Big Rewrite Strikes Again - Lead Dev London 2017

There’s nothing more frustrating than not being able to deliver new features because of unnecessarily complicated code. You may decide it’s time to throw it all away and start over… and what starts off full of optimism, drags on for months and months, adding even more complexity and various levels of legacy.

It doesn’t have to be this way! In this presentation, you’ll hear a first-hand experience of how to approach technical debt at its worst, and how a rewrite project was successful in more ways than expected.

This talk will teach you lessons on how to start, and most importantly, finish a big rewrite project. You will learn how to approach the conversation with the “business”, avoid the most common pitfalls when changing the architecture of a complex codebase, and ensure the rewrite brings value from the start till the very happy end.

Transcript

1. BIG REWRITE STRIKES AGAIN
   Sabrina Leandro @saleandro
   The Lead Developer UK 2017
   

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2. Lessons from
   Big rewrite projects
   

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3. BIG REWRITE STRIKES AGAIN
   

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4. This talk
   • The problem
   • How to start it
   • How to run it
   • How to finish it
   • How to not need it again!
   

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5. The problem
   Stop me if you think you’ve heard this one before
   

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6. Software Entropy
   

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8. How to start it
   

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9. •Is it the right time?
   •Is it the right reason?
   

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10. Product discovery
    Is it the right time?
    

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11. Product discovery
    Product delivery
    Is it the right time?
    

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12. Is it the right time?
    Yes, if the product has a
    clear business value today.
    

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13. What difference does it make?
    Is it the right reason?
    

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14. •Do you have a business case?

    

    

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15. •Do you have a business case?
    •Can you explain it to anyone in
    your organisation?
    

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16. Is it the right reason?
    Yes, if there’s one clear
    business case.
    

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17. PLEASE
    PLEASE
    PLEASE
    Let me get what I want
    

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18. Have one clear business case
    How to sell it
    

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19. How to sell it
    Show what a great new world 

    it will be!
    

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20. How to sell it
    Find allies outside of your team
    

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21. Make
    the pain
    visible
    How to sell it
    

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22. How to sell it
    Do Repeat Yourself
    

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23. How to sell it
    Do Repeat Yourself
    Do Repeat Yourself
    

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24. How to run it
    

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25. Technical
    vision
    and
    strategy
    Now The future!
    

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26. Now The future!
    Technical
    vision
    and
    strategy
    

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27. Technical approaches
    

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28. Now Bright future!
    Team 2: Building new application
    Rewrite from scratch
    Legacy
    application
    Team 1: Maintaining legacy application
    New
    New
    application
    New
    application
    VALUE!
    Legacy
    application
    Legacy
    application
    

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29. Now Bright future!
    Team 2: Building new application
    Rewrite from scratch
    Legacy
    application
    Team 1: Maintaining legacy application
    New
    New
    application
    New
    application
    VALUE!
    Legacy
    application
    Legacy
    application
    Legacy
    application
    

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30. The strangler
    application
    

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31. Now Bright future!
    Team 1: Maintaining legacy and building new application
    New
    application
    Rewrite using strangler approach
    

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32. Now Bright future!
    Team 1: Maintaining legacy and building new application
    New
    application
    VALUE!
    Rewrite using strangler approach
    

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33. “ Deleting is faster
    than rewriting.
    

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34. Bones
    Muscle
    Fat
    Cut features
    to move
    faster
    

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35. “ If we were starting over,
    what would we build today,
    knowing what we know now?
    

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36. 1) Find the biggest blocker
    2) Remove it completely
    3) Repeat
    What to do first?
    

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37. During the project
    

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38. How to run it
    Show internal progress
    

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39. How to run it
    Celebrate your successes!
    

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44. That joke isn’t funny anymore…
    How to run it
    Do Repeat Yourself, again
    

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45. How to finish it
    I started something I couldn’t finish
    

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46. These things 

    take time
    How to finish it
    

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47. How to not need it
    again
    

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48. Software Entropy
    

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49. How to not need it again
    Make the cost visible
    

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51. DELETE
    CODE
    FEATURES
    PRODUCTS
    

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52. “ If we were starting over,
    what would we build today,
    knowing what we know now?
    

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53. How to not need it again
    Make it part of your day-to-day
    

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54. “ A refactor a day
    keeps the rewrite
    away!
    

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55. How to not need it again
    Get used to inconsistencies
    

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56. How to not need it again
    Promote a culture of collaboration
    

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57. Technical migrations
    Continuously deliver
    value
    Delete what’s not
    valuable
    One business goal
    

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58. Sustainable Software
    Make maintenance
    cost visible
    Learn and collaborate
    Refactor a little bit
    and often
    

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59. Bigmouth Strikes Again
    This Charming Man
    Stop Me If You Think You’ve Heard This One Before
    What Difference Does It Make?
    Please, Please, Please, Let Me Get What I Want
    That Joke Isn’t Funny Anymore
    I Started Something I Couldn’t Finish
    These Things Take Time
    Sheila Take A Bow
    Thanks!
    Sabrina, take a bow…
    sabrina@saleandro.com
    @saleandro
    

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60. References
    Songkick.com rewrite
    • https://devblog.songkick.com/the-path-to-soa-d986a18d4a8b
    • https://devblog.songkick.com/our-object-based-rails-frontend-3e2ddc048d12
    • https://www.youtube.com/watch?v=-VEf8j6aGMk
    • https://www.martinfowler.com/bliki/StranglerApplication.html
    Celebrate your successes
    • https://medium.com/@Songkick/gamify-your-product-team-to-power-level-9000-261e9fceaa22
    Hoarders metaphor / Liveable code
    • https://twitter.com/sarahmei/status/783115752794492928
    • https://www.youtube.com/watch?v=mz3l_oEA2cU
    • https://twitter.com/kentbeck/status/856537528886673408
    Product discovery and product delivery
    • http://jpattonassociates.com/dual-track-development/
    • https://martinfowler.com/bliki/DesignStaminaHypothesis.html
    • https://www.facebook.com/notes/kent-beck/teams-in-3x/1244519748914220/
    

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61. References
    Make the cost visible
    • http://codemanship.co.uk/parlezuml/blog/?postid=1433
    • http://blogs.msdn.com/b/elee/archive/2009/03/11/source-code-is-a-liability-not-an-
    asset.aspx
    Make it part of your day-to-day
    • https://martinfowler.com/bliki/OpportunisticRefactoring.html
    • http://ronjeffries.com/xprog/articles/refactoring-not-on-the-backlog/
    • http://firstround.com/review/forget-technical-debt-heres-how-to-build-technical-wealth/
    • https://www.infoq.com/presentations/microservices-replaceability-consistency
    • https://www.sandimetz.com/blog/2017/6/1/the-half-life-of-code
    • https://www.infoq.com/presentations/remove-unneeded-code
    Playlist :)
    • https://open.spotify.com/user/saleandro/playlist/6i3RVHtys4djlYlLLGZc26
    

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