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Reactive Spring 5
The document provides an overview of reactive programming and Spring WebFlux. It defines reactive programming as an asynchronous paradigm concerned with data streams and change propagation. It discusses why reactive programming is useful for handling back-pressure, communicating change, and improving scalability and performance. It also summarizes key concepts in reactive programming like Project Reactor's Mono and Flux types, and how Spring WebFlux allows developing reactive applications with annotated controllers or functional routing.
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Reactive Spring 5
- 1. Reactive Spring 5 ReactiveProgramming with Spring WebFlux and Spring Data Corneil du Plessis
- 2. About Me • Workingas Programmer since 1985 • Smallest to very large systems. • Cobol, Fortan, Pascal, Algol, C/C++, Java, JavaScript, Groovy, Python, Scala, Kotlin and more. • Scientific instrumentation, Sports event management, Mining, Banking, Treasury and Insurance. • Software Architect (with a preference for coding)
- 3. A definition reactive programmingis an asynchronous programming paradigm concerned with data streams and the propagation of change Wikipedia
- 4. Reactive Manifesto • Responsive •Resilient • Elastic • Message Driven
- 5. Why reactive programming? •Handle back-pressure • Communicate change • Scalability • Performance • Reliability
- 6. Reactive Programming Models •Windows API • JVM Based • NIO • LMAX Disruptor • Akka Actor Model • JavaScript • AJAX • Promises • jQuery • Angular • React • FRP – Functional Reactive Programming • map, reduce, filter • Languages not limited to: • Scala • Kotlin • Haskell • Elm • Groovy • JavaScript • Java 8
- 7. Road to ReactiveSpring • RxJava – 2011-2012 by Netflix • Project Reactor – 2013 by Pivotal • Reactive Streams Specification – 2014 collaboration by Netflix, Pivotal, Red Hat, Twitter, Typesafe and more. • reactor-spring • Spring 5
- 8. Implementing Technologies HttpHander /WebHander API • Netty • Undertow • Tomcat with Servlet 3.1 • Jetty with Servlet 3.1 Reactive Databases • MongoDB Reactive Streams Driver • Reactive Cassandra (RxJava) • Lettuce (Reactive Streams for Redis) • Reactive Couchbase.
- 9. Reactive Streams specification •Publisher • Subscriber • Subscription • Processor
- 10. Reactive Streams –Sequence Diagrams Subscribe Publish
- 11. Project Reactor • ImplementsReactive Streams specification • Influenced by RxJava • Influenced by Java 8 Streams • Improved Developer Experience • Mono<T> - 0 or One • Flux<T> - 0 or More
- 12. Project Reactor -Mono static <T> Mono<T> just(T data); static <T> Mono<T> fromFuture( CompleteableFuture<? extends T>); Mono<T> log(String category); T block(); T block(Duration timeout); map, flatMap, filter
- 13. Project Reactor -Flux static <T> Flux<T> just(T data); static <T> Flux<T> just(T … data); static <T> Flux<T> fromStream(Stream<T> s); static <T> Flux<T> fromIterable<Iterable<T> i); Flux<T> log(String category); static <T> Mono<List<T>> collectList(); Mono<T> next(); Iterable<T> toIterable(); Stream<T> toStream(); map, flatMap, filter, reduce
- 14. Reactive Spring WebFlux •Annotated Controllers • @Controller or @RestController • @RequestMapping / @GetMapping / @PostMapping etc. • Flux instead of Collection • Functional Endpoints • Router Function • Handler Function • HandlerFilter Function
- 15. Spring MVC @RestController public classHistoryController { private HistoryInterface locHist; public HistoryController(HistoryInterface locHist) { this. locHist = locHist; } @GetMapping(path = "/last30days") public Collection<LocationHistory> find( @RequestParam("startDate") Date startDate, @RequestParam("endDate") Date endDate) { return locHist.find(startDate, endDate); } }
