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Servlet vs Reactive Choosing the Right Stack
Rossen Stoyanchev
Servlet vs Reactive Choosing the Right Stack Rossen Stoyanchev - - PowerPoint PPT Presentation
Servlet vs Reactive Choosing the Right Stack Rossen Stoyanchev - - PowerPoint PPT Presentation
Servlet vs Reactive Choosing the Right Stack Rossen Stoyanchev This talk Servlet and Reactive stacks Spring Framework 5 Big shift towards async Learn about the options, make choices About me Spring Framework committer Web development
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Spring Framework committer Web development Spring WebFlux from inception to GA
About me
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(immediately after this session)
Also featuring:
Ask Me Anything
Phil Webb → Spring Boot lead Stephane Maldini → Reactor lead
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Motivation for change
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??
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Asynchronicity Thread pools
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Event loop Coroutines Actors
Asynchronicity Thread pools
Fibers / Project Loom
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Small, fixed # of threads (running) 100s, 1000s threads (blocked)
Servlet Reactive
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Non-blocking concurrency
Even Loop
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Declarative composition of asynchronous logic
CompletableFuture, ReactiveX, Reactor, …
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Java 8 lambdas Functional programming models
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Stack choices
and why choice matters
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Servlet Reactive
@Controller @Controller
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Servlet Reactive
@Controller Reactive client @Controller Reactive client
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Servlet Reactive
Functional endpoint @Controller Reactive client @Controller Reactive client
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Servlet Reactive
Functional endpoint @Controller Reactive client @Controller Reactive client Tomcat Jetty Servlet 3.1 container Tomcat Jetty Servlet container
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Servlet Reactive
Functional endpoint @Controller Reactive client @Controller Reactive client Netty Undertow Tomcat Jetty Servlet 3.1 container Tomcat Jetty Servlet container
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Demo
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Stack architecture
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Tomcat, Jetty, … Servlet API Spring MVC Blocking I/O
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History of Servlet API
1997 1.0 … … 2009 3.0 Async Servlet 2009 3.1 Servlet non-blocking I/O … …
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Tomcat, Jetty, … Servlet API Blocking I/O
Controller + Reactive client
Async Servlet
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History of Servlet API
1997 1.0 … … 2009 3.0 Async Servlet 2009 3.1 Servlet non-blocking I/O … …
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Tomcat, Jetty, … Servlet API Blocking I/O