never done jalewis@thoughtworks.com @boicy 1 never done 2 never - - PowerPoint PPT Presentation

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never done jalewis@thoughtworks.com @boicy 1 never done 2 never - - PowerPoint PPT Presentation

Oct 23, 2022 804 likes •2.36k views

building systems that are never done jalewis@thoughtworks.com @boicy 1 never done 2 never done Incomplete adjective not having all the necessary or appropriate parts 3 never done Incomplete adjective not having all the necessary or

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never done

building systems that are

jalewis@thoughtworks.com @boicy
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never done

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never done

Incomplete adjective not having all the necessary or appropriate parts

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never done

Incomplete adjective not having all the necessary or appropriate parts

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KERRBOX!

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How big are they?

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never done

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never done

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“This, milord, is my family's axe. We have owned it for almost nine hundred years, see. Of course, sometimes it needed a new blade. And sometimes it has required a new handle, new designs on the metalwork, a little refreshing of the

  • rnamentation . . . but is this not

the nine hundred-year-old axe of my family? And because it has changed gently over time, it is still a pretty good axe, y'know. Pretty good.”

never done

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replaceable component architectures

Dan North
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the future is scary

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BACK IN 2004 (ISH)

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TIME PASSES…

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TIME PASSES…

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These companies are doing things a bit differently

They can deploy small, independent services on demand They scale teams independently of one another around these services They operate at web-scale if they need to
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CONSULTANTS! HELL YEAH!

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SLIDE 24 19 Enterprise Unicorns Ability to adopt new technologies and practices

And the speed at which they can deliver software is increasing

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SLIDE 25 20 https://www.thoughtworks.com/radar/
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SLIDE 26 21

be cheap to replace microservices should allow us to go as “fast as possible” be deployable on demand be resilient on imperfect networks but it’s not as simple as that

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“the first post-devops architectural style”

Neal Ford
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a note on the law of unintended consequences

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Consider a single application - its a website, lets call it A

A

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SLIDE 30 25 we want to get A into production and since we are hipsters we are going to practice continuous delivery - we will have a full automated build pipeline compile, unit and functional test integration test acceptance test deploy to production run on build machine deployed on build machine deployed to integration environment
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SLIDE 31 25 we want to get A into production and since we are hipsters we are going to practice continuous delivery - we will have a full automated build pipeline Tappety tap compile, unit and functional test integration test acceptance test deploy to production run on build machine deployed on build machine deployed to integration environment
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SLIDE 32 25 we want to get A into production and since we are hipsters we are going to practice continuous delivery - we will have a full automated build pipeline Tappety tap compile, unit and functional test integration test acceptance test deploy to production run on build machine deployed on build machine deployed to integration environment
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SLIDE 33 26

How many environments do we need?

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How many environments do we need?

compile, unit and functional test integration test acceptance test deploy to production run on build machine deployed on build machine deployed to integration environment
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SLIDE 35 28 OK, so we are going to be cool and use microservices

A B

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SLIDE 36 29 and we might as well call them something interesting

webapp customers

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SLIDE 37 30 and they have a dependency on one another…

webapp customers

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SLIDE 38 31

How do we traditionally make sure that new versions of the services work with each other? Let me illustrate this

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V1 V1

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SLIDE 40 32 git push origin master

V1 V1

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V2

git push origin master

V1 V1

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SLIDE 42 32

V2

git push origin master

V1 V1

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V2

git push origin master

V1 V1

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SLIDE 44 32

V2

git push origin master

V1 V1

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V2

git push origin master

V1 V1

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V2 V1

What should V2 of the blue app be tested against here

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V1

This is in production, so presumably we should test against this?

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V1 V1

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SLIDE 49 35 git push origin master

V1 V1

git push origin master
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V2

git push origin master

V1 V1 V2

git push origin master
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V2

git push origin master

V1 V1 V2

git push origin master
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V2

git push origin master

V1 V1 V2

git push origin master
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SLIDE 53 35

V2

git push origin master

V1 V1 V2

git push origin master
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SLIDE 54 35

V2

git push origin master

V1 V1 V2

git push origin master
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SLIDE 55 36 I’m sorry Dave, I can’t let you do that

I’m sorry Dave, I can’t let you do that

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Locks == Delay

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V1 V1 s s V1 V1

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2 services

4 environments =>

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2 services

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2 services 4

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2 services 4 >600

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SLIDE 68 45
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SLIDE 69 45 http://james-iry.blogspot.com.au/2009/05/brief-incomplete-and-mostly-wrong.html
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<thinks>

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if:

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if:

Integration testing

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if:

Integration testing Independent deployment

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if:

Integration testing Independent deployment Service versioning / evolution

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if:

Integration testing Independent deployment Service versioning / evolution

is hard

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SLIDE 76 48

What about some of our other sacred cows?

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SLIDE 77 48 agile XP TDD BDD YAGNI DRY SOLID Continuous Delivery Refactoring GoF GRASP emergent design World of Warcraft KISS

What about some of our other sacred cows?

