Presentation: Agile Architecture Is Not Fragile Architecture
Architecture is perceived as a heavy-weight activity which does not fit well into an Agile process, so many teams start without it, just to find themselves re-doing the software later because the code structure was not good enough to support maintainability and growth. Because the domain was not understood in the first place, the code that reflects it needs to be changed beyond the point of refactoring, and when that happens some architectural decisions are to be made. That defers the initial software design to a later point, introducing unnecessary delays and costs in the project.
In this presentation filmed during QCon 2007, Coplien and Henney describe how to start with enough architecture to ensure long term success of the project.
I love this presentation!
To do agile you should be standing on a firm foundation.
Stability != Static
I also was a bit disappointed that they confuse the adjective "agile" with the *name* "Agile Software Development". Scrum, DSDM and XP are instances of the latter, which is *defined* by the Agile Manifesto.
Agile Fragile Architecture summary
Martien van Steenbergen
Free interpretation of [www.infoq.com/presentations/Agile-Architecture-... InfoQ: Agile Architecture Is Not Fragile Architecture]
By James Coplien and Kevlin Henny.
- Agile Architecture is not a blueprint.
- Agile Architecture is about what changes you can ignore.
- Agile Architecture is about impactful choices up front that will make later chioces easy..
- Agile Architecture is not laissez fair.
- Agile Architecture embodies the critical design decisions that typify a system: relates to cost of change, organisational structure (isomorph; ...'s law)m structure of code, capabilities of a system, etc.
- Agile Architecture is about the significance of decisions that need to be understood and assessed.
- Agile Architecture is about to see the forest for the trees.
- Agile Architecture is subject to change.
- Agile Architecture is not about insuring fear.
- Agile Architecture is about stable ground, but not frozen (static) ground.
- CAT DOG‚ÄîComponent Architecture Group and Distributed Objects Group
- Agile Architecture is about a shared vision that educes the best out of smart knowledgeable developers and delivers (business) value in the most effective and efficient way.
- Agile Architecture is not about big (outdated buggy) documents.
- Agile Architecture is about the documentation that packs the punch, that describes what matters.
- Agile Architecture is about writing that what matters in a way that matters (go, have a writing course).
- Agile Architecture is about getting a Mercenary Analist.
- Agile Architecture is about empowering local decisions (decision makers near the action).
- Agile Architecture is about patterns and principles.
- Agile Architecture is about team conversations and communication and team effort and team organisation and team structure.
- Agile Architecture is about minimal coupling and maximum cohesion.
- Agile Architecture is about speeding up, getting velocity in your team.
- Agile Architecture is the foundation for interaction design (GUI)‚ÄîThe Interface is the Program, (Raskin))‚Äîthe user interacts almost immediately with the architecture (tightly linked through the user interface).
- Agile Architecture is about separation of concerns, not about divorce‚Äîinvites to focus on protocol over API.
- Agile Architecture is guided (driven) by interaction design (and the domain model).
- Agile Architecture is about understanding the thing you are building, about the process of building it, and about making progress in building it.
- Agile is an adjective (bijvoegelijk naamwoord)‚Äîhaving the faculty of quick motion, nimble, active, ready. Latin: to do. (You actually have to do something.) Agilious.
- Agile is not a method, a religion. (Although, in the English language, you can verb any noun and noun any verb.)
- Agile can describe a process, an organisation, an architecture, a mentality, an attitude, a mindset, a skill set, etc.
- Agile is not "done" (you cannot "do" agile).
- Agile does not sound scary.
- Agile Architecture makes you ready.
- Agile Architecture makes you active.
- Agile Architecture makes you nimble.
- Agile Architecture enables you to move quickly.
- Agile Architecture is good when it reduces the significance of decisions (so you can have decision makers near the action with confidence).
- Agile Architecture helps amortising cost of change. (Architectuur helpt met teniet doen van veranderkosten).
- Agile Architecture helps releasing energy and passion in those who use it, live it or grow on it.
- Agile Architecture becomes ossified (verbeend, versteend, afgestompt) door FUD (AOT) en bureaucracy.
- Agile Architecture is about making the hard decisions early so the easy decisions become easier. Doing the easy ones first makes the hard ones harder. Metpahor: fill up a barrel with various size stones: first the big ones, then the small ones: gives more leverage: the small rocks will find the spaces to fit into.
- Agile Architecture is about discrimination between reversible and irreversible decisions (at the appropriate time; sometimes knowing that it is or will be an important decision, and you are not yet able to decide but know when you must be. So you can safely defer your decision until then).
