aas2015001/springboot-graphql-databases

The goal of this project is to explore GraphQL. For it, we will implement two microservices: author-book-api and book-review-api.

springboot-graphql-databases

The goal of this project is to explore GraphQL. For it, we will implement two Spring Boot Web Java applications: author-book-api and book-review-api.

Note: In kubernetes-minikube-environment repository, it's shown how to deploy this project in Kubernetes (Minikube)

Project Diagram

Applications

• author-book-api

  Spring Boot Web Java application that handles authors and books. It exposes a GraphQL endpoint and traditional REST API endpoints. author-book-api uses MySQL as storage and calls book-review-api to get the reviews of the books. It uses Feign to easily create a client for book-review-api and Resilience4j (fault tolerance library) to handle fallback when book-review-api is down. The book ISBN is what connects books stored in author-book-api with the ones stored in book-review-api.

• book-review-api

  Spring Boot Web Java application that handles books and their reviews. It only exposes a GraphQL API and uses MongoDB as storage.

Frontend applications

In the repository react-graphql-databases, I have implemented two ReactJS applications author-book-ui and book-review-ui that are frontend applications for author-book-api and book-review-api, respectively.

If you want to see the complete communication frontend-backend using GraphQL, clone the react-graphql-databases and follow the README instructions.

Prerequisites

• Java 11+
• Docker
• Docker-Compose

Start Environment

• Open a terminal and inside springboot-graphql-databases root folder run

  docker-compose up -d
  

• Wait for containers to be with status running (healthy). To check it, run

  docker-compose ps
  

Run applications with Maven

Inside springboot-graphql-databases, run the following Maven commands in different terminals

• author-book-api

  ./mvnw clean spring-boot:run --projects author-book-api \
  -Dspring-boot.run.jvmArguments="-Dspring.datasource.username=authorbookuser -Dspring.datasource.password=authorbookpass"
  

• book-review-api

  ./mvnw clean spring-boot:run --projects book-review-api \
  -Dspring-boot.run.jvmArguments="-Dspring.data.mongodb.username=bookreviewuser -Dspring.data.mongodb.password=bookreviewpass"
  

Run Applications as Docker containers

Build Application's Docker Images

• Open a terminal and make sure you are in springboot-graphql-databases root folder

• In order to build the docker images, run the following script

  ./docker-build.sh
  

Application's environment variables

• author-book-api

  Environment Variable	Description
  MYSQL_HOST	Specify host of the MySQL database to use (default localhost)
  MYSQL_PORT	Specify port of the MySQL database to use (default 3306)
  ZIPKIN_HOST	Specify host of the Zipkin distributed tracing system to use (default localhost)
  ZIPKIN_PORT	Specify port of the Zipkin distributed tracing system to use (default 9411)
  BOOK_REVIEW_API_HOST	Specify host of the book-review-api service (default localhost)
  BOOK_REVIEW_API_PORT	Specify port of the book-review-api service (default 9080)

• book-review-api

  Environment Variable	Description
  MONGODB_HOST	Specify host of the MongoDB database to use (default localhost)
  MONGODB_PORT	Specify port of the MongoDB database to use (default 27017)
  ZIPKIN_HOST	Specify host of the Zipkin distributed tracing system to use (default localhost)
  ZIPKIN_PORT	Specify port of the Zipkin distributed tracing system to use (default 9411)

Start Applications as Docker containers

• In a terminal, make sure you are inside springboot-graphql-databases root folder

• Run following script

  ./start-apps.sh
  

Application's Link

Application	URL Type	URL
author-book-api	Swagger	http://localhost:8080/swagger-ui.html
author-book-api	GraphiQL	http://localhost:8080/graphiql
book-review-api	GraphiQL	http://localhost:9080/graphiql

How to use GraphiQL

• book-review-api

  1. In a browser, access http://localhost:9080/graphiql

  2. Create a book and return its id

     mutation {
       createBook(bookInput: {title: "Learning GraphQL and Relay", isbn: "9781786465757"}) {
        id
       }
     }
     

  3. Add one review for the book created above, suppose the id is 5bd4bd4790e9f641b7388f23

     mutation {
       addBookReview(bookId: "5bd4bd4790e9f641b7388f23", reviewInput: {reviewer: "Ivan Franchin", comment: "It is a very good book", rating: 5}) {
         id
       }
     }
     

  4. Get all books stored in book-review-api, including their reviews

     {
       getAllBooks {
         id
         title
         isbn
         reviews {
           comment
           rating
           reviewer
           createdAt
         }
       }
     }
     

• author-book-api

  1. In a browser, access http://localhost:8080/graphiql

  2. Create an author and return its id

     mutation {
       createAuthor(authorInput: {name: "Samer Buna"}) {
         id
       }
     }
     

  3. Create a book and return the book id and author name

     Note: while creating this book in author-book-api, we are setting the same ISBN, 9781786465757, as we did when creating the book in book-review-api.

     mutation {
       createBook(bookInput: {authorId: 1, isbn: "9781786465757", title: "Learning GraphQL and Relay", year: 2016}) {
         id
         author {
           name
         }
       }
     }
     

  4. Get author by id and return some information about his/her books including reviews of the book from book-review-api.

     Note: as the book stored in author-book-api and book-review-api has the same ISBN, 9781786465757, it's possible to retrieve the reviews of the book. Otherwise, an empty list will be returned in case book-review-api does not have a specific ISBN or the service is down.

     {
       getAuthorById(authorId: 1) {
         name
         books {
           isbn
           title
           bookReview {
             reviews {
               reviewer
               rating
               comment
               createdAt
             }
           }
         }
       }
     }
     

  5. Update book title and return its id and new title

     mutation {
       updateBook(bookId: 1, bookInput: {title: "Learning GraphQL and Relay 2"}) {
         id
         title
       }
     }
     

  6. Delete the author and return his/her id

     mutation {
       deleteAuthor(authorId: 1) {
         id
       }
     }
     

Useful links & commands

• Zipkin

  It can be accessed at http://localhost:9411

• MySQL monitor

  docker exec -it mysql mysql -uauthorbookuser -pauthorbookpass --database=authorbookdb
  show tables;
  select * from authors;
  select * from books;
  

  Type exit to get out of MySQL monitor

• MongoDB shell

  docker exec -it mongodb mongo -ubookreviewuser -pbookreviewpass --authenticationDatabase bookreviewdb
  use bookreviewdb;
  db.books.find().pretty();
  

  Type exit to get out of MongoDB shell

Shutdown

• To stop applications
  • If they were started with Maven, go to the terminals where they are running and press Ctrl+C
  • If they were started as a Docker container, go to a terminal and, inside springboot-graphql-databases root folder, run the script below

    ./stop-apps.sh
    

• To stop and remove docker-compose containers, network and volumes, go to a terminal and, inside springboot-graphql-databases root folder, run the following command

  docker-compose down -v
  

Cleanup

To remove the Docker images created by this project, go to a terminal and, inside springboot-graphql-databases root folder, run the following script

./remove-docker-images.sh

TODO

• study how to implement authentication/authorization to GraphQL endpoint;
• implement graphql subscription;

References

• https://graphql.org/learn
• https://www.pluralsight.com/guides/building-a-graphql-server-with-spring-boot
• https://www.baeldung.com/spring-graphql
• https://docs.spring.io/spring-cloud-openfeign/docs/current/reference/html/