Agile software architecture

Agile and Architecture: An Oxymoron?
Building robust software in an agile world

● 6+ years fullstack developer
● 3+ years technical architect @ one45 software
What I like to code in:
● iOS (objective-c, swift)
● PHP, Symfony 2,3,4(coming soon)
● AngularJS ??(1,2) ===> (React vs Vu)
Currently working on:
● Data Integration
● ML/AI
● Data visualization
Slido.com #6512
Hi my name is Scott Hsieh

Agile development
Lean Agile
Find the right
product
Building product
and getting the
product to client
MVP
Product
Management
Project
Management
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3 Amigos approach
- Plan
- Develop
- Test/Verify
- Ship
Good for getting things out the
door but not so much for putting
out robust code. We will see why
later.
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Typical Lifespan of a project (what management expects)
Time
Project
health
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Typical Lifespan of a project (What actually happened)
Time
Project
Health
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Journey of a software project - the beginning
Time
beginning
coupling
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Journey of a software project - the middle
Time coupling
a mistake
occurred
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Journey of a software project - the beginning
coupling
compensation
for mistake
Time
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Journey of a software project - the end
Time
rewrite
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The finished product
● A product that ...
○ That is 100% functional (MVP)
○ Changes made overtime have
reduced the ability to make future
changes as fast original pace
○ Full of software mistakes that are
invisible to Clients and QA aka
“technical debt”
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● Code does not moist, rot, degrade
● There are no crap elves that comes out at night and add
bad code
Code does not go bad on its own
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Code is bad only if we
put it there.
We are the crap elves.
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Most common causes for software mistakes
● Change in product requirements
● Software management
● Compounding existing technical debts
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Current Development Process
Lean Agile
Customer
Value
Speed/AgilityMVP
Fastest
way to
deliver
value
Product
Management
Project
Management
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The missing link
Lean Agile
Speed/Agility
Product
Management
Structure of
Development
Customer
Value
Architecture
Quality
MVP
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Software Architecture in Agile world
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Agility in Software Architecture
Adaptation Anticipation
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How does Software Architecture help?
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Change in requirement
● Change in scope of the project
● Adding new functionality to systems that
was not originally designed to support
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3 Amigos approach
- Plan
- Develop
- Test/Verify
- Ship
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Software management
Input Output
100% 85% 60% 45%
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Software development is a Relay race
Development as a team is all
about “Momentum transfer”
- Get to the end with minimum
loss in quality
- We spent a lot of time thinking
about how to get started on a
task. If receiver can build
momentum before he/she
receive the task we minimize
“outages”
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Software development
I’m done my
lap. Your turn.
K.
Wall of Confusion

Dual track Agile
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The Zipper model
From product requirements derive:
● Functional requirements
● Architectural requirements
Establish
● Dependencies
● Cost
Plan interleaving:
● Functional increments
● Architectural increments
● Functional Requirement
● Technical Requirement
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The Zipper model benefits
● Gradual emergence of architecture
– Deliberate, not accidental
● Validate on architecture with actual
functionality (not mere hypotheses)
● Just enough to support development
● Functional Requirement
● Technical Requirement

Dual Track Agile
Product Manager, Technical Lead, UX
Scrum master, Technical Lead, Developers

Dual Track Agie
Scrum master, Technical Lead, Developers

Dual Track Agile
Balances between the big picture and
now – an agile software architect has
to think about what is happening
during the development together with
aligning it with the big picture of the
entire system.
Hands-on experience – an agile software
architect is also a developer and
works on the implementation of the
system. This gives first-hand
feedback on the taken architectural
decisions.
Produces prototypes to make Focus on
sustainability
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Project Manager, Technical Lead, Developers

Technical Debt are software mistakes
- When a mistake
happened, this is pretty
much the only chance
you had to fix it
coupling
a mistake
occurred
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Technical Debts are software mistakes
- You cannot build on top of
things you don’t understand
- most of it are compensating flaws
of other mistakes
- most software mistakes can’t be
fixed
- cost/time
- invisible coupling
compensation
for mistake
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● when a mistake happens in a N-tier
architecture if a mistake happened. It will
smooth itself out further away the layer is
from the source
● Components with compensation logic is
no longer re-usable or else technical debt
will multiply
● More expensive to fix down the road
more layer the technical debt is seen
regardless how small it is
N-tier architecture compounding debt
Database/
Repository
Service
View
First mistake, had
the chance to fix it
but ignored
compensation
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- what we can do is correct the
mistakes at the level where the
mistakes happens
- dev team don’t allow direct access
to the resources with mistakes,
only interfacing through the
correction layer
- dev team has to agree on where
the correction layer lives
N-tier architecture debt correction
Database/R
epository
Service
View
mistake
correction
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Conclusion
● Architecture is only as effective if the end goal is clear
● Architecture and Product requirement has to align
● If requirement or the scope of the project change dramatically we don’t
repair/refactor we re-design
● Never access the the resource/logic directly if it has correction to fix the
original mistake
● Dev team should agree upon a standard way on how we should access
those problematic resources in systems going forward
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Agile software architecture

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