Collaborative Contract Driven Development Billy Korando Developer - - PowerPoint PPT Presentation

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Collaborative Contract Driven Development Billy Korando Developer - - PowerPoint PPT Presentation

Sep 08, 2023 310 likes •763 views

Collaborative Contract Driven Development Billy Korando Developer Advocate - IBM @BillyKorando william.korando@ibm.com Subscribe to the Java Newsletter https://developer.ibm.com/newsletters/java/ For your Spring & JakartaEE needs

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Collaborative Contract Driven Development

Billy Korando Developer Advocate - IBM @BillyKorando william.korando@ibm.com 📭

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@BillyKorando

Subscribe to the Java Newsletter

https://developer.ibm.com/newsletters/java/

For your Spring & JakartaEE needs

https://cloud.ibm.com/docs/java

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@BillyKorando

https://billykorando.com/

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@BillyKorando

CONTRACT DRIVEN DEVELOPMENT DEFINED

(BRIEFLY)

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@BillyKorando

DEFINING THE BEHAVIOR OF AN API

SERVICE CLIENT

Response: 200 { … } Request /api/… { … }

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@BillyKorando

DECONSTRUCTING THE STATUS QUO (i.e. WHY DEVELOPMENT IS DIFFICULT WITHOUT CONTRACTS)

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@BillyKorando

POORLY DEFINED SERVICES

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@BillyKorando

POORLY DEFINED SERVICES

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@BillyKorando

SCENE BREAKDOWN

  • Poorly defined or undocumented API
  • Inconsistent behavior or patterns
  • Testing against a live service can lead to inconsistent results
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@BillyKorando

VERY SERIAL DEVELOPMENT

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@BillyKorando

VERY SERIAL DEVELOPMENT

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@BillyKorando

SCENE BREAKDOWN

  • Inability to develop in parallel
  • Timeline impacted by delays from both service and client developers
  • Client developer will have to get back up to speed
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@BillyKorando

I AM ALTERING THE API

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@BillyKorando

I AM ALTERING THE API

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@BillyKorando

SCENE BREAKDOWN

  • Breaking API changes not caught until production
  • API design governed almost entirely by service developer
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@BillyKorando

CONTRACT DRIVEN DEVELOPMENT EXPLAINED

USING SPRING CLOUD CONTRACT

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@BillyKorando

SPRING CLOUD CONTRACT

  • Very active project
  • Inter-operable with other tools/standards: OpenAPI, Packt, Swagger
  • Flexible documentation support with Spring REST Docs
  • Polyglot support

More: https://spring.io/projects/spring-cloud-contract

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@BillyKorando

WRITING THE CONTRACT

Contract.make { label “Add New Person” request { method 'POST' url '/api/persons' body([ fName: “John” lName: “Doe”]) headers { header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_UTF8_VALUE)} } response { status 201 headers { header(HttpHeaders.LOCATION, 'api/persons/1')} } }

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@BillyKorando

VALIDATING THE CONTRACT

✅

Add New Person Service

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@BillyKorando

SHARING THE CONTRACT Stubs Artifact

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@BillyKorando

SHARING THE CONTRACT Artifact Repository Stubs Artifact

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@BillyKorando

DOCUMENTING THE API

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@BillyKorando

VALIDATING AGAINST THE CONTRACT Stubs Artifact Client

✅

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@BillyKorando

CONTRACT DRIVEN DEVELOPMENT IN REVIEW

  • 1. Write contract(s) to define API behavior
  • 2. Contracts validate API matches behavior
  • 3. Bundle contracts as shareable artifact
  • 4. Generate documentation from contracts
  • 5. Clients can test/develop against artifact}

Automated

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@BillyKorando

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@BillyKorando

PRODUCER DRIVEN CONTRACTS THE API WILL LOOK LIKE THIS

OK

SERVICE CLIENT

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@BillyKorando

CONSUMER DRIVEN CONTRACTS

OK

I NEED THIS FROM THE SERVICE SERVICE CLIENT

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@BillyKorando

WHY COLLABORATION IS IMPORTANT

  • Better utilization of developer time
  • More input from parties on API design
  • More buy-in from parties on API design
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@BillyKorando

CAN’T SPELL “COLLABORATIVE” WITHOUT “POLYGLOT”

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@BillyKorando

Javascript Developers JDK Maven Java friendly IDE Docker Text editor Java Developers JDK Maven Java friendly IDE Docker Text editor Other Developers JDK Maven Java friendly IDE Docker Text editor ✅ ✅ ✅ ✅ ✅ ❌ ❌ ❌ ✅ ✅ ❌ ❌ ❌ ✅ ✅ LANGUAGE INDEPENDENT TOOLS

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@BillyKorando

YAML CONTRACT

request: label: “Add New Person” method: POST url: /api/persons body: fName: “John” lName: “Doe” headers: Content-Type: application/json response: status: 201 headers: Location: api/persons/1

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@BillyKorando

DOCKER IMAGES FOR READING CONTRACTS

  • Encapsulates all Java and Spring Cloud Contract logic within a Docker container
  • Images for both consumers and producers
  • Configured by passing in environment variables
  • Example of using producer image link
  • Example of using consumer image link
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@BillyKorando

CONTRACT TESTING WITH DOCKER Client

✅

Stubs Artifact

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@BillyKorando

Service

✅

CONTRACT TESTING WITH DOCKER

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DEMO TIME!

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@BillyKorando

POORLY DEFINED SERVICES

X

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@BillyKorando

SCENE BREAKDOWN

  • API is documented automatically as a result of the process
  • Accurate documentation encourages discussion on design/consistency
  • Clients can develop/test against contracts which give consistent results
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@BillyKorando

VERY SERIAL DEVELOPMENT

X

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@BillyKorando

SCENE BREAKDOWN

  • Client and service developers can work in parallel once contract is written
  • Process encourages discussion on API design
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@BillyKorando

I AM ALTERING THE API

X

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@BillyKorando

SCENE BREAKDOWN

  • API is checked as part of build process
  • Changes will cause either service or client to fail
  • Prevents “rogue” changes from reaching PROD and becoming “finalized”
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@BillyKorando

FINAL POINTS

  • Not just REST/HTTP

, can also write contracts for messages

  • It’s ok to change contracts
  • Contract tests are not acceptance tests nor replace end-to-end tests

○ Not tested: ■ Resiliency ■ Timeout ■ Performance ■ Edge cases

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@BillyKorando

Q & A

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@BillyKorando

SOURCES Code: https://github.com/wkorando/collaborative-contract-driven-development-2-0 https://cloud.spring.io/spring-cloud-contract/single/spring-cloud-contract.html https://spring.io/blog/2018/02/13/spring-cloud-contract-in-a-polyglot-world Contact me: Twitter: @BillyKorando Email: William.Korando@ibm.com