Head First Software Architecture: A Learner's Guide to Architectural Thinking 9781098134358

Table of contents :
O’Reilly Books
Table of Contents (the real thing)
How to use this Book: Intro
Who is this book for?
Who should probably back away from this book?
We know what you’re thinking
We know what your brain is thinking
This must be important! Don’t forget it!
Metacognition: Thinking about thinking
So just how DO you get your brain to treat software architecture like it’s a hungry tiger?
Here’s what WE did
Here’s what YOU can do to bend your brain into submission
Read me
We break things down, then build them back again.
We don’t exhaustively cover everything.
The activities are NOT optional.
The redundancy is intentional and important.
The examples are as generic as possible.
The Brain Power exercises don’t always have answers.
O’Reilly online learning
Do it yourself chapters
The technical review team
Joint acknowledgments
Individual acknowledgments
1. Software Architecture Demystified: Let’s Get Started!
Building your understanding of software architecture
Building plans and software architecture
The dimensions of software architecture
Puzzling out the dimensions
The first dimension: Architectural characteristics
The second dimension: Architectural decisions
The third dimension: Logical components
The fourth dimension: Architectural styles
A design perspective
An architectural perspective
The spectrum between architecture and design
Where along the spectrum does your decision fall?
Is it strategic or tactical?
How much effort will it take to construct or change?
Does it have significant trade-offs?
Strategic versus tactical
High versus low levels of effort
Code Magnets
Significant versus less-significant trade-offs
Putting it all together
You made it!
Software Architecture Crossword
Code Magnets Solution
Software Architecture Crossword Solution
2. Architectural Characteristics: Know Your Capabilities
Causing Lafter
Cubicle conversation
What are architectural characteristics?
Defining architectural characteristics
Characteristics are nondomain design considerations
Characteristics influence architectural structure
Limit characteristics to prevent overengineering
Consider explicit and implicit capabilities
The International Zoo of “-ilities”
Process architectural characteristics
Structural architectural characteristics
Operational architectural characteristics
Cross-cutting architectural characteristics
Sourcing architectural characteristics from the problem domain
Sourcing architectural characteristics from environmental awareness
Sourcing architectural characteristics from holistic domain knowledge
Composite architectural characteristics
Priorities are contextual
Lost in translation
Architectural characteristics and logical components
Architectural characteristics ≈ capabilities
Logical components = behavior
Balancing domain considerations and architectural characteristics
Limiting architectural characteristics
The magical number 7
Characteristics Crossword
Characteristics Crossword Solution
3. The Two Laws of Software Architecture: Everything’s a Trade-Off
It starts with a sneaker app
What do we know so far?
Communicating with downstream services
Analyzing trade-offs
Trade-off analysis: Queue edition
Trade-off analysis: Topic edition
The first law of software architecture
It always comes back to trade-offs
Making an architectural decision
What else makes a decision architectural?
The second law of software architecture
Architectural decision records (ADRs)
Cubicle conversation
Writing ADRs: Getting the title right
Writing ADRs: What’s your status?
Writing ADRs: What’s your status? (recap)
Writing ADRs: Establishing the context
Writing ADRs: Communicating the decision
Writing ADRs: Considering the consequences
Writing ADRs: Ensuring governance
Writing ADRs: Closing notes
The benefits of ADRs
Two Many Sneakers is a success
“Two Laws” Crossword
“Two Laws” Crossword Solution
4. Logical Components: The Building Blocks
Logical components revisited
Adventurous Auctions goes online
Logical versus physical architecture
Creating a logical architecture
Step 1: Identifying initial core components
Workflow approach
Actor/action approach
The entity trap
Step 2: Assign requirements
Step 3: Analyze roles and responsibilities
Sticking to cohesion
Step 4: Analyze characteristics
The Bid Capture component
Component coupling
Afferent coupling
Efferent coupling
Measuring coupling
A tightly coupled system
Applying the Law of Demeter
A balancing act
Some final words about components
Logical Components Crossword
Logical Components Crossword Solution
5. Architectural Styles: Categorization and Philosophies
There are lots of architectural styles
The world of architectural styles
Partitioning: Technical versus domain
Deployment model: Monolithic versus distributed
Monolithic deployment models: The pros
Monolithic: The cons
Distributed deployment models: The pros
Distributed deployment models: The cons
Fireside Chats
And that’s a wrap!
