Paul Davis - Compiling - Reduce your wait times and “get back to work”

Transcript

1. compiling….. reduce your wait times and “get back to work” Paul Davies rentalcars.com BookingGo (part of Booking.com) @pauldavies83 linkedin.com/in/pauldavies83
2. Who am I • Android software engineer • rentalcars.com app at BookingGo (Booking.com) • Previous life: • BBC iPlayer, BBC iPlayer Radio
3. • Ground transportation division of Booking.com • Manchester, UK • YES, we are hiring :-) • NO, it doesn’t always rain
4. What this talk is... • Our experience at BookingGo with our Android app • My observations gathered from previous roles/apps • A plea for you to care about your build time
5. What this talk isn’t... • A one-size-fits-all answer (sorry!) • Exact numbers
6. What’s “wrong” with Gradle? • It’s “slow”
7. Compiling….. https://xkcd.com /303/
8. What did we start with
9. What we started this year with (Jan 2018) • Gradle v3.5, Android Gradle Plugin v2.3.3 • 1 main app module - 4 small library modules • Java + Kotlin sources • Lots of dependencies, plugins, annotation processors • Clean build ~3 mins 20 secs • Small change in module ~1 min 50 secs
10. What did we try
11. What did we try (Jan 2018) • Move tools to most recent version • Gradle v4.4, AGP v3.0.1 • Enabled parallel tasks • Turned the daemon ON!! • Clean build ~2 mins 25 secs • Small change in module ~1 min 45 secs
12. Why? • CONFIGURATION • Incremental compilation (for Java) • Annotation processors off compile classpath • Compile avoidance (for Java) • Gradle daemon
13. Version bumps
14. What did we try • Gradle v4.4.1, AGP v3.1.2 • Kotlin Gradle Plugin v1.2.21 • Build (-10 secs)
15. Configuration optimizations
16. What did we try • Change ALL PNG resources to WebP • No improvement in build time L • BUT… • Reduced APK size ~5MB J
17. What did we try • Create a dev flavour (remove legacy mutlidex / constrain resources) • Build (- 11 secs)
18. Remove annotation processors
19. What did we try • AutoValue (- 15 secs ) • https://github.com/riclage/ConvertToDataClassPlugin • ButterKnife in .kt files (- 4.5 secs ) • ButterKnife in .java files ( - 5 secs )
20. Build cache
21. Build cache • Turn on Gradle build cache • Build time < 45 seconds (-1 min 40 secs!!)
22. Build cache • Disable Crashlytics on dev variant • Build time < 5 seconds !!!
23. Remote build cache?
24. Remote build cache? • Artifactory (JFrog) has this built in • Gradle provide Docker image • Roll-your own • docs.gradle.org/current/userguide/build_cache.html
25. Can we go even faster?
26. Can we go even faster? • MORE MODULES • More JVM modules / less Android modules • More Kotlin / Less Java
27. Kotlin & Java sources https://jakewharton.com/its-a-kotlin-kotlin-kotlin-world/
28. Can we go even faster? • Change your workflow • Get a faster computer (or use cloud) • https://github.com/gojuno/mainframer • Flutter??? J
29. Tools
30. Tools ./gradlew <task> --profile
31. Tools
32. Tools
33. Tools • Gradle build scan • https://guides.gradle.org/creating-build-scans/
34. Bazel
35. Bazel • Open-source variant of Google’s Blaze • Famed for fast, repeatable builds • Worth a try?
36. Bazel - dependencies • No transitive dependencies with built-in rules • e.g. Retrofit -> OkHttp. Need to specify both • No fun trying to port an Android project! • Open-source rule supporting maven transitive dependencies • Doesn’t support .aar dependencies, only .jar • No fun trying to port an Android project!
37. Bazel - Kotlin • ”Official” rules forked from an open-source project @pubref • “Official” rules support mixed-mode compilation (.kt & .java in one pass). @pubref wouldn’t do this • “Official” rules cannot simply provide its output to an Android application rule (workaround needed)
38. Bazel – my spike experience • Seems difficult at this point to port an existing, complex Android project structure • Bazel IntelliJ plugin doesn’t work in Android Studio 3.1 (but should be fixed in 3.2) • I’ll be really interested in looking again the next time I press File -> New Project!
39. Summary
40. Does all this matter? • How many times do you build each day? • 10 x 3 mins = 30 mins day / 2.5 hrs week • 10 x 0.5 mins = 5 mins day / 25 mins week • Time savings add up • Decide whether savings are worth the cost
41. Summary • Build tools are not fit-and-forget • Gradle isn’t magic - needs configuration and your scripts need maintenance • If you need a nudge/reminder, write it into your CI workflow • Mixing Java & Kotlin means slower builds!
42. Summary • Optimize your work environment • real device instead of an emulator • faster machine / remote build like “mainframer” • ask for a new computer J • Other options (eg Bazel) may be faster in certain circumstances, but not as much support
43. Resources • d.android.com/studio/build/optimize-your-build • docs.gradle.org/current/userguide/troubleshooting.html
44. Resources • Two other great talks from today you to check out…
45. (Less) Compiling….. https://xkcd.com /303/
47. compiling….. reduce your wait times and “get back to work” Paul Davies rentalcars.com BookingGo (part of Booking.com) @pauldavies83 linkedin.com/in/pauldavies83