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SLIDE 78 49 agile XP TDD BDD

YAGNI

DRY SOLID Continuous Delivery Refactoring GoF GRASP emergent design World of Warcraft KISS
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SLIDE 79 50
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SLIDE 80 50 http://martinfowler.com/bliki/Yagni.html
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build out services as you need them minimise holding cost and batch size

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SLIDE 82 52 agile XP TDD BDD YAGNI DRY SOLID Continuous Delivery Refactoring GoF

GRASP

emergent design World of Warcraft KISS
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SLIDE 83 53 Fulfilment Retail
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SLIDE 84 54 Fulfilment Retail
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SLIDE 85 55 Fulfilment Retail
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SLIDE 86 56 Fulfilment Retail

High cohesion Low coupling

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SLIDE 87 57 agile XP TDD BDD YAGNI

DRY

SOLID Continuous Delivery Refactoring GoF GRASP emergent design World of Warcraft KISS
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“Every piece of knowledge must have a single, unambiguous, authoritative representation within a system”

Andrew Hunt, Dave Thomas: The Pragmatic Programmer. 1999-10-01. ISBN: 978-0-2016-1622-4 https://pragprog.com/book/tpp/the-pragmatic-programmer
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DRY holds across services

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SLIDE 90 60 agile XP

TDD

BDD YAGNI DRY SOLID Continuous Delivery Refactoring GoF GRASP emergent design World of Warcraft KISS
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“The London school

  • f Test Driven

Development”

Mike Feathers
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should we bother with test driving our code if we are going to throw it away?

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SLIDE 93 63 http://moleseyhill.com/blog/2009/08/27/dreyfus-model/
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All rules are contextual

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SLIDE 95 65 Start
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SLIDE 96 Am I Kent Beck? 65 Start
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SLIDE 97 Do what I think is best Yes Am I Kent Beck? 65 Start
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No

Do what I think is best Yes Am I Kent Beck? 65 Start Am I Dan North?
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SLIDE 99 Do what I think is best Yes

No

Do what I think is best Yes Am I Kent Beck? 65 Start Am I Dan North?
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SLIDE 100 No Do what I think is best Yes

No

Do what I think is best Yes Am I Kent Beck? 65 Start Am I Dan North?
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SLIDE 101 No Do what I think is best Yes

No

Do what I think is best Yes Am I Kent Beck? 65 Start Am I Dan North?

USE TDD ALREADY!

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should we write unit tests?

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Most of the other stuff is made so much easier

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SLIDE 105 68 agile XP TDD BDD YAGNI DRY Continuous Delivery Refactoring GoF GRASP emergent design World of Warcraft KISS

SRP

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a class should be no bigger than my head

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SRP a service should be no bigger than my head

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SLIDE 108 71 agile XP TDD BDD YAGNI DRY SOLID Continuous Delivery Refactoring GoF GRASP emergent design World of Warcraft

KISS

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“Simplicity is a great virtue but it requires hard work to achieve it and education to appreciate it. And to make matters worse: complexity sells better.” Edsger W. Dijkstra

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WWJD?

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WWJD?

(what would Joe do?)

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cron, python, boto, pydot, graphviz

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cron, python, boto, pydot, graphviz

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cron, python, boto, pydot, graphviz

Do the simplest thing possible

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maybe we can use CD to help with our testing problem?

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“There is nothing so useless as doing efficiently that which should not be done at all”

Peter Drucker

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SLIDE 121 80 Good Monitoring
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SLIDE 122 80 Good Monitoring Fast Remediation
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SLIDE 123 80 Good Monitoring Fast Remediation

QA

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Test in production

Good Monitoring Fast Remediation

QA

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SLIDE 127 81

SEMANTIC MONITORING

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SLIDE 128 82 Customer Service Web Shop
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SLIDE 129 82 Customer Service Web Shop Expectations
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SLIDE 130 82 Customer Service Web Shop Expectations
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SLIDE 131 82 Customer Service Web Shop Expectations
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SLIDE 132 82 Customer Service Web Shop Expectations

Consumer Driven Contracts

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integration environment

the death of the

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production != live

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the future is scary

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SLIDE 138 87 Enterprise Startup Ability to adopt new technologies and practices

And the speed at which they can deliver software is only increasing

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EVEN FINANCE IS NOT IMMUNE

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we have to learn how to: Craft my families axe Deploy small services independently Test microservices in isolation Test microservices in production

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the future is bright

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we have old techniques that apply: SRP GRASP YAGNI KISS TDD DRY

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and new techniques to apply: Consumer Driven Contracts Semantic Monitoring Semantic Versioning Testing in Production Failure Isolation

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SLIDE 146 95 jalewis@thoughtworks.com @boicy

Thanks!

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"ever accelerating progress of technology and changes in the mode of human life, which gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue”

John von Neumann, as recorded by Ulam, 1958

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SLIDE 148 97 “Around the world, laboring women produce forty-five thousand babies a day, representing 1023 MIPS of processing power. Also around the world, fab lines casually churn out thirty million microprocessors a day, representing 1023 MIPS. In another ten months, most of the MIPS being added to the solar system will be machine-hosted for the first time”
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SLIDE 149 98 yeah, it’s just science fiction right>

yeah, it’s just science fiction right?

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SLIDE 150 98 yeah, it’s just science fiction right>

yeah, it’s just science fiction right?

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“Self-Driving Trucks Are Going to Hit Us Like a Human-Driven Truck”

https://medium.com/basic-income/self-driving-trucks-are-going-to-hit-us-like-a-human-driven-truck-b8507d9c5961 source: Morgan Stanley

This is where we’re at and this is what we face as we look towards a quickly approaching horizon of over 3 million unemployed truckers and millions more unemployed service industry workers in small towns all over the country dependent on truckers as consumers of their services.

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“If you aren’t worried about strong AI within the next 5-10 years then you aren’t working closely enough with AI teams” (paraphrasing Elon Musk)

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