Prioritizing Technical Debt

Presented at React Knowledgeable.

Google Slides: https://docs.google.com/presentation/d/1Gy_lpD_mjdqpFFx40v19E1sEPXqy5SJSnDwWuLkktz0/edit?usp=sharing

1. Prioritizing Technical Debt Taming the beast!
2. What is technical debt? Tech Debt reflects the implied cost of additional rework caused by choosing an easy (limited) solution now instead of using a better approach that would take longer. - "We took a shortcut" - "This is a hack" - "We'll fix that later"
3. • Reckless & accidental • Reckless & deliberate • Prudent & deliberate • Prudent & accidental (unintentional) Source: https://softwarebrothers.co/blog/technical-debt-what-it-means-and-how-to-deal-with-it/ Types of technical debt
4. Paying off the technical debt • Like any kinds of debt, you eventually need to pay it off. • When is the moment to start paying tech debt? ◦ When the cost of change is too high: ▪ "It takes 3 weeks to implement a button". ◦ Brittle code: Too many moving parts, change one line and everything fails. ◦ You need more effort to understand the code.
5. Stop the leak Step 1
7. Stop the leak • Be deliberate in your code design. • Refactor your code as soon as it works. ◦ TDD Cycle: Red, Green, Refactor ◦ Tests gives you more confidence in refactoring your code • DRY is not always a good thing ◦ Wrong layer of abstraction ◦ Premature optimization
8. Stop the leak • Recognize code smells • https://refactoring.guru/refactoring/smells
9. Tech Debt Sprints Step 2
10. Tech Debt Sprints • Run a Tech Debt Workshop a. Get everyone to identify tech debt in the code and put them on 1 post-it note each. b. Put them all on the board. Identify clusters. c. Organize them into value & complexity/effort quadrants. • Plan and do the tech debt recovery.
11. 1 2 3 4 4
12. Examples • Documentation for a shared library. • Removing dead code from a feature toggle. • Audit on Open Source licenses used. • Upgrade to the latest version of Preact. • Remove use of IE7 Shims. • Decouple library A from B. • Refactor Payment module. • Extract out a repeated method into a shared library. • Use dependency injection instead of initializing a new instance everywhere. • Performance tuning for API requests. • Reduce memory footprint of all app servers. • Standardize the use of Webpack config across all microservices. • Enhance stability of build pipeline. • Reduce load time of web front-end by 2 seconds. Where would you put these stories on the Value vs Complexity/Effort quadrant?
13. Continuous Pay Down Step 3
14. Continuous Pay Down • Include tech debt repayment stories in every sprint. ◦ Example: "10% of stories in this sprint backlog should be tech debt stories." ◦ Pull from the tech debt sprint board.
15. Continuous Pay Down • Opportunistic refactoring - as you are working on a story spend some time to refactor. ◦ Do it after you are done with the "acceptance criteria". ◦ Beware the rabbit hole.
16. Continuous Pay Down • Revisit the tech debt board once in a while. ◦ Revise with another workshop.
17. Continuous Pay Down • Add test coverage of legacy code before you refactor. • Document the coding conventions, styles and design patterns that are "good practices". ◦ Help new joiners to understand why certain things are good and bad. ◦ Architecture Decision Record (https://github.com/joelparkerhenderson/architecture_decision_record)
18. Continuous Pay Down • Resist the urge to restructure until you know enough about the current & future use cases. ◦ "Duplication is far cheaper than the wrong abstraction" ◦ "Prefer duplication over the wrong abstraction" ▪ Sandi Metz (https://www.sandimetz.com/blog/2016/1/20/the-wrong-abstraction)
19. Conclusion • Tech debt can be managed but never quite paid off completely. ◦ New code can accidentally introduce tech debt. • Tech debt can be a matter of opinion too. ◦ Some repetition results in less indirection and more readable code. • To pay or not to pay - you have to decide as a team.
20. Questions? @CoderKungfu (Instagram & Twitter)
21. About Me • 1998-2002 - Majored in History & Political Science in NUS • 2004 - Started my own web design company (eNeighbourhoodStore) • 2006 - Sold it to a digital agency (Comwerks) Founded Singapore PHP User Group • 2011 - Joined my first startup: Foound • 2012 - Co-founded iOS Dev Scout • 2013 - Started Engineers.SG • 2012-2019 - Software engineer (migme, Neo Innovation, Pivotal Labs, SP Digital (SPGroup)) • 2018 - Started JuniorDevSG • June 2019 - Joined GovTech Singapore
22. Michael Cheng @CoderKungfu (Twitter & Instagram)