- 16. Reactive Spring WebFlux @RestController publicclass HistoryController { private HistoryInterface locHist; public HistoryController(HistoryInterface locHist) { this. locHist = locHist; } @GetMapping(path = "/last30days") public Flux<LocationHistory> find( @RequestParam("startDate") Date startDate, @RequestParam("endDate") Date endDate) { return locHist.find(startDate, endDate); } }
- 17. Reactive Spring WebFlux(Functional Endpoint) public class HistoryHandler { private HistoryInterface locHist; public History HistoryHandler( HistoryInterface locHist) { this. locHist = locHist; } public Mono<ServerResponse> find(ServerRequest request) { Date startDate = DateUtils.from(request.queryParam("startDate")); Date endDate = DateUtils.from(request.queryParam("endDate")); return ServerResponse.ok() .contentType(APPLICATION_JSON) .body(locHist.find(startDate, endDate), LocationHistory.class); } }
- 18. Reactive Spring WebFlux(Functional Endpoint) @Configuration @EnableWebFlux public class HistoryConfiguration { @Autowire private HistoryHandler histHandler; @Bean RouterFunction<ServerResponse> router() { return route(GET("/last30days") .and(accept(APPLICATION_JSON)), histHandler::find); } }
- 19. Spring Data public interfaceLocationHistoryRepository extends CrudRepository<LocationHistory, String> { Collection<LocationHistory> findByTimestampBetween( Date s, Date e); }
- 20. Reactive Spring Data publicinterface LocationHistoryRepository extends ReactiveCrudRepository<LocationHistory, String> { Flux<LocationHistory> findByTimestampBetween( Date s, Date e); }
- 21. Spring Data JPA •Spring Data JPA does not have Reactive Support. • Streams will provide best experience until reactive JDBC and JPA is available. // Repository method Stream<LocationHistory> findByDateBetween( Date startDate, Date endDate); // Service method return Flux.fromStream(repository.findByDateBetween(s,e));
- 22. Demo Non-reactive • Spring Boot1.5.8 • Spring MVC • Spring Data MongoDB Reactive • Spring Boot 2.0 RC • Spring WebFlux • Spring Data Reactive MongoDB
- 23. Call timing Non-reactive • 0.000>> controller • 0.000 >> service • 0.409 << service • 0.409 << controller Reactive • 0.000 >> controller • 0.000 >> service • 0.001 << service • 0.001 << controller
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- 26. Network timing Non-reactive Type Time Namelookup 0.004 Connect 0.005 Pre transfer 0.005 Start Transfer 0.419 Total 0.532 Reactive Type Time Name lookup 0.004 Connect 0.005 Pre transfer 0.005 Start Transfer 0.385 Total 0.425
- 27. More aspects ofReactive Programming • Error handling • Back pressure • Retry • Timeouts • Transactions
- 28. Thoughts on ReactiveSpring • Pros • Great documentation • Preserves program structure • Safer concurrency • Simpler abstraction than RxJava without sacrificing the power. • Facilitates good practice • Kotlin support in Core • Cons • Debugging complexity • Could not find any other negative comments
- 29. See Also • ReactiveX •Languages • RxJava • RxKotlin • RxGroovy • RxClojure • RxSwift • Rx.Net (C#) and more… • Platforms • RxAndroid • RxCocoa • RxNetty • Akka & Akka Streams • Ratpack • Vert.x • Play Framework • Languages • Reactor Scala Extensions • Reactor Kotlin Extensions (now in core) • Messaging Communication • Reactor Kafka • Reactor RabbitMQ • Reactor Aeron • Reactor Netty
- 30. Finally • Source -https://github.com/corneil/reactive-spring-5 • Slides - https://www.slideshare.net/CorneilduPlessis/reactive- spring-5 • Resources • Project Reactor Site - https://projectreactor.io/ • David Karnok's Blog - http://akarnokd.blogspot.co.za/ Questions?