Contract-driven development with OpenAPI 3 and Vert.x | DevNation Tech Talk

Contract-driven development with OpenAPI 3 and Vert.x | DevNation Tech Talk

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  Contract-driven development with OpenAPI 3and Vert.x Francesco Guardiani @slinkydeveloper Software Engineer, Red Hat
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  @slinkydeveloper routerFactory .operation("slinkydeveloperAboutMe") .handler(context -> context .json(new JsonObject() .put("first_name","Francesco") .put("last_name", "Guardiani") .put("employer", "Red Hat") .put("job", "Software Engineer - Middleware") .put("education", "BsC IT Engineering @ PoliMi") .put("oss_contributions", new JsonArray() .add("Eclipse Foundation member") .add("Knative Eventing approvers member") ).put("social", new JsonObject() .put("website", "slinkydeveloper.com") .put("mail", "[email protected]") .put("github", "@slinkydeveloper") .put("twitter", "@SlinkyGuardiani")) ) );2
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  How do youtell your frontend colleague how to get a User from the backend? Motivation 3
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  Poll Motivation 4 1) Document sharedbetween teams 2) “For that query parameter, just look at line 13562 of UserRESTResource” 3) You’re a rockstar developer!
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  ⓘ Start presentingto display the poll results on this slide. How do you doc HTTP APIs?
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  HTTP service contracts shouldbe no different from Java APIs! Motivation 6 Schematic Versioning Description Metadata
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  OpenAPI and ContractDriven Development 7 Tl;dr a bunch of YAMLs to describe the contract, so you can finally say to your frontend colleague the name of that query parameter! The OpenAPI Specification (OAS) defines a standard, programming language-agnostic interface description for HTTP APIs, which allows both humans and computers to discover and understand the capabilities of a service without requiring access to source code, additional documentation, or inspection of network traffic. The OpenAPI Specification (OAS) defines a standard, programming language-agnostic interface description for HTTP APIs, which allows both humans and computers to discover and understand the capabilities of a service without requiring access to source code, additional documentation, or inspection of network traffic. Source: https://github.com/OAI/OpenAPI-Specification
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  OpenAPI and ContractDriven Development 8 Source: https://swagger.io/blog/api-strategy/benefits-of-openapi-api-development/
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  And more! OpenAPI.Tools OpenAPIand Contract Driven Development 9 OpenAPI Generator Microcks
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  OpenAPI and ContractDriven Development 10 /pets: get: summary: List all pets operationId: listPets parameters: - name: limit in: query description: How many items to return at one time required: false schema: type: integer format: int32 maximum: 100 responses: '200': description: A array of pets content: application/json: schema: $ref: "#/components/schemas/Pets" '500': description: unexpected error content: application/json: schema: $ref: "#/components/schemas/Error" Json Schema to identify the properties of limit parameter List of parameters GET /pets understands Limit lives in query params When there is a failure, the endpoint replies with a 500 containing a Json The response schema refers to the Json Schema describing the Pets What can I describe with OpenAPI?
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  OpenAPI and ContractDriven Development ● Code-First: Develop the backend code, then generate the contract ● Design-First (or Contract-driven): Develop the contract, then implement the contract (backend code) 11 Including OpenAPI in your workflow
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  OpenAPI and ContractDriven Development 12 What is Contract-Driven Dev? Source: https://apievangelist.com/2018/04/03/openapi-is-the-contract-for-your-microservice/
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  OpenAPI and ContractDriven Development 13 Why Contract-Driven? ● Because you want to allow people to work independently ● Because you want to ensure consistency ● Because you need strong guarantees about service contracts ● Because you, your team, your colleagues, your customers, and your partners can collaborate ● Because you can save time with automation
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  Eclipse Vert.x 14 Resource efficient withnon-blocking I/O Asynchronous by nature Lightweight, modular, flexible Simple APIs, little abstractions Great ecosystem and community Source: https://vertx-web-site.github.io/
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  Eclipse Vert.x 15
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  Eclipse Vert.x 16 ● Documentation ●Introduction to Vert.x - Deven Philips ● Real-world HTTP performance benchmarking, lessons learned - Julien Viet ● Yes, JavaScript Is Faster Than Java (When You Use GraalVM)! - Paulo Lopes ● Modern app programming with RxJava and Eclipse Vert.x - Thomas Segismont ● Vert.x in action - Julien Ponge
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  CONFIDENTIAL Designator Demo demo demodemo demo demo demo demo 17
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  Demo demo demodemo 18 1. Develop the contract with Apicurio 2. Implement the API backend with Vert.x 3. Test it with Postman 4. Hope it works!
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  Questions?
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  Github: @slinkydeveloper Twitter: @SlinkyGuardiani Thankyou!