Reactive Spring 5

Reactive Programming with Spring WebFlux and Spring Data in Spring 5.

Transcript

1. Reactive Spring 5 Reactive Programming with Spring WebFlux and Spring Data Corneil du Plessis
2. A defnition reactive programming is an asynchronous programming paradigm concerned with data streams and the propagation of change Wikipedia
3. Reactive Manifesto • Responsive • Resilient • Elastic • Message Driven
4. Why reactive programming? • Handle back-pressure • Communicate change • Scalability • Performance • Reliability
5. 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, flter • Languages not limited to: • Scala • Kotlin • Haskell • Elm • Groovy • JavaScript • Java 8
6. Road to Reactive Spring • RxJava – 2011-2012 by Netfix • Project Reactor – 2013 by Pivotal • Reactive Streams Specifcation – 2014 collaboration by Netfix, Pivotal, Red Hat, Twitter, Typesafe and more. • reactor-spring • Spring 5
7. 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.
8. Reactive Streams specifcation • Publisher • Subscriber • Subscription • Processor
9. Reactive Streams – Sequence Diagrams Subscribe Publish
10. Project Reactor • Implements Reactive Streams specifcation • Infuenced by RxJava • Infuenced by Java 8 Streams • Improved Developer Experience • Mono<T> - 0 or One • Flux<T> - 0 or More
11. 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
12. 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
13. Reactive Spring WebFlux • Annotated Controllers • @Controller or @RestController • @RequestMapping / @GetMapping / @PostMapping etc. • Flux instead of Collection • Functional Endpoints • Router Function • Handler Function • HandlerFilter Function
14. Spring MVC @RestController public class HistoryController { private HistoryInterface locHist; public HistoryController(HistoryInterface locHist) { this. locHist = locHist; } @GetMapping(path = "/search") public Collection<LocationHistory> find( @RequestParam("startDate") Date startDate, @RequestParam("endDate") Date endDate) { return locHist.find(startDate, endDate); } }
15. Reactive Spring WebFlux @RestController public class HistoryController { private HistoryInterface locHist; public HistoryController(HistoryInterface locHist) { this. locHist = locHist; } @GetMapping(path = "/search") public Flux<LocationHistory> find( @RequestParam("startDate") Date startDate, @RequestParam("endDate") Date endDate) { return locHist.find(startDate, endDate); } }
16. 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); } }
17. Reactive Spring WebFlux (Functional Endpoint) @Configuration @EnableWebFlux public class HistoryConfiguration { @Autowire private HistoryHandler histHandler; @Bean RouterFunction<ServerResponse> router() { return route(GET("/search") .and(accept(APPLICATION_JSON)), histHandler::find); } }
18. Spring Data public interface LocationHistoryRepository extends CrudRepository<LocationHistory, String> { Collection<LocationHistory> findByTimestampBetween( Date s, Date e); }
19. Reactive Spring Data public interface LocationHistoryRepository extends ReactiveCrudRepository<LocationHistory, String> { Flux<LocationHistory> findByTimestampBetween( Date s, Date e); }
20. 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));
21. Demo Non-reactive • Spring Boot 1.5.8 • Spring MVC • Spring Data MongoDB Reactive • Spring Boot 2.0.3 • Spring WebFlux • Spring Data Reactive MongoDB
22. 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
23. Synchronous process
24. Asynchronous process
25. Network timing Non-reactive Type Time Name lookup 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
26. WebFlux vs Servlet
27. More aspects of Reactive Programming • Error handling • Back pressure • Retry • Timeouts • Transactions
28. Thoughts on Reactive Spring • Pros • Great documentation • Preserves program structure • Safer concurrency • Simpler abstraction than RxJava without sacrifcing the power. • Facilitates good practice • Kotlin support in Core • Cons • Debugging complexity • Could not fnd 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 • Contact: @corneil • Source - https://github.com/corneil/reactive-spring-5 • Resources • Project Reactor Site - https://projectreactor.io/ • David Karnok's Blog - http://akarnokd.blogspot.co.za/ • WebFlux vs Servlet https://dzone.com/articles/raw-performance-numbers-spring-boot-2-webfux-vs-s Questions?