Reactive Microservices with Spring 5 WebFlux

WebFlux functional reactive services demo presented by IPT-Intellectual Products & Technologies @jProfessionals 2018

This is a demo application, which shows how to develop functional reactive (micro-)services using Spring 5 WebFlux, Spring Boot 2.0, Spring Data reactive repositories, MongoDB, reactive Spring Security and more.

You can find links to the presentation in this post.

All demos use Gradle for building.

Whats new in Spring 5

Spring 5 adds a plenty of new features. Following are my favourits:

• Reactive Programming Model
• Spring Web Flux
• Reactive DB repositories & integrations + hot event streaming: MongoDB, CouchDB, Redis, Cassandra, Kafka
• Testing improvements – WebTestClient (based on reactive WebFlux WebClient)
• JDK 8+ and Java EE 7+ baseline - see the reactive-quotes demo for Java 9 example
• Kotlin functional DSL

How to run the demos

reactive-streaming-demos (requires Java 9)

1. Be sure to configure JAVA_HOME environment variable to point to JDK 9, and PATH to include bin sub-folder of JDK 9 (for Windows). For Linux use something like sudo update-java-alternatives --list and sudo update-java-alternatives --set [JDK/JRE name e.g. java-9-oracle] to choose the java 9.
2. Build and run the Spring Boot-Gradle application (reactive-streaming-demos module) - e.g. run gradle bootRun from the reactive-streaming-demos folder. The application main class is org.iproduct.demos.spring.streamingdemos.ReactiveStreamingDemosApp.
3. Open http://localhost:9000/ for Java Processes CPU Profiling demo (using novelties in Java 9 Process API: ProcessHandle and ProcessInfo classes), and http://localhost:9000/quotes.html for Reactive Option Quotes demo respectively in your browser.

Streaming demo REST and SSE endpoints

Provides information about runiiing Java processes and streaming data about their CPU ussage. Second demo provides streaming data about fictional options quote prices. All data is purely fictional - NO real stock prices are quoted :):

Method	Path	Description	JSON	SSE Streaming
GET	/api/processes	List all currently running Java processes	*
SSE	/api/cpu	Get realtime stream of CPU consumption for all Java processes	*	*
SSE	/api/quotes	Get fictional options quote prices in realtime	*	*

webflux-users (requires Java 8)

1. Be sure to configure JAVA_HOME environment variable to point to JDK 8, and PATH to include bin sub-folder of JDK 8 (for Windows). For Linux use something like sudo update-java-alternatives --list and sudo update-java-alternatives --set [JDK/JRE name e.g. java-8-oracle] to choose the java 8.
2. Install (if not already installed) latest version of MongoDB, create <local_database_folder>, and start MongoDB - e.g. run mongod --dbpath="<local_database_folder>".
3. Build and run the Spring Boot-Gradle application (webflux-users module) - e.g. run gradle bootRun from the webflux-users folder. The application main class is org.iproduct.demos.spring.manageusers.WebfluxUsersApplication.
4. Open http://localhost:8080/api/users in your browser - you should be asked to login using BASIC authentication with default admin cedentials - user: admin, password: admin. Should see something like: [{"id":"","username":"admin","fname":"Default","lname":"Admin","role":"ADMIN","active":true}]. You could use a REST client such as Postman or curl to read, create, update and delete users following the standard REST API conventions.
5. Run the unit tests (does not require server to be started) with: gradle clean test or gradle clean test --info

Users service

Provides CRUD operations for the Users:

Method	Path	Description	Requires authentication	Admin only
GET	/api/users	List all users	*
GET	/api/users/{userId}	Get current account statistics
POST	/api/users	Create new user	*
PUT	/api/users/{userId}	Update user data	*
DELETE	/api/users/{userId}	Delete existing user	*	*