A project with main goal to have a hands-on experience with GraphQL and the Spring Reactive Web project for non-blocking code execution and have a CRUD application. I've chosen to use CQS here in combination with Vertical Slices to have a clearer separation of concerns and also because I know the code would be very short so fitting everything related to a specific feature seemed to me like a great choice. For this project I didn't focus on the domain and event driven architecture. I also took the chance to practice Kotlin in a backend context instead of Android Development as usual. Since I'm using Kotlin, I could have skipped using Spring Reactive Web and rely on Kotlin's built-in support for non-blocking, Coroutines, maybe it's a nice idea for another project. During the project I stumbled upon some challenges/details I didn't foresee when starting with this:
- Spring Reactive Web is not compatible with JPA and jdbc, you really need to use r2dbc only.
- Since you can't use JPA, there's not create-drop feature for development, so I opted out to use Flyway with a migration schema to create the table and trash the docker container whenever I wanted to delete data from the db
- Streaming Flux of responses with GraphQL seems not to be possible, which is an interesting feature of Spring Reactive Web project
- The really visualize the stream of responses, Swagger is not the best tool for the job, just use Postman or the Browser instead
- Catching and Handling exceptions doesn't seem very straight forward when using REST. I didn't explore much about this, maybe later on. As for GraphQL, the return is just null, maybe there's a more descriptive way instead of swallowing exceptions and throw in a null for the frontend.
- Spring Web
- Spring Reactive Web
- PostgreSQL Driver
- Spring Data R2DBC
- Spring for GraphQL
- Swagger (springdoc-openapi-starter-webmvc-ui)
- Flyway
- For the moment I've just containerized the database, later on I might also add the application
docker-compose up -d- Once the application is started you can navigate to http://localhost:8080/swagger-ui/index.html to use the REST Controllers or navigate to http://localhost:8080/graphiql to use the GraphQL UI and shoot requests to the backend