Trunk-Based Development
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The document discusses trunk-based development (TBD) and its advantages over traditional branching methods, emphasizing short-lived feature branches and the use of feature toggles. It highlights the importance of committing to trunk daily and maintaining a releasable state, while also addressing inefficiencies in software development that can be minimized through TBD practices. Furthermore, it mentions the successes of companies like LinkedIn and Facebook in adopting continuous deployment and A/B testing strategies.
Trunk-Based Development
- 1. 百倍速交付 ~ 談Trunk-Based Development Bryan Liu 劉栢峰 2017
- 3. Long-Lived (Feature) Branch • Creates lots of overhead Git Flow GitHub Flow
- 4. Short-Lived Feature Branch • Branch’s length of life: less than 2 days • Shared for code-review and CI only • Easily becomes long-lived branch https://trunkbaseddevelopment.com/short-lived-feature-branches/
- 5. Trunk-Based Development (TBD) • Commit in trunk at least once a day • Trunk is always in a releasable state • Hide unfinished code with feature toggle • Refactor with branch by abstraction http://www.alwaysagileconsulting.com/articles/organisation-pattern-trunk-based-development/
- 6. Facts
- 7. Always the bridesmaid* from Paul Hammant
- 8. TBD Only search few of these kings… Also other TBD giants, ex: Google, Netflix were not included in this startups research. Never mind become A Category King 2000 ~ 2015 yr 600k companies 34 of them 76 % market cap Winner-takes-all Category King
- 9. ‘‘Somewhere in the middle of this two-month process you’re going to run across a bridge and burn it behind you.’’ ‘‘LinkedIn’s big switch to continuous deployment has been linked to very concrete and visible financial success…’’ ~ Kevin Scott, the senior VP of engineering http://www.wired.com/2013/04/linkedin-software-revolution/
- 11. TBD & Feature Toggle
- 12. if ( ToggleManager.isEnabled(“FastCheckout”, user) ) { useFastCheckout() } else { useOriginCheckout() } https://martinfowler.com/articles/feature-toggles.html What’s Toggle
- 13. Business Toggle: • A/B Testing Low Risk Release and Zero-Downtime • Canary Release, Dark Launch, Blue-Green deployment • DB/Schema Migration Decouple Feature Rollout from Code Deployment • Re-planning • Microservices Some Toggle Use Cases
- 14. Canary Release / Blue-Green Deployment & A / B Testing http://featureflags.io/ • Phased rollout • Monitor performance • Check user feedback
- 15. • Features in live but NOT visible to user • Warm up cache, load DB tables with real production traffic • Soak test, verify performance Dark Launch
- 16. DB / Schema Change • Forwards & backwards compatible • Stage roll-out with verification online • No downtime needed
- 17. Q: What are the requirements to achieve previous scenarios ? A: • Feature toggles & • Old and new code co-exists in the same delivery “Get good with build-flags and toggles” ~ Paul Hammant “ This is also the major difference between short-lived branch and TBD!”
- 19. Decouple Release from Code Deployment • TBD reduce merge pain • Merge hell is error prone and risky • Inefficiency on spending time in bug fix - merge - test cycle.
- 20. As in Microservices: Any attempt trying to set release pace is not realistic!! Feature flags + Microservices = True decoupling
- 21. Re-planning • It happens • Leads to weeks of un-merge for teams Image from: https://devops.paulhammant.com/
- 22. Inefficiencies in SW development: • It slows down throughput • Can’t keep talent
- 24. Frequently commits to mainline: • More communication with your team • More frequent builds and tests (CI) • More frequent deployment (CD) • More experiments and faster feedback
- 25. Implementation
- 26. Pre-Commit Testing & Code Review • Pre-commit (CI) test (option but best) • Continuous (code) review • Code ownership Figure from https://trunkbaseddevelopment.com/continuous-integration/
- 27. Why Continuous Review (Large Diffs Hurts) • Large diffs won’t get reviewed • Reverting large diffs is hard • Rebasing/merging large diffs is error-prone Code review statistics: http://blogs.atlassian.com/2011/07/creating_optimal_reviews/
- 28. Pull Request Code Review git commit -m "fixed issue with fan"
- 30. Code Review Page • Code statistics • CI test results • Review discussion & comments
- 33. Hello, about me … DevOps Evangelist QA Architect Bryan Liu 劉栢峰
- 34. • trunkbaseddevelopment.com • trunk-based development, Paul Hammant • Facebook's Trunk-Based Development, Paul Hammant • Branch by Abstraction, Martin Fowler • Feature Toggles, martinfowler.com • Category King, J. Van Grove and Play Bigger • The Death of Continuous Integration, Steve Smith • And many links inside each slide deck ~ Reference