Agile architecture

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Agile architecture

The next silver bullet to solve all your problems

Magnus Mickelsson, Citerus AB

[email protected]

mailto:[email protected]

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Citerus - Magnus Mickelsson, 2011 - [email protected] - 0708-444183

Upfront


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Upfront


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Agile methods

• Deliver working software

• Individuals/communication > processes and tools

• Close to the business

• User stories

• Engineering practices

As a .. <role>I want .. <function>So that .. <purpose>


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Engineering Practices

DONE


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Cowboy-architecture

• Hack something that works, then ”refactoring”

• Structures and patterns emerge..

• .... sometimes.


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Cowboy-architecture

• Hack something that works, then ”refactoring”

• Structures and patterns emerge..

• .... sometimes.


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Where do we place ourselves on the scale?


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Lean-principles

• Go out and see

• Optimize value flow

• Eliminate waste

• 5xWhy?

• Pull, not push


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Lean-principles

• Go out and see

• Optimize value flow

• Eliminate waste

• 5xWhy?

• Pull, not push

• Defects

• Waiting

• Over-production

• Transport

• Complexity

• Unused creativity


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Systems thinking

• How do things really work?

• How do our users work?

• What are the consequences of the current way?

• Improve the process (without IT)

• Pull IT into the improvement work

http://vimeo.com/19122939


http://vimeo.com/19122939

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Lean/Agile architecture work

• Working software

• Working with people > specifications

• Increase knowledge in the organisation

• Eliminate waste

• Systems thinking - optimise the whole

• Be ready to get ”pulled” in


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”Lean Architecture” - Coplien/Björnvig

• ”All together, from early on”

• Reduce need for things that slow down

• Think Lean, be Agile

• Some upfront-work => what the system is

• Use-cases good for what the system does


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DDD - Domain-driven Design

• Cooperation with domain experts yields invaluable knowledge

• Let the domain control the solution design, not technology

• Design that makes maintenance and developer testing easier


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DDD is not just application design

• Big Balls of Mud + Entropy -> Core Domain

• Context mapping


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Whirlpool model exploration method


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Example #1 - simple/isolated webapp

• Now, target, expectations

• How do things really work?

• What can be done without IT?

• Gather user stories (detail a few)

• Ubiqutous language (DDD)

• Explore architecture/design - sprint 0

• 1-2 spikes


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Explore, think, test, measure, improve...


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... and maybe, just maybe ...


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Example #2 - average to large system

• Systems thinking

• Use-cases or user stories?

• Context mapping

• Architecture (form) - what is the system?

• Map subsystems to teams

• Explore what the system does

• Focus on Lean, to be Agile


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Model-View-Controller

Account

Customer

Model

View

Controller Serv

ice


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DCI - Data, Context, Interaction

Account

Customer

Model/Data

View

Controller Context

Role Role

Interaction


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Account

Customer

Model/Data

View

Controller Account transfer

Source account

Target account

Interaction


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Account

Customer

Model/Data

View


Source account

Target account

Account Account

Interaction


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Account

Customer

Model/Data

View


Source account

Target account

Account Account

Interaction

€$


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What’s worth taking home?

• What can be done without IT? Systems thinking

• Use-cases or user stories?

• How much ”form” upfront depends

• Lean principles help us stay Agile

• DDD, Context mapping, DCI


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Questions?

[email protected]@gmail.com

Twitter: magnusmickel



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Reading tips

• Lean architecture (Coplien/Björnvig)

• The Pragmatic Programmer (Hunt/Thomas)

• Domain Driven Design (Evans)

• Working effectively with legacy code (Feathers)

• Refactoring to patterns (Kerievsky)

• Lean Software Development (2*Poppendieck)

• Freedom from Command & Control ... (Seddon)

• Evolutionary architecture & Emergent Design (Ford)

Agile architecture

Technology

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