Stylin’ Architectures Crossword
Stylin’ Architectures Crossword Solution
6. Layered Architecture: Separating Concerns
Naan & Pop: Gathering requirements
Cubicle conversation
Design patterns redux
Layering MVC
Layering it on
Translating layers into code
Domains, components, and layers
Drivers for layered architecture
Layers, meet the real world: Physical architectures
Physical architecture trade-offs
Cubicle conversation
One final caveat about domain changes
Layered architecture superpowers
Layered architecture kryptonite
Layered architecture star ratings
Wrapping it up
Layered Architecture Crossword
Layered Architecture Crossword Solution
7. Modular Monoliths: Driven by the Domain
Cubicle conversation
Modular monolith?
Domain pains changes
Why modular monoliths?
Show me the code!
Cubicle conversation, continued...
Keeping modules modular
Keeping modules modular (last time!)
Taking modularity all the way to the database
Beware of joins
Modular monolith superpowers
Modular monolith kryptonite
Modular monolith star ratings
Naan & Pop is delivering pizza!
Modular Monolith Crossword
Modular Monolith Crossword Solution
8. Microkernel Architecture: Crafting Customizations
The benefits of Going Green
Cubicle conversation
The two parts of microkernel architectures
The spectrum of “microkern-ality”
Device assessment service core
Encapsulated versus distributed plugins
Plugin communication
Cubicle conversation
Plugin contracts
Going Green goes green
Microkernel superpowers
Microkernel kryptonite
Microkernel star ratings
Wrapping it up
Microkernel Crossword
Microkernel Crossword Solution
9. Do It Yourself: The TripEZ Travel App
Making travel easier
TripEZ’s user workflow
Planning the architecture
The architects’ roadmap
Step 1: Identify architectural characteristics
Step 2: Identify logical components
Step 3: Choose an architectural style
Step 4: Document your decision
Step 5: Diagram your architecture
There are no right (or wrong) answers
10. Microservices Architecture: Bit by Bit
Are you feeling okay?
Cubicle conversation
What’s a microservice?
It’s my data, not yours
How micro is “micro”?
Granularity disintegrators
Why should you make microservices smaller?
Granularity integrators
Why should you make microservices bigger?
It’s all about balance
Sharing functionality
Code reuse with a shared service
Code reuse with a shared library
Fireside Chats
Managing workflows
Orchestration: Conducting microservices
Choreography: Let’s dance
Microservices architecture superpowers
Microservices architecture kryptonite
Microservices star ratings
Wrapping it up
Microservices Crossword
Microservices Crossword Solution
11. Event-Driven Architecture: Asynchronous Adventures
Too slow
Speeding things up
Der Nile flows faster than ever
What is an event?
Events versus messages
Initiating and derived events
Is anyone listening?
Asynchronous communication
Fireside Chats
Fire-and-forget
Asynchronous for the win
Synchronous for the win
Database topologies
Monolithic database
Monolithic database topology scorecard
Domain-partitioned databases
Domain-partitioned databases topology scorecard
Database-per-service
Database-per-service topology scorecard
EDA versus microservices
Hybrids: Event-driven microservices
Event-driven architecture superpowers
Event-driven architecture kryptonite
Event-driven architecture star ratings
Putting it all together
Wrapping up
Event-Driven Crossword
Event-Driven Crossword Solution
12. Do It Yourself: Testing Your Knowledge
Welcome to Make the Grade
Student testing workflow
Planning the architecture
The architects’ roadmap
Step 1: Identify architectural characteristics
Step 2: Identify logical components
Step 3: Choose an architectural style
Step 4: Document your decision
Step 5: Diagram your architecture
There are no right (or wrong) answers!
A. Leftovers: The Top Six Topics We Didn’t Cover
#1 The coding architect
#2 Expectations for architects
#3 The soft skills of architecture
#4 Diagramming techniques
#5 Knowledge depth versus breadth
#6 Practicing architecture with katas
How to run katas
Preparation
Discussion
Presentation
Don’t worry. This isn’t goodbye.
Index