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JakartaOne Livestream CN4J: Bringing Reactive to Enterprise Developers
This document discusses bringing reactive programming to enterprise developers. It defines reactive as responding to stimuli without blocking. Reactive programming uses non-blocking I/O and callbacks to build concurrent and distributed systems that are responsive, message-driven, and resilient. The document advocates using reactive techniques with messaging systems like Kafka to build distributed applications and services that can handle failures and elastic workloads. It presents the Quarkus framework as unifying imperative and reactive programming for Java developers.
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JakartaOne Livestream CN4J: Bringing Reactive to Enterprise Developers
- 1. Bringing Reactive toEnterprise Developers Clement Escoffier, Red Hat, @clementplop
- 2. What is Reactive? Dowe need this new thing?
- 3. 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. ... https://www.oxfordlearnersdictionaries.com/definition/english/reactive
- 4. 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
- 5. What is Reactive? Dowe need this new thing?
- 6. Events Signals Failures Is Reactive ==Event-Driven ?
- 7. Events Signals Failures Is Reactive ==Event-Driven ? EJBs Message-Driven Beans CDI Observers
- 8. Event-Driven with adifferent concurrency model Non-Blocking IO (Netty) Reactive Framework Application Code Callbacks, RX, Co-routines... } 1 Thread Reactive programming Non-Blocking IO Build concurrent applications
- 9. FROM EVENT-DRIVEN TOSYSTEMS
- 10. “A distributed systemis one in which the failure of a computer you didn't even know existed can render your own computer unusable.” Leslie Lamport
- 11. Build responsive distributed systems Reactive Systems Elasticity, Resilience, Messages REACTIVE== BUILD BETTER SYSTEMS Build concurrent applications Reactive programming Non-Blocking IO
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- 13. What’s wrong withHTTP?
- 14. HTTP => STRONGCOUPLING
- 15. HTTP => UPTIMECOUPLING
- 16. CB CB CB CB CB CB THE RISE OFCIRCUIT BREAKERS
- 17. Non-Blocking Message Passing Elasticity Resilience THE BENEFITSOF MESSAGING Virtual Addresses
- 18. APPLYING REACTIVE TODISTRIBUTED SYSTEMS RESPONSIVE ASYNC MESSAGE PASSING ELASTICITY RESILIENCE
- 19. APPLYING REACTIVE TODISTRIBUTED SYSTEMS RESPONSIVE ASYNC MESSAGE PASSING ELASTICITY RESILIENCE Asynchronous Non-Blocking Message Passing
- 20. Reactive != multi-thread Reactive== never-block
- 21. Containers are aboutsharing and deployment density Container Host Threads costs memory cost lots of memory cost CPU cycles + quotas = BOOM The hidden truth of containers
- 22. Asynchronous & Non-Blockingexecution model Ideal world Task A Task B Task C Real world Blocking I/O Asynchronous execution
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- 26. @GET @Produces(MediaType.TEXT_PLAIN) @Path("/greeting/{name}") public Uni<String> greeting(@PathParamString name) { return service.greeting(name); } Using Unis in JAX-RS resources / Rest Client @GET @Path("/name/{name}") @Produces("application/json") Uni<Country> getByName(@PathParam String name);
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- 28. CompletionStage vs. Publisher Publisher(Flow) 0..n items Completion Stage Eager 0..1 items Lazy Back-Pressure Has operators No Operators
- 29. Mutiny: Uni andMulti Multi 0..n items Uni Lazy (subscription) 1 item Lazy (subscription + request) Back-Pressure Operators Operators
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- 31. JAX-RS returning Multi @Produces(MediaType.APPLICATION_JSON) @Path("/greeting/{count}/{name}") publicMulti<String> greetings(@PathParam int count, @PathParam String name) { return service.greetings(count, name); } @Produces(MediaType.SERVER_SENT_EVENTS) @SseElementType(MediaType.TEXT_PLAIN) @Path("/stream/{count}/{name}") public Multi<String> greetings(@PathParam String name) { return service.infiniteGreetings(name); }
- 32. I heard alot about Kafka. Does Kafka make me reactive?
- 33. Messaging / Streaming Quarkus ApplicationCode Container Host / Operating System HTTP Messaging Quarkus Application Code Container Host / Operating System Messaging Middleware HTTP, MESSAGING, STREAMING
- 34. Coffee Shop BaristaCoffee Shop Barista HTTP Dashboard REACTIVE COFFEE SHOP https://github.com/cescoffier/quarkus-coffeeshop-demo Orders, Queue * Also applies to AMQP and other messaging protocols but we want to be “cool” *
- 35. Bridge imperative ->reactive DROP HTTP, SEND MESSAGES @Inject @Channel("orders") Emitter<Order> orders; @Inject @Channel("queue") Emitter<Beverage> states; @POST @Path("/messaging") public Order messaging(Order order) { order.setOrderId(getId()); states.send(Beverage.queued(order)); orders.send(order); return order; } Send to the channel “orders”
- 36. @Incoming("orders") @Outgoing("queue") public Uni<Beverage> process(Orderorder) { return Uni.createFrom(() -> { Beverage coffee = prepare(order); return coffee; }); } Process data asynchronously* * Many other options available to produce, process or consume data Read from “orders” Write to “queue” PROCESSING MESSAGES
- 37. 37 @Inject @Channel("beverages") Multi<String> queue; @GET @Produces(MediaType.SERVER_SENT_EVENTS) public Multi<String>getQueue() { return queue; } Inject the data from the channel “beverages” Returns a stream PUSHING DATA TO SSE
- 38. Is it aReactive System?
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- 41. APPLYING REACTIVE TODISTRIBUTED SYSTEMS RESPONSIVE ASYNC MESSAGE PASSING ELASTICITY RESILIENCE
- 42. Messaging / Streaming Quarkus ApplicationCode Container Host / Operating System Reactive HTTP Server Messaging Quarkus Application Code Container Host / Operating System Messaging Middleware BUT WHAT ABOUT REACTIVE STREAMS? Reactive Streams
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- 44. Developer Joy SupersonicSubatomic Java Unifies imperative and reactive Best of breed libraries and standards QUARKUS
- 45. QUARKUS = (REACTIVE+ IMPERATIVE) / REACTIVE Eclipse Vert.x / Netty Undertow (Servlet) RESTEasy (JAX-RS) Reactive Routes Reactive Messaging Reactive Data Access Events HTTP Messages
- 46.