Dreaming of Streaming with Reactive Programming

Reactive programming, Reactive Extensions, Reactive Streams, reactive systems, Reactive Manifesto… Do you know what they mean? Do you know why it matters?

Learn about reactive and why it matters in this new cloud-native era. We’ll use live coding demos to explain how to be reactive and benefit from this brave new streaming world.

Transcript

1. !1 Dreaming of Streaming with Reactive Programming Edson Yanaga, Red Hat @yanaga
2. !2 A stack to write Java apps Cloud Native Microservices Serverless
3. !3 Developer Joy Quarkus Benefits Supersonic Subatomic Java Unifies imperative and reactive Best of breed libraries and standards
4. System eXtensions Programming Manifesto Streams Asynchrony Resilience Elasticity Back-Pressure Spreadsheets Actor Events Messages Data Flows RX Java Responsiveness Fibers Non-Blocking Reactor Spring MicroProfile REACTIVE ALL THE THING
5. reactive | rēˈaktiv | adjective showing a response to a stimulus: pupils are reactive to light. • acting in response to a situation rather than creating or controlling it: a proactive rather than a reactive approach. • having a tendency to react chemically: nitrogen dioxide is a highly reactive gas. • Physiology showing an immune response to a specific antigen. ...
6. reactive | rēˈaktiv | adjective showing a response to a stimulus: pupils are reactive to light. • acting in response to a situation rather than creating or controlling it: a proactive rather than a reactive approach. • having a tendency to react chemically: nitrogen dioxide is a highly reactive gas. • Physiology showing an immune response to a specific antigen. ... • Software application reacting to stimuli such as user inputs, messages, and failures
7. Events Messages Failures Is Reactive == Event-Driven ?
8. Build concurrent applications Reactive programming Reactive streams Non-Blocking Asynchronous Event-Driven => Concurrent Applications Non-Blocking IO (Netty) Reactive Framework Application Code Callbacks, RX Java, Reactor, Co-routines... } 1 Thread -> n concurrent tasks
9. FROM EVENT-DRIVEN TO SYSTEMS
10. Build responsive distributed systems Reactive Systems Elasticity, Resilience, Messages Build concurrent applications Reactive programming Reactive streams Non-Blocking Asynchronous TWO SIDES OF THE SAME COIN
11. REACTIVE => RESPONSIVE
12. Asynchronous Message Passing REACTIVE => RESPONSIVE
13. Async != multi-thread Async == never-block
14. FROM HTTP 
 TO MESSAGING
15. HTTP => STRONG COUPLING
16. HTTP => UPTIME COUPLING
17. CB CB CB CB CB CB THE RISE OF CIRCUIT BREAKERS
18. Non-Blocking Message Passing Elasticity Resilience THE BENEFITS OF MESSAGING
19. Message Stream Publish/ Subscribe Request-Reply DATA AT REST => DATA IN MOTION
20. Supersonic. Subatomic. REACTIVE.
21. Messaging / Streaming Quarkus Application Code Container Host / Operating System Async HTTP Messaging Quarkus Application Code Container Host / Operating System Messaging Middleware QUARKUS = {HTTP, MESSAGING, STREAMING}
22. MicroProfile Reactive Messaging Quarkus Application Code Container Host / Operating System Async HTTP Messaging Quarkus Application Code Container Host / Operating System Messaging Middleware QUARKUS = {HTTP, MESSAGING, STREAMING}
23. Coffee Shop Barista Coffee Shop Barista HTTP Board Kafka REACTIVE COFFEE SHOP https://github.com/cescoffier/quarkus-coffeeshop-demo Orders, Queue
24. Coffee Shop Barista HTTP WHAT’S THE PROBLEM WITH SYNCHRONOUS On a peak of load • Concurrency limited by the coffee shop thread pool • Must scale up the number of baristas • Require some kind of load-balancer • COLD COFFEE or NO COFFEE On failing barista • Orders are lost • NO COFFEE On slow barista • Coffee Shop gets slow • COLD COFFEE
25. @POST @Path("/http") public Beverage order(Order order) { return client.order(order); } @POST @Path("/async") public CompletionStage<Beverage> order(Order order) { return client.orderAsync(order); } FROM SYNC TO ASYNC HTTP Non-Blocking Thread released @POST @Produces("application/json") @Consumes("application/json") Beverage order(Order order); @POST @Produces("application/json") @Consumes("application/json") CompletionStage<Beverage> orderAsync(Order order);
26. Coffee Shop Barista DEMO HTTP
27. Bridge imperative -> reactive DROP HTTP, SEND MESSAGES @Inject @Stream("orders") Emitter<String> orders; public Order enqueue(Order order) { order.setOrderId(UUID.randomUUID().toString()); orders.send(jsonb.toJson(order)); return order; } Send “data” to the channel “orders”
28. @Incoming("orders") @Outgoing("queue") public CompletionStage<String> prepare(String message) { Order order = fromJson(message, Order.class); return makeIt(order) .thenApply(beverage -> PreparationState.ready(order, beverage) ); } Process data async* * Many other options available to produce, process or consume data Read from “orders” Write to “queue” PROCESSING MESSAGES
29. Coffee Shop Barista Board Queue Orders PROGRESS
30. @Inject @Stream("beverages") Publisher<String> queue; @GET @Produces(MediaType.SERVER_SENT_EVENTS) public Publisher<String> getQueue() { return queue; } Inject a stream Returns a stream PUSHING DATA TO SSE
31. Coffee Shop Barista Board Queue Orders DEMO
32. mp.messaging.smallrye-kafka.bootstrap.servers=localhost:9092 mp.messaging.smallrye-kafka.key.serializer=...StringSerializer mp.messaging.smallrye-kafka.value.serializer=...StringSerializer mp.messaging.outgoing.queue.connector=smallrye-kafka mp.messaging.outgoing.queue.acks=1 Direction MAPPING CHANNELS TO KAFKA TOPICS Channel Name 
 (= topic if not set)
33. Coffee Shop Barista Board Queue Orders BARISTAS TAKE BREAKS
34. Coffee Shop Baristas (Julie and Tom) Queue Orders RUSH HOUR! Board
35. SUMMARY
36. HTTP, Messaging, Streaming Quarkus Non-Blocking IO QUARKUS = {HTTP, MESSAGING, STREAMING}
37. WHAT ABOUT REACTIVE STREAMS? @Stream(“foo”) Emitter @Incoming(“foo”) @Outgoing(“bar”) @Stream(“bar”) Publisher @Outoing(“foo”) @Incoming(“bar”) Publisher Processor Subscriber Connector Connector
38. BRIDGE REACTIVE AND IMPERATIVE @Stream(“foo”) Emitter @Incoming(“foo”) @Outgoing(“bar”) @Stream(“bar”) Publisher @Outoing(“foo”) @Incoming(“bar”) Publisher Processor Subscriber Connector Connector
39. Non-Blocking Message Passing Elasticity Resilience REACTIVE SYSTEMS MADE EASY
40. Quark us Imperativ e Reactive CRUD, REST, CLI... Reactiv e System s Data Streamin g Supersonic, Subatomic, REACTIVE
41. !41 Thank you.