REST APIs Versioning: Hands-on !

This workshop aims to

• Introduce REST API Versioning
• Highlight API breaking and non breaking changes
• Dive into all the impacts: configuration, code, security,...

🎯 Big picture

During this workshop we will strive with API versioning on a (small) microservice application. Here is a short description of it.

This platform aims to store and get books of a bookstore.

System View

C4Context
      title System Context diagram for Bookstore System
      Person(customerA, "Bookstore Customer", "A customer of the bookstore") 
      Person(adminA, "Bookstore Administrator", "An administrator of <br/> the bookstore") 
      Enterprise_Boundary(b0, "Bookstore Boundary") {
        System(bookstoreSystem, "Bookstore System", "Allows Book <br/> creation, search,...")  
        System(iamSystem, "Bookstore IAM", "Allows Identification <br/> & authorization...")  
      }
      Rel(customerA, bookstoreSystem, "Uses")
      Rel(adminA, bookstoreSystem, "Uses & manage users")
      Rel(customerA, iamSystem, "identifies & authorizes")
      Rel(adminA, iamSystem, "identifies & authorizes")

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Explanations

Here we have two main kind of users:

• Customer : He can browse and create books
• Administrator: He can create books and activate/deactivate the maintenance mode

Within our platform, we have two main systems:

• Bookstore system which operate all the book related operations
• Bookstore IAM which is responsible for identifying and authorizing users

Container view

C4Container
      title Container Context diagram for Bookstore System


      Person(customerA, "Bookstore Customer", "A customer of the bookstore") 
      Person(adminA, "Bookstore Administrator", "An administrator <br/> of the bookstore") 

      Enterprise_Boundary(b0, "Bookstore Boundary") {
        Container_Boundary(b2,"Bookstore IAM"){
          Container(iam,"IAM","Provides a JWT token with roles in claims")

               }
        Container_Boundary(b1,"Bookstore System"){
            Container(bookstoreApi,"Bookstore API","Spring Boot, Cloud","Exposes the Bookstore APIs")
            Container(gateway,"API Gateway","Spring Cloud Gateway","Exposes the APIs")
            ContainerDb(database, "Database", "PostgreSQL Database", "Stores bookstore")
            Container(isbnApi,"ISBN","Spring Boot, Cloud","Exposes the ISBN APIs")
            Container(configuration,"Configuration Server","Spring Cloud Config","Exposes the configuration")
            Container(zipkin,"Zipkin","Zipkin","Gathers and <br/> provides distributed tracing")
        }
      }

      Rel(customerA,gateway, "Uses")
      Rel(adminA, gateway, "Uses & manage users")
      Rel(customerA, iam, "identifies & authorizes")
      Rel(adminA, iam, "identifies & authorizes")
      Rel(gateway, iam, "verify token")
      Rel(gateway, bookstoreApi, "exposes")
      Rel(gateway, isbnApi, "exposes")
      Rel(bookstoreApi, isbnApi, "uses")
      Rel(bookstoreApi, database, "stores data")
      UpdateLayoutConfig($c4ShapeInRow="3", $c4BoundaryInRow="1")

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Explanations

This diagram digs into the systems exposed above in the system view.

The Bookstore system is composed of:

• The API Gateway which exposes our APIs
• The Bookstore API which exposes all the related book APIs and stores data to a PostgreSQL database
• The ISBN API which provides random ISBN numbers
• A Configuration server which centralizes all the configuration files

The Bookstore IAM is composed of:

• A mock server which provides JWT token with appropriate roles and information.

📏 Stack

Here is a summary of the stack used in this workshop for this architecture:

Container	Tools	Comments
API Gateway	Spring Cloud Gateway 2023.0.0
Bookstore API	JAVA 21,Spring Boot 3.2.X
ISBN API	JAVA 21,Spring Boot 3.2.X
Configuration Server	Spring Cloud Config 2023.0.0
Database	PostgreSQL
Authorization Server	JAVA 21,Spring Boot 3.2.X, Spring Authorization Server 1.1.0

Customers

Our API Roadmap

%%{init: { 'logLevel': 'debug', 'theme': 'base', 'gitGraph': {'rotateCommitLabel': true}} }%%
gitGraph:
    commit id:"Init"
    commit id: "new features" tag:"Adding excerpt attribute & operation"
    branch V1
    checkout V1
    commit id:"add URI PATH versions"
    commit id: "add HTTP Header versions"
    commit id: "add accept HTTP Header versions"
    checkout main
    branch V2
    commit id: "revamping"
    commit id: "Add author list feature"
    checkout V1
    commit id: "Add fallback behaviour in V1"
    checkout V2
    commit id: "Authorization management"
    merge V1
    commit id: "Deprecating V1"

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🚥 Prerequisites

🎓 Skills

Skill	Level
REST API	proficient
Java	novice
Gradle	novice
Spring Framework, Boot, Cloud Config, Cloud Gateway Spring Authorization Server	novice
OpenID Connect	novice
Docker	novice

🔧 Tools

If you want to execute this workshop locally

You MUST have set up these tools first:

• Java 21+
• Gradle 8.5+
• Docker & Docker compose
• Any IDE (IntelliJ IDEA, VSCode, Netbeans,...) you want
• cURL, jq, HTTPie or any tool to call your REST APIs

Here are commands to validate your environment:

Java

java -version
openjdk version "21.0.1" 2023-10-17 LTS
OpenJDK Runtime Environment Temurin-21.0.1+12 (build 21.0.1+12-LTS)
OpenJDK 64-Bit Server VM Temurin-21.0.1+12 (build 21.0.1+12-LTS, mixed mode, sharing)

Gradle

If you use the wrapper, you won't have troubles. Otherwise...:

gradle -version

------------------------------------------------------------
Gradle 8.5
------------------------------------------------------------

Build time:   2023-11-29 14:08:57 UTC
Revision:     28aca86a7180baa17117e0e5ba01d8ea9feca598

Kotlin:       1.9.20
Groovy:       3.0.17
Ant:          Apache Ant(TM) version 1.10.13 compiled on January 4 2023
JVM:          21.0.1 (Eclipse Adoptium 21.0.1+12-LTS)
OS:           Linux 5.15.133.1-microsoft-standard-WSL2 amd64

Docker Compose

docker compose version
    
Docker Compose version v2.22.2

🚀 If you don't want to bother with a local setup

With Gitpod (recommended)

You can use Gitpod. You must create an account first. You then can open this project in either your local VS Code or directly in your browser:

With Github Codespaces

You can also use Github Codespaces. You can create a new one by running "Code > Create codespace on main".

You have then to run the command in the shell:

pip install httpie
sdk install java 21.0.1-tem
sdk default java 21.0.1-tem

💥 Ready ?

If you fork this repo

Don't forget to change the "Open in GitPod" button URL:

[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#github.com/%%MY_NAMESPACE%%/rest-apis-versioning-workshop.git)

or you can directly browse this URL (think to change the %%MY_NAMESPACE%% prefix):

https://gitpod.io/#github.com/%%MY_NAMESPACE%%/rest-apis-versioning-workshop.git

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Now, you can start the workshop 🎉.