The goals of this project are:

• Create a Spring Boot application that manages books, called book-service;
• Use Keycloak as OpenID Connect provider;
• Test using Testcontainers;
• Explore the utilities and annotations that Spring Boot provides for testing applications.

On ivangfr.github.io, I have compiled my Proof-of-Concepts (PoCs) and articles. You can easily search for the technology you are interested in by using the filter. Who knows, perhaps I have already implemented a PoC or written an article about what you are looking for.

• [Medium] Implementing and Securing a Simple Spring Boot REST API with Keycloak
• [Medium] Implementing and Securing a Simple Spring Boot UI (Thymeleaf + RBAC) with Keycloak
• [Medium] Implementing and Securing a Spring Boot GraphQL API with Keycloak
• [Medium] Building a Single Spring Boot App with Keycloak or Okta as IdP: Introduction

• book-service

  Spring Boot Web application that manages books. MongoDB is used as storage, and the application's sensitive endpoints (like create, update and delete books) are secured.

  book-service-swagger

• Java 21 or higher;
• A containerization tool (e.g., Docker, Podman, etc.)
• jq

Open a terminal and, inside the springboot-keycloak-mongodb-testcontainers root folder, run the script below

./init-environment.sh

There are two ways: running a script or using the Keycloak website

• In a terminal, make sure you are inside the springboot-keycloak-mongodb-testcontainers root folder

• Run the following script to configure Keycloak for book-service application

  ./init-keycloak.sh

  This script will create:

  • company-services realm;
  • book-service client;
  • manage_books client role;
  • user with username ivan.franchin and password 123 and with the role manage_books assigned.

• The book-service client secret (BOOK_SERVICE_CLIENT_SECRET) is shown at the end of the execution. It will be used in the next step.

• You can check the configuration in Keycloak by accessing http://localhost:8080. The credentials are admin/admin.

• Access http://localhost:8080

• Login with the credentials

  Username: admin
  Password: admin
  

• On the left menu, click the dropdown button that contains Keycloak and then, click Create Realm button
• Set company-services to the Realm name field and click Create button

• On the left menu, click Authentication
• Select Required actions tab
• Disable Verify Profile

• On the left menu, click Clients
• Click Create client button
• In General Settings
  • Set book-service to Client ID
  • Click Next button
• In Capability config
  • Enable Client authentication toggle switch
  • Click Next button
• In Login settings tab
  • Set http://localhost:9080/* to Valid redirect URIs
  • Click Save button
• In Credentials tab, you can find the secret generated for book-service
• In Roles tab
  • Click Create role button
  • Set manage_books to Role Name
  • Click Save button

• On the left menu, click Users
• Click Create new user button
• Set ivan.franchin to Username field
• Click Create
• In Credentials tab
  • Click Set password button
  • Set the value 123 to Password and Password confirmation
  • Disable the Temporary toggle switch
  • Click Save button
  • Confirm by clicking Save password button
• In Role Mappings tab
  • Click Assign role button
  • Click Filter by realm roles dropdown button and select Filter by clients
  • Select [book-service] manage_books name and click Assign button

• Open a new terminal and navigate to the springboot-keycloak-mongodb-testcontainers root folder

• Run the following command to start the application

  ./gradlew book-service:clean book-service:bootRun --args='--server.port=9080'

• In a terminal, navigate to the springboot-keycloak-mongodb-testcontainers root folder

• Build Docker Image

  ./build-docker-images.sh

  Environment Variable	Description
  MONGODB_HOST	Specify host of the Mongo database to use (default localhost)
  MONGODB_PORT	Specify port of the Mongo database to use (default 27017)
  KEYCLOAK_HOST	Specify host of the Keycloak to use (default localhost)
  KEYCLOAK_PORT	Specify port of the Keycloak to use (default 8080)

• Run book-service docker container, joining it to project Docker network

  docker run --rm --name book-service \
   -p 9080:8080 \
   -e MONGODB_HOST=mongodb \
   -e KEYCLOAK_HOST=keycloak \
   --network=springboot-keycloak-mongodb-testcontainers-net \
   ivanfranchin/book-service:1.0.0

• In a terminal, create an environment variable that contains the Client Secret generated by Keycloak to book-service at Configure Keycloak step

  BOOK_SERVICE_CLIENT_SECRET=...

