Trunk-Based Development
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What's TBD, some facts and how TBD with feature toggle can increase release frequency, lower release risk, decouple release from code deployment. DevOpsDays, Taipei, 2017
Trunk-Based Development
- 1. 為蔚堀住原 ~ Trunk-Based Development Bryan Liu 犒 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 ?nancial success´¨¨ ~ Kevin Scott, the senior VP of engineering http://www.wired.com/2013/04/linkedin-software-revolution/
- 10. https://paulhammant.com/2013/03/13/facebook-tbd-take-2/ Facebook¨s Trunk-Based Development branching models v.s. release frequency
- 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://feature?ags.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 犒
- 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