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#QConSP @vertx_project
Modern app programming
with RxJava and Eclipse Vert.x
#QConSP @vertx_project
Who am I?
Vert.x core team member since 2016 Working at since 2012 Contributing specifically to monitoring and clustering
@tsegismont
Modern app programming with RxJava and Eclipse Vert.x #QConSP - - PowerPoint PPT Presentation
Modern app programming with RxJava and Eclipse Vert.x #QConSP - - PowerPoint PPT Presentation
Modern app programming with RxJava and Eclipse Vert.x #QConSP @vertx_project Who am I? Vert.x core team member since 2016 Working at since 2012 Contributing specifically to monitoring and clustering @tsegismont
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Eclipse Vert.x
A toolkit to build reactive applications on the JVM
Started in 2O12 Eclipse / Apache licensing 7K on Built on top of Netty
@vertx_project https://vertx.io
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#QConSP @vertx_project
Pay the right price
- Tiny footprint
- Do one thing and do it well
- Modular set of extensions
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Why going reactive?
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#QConSP @vertx_project
A hotel room booking startup story
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2
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2002
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2003
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2006
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2009
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2011
NoSQL
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1/ Many channels 2/ Lots of I/O
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while (isRunning) { String line = bufferedReader.readLine(); switch (line.substring(0, 4)) { case "ECHO": bufferedWriter.write(line); break; // ... // other cases (...) // ... } }
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x 1000 =
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“But I don’t do Internet scale. I do enterprise!”
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2018 server: 28 cores, 512 GB memory
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Microservices
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Your container share: 2 vCPU, 512 MB memory
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1/ Keep the number of threads to a minimum 2/ Keep them busy
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Thread Events Event-loop
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Event loops in Vert.x project
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2 event-loops per core
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class HttpServerVerticle extends AbstractVerticle { public static void main(String[] args) { Vertx vertx = Vertx.vertx(); vertx.deployVerticle(HttpServerVerticle.class.getName()); } @Override public void start() throws Exception { vertx.createHttpServer() .requestHandler(req -> { req.response().end("Hello world!"); }).listen(8080); } }
Verticles
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DeploymentOptions options = new DeploymentOptions() .setInstances(3); vertx.deployVerticle(httpVerticle, options);
Load-balancing
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Communication between verticles?
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EventBus
Messaging passing, not shared data
Multi-paradigm Standalone or clustered Browser and mobile bridges
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EventBus eventBus = vertx.eventBus(); eventBus.<String>consumer("greeting").handler(msg -> { String name = msg.body(); msg.reply(String.format("Hello %s!", name)); }); EventBus eventBus = vertx.eventBus(); eventBus.<String>send("greeting", "QConSP", ar -> { if (ar.succeeded()) { System.out.println(ar.result().body()); } else { ar.cause().printStackTrace(); } });
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Verticle Bridge
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#QConSP @vertx_project
Distributed EventBus demo
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#QConSP @vertx_project
Reactive Programming with RxJava
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Everything is a stream: data or events
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Java 8 streams on steroids
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Lazy and push based
Observable Observer Subscription
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Backpressure
Observable Observer Subscription Request
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#QConSP @vertx_project
Different flavors
None One Many Completable Single<T> Observable<T> * plus Maybe<T> and Flowable<T> in RxJava 2
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Composing data flows
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Great to deal with failures and latencies in distributed systems
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Observable<String> loadPostsFromRDBMS(LocalDate date); Observable<Comment> loadFromDocumentStore(String postId); loadPostsFromRDBMS(date) .concatMap(postId -> loadFromDocumentStore(postId)) .retry(4) .timeout(500, TimeUnit.MILLISECONDS) .subscribe();
Composition
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No need to create your own Observables with Vert.x
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#QConSP @vertx_project
Rxified APIs
import io.vertx.ext.web.Router; import io.vertx.reactivex.ext.web.Router;
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#QConSP @vertx_project
Rxified APIs
Single<HttpServer> rxListen(int port); void listen(int port, Handler<AsyncResult<HttpServer>> handler);
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#QConSP @vertx_project
Rxified ReadStream<T>
class AsyncFile implements ReadStream<Buffer> { // ... // RxJava1 Observable<Buffer> toObservable(); // RxJava2 Flowable<Buffer> toFlowable(); // ... }
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#QConSP @vertx_project
Music Store demo
https://github.com/tsegismont/vertx-musicstore
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Mongo Postgres Cover Art Archive
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#QConSP @vertx_project
Learning
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#QConSP @vertx_project
Learning
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Thank you!
More questions? Come to the Red Hat booth!