book

Building Evolutionary Architectures

by Neal Ford, Rebecca Parsons, Patrick Kua

September 2017

Intermediate to advanced

188 pages

5h 39m

English

O'Reilly Media, Inc.

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Conventions Used in This BookO’Reilly SafariHow to Contact UsAdditional InformationAcknowledgments
Evolutionary ArchitectureHow Is Long-term Planning Possible When Everything Changes All the Time?Once I’ve Built an Architecture, How Can I Prevent It from Gradually Degrading Over Time?Incremental ChangeGuided ChangeMultiple Architectural DimensionsConway’s LawWhy Evolutionary?Summary
What is a Fitness Function?CategoriesAtomic Versus HolisticTriggered Versus ContinualStatic Versus DynamicAutomated Versus ManualTemporalIntentional Over EmergentDomain-specificIdentify Fitness Functions EarlyReview Fitness Functions
Building BlocksTestableDeployment PipelinesCombining Fitness Function CategoriesCase Study: Architectural Restructuring while Deploying 60 Times/DayConflicting GoalsCase Study: Adding Fitness Functions to PenultimateWidgets’ Invoicing ServiceHypothesis- and Data-Driven DevelopmentCase Study: What to Port?
ModularityArchitectural Quanta and GranularityEvolvability of Architectural StylesBig Ball of MudMonolithsEvent-Driven ArchitecturesService-Oriented Architectures“Serverless” ArchitecturesControlling Quantum SizeCase Study: Guarding Against Component Cycles
Evolutionary Database DesignEvolving SchemasShared Database IntegrationInappropriate Data CouplingTwo-Phase Commit TransactionsAge and Quality of DataCase Study: Evolving PenultimateWidgets’ Routing
Mechanics1. Identify Dimensions Affected by Evolution2. Define Fitness Function(s) for Each Dimension3. Use Deployment Pipelines to Automate Fitness FunctionsGreenfield ProjectsRetrofitting Existing ArchitecturesAppropriate Coupling and CohesionEngineering PracticesFitness FunctionsCOTS ImplicationsMigrating ArchitecturesMigration StepsEvolving Module InteractionsGuidelines for Building Evolutionary ArchitecturesRemove Needless VariabilityMake Decisions ReversiblePrefer Evolvable over PredictableBuild Anticorruption LayersCase Study: Service TemplatesBuild Sacrificial ArchitecturesMitigate External ChangeUpdating Libraries Versus FrameworksPrefer Continuous Delivery to SnapshotsVersion Services InternallyCase Study: Evolving PenultimateWidgets’ Ratings
Technical ArchitectureAntipattern: Vendor KingPitfall: Leaky AbstractionsAntipattern: Last 10% TrapAntipattern: Code Reuse AbuseCase Study: Reuse at PenultimateWidgetsPitfall: Resume-Driven DevelopmentIncremental ChangeAntipattern: Inappropriate GovernanceCase Study: Goldilocks Governance at PenultimateWidgetsPitfall: Lack of Speed to ReleaseBusiness ConcernsPitfall: Product CustomizationAntipattern: ReportingPitfall: Planning Horizons
Organizational FactorsCross-Functional TeamsOrganized Around Business CapabilitiesProduct over ProjectDealing with External ChangeConnections Between Team MembersTeam Coupling CharacteristicsCultureCulture of ExperimentationCFO and BudgetingBuilding Enterprise Fitness FunctionsCase Study: PenultimateWidgets as a PlatformWhere Do You Start?Low-Hanging FruitHighest-ValueTestingInfrastructureCase Study: Enterprise Architecture at PenultimateWidgetsFuture State?Fitness Functions Using AIGenerative TestingWhy (or Why Not)?Why Should a Company Decide to Build an Evolutionary Architecture?Case Study: Selective Scale at PenultimateWidgetsWhy Would a Company Choose Not to Build an Evolutionary Architecture?Convincing OthersCase Study: Consulting JudoThe Business Case“The Future Is Already Here…”Moving Fast Without Breaking ThingsLess RiskNew CapabilitiesBuilding Evolutionary Architectures

Overview

The software development ecosystem is constantly changing, providing a constant stream of new tools, frameworks, techniques, and paradigms. Over the past few years, incremental developments in core engineering practices for software development have created the foundations for rethinking how architecture changes over time, along with ways to protect important architectural characteristics as it evolves. This practical guide ties those parts together with a new way to think about architecture and time.