Reactive, Non-blocking Java Spring + PostgreSQL backend, JWT-authenticated REST endpoints

Description

Implementation of a Java and Spring Reactive stateless backend with REST APIs, which is fully non-blocking and supports reactive streams back pressure. The service provides endpoints to create users, authenticate users, create/retrieve chat threads, and create/retrieve thread replies. Authentication and authorization provided via stateless JSON Web Tokens (JWT). The service deploys on the Netty NIO framework.

This project uses the following technologies:

• Spring WebFlux for reactive REST APIs
• Spring Security OAuth2 for Webflux for reactive JWT / OAuth2 Resource Server support
• Spring Data R2DBC: Reactive, non-blocking version of Spring Data
• R2DBC Non-blocking PostgreSQL Driver (unlike JDBC which blocks!)
• FlywayDB: Database migrations (uses JDBC)
• Netty: Asynchronous, event-driven network application framework

Getting Started

Dependencies

1. Java 19
2. PostgreSQL (Macos install)
3. Gradle

Run the server

1. Generate RSA keys for signing and validating the JWTs: ./gradlew createKeys
2. Update application-local.yml to point to your local PostgreSQL database
3. Start the server (port 8080): ./start.sh

Query the server

A Postman import file is included to test the API endpoints: reactive-java-spring-postgres-jwt.postman_collection.json

Be sure to update the Authorization tab on the User API with the response from the token endpoint.

Sample console output

Notably, the server starts in ~2 seconds on modest hardware.

~/workspace/reactive-java-spring-postgres » ./start.sh                                                                                                                                              130 ↵ brent@Mac-mini
Running ./gradlew bootRun

> Task :bootRun
2023-08-01 18:23:50.066 -  INFO 74734 --- [main] .b.ReactiveJavaSpringPostgresApplication : Starting ReactiveJavaSpringPostgresApplication using Java 19.0.2
2023-08-01 18:23:50.068 - DEBUG 74734 --- [main] .b.ReactiveJavaSpringPostgresApplication : Running with Spring Boot v3.0.6, Spring v6.0.8
2023-08-01 18:23:50.068 -  INFO 74734 --- [main] .b.ReactiveJavaSpringPostgresApplication : The following 1 profile is active: "local"
2023-08-01 18:23:50.453 -  INFO 74734 --- [main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data R2DBC repositories in DEFAULT mode.
2023-08-01 18:23:50.554 -  INFO 74734 --- [main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 98 ms. Found 3 R2DBC repository interfaces.
2023-08-01 18:23:51.578 -  INFO 74734 --- [main] o.f.c.internal.license.VersionPrinter    : Flyway Community Edition 9.17.0 by Redgate
2023-08-01 18:23:51.578 -  INFO 74734 --- [main] o.f.c.internal.license.VersionPrinter    : See release notes here: https://rd.gt/416ObMi
2023-08-01 18:23:51.578 -  INFO 74734 --- [main] o.f.c.internal.license.VersionPrinter    :
2023-08-01 18:23:51.652 -  INFO 74734 --- [main] o.f.c.i.database.base.BaseDatabaseType   : Database: jdbc:postgresql://localhost:5432/brentcodesdb (PostgreSQL 15.2)
2023-08-01 18:23:51.674 -  INFO 74734 --- [main] o.f.core.internal.command.DbValidate     : Successfully validated 1 migration (execution time 00:00.012s)
2023-08-01 18:23:51.685 -  INFO 74734 --- [main] o.f.core.internal.command.DbMigrate      : Current version of schema "public": 0001
2023-08-01 18:23:51.685 -  INFO 74734 --- [main] o.f.core.internal.command.DbMigrate      : Schema "public" is up to date. No migration necessary.
2023-08-01 18:23:51.814 -  INFO 74734 --- [main] o.s.b.web.embedded.netty.NettyWebServer  : Netty started on port 8080
2023-08-01 18:23:51.820 -  INFO 74734 --- [main] .b.ReactiveJavaSpringPostgresApplication : Started ReactiveJavaSpringPostgresApplication in 2.137 seconds (process running for 2.358)

Author

Brent Frederick

@brentcodes

License

This project is licensed under the MIT License - see the LICENSE.md file for details