Continuous Integration in a monorepo

Slides from presentation given alongside Max Friedrich at CocoaHeads Hamburg May 2017 meet up.

Transcript

1. CONTINUOUS INTEGRATION IN A MONOREPO RENZO CRISÓSTOMO MAX FRIEDRICH
2. IOS @ XING
3. > First commit: Thu Oct 28 11:52:30 2010 > Objective-C: 228001 LOC, Swift : 16215 LOC > Internal libs: 20. External libs: 40 > Over 30 contributors > Over 50 commits per day merged on master > Over 20 builds per day
5. BEFORE THE MONOREPO > CocoaPods (CocoaPods/Rainforest) > Heavy use of development Pods
6. . !"" Rakefile !"" Gemfile !"" XNGABTest # !"" .git # !"" Rakefile # !"" Gemfile ... # $"" Sources !"" XNGAdvertising !"" XNGComponents ... $"" iphone-app !"" .git !"" Rakefile !"" Gemfile ... $"" Sources
7. > Checkout branch and install deps: 00:04:38 > Checkout out a different branch: 00:04:15 > Indexing: 00:04:05
8. MONOREPO > Workspace with multiple projects/targets > Shared xcconfig files > CocoaPods/Rome to build third party dependencies
9. . !"" XING.xcworkspace !"" apps # !"" XING # $"" examples !"" libraries # !"" XNGABTest # !"" XNGAdvertising ... # $"" XNGUnitTestHelper !"" third_party_dependencies !"" tooling $"" vendored_dependencies
10. > bootstrap (only once*): 00:02:12 > checkout branches: instantly! > indexing (only once): 00:03:44 > indexing (delta): 00:00:25
11. CI SETUP
13. > 2 Mac Pros (2013) > We use Jenkins > 16 VM running macOS on top of VMware host > 6 VM connected through SSH (headless): 1 executor > 10 VM connected through JNLP: 1 executor > Open source: xing/XNGMacBuildNodeSetup
15. DEMO
16. HOW DOES IT WORK?
18. MAKING CI WORK ON THE MONOREPO > Be smart about when to test > Be smart about what to test > Parallelize the work
19. STEP BY STEP 1. Comment Triggers 2. GitHub Pull Request Builder (Jenkins plugin) 3. Pandan 4. Jenkins Pipelines 5. Danger
20. 1. COMMENT TRIGGERS A.K.A. "PLEASE TEST X"
22. > Swift build & test takes hours > We have TODO: N test targets, half are tested on 3 simulators > Building and testing everything takes an hour on one machine
23. MAKING CI WORK ON THE MONOREPO > Be smart about when to test !"#$% > Be smart about what to test > Parallelize the work
24. 2. GITHUB PULL REQUEST BUILDER HTTPS://GITHUB.COM/JENKINSCI/ GHPRB-PLUGIN
25. > Trigger comment regex > Build origin/pr/42/merge/ or actual commit
26. 3. PANDAN HTTPS://GITHUB.COM/XING/PANDAN
27. Hack week project! > We stopped using CocoaPods for internal libraries > Dependencies stored in the Xcode project > CLI tool to get dependency graph from Xcode workspace > Uses xcodeproj gem
28. Output a target's dependencies: $ pandan query XNGComponents XNGFoundation XNGLocalizedString ...
29. Output all targets that depend on a target: $ pandan query --reverse XNGComponents XNGJobs XNGEvents ...
30. Bonus: export a dependency graph $ pandan dependency-graph
31. MAKING CI WORK ON THE MONOREPO > Be smart about when to test !"#$% > Be smart about what to test ✅ > Parallelize the work
32. 4. JENKINS PIPELINES HTTPS://JENKINS.IO/DOC/BOOK/ PIPELINE/
34. BEFORE MONOREPO: MASTER/SLAVE JOBS xcodebuild test -scheme XNGComponents - destination ...
35. AFTER THE SWITCH: ONE NODE PER JOB xcodebuild build-for-testing and test- without-building
36. PIPELINES Build once, stash the result, parallel test
39. > See at first glance what failed > Small speedups with parallel steps > Easier to maintain Jenkins config (Jenkinsfile in SCM)
41. MAKING CI WORK ON THE MONOREPO > Be smart about when to test !"#$% > Be smart about what to test ✅ > Parallelize the work ✅
42. 5. DANGER HTTPS://DANGER.SYSTEMS
44. DANGER-JUNIT PLUGIN junit.parse 'logs/*.xml' junit.report
46. WHAT WE LEARNED
47. WHAT WE LEARNED > Reference repository > Simulator is expensive on VMs > Stashing is expensive
48. WHAT WE NEED TO IMPROVE > Our CI is not continuous anymore :( > Build time is still high, keep derived data? > Get better at analyzing our new numbers