- Agile Architecture is about forgiveness and that it is okay to make mistakes.
- Agile Architecture is about sustainability of people, process and code.
- Agile Architecture is about feedback at different levels of (time) scale.
- Agile Architecture is about awareness and visibility of what is being built and how.
- Agile Architecture is about the right detail at the right time and in the right place (TDD).
- Agile Architecture facilitates and guides test-driven development.
- Agile Architecture is about the engagement of the people in the process.
- Agile Architecture is about failing comfortably fast (rather than slow and in an agonizing and painful) and knowing about it.
- Agile Architecture is about fashionable systems.
- Agile Architecture is about dramatically reducing risk at all levels.
- Agile Architecture is about dramatically reducing evolutionary costs (operations and maintenance, even demolition).
- To Architect is not a verb. To Design is. Architecture is a product of design.
- Architects are developers, coders and designers.
- Agile Architecture is about (SSSUFD) Some Short Small Design Up Front.
- Ten minutes is good, half an hour is max.
- Let the code participate in the design session.
- BUFD the project slayer.
- Analyze This To Death (ATTD).
- Fear-driven design (FDD) vs. Courage Driven Design (CDD) with TDD at different levels of (time) scale for your feedback loops.
- Niels Bohr: Be careful about predicting things, especially if they concern the future. The joy of quantum mechanics.
- BUFD is on one extreme.
- NUFD (No Up Front Design) is the other extreme.
- Can work under condition (circumstances) degree of familiarity.
- There is no such thing as NUFD‚Äîyour years of experience do count as UFD.
- Architectural patterns are UFD based on up front experience.
- NUFD needs YNUFE (You Need Up Front Experience)).
- Risky paths do need SSSUFD.
- RUFD (Rough Design Up Front): give me the map, the whole elephant, the countours, the vision, the overview, that's enough. I can then figure out the right details at the right time.
- How much of RUFD is enough?
- It depends.
- Develop your feel about it.
- It can take as long as two sprints and as short as '''about a week'''.
- A nice packaging is to use a single sprint.
- Must have working code at the end of this sprint.
- Deliver your architecture as code, as abstract base classes and some '''base-lined''' documents.
- It grounds you in reality and gives you the platform to take off and implement the user stories as you go forward.
- Spike it.
- Agile Architecture is about pay now or pay later:
- Especially in the financial market.
- Second or third to market are often more successful thant first to market.
- Marktonderzoek wijst uit dat sterftecijfer onder first to market is veel hoger dan onder second or third to market.
- Als tweede of derde in de markt zijn geeft je de mogelijkheid te leren van de fouten van anderen.
- Zie bijvoorbeeld AltaVista -> Yahoo -> Google.
- Agile Architecture is about a single up front sprint doing inception, cranking out abstract base classes and some relevant baselined documentation.
- Accelerating during the third and subsequent sprints.
- Agile Architecture is about doing RUFD and poetry or short stories as documentation during the first sprint.
- Agile Architecture is about continuously evolving the architecture after the first sprint.
- Agile Architecture is about having it finished at the end of each sprint.
- Agile Architecture is about structure that aligns with the domain and its organization (and its ecosystem).
- Agile Architecture is about efficient refactoring‚ÄîNot about being first to market, then redesigning your whole system during the fourth sprint after you had the "Oh, shit" experience during the third sprint, taking a three-month slip, and ending up as last and loser.
- Agile Architecture is about the critical things that we currently do not know enough and will '''inform''' (give form and shape to) our system and take responsibility for it now, and defer the less critical ones to a subsequent sprint and handle them at the right time.
- Agile Architecture is about interfaces: locality, dependancy horizon: put yourself in a class and look for its boundaries:
- Where do you enter the system classes?
- How much and how far can you see?
- It's really worrying if you can see yourself‚Äîstrange loops.
- How distant is it?
- How much do you need to know (of the world) in order to implement yourself?
- You want the world to be relatively small in order to be good at your responsibilities.
- You want the horizon to be fairly close. Interfaces are a very useful way to increase locality (as well as decision makers near the action).
- Agile Architecture is about having the courage to change architecture
- Don't be afraid of changing architecture‚Äîtt's software.
- Hindsight often shows that it wasn't so hard after all‚Äîit's software. It's malleable.
- Be suprised by how '''soft''' you can make it, especially the coupling‚Äîmake it loose.
- Hardware is relatively easy to change too.
- Decompose it and rearrange it in new, innovative ways and be surprised.
- Decompose with respect to time.
Pity no write up...
Architecture can't be only made of hope!