Post on 31-Jul-2020
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never donebuilding 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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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 ornamentation . . . 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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microservices should be:
cheap to replace
and should allow us to go as “fast as possible”?
quick to scale
able to withstand failure
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“the first post-devops architectural style”Neal Ford
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replaceable component architecturesDan North
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the future is scary
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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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Singularity
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SingularityJavaScript
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SingularityJavaScript
Container
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SingularityJavaScriptLog aggregation
Container
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even closer to home
HOW WE DESIGN SOFTWARE IS CHANGING
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Hardest things to do:
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Hardest things to do: End-to-end testing
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Hardest things to do: End-to-end testing
Independent deployment
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Hardest things to do: End-to-end testing
Independent deployment
Service versioning / evolution
TESTING MICROSERVICES IS HARD
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Service A
Service
Large
Medium
Small
TESTING MICROSERVICES IS HARD
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Service A
Service
Large
Medium
Small
Service Stub
TESTING MICROSERVICES IS HARD
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Service A
Large
Medium
Small
INTEGRATING MICROSERVICES IS HARD
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INTEGRATING MICROSERVICES IS HARD
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Integration Test
INTEGRATING MICROSERVICES IS HARD
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Integration Test Prod…
INTEGRATING MICROSERVICES IS HARD
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Integration Test Prod…
INTEGRATING MICROSERVICES IS HARD
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Integration Test Prod…
INTEGRATING MICROSERVICES IS HARD
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Integration Test Prod…
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<thinks>
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agile
XPTDD
BDD
YAGNI
DRY
SOLID
Continuous Delivery
Refactoring
GoF
GRASP
emergent design
World of Warcraft
KISS
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Gemini Project, Rogallo wing
Source: wikipedia.org
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<thinks>
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Gemini Project, Rogallo wing
Source: wikipedia.org
it’s turtles all the way down
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agile
XPTDD
BDD
YAGNI
DRY
SOLID
Continuous Delivery
Refactoring
GoF
GRASP
emergent design
World of Warcraft
KISS
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agile
XPTDD
BDDYAGNIDRY
SOLID
Continuous Delivery
Refactoring
GoF
GRASP
emergent design
World of Warcraft
KISS
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Build out services as you need
them
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agile
XPTDD
BDD
YAGNI
DRY
SOLID
Continuous Delivery
Refactoring
GoFGRASPemergent design
World of Warcraft
KISS
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Fulfilment
Retail
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Fulfilment Retail
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Fulfilment Retail
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Fulfilment Retail
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Fulfilment Retail
High cohesion
Low coupling
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(incidentally, if you were playing the Conway’s law lottery, that’s
when you number came up)
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agile
XPTDD
BDD
YAGNI
DRYSOLID
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”
Dave Thomas, interviewed by Bill Venners (2003-10-10). "Orthogonality and the DRY Principle". Retrieved 2006-12-01.
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shared binary dependencies
∆ dep ⇒ ∆S1 + ∆S2 + … + ∆Sn
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git clone https://github.com/boicy/service-template
(note this doesn’t exist)
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DRY within services
duplication between services
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agile
XP
TDDBDD
YAGNI
DRY
SOLID
Continuous Delivery
Refactoring
GoF
GRASP
emergent design
World of Warcraft
KISS
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Small
Medium
Large
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“The London school of Test Driven Development”
Mike Feathers
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should we write unit tests?
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should bother with test driving our code if we are going to throw it away?
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Nat Pryce Steve Freeman Dan North Sydney ‘Hoppalong’ Redelinghuys Jim Webber Ian Robinson Ivan Moore Liz Keogh Simon Stewart Jez Humble Dave Farley Jay Fields Dan Worthington-Bodart Joe Walnes
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http://moleseyhill.com/blog/2009/08/27/dreyfus-model/
should we write unit tests?
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personally I think it’s more important than *ever*
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agile
XPTDD
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
5454
a:Class
5555
a:Class
a:Class
a:Class
a:Class
5656
5757
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SRP
a service should be no bigger than
my head
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agile
XPTDD
BDD
YAGNI
DRY
SOLID
Continuous Delivery
Refactoring
GoF
GRASP
emergent design
World of Warcraft
KISS
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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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integration and deployment
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SEMANTIC MONITORING
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service bservice a
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service bservice a
Small
Medium
Large
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service bservice a
Small
Medium
Large
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service bservice a
Small
Medium
LargeConsumer Driven Contracts
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Customer ServiceWeb Shop
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Customer ServiceWeb Shop
Expectations
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Customer ServiceWeb Shop
Expectations
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Customer ServiceWeb Shop
Expectations
Prod
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Customer ServiceWeb Shop
Expectations
Prod
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Prod
Prod
Prod
Prod
QA
Good Monitoring
Fast Remediation
TESTING IN PRODUCTION
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integration environment
the death of the
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production != live
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CHANGING SERVICES INDEPENDENTLY
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CHANGING SERVICES INDEPENDENTLY
What is the blast radius of the change?
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CHANGING SERVICES INDEPENDENTLY
What is the blast radius of the change?
Limited to your team?
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CHANGING SERVICES INDEPENDENTLY
What is the blast radius of the change?
business capability?Limited to your team?
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CHANGING SERVICES INDEPENDENTLY
What is the blast radius of the change?
business capability?organisation?
Limited to your team?
75Thomas J. Allen, 1977
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0 10 20 30 40 50 60 70 80 90 1000
0.05
0.10
0.15
0.20
0.25
0.30
m
Probability of weekly interaction
x
x x
x xxxxxxxxx
x
x xx
x xx x
The effect of distance on communication
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Low change rate
inter-company integration
High stability
Semantic Versioning
Contract Testing
Tolerant Reader
“Conversational change”
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higher change rate
inter-team integration
lower stability
Semantic Versioning
Contract Testing
Tolerant Reader
“Conversational change”
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highest change rate
intra-team
lowest stability
Semantic Versioning
Contract Testing
Tolerant Reader
“Conversational change”
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the future is scary
we are learning 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
and new techniques to apply:
Consumer Driven Contracts Semantic Monitoring Semantic Versioning Testing in Production Failure Isolation
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do the simplest thing possible
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jalewis@thoughtworks.com
@boicy
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jalewis@thoughtworks.com
@boicy
Thanks!