Decisions Decisions

Architecture isn't just the static "shape" of your software. It's the set of decisions that define it, enabling — or inhibiting — change, evolution and improvement over time.

It is also the decisions about how you verify, deploy, version, manage and monitor an application. Each of these decisions is a trade-off: there are no Best Practises. Some decisions can have a huge forward impact, and it isn't always obvious which ones!In this talk Dan offers several strategies to help you improve your architecture decision-making.

He won't tell you whether to prefer stability or uncertainty, DRYness or coupling, latency or throughput, manual or automated testing. That's up to you. But he might help you go into those decisions with your eyes open.

Transcript

1. Decisions, Decisions
   Dan North
   @tastapod
   

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2. @tastapod
   Every decision is a trade-off
   development
   architecture
   deployment
   

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3. @tastapod
   Development – the trade-offs
   automated or manual build
   automated or manual testing
   test-driven or test-after development
   or test-first
   or test-whenever!
   

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4. @tastapod
   Spike and Stabilize – a pattern
   Why do we do TDD?
   What is the opportunity cost of TDD?
   feedback from defects or feedback from users
   Invest in code based on evidence
   

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5. @tastapod
   Architecture – the trade-offs
   monolith or components
   objects or functions
   synchronous or asynchronous
   threads or single event loop
   or actors or CSP
   

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6. @tastapod
   Short Software Half-Life – a pattern
   Small, separate components
   Each component does one thing
   Hard shell, soft centre
   The message is the API
   identifiable boundaries for experimenting
   

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7. @tastapod
   Evolvable architecture
   DRY or ...?
   Evolution is anything but DRY!
   DNA doesn't refactor
   decoupled
   

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8. @tastapod
   Ginger Cake – a pattern
   

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9. 1.5 cups flour 3 tablespoons cocoa
   1 teaspoon baking soda 1 cup sugar
   1/2 teaspoon salt 1 tablespoon white vinegar
   1 tablespoon vanilla 4 tablespoons melted butter
   1 cup cold water
   Mix dry ingredients together. Make three wells in the
   mixture. In the first well, pour vinegar, in the second
   vanilla, and in the third, the liquid fat. Pour cold
   water over the whole thing and mix together well. Pour
   batter into a 9x9 pan, ungreased, and bake at 350
   degrees for 35 to 40 minutes.
   chocolate cake
   @tastapod
   

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10. ginger cake
    like chocolate cake
    (but with ginger)
    @tastapod
    

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11. @tastapod
    Deployment – the trade-offs
    automated or manual deployment
    vertical or horizontal scaling
    managed or in-house
    virtual or physical
    

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12. @tastapod
    Dancing Skeleton – a pattern
    Get something – anything! – into production
    Full stack, with an interface
    Fire, aim, ready!
    Theory is only like practice in theory
    

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13. @tastapod
    When you know what you are
    trading off
    you can make
    informed decisions
    

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14. Thanks for listening
    @tastapod
    http://dannorth.net
    dan@dannorth.net
    

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