Reactive Microservices with Spring Boot and JHipster - St Louis Java Users Group 2021

Microservice architectures are all the rage in JavaLand. They allow teams to develop services independently and deploy autonomously.

Why microservices?
IF
you are developing a large/complex application
AND
you need to deliver it rapidly, frequently, and reliably over a long period of time
THEN
the Microservice Architecture is often a good choice

Reactive architectures are becoming increasingly popular for organizations that need to do more, with less hardware. Reactive programming allows you to build systems that are resilient to high load.

In this session, I'll show you how to use JHipster to create a reactive microservices architecture with Spring Boot, Spring Cloud, Keycloak, and run it all in Docker. You will leave with the know-how to create your own resilient apps!

Related blog post: https://developer.okta.com/blog/2021/01/20/reactive-java-microservices
YouTube demo: https://youtu.be/clkEUHWT9-M
YouTube recording: https://youtu.be/5IBXnZRLrjc
GitHub repo: https://github.com/oktadev/java-microservices-examples/tree/main/reactive-jhipster

Transcript

1. Reactive Java Microservices with Spring Boot and JHipster May 13, 2021 Matt Raible | @mraible Photo by Morgan Burke 
 https://flickr.com/photos/themorganburke/23320245524
3. What is JHipster?
4. How to Use JHipster Install JHipster and Yeoman, using npm: npm install -g generator-jhipster Create a directory and cd into it: take app Run it! jhipster
5. Monolith, Gateway, or Microservices? Spring MVC or Spring WebFlux? Authentication Type? Database Type? Build Tool? Web Framework? JHipster Options
6. Does JHipster Provide the Paradox of Choice?
7. start.jhipster.tech
8. https://start.jhipster.tech/jdl-studio
9. Thriving OSS Project Started by Julien Dubois on October 21, 2013 App Generator, Platform, Learning Tool …
10. @mraible Hi, I’m Matt Raible Father, Husband, Skier, Mountain Biker, Whitewater Rafter Bus Lover Web Developer and Java Champion Okta Developer Advocate Blogger on raibledesigns.com and developer.okta.com/blog @mraible
14. developer.okta.com
15. Spring History of Spring October 2002 - Rod Johnson writes J2EE Design & Development 2004 - Spring 1.0 2006 - Spring 2.0 with better XML 2009 - JavaConfig 2014 - Spring Boot 1.0 2015 - Spring Cloud 1.0 🍃
16. Microservices Visionaries
17. “Any organization that designs a system (defined broadly) will produce a design whose structure is a copy of the organization's communication structure.” Conway’s Law Melvin Conway 1967
19. “Do one thing and do it well.”
22. Spring WebFlux!
23. Spring MVC Code @PostMapping("/points") public ResponseEntity<Points> createPoints(@Valid @RequestBody Points points) throws URISyntaxException { log.debug("REST request to save Points : {}", points); if (points.getId() != null) { throw new BadRequestAlertException("A new points cannot already have an ID", ENTITY_NAME, "idexists"); } Points result = pointsRepository.save(points); pointsSearchRepository.save(result); return ResponseEntity .created(new URI("/api/points/" + result.getId())) .headers(HeaderUtil.createEntityCreationAlert( applicationName, true, ENTITY_NAME, result.getId().toString())) .body(result); }
24. Spring WebFlux Code @PostMapping("/points") public Mono<ResponseEntity<Points>> createPoints(@Valid @RequestBody Points points) throws URISyntaxException { log.debug("REST request to save Points : {}", points); if (points.getId() != null) { throw new BadRequestAlertException("A new points cannot already have an ID", ENTITY_NAME, "idexists"); } return pointsRepository .save(points) .flatMap(pointsSearchRepository::save) .map( result -> { try { return ResponseEntity .created(new URI("/api/points/" + result.getId())) .headers(HeaderUtil.createEntityCreationAlert( applicationName, true, ENTITY_NAME, result.getId().toString())) .body(result); } catch (URISyntaxException e) { throw new RuntimeException(e); } } ); }
25. Spring Cloud Gateway
26. yelp.com/callback Back to redirect URI with authorization code Exchange code for access token and ID token accounts.google.com Email ********** Go to authorization server Redirect URI: yelp.com/cb Scope: openid profile Authorization Server yelp.com Connect with Google Resource owner Client accounts.google.com 
 Allow Yelp to access your public profile and contacts? No Yes Request consent from resource owner Hello Matt! accounts.google Get user info 
 with access token /userinfo OAuth 2.0 and OIDC
28. Demo Create microservices with JDL Run apps and e2e tests Switch identity providers Run everything with Docker https://github.com/oktadev/java- microservices-examples 🤓
29. Reactive Microservices with Spring Cloud Gateway https://developer.okta.com/blog/2019/08/28/reactive-microservices-spring-cloud-gateway
30. What You Learned
31. https://developer.okta.com/blog/2021/01/20/reactive-java-microservices
32. npm install -g generator-jhipster-kotlin
33. https://wiki.openjdk.java.net/display/loom/Main
34. What’s Next for JHipster? Micro Frontends Spring Boot 2.5 GraphQL * These are my personal interests.
35. JHipster is Knowledge
36. The JHipster Mini-Book 
 Written with Asciidoctor Free download from InfoQ: infoq.com/minibooks/jhipster-mini-book Quick and to the point, 164 pages Developed a real world app: www.21-points.com Buy for $20 or download for FREE
37. Learn More stackoverflow.com Spring Boot spring.io/guides JHipster www.jhipster.tech Okta APIs developer.okta.com
38. developer.okta.com/blog @oktadev
39. Action: Try JHipster 7! 🚀 npm i -g generator-jhipster@7
40. git clone https://github.com/oktadeveloper/okta-spring-webflux-react- example.git https://github.com/oktadev/java-microservices-examples Use the Source, Luke!
41. Thanks! Keep in Touch raibledesigns.com @mraible Presentations speakerdeck.com/mraible Code github.com/oktadev developer.okta.com
42. developer.okta.com