• When running book-service with Gradle

  Run the commands below to get an access token for ivan.franchin

  ACCESS_TOKEN=$(curl -s -X POST \
   "http://localhost:8080/realms/company-services/protocol/openid-connect/token" \
   -H "Content-Type: application/x-www-form-urlencoded" \
   -d "username=ivan.franchin" \
   -d "password=123" \
   -d "grant_type=password" \
   -d "client_secret=$BOOK_SERVICE_CLIENT_SECRET" \
   -d "client_id=book-service" | jq -r .access_token)
  echo $ACCESS_TOKEN

• When running book-service as a Docker Container

  Run the commands below to get an access token for ivan.franchin

  ACCESS_TOKEN=$(
   docker run -t --rm -e CLIENT_SECRET=$BOOK_SERVICE_CLIENT_SECRET --network springboot-keycloak-mongodb-testcontainers-net alpine/curl:latest sh -c '
   curl -s -X POST http://keycloak:8080/realms/company-services/protocol/openid-connect/token \
   -H "Content-Type: application/x-www-form-urlencoded" \
   -d "username=ivan.franchin" \
   -d "password=123" \
   -d "grant_type=password" \
   -d "client_secret=$CLIENT_SECRET" \
   -d "client_id=book-service"' | jq -r .access_token)
  echo $ACCESS_TOKEN

  Note: We are running a alpine/curl Docker container and joining it to the project Docker network. By specifying "keycloak:8080" as host/port, we won't encounter the error related to an invalid token issuer.

• In jwt.io, you can decode and verify the JWT access token

• In terminal, call the endpoint GET /api/books

  curl -i http://localhost:9080/api/books

  It should return:

  HTTP/1.1 200
  []
  

• Try to call the endpoint POST /api/books, without access token

  curl -i -X POST http://localhost:9080/api/books \
   -H "Content-Type: application/json" \
   -d '{"authorName": "Ivan Franchin", "title": "Java 8", "price": 10.5}'

  It should return:

  HTTP/1.1 401
  

• Get the Access Token as explained on section Getting Access Token

• Call the endpoint POST /api/books, now informing the access token

  curl -i -X POST http://localhost:9080/api/books \
   -H "Authorization: Bearer $ACCESS_TOKEN" \
   -H "Content-Type: application/json" \
   -d '{"authorName": "Ivan Franchin", "title": "Java 8", "price": 10.5}'

  It should return something like:

  HTTP/1.1 201
  {"id":"612f4f9438e39e473c4d098b", "authorName":"Ivan Franchin", "title":"Java 8", "price":10.5}
  

• Access http://localhost:9080/swagger-ui.html

• Click GET /api/books to open it. Then, click Try it out button and, finally, click Execute button.

  It will return a HTTP status code 200 and an empty list or a list with some books if you've already added them.

• Now, let's try to call a secured endpoint without authentication. Click POST /api/books to open it. Then, click Try it out button (you can use the default values) and, finally, click Execute button.

  It will return:

  Code: 401
  Details: Error: response status is 401
  

• Get the Access Token as explained on section Getting Access Token

• Copy the token generated and go back to Swagger

• Click the Authorize button and paste the access token in the Value field. Then, click Authorize and, to finalize, click Close

• Go to POST /api/books, click Try it out and, finally, click Execute button.

  It should return something like:

  HTTP/1.1 201
  {
   "id": "612f502f38e39e473c4d098c",
   "authorName": "Ivan Franchin",
   "title": "SpringBoot",
   "price": 10.5
  }
  

• MongoDB

  List books

  docker exec -it mongodb mongosh bookdb
  db.books.find()

  Type exit to get out of MongoDB shell

• To stop book-service, go to the terminal where the application is running and press Ctrl+C;
• To stop the Docker containers started using the ./init-environment.sh script, make sure you are in springboot-keycloak-mongodb-testcontainers and run the script below:

  ./shutdown-environment.sh

To remove the Docker image created by this project, go to a terminal and, inside the springboot-keycloak-mongodb-testcontainers root folder, run the following script:

./remove-docker-images.sh

• In a terminal and inside the springboot-keycloak-mongodb-testcontainers root folder, run the command below to run unit and integration tests

  ./gradlew book-service:clean book-service:assemble \
   book-service:cleanTest \
   book-service:test \
   book-service:integrationTest

  Note: During integration tests, Testcontainers will automatically start MongoDB and Keycloak containers before the tests begin and shut them down when the tests finish.

• From the springboot-keycloak-mongodb-testcontainers root folder, the Unit Testing Report can be found at:

  book-service/build/reports/tests/test/index.html
  

• From the springboot-keycloak-mongodb-testcontainers root folder, the Integration Testing Report can be found at:

  book-service/build/reports/tests/integrationTest/index.html