speed in Android Studio https://medium.com/androiddevelopers/improving-build-speed-in-android- studio-3e1425274837
56. Update JVM
57. Update Android Studio and SDK Tools
58. Update Android Plugin for Gradle
59. • Gradle • JVM • Android Studio and SDK Tools • Android Plugin for Gradle Update
60. Use instant run
61. Deploy to a device with Android API level 24 or higher.
62. gradle.properties
63. Caching org.gradle.caching=true
64. If neither a task’s inputs nor its output have changed since the last time it was run, Gradle will not run it again.
65. Enabled by default. Since Android Plugin 2.3.0 https://developer.android.com/studio/build/build-cache
67. Gradle Build Cache https://docs.gradle.org/current/userguide/build_cache.html
68. Incremental Compilation kotlin.incremental=true
69. Parallel Builds org.gradle.parallel=true
70. Create a build variant for development
71. flavorDimensions "mode" productFlavors { dev { dimension "mode" resConfigs "en", "xxhdpi" buildConfigField "long", "TIMESTAMP", "0L" } full { dimension "mode" } }
72. Quick wins 1. Update your Tools 2. Use Instant Run 3. Caching 4. Incremental Compilation 5. Parallel Builds 6. Build Variant for Develop Photo by Richard R Schünemann on Unsplash
73. Professional Stuff
74. Optimize your build speed https://developer.android.com/studio/build/optimize-your-build
75. Improving the Performance of Gradle Builds https://guides.gradle.org/performance/
76. Check your memory settings org.gradle.jvmargs= -Xmx3g -XX:MaxPermSize=2048m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
77. Java Performance Tuning https://dzone.com/articles/java-performance-tuning
78. Modularisation and Build Speed
79. Modules can speed up your build, but can also slow down your build.
80. 1. Build modules in parallel
85. Example
86. Small app with one module.
90. Optimise • Update gradle and gradle plugin • Update Kotlin • Enable parallel builds and incremental compilation • Split up code into multiple modules
92. Reduced build time for around 25%.
93. 2. Build just what you need
96. A taste of bluetooth.
97. Change Run
100. 18 seconds when in layout
101. 7 seconds when in Fragment
102. Change Run
105. 6 seconds when in layout
106. 3 seconds when in Fragment
107. Change Run
108. 65 seconds
109. Change Run
110. Change Run
111. 65 seconds
112. 9 seconds
113. Build just what you need • Build only the code you want to check. • Let you iterate faster on your feature modules.
114. 3. Faster Tests
115. Run tests 15 seconds
116. Run tests 4 seconds
117. I promised 2 seconds.
118. Plain Kotlin or Java No Android dependencies
120. Advantages of Multiple Modules
121. Advantages of Multiple Modules 1. Build modules in parallel 2. Build just what you need 3. Faster Tests 4. And all the other advantages … (Reusability, Maintainability, SOLID, …)
122. Spotify has over 600 modules.
123. Modularisation - How hard can it be? (Droidcon London 2018)
124. Sum it up
125. Faster Builds = Faster Development Photo by Andrea Leopardi on Unsplash
126. Photo by Richard R Schünemann on Unsplash Quick wins 1. Update your tools 2. Use instant run 3. Use Gradle caching 4. Incremental compilation 5. Parallel builds 6. Build variant for develop
127. Modules can speed up your build, but can also slow down your build.
128. Advantages of multiple modules 1. Build modules in parallel 2. Build just what you need 3. Faster Tests
129. I optimise the build speed!
130. Measure Optimise
131. @muffls Philipp Hofmann
132. @muffls Philipp Hofmann Thanks!
133. Questions ? http://bit.ly/droidconit-faster-builds-feedback @muffls Philipp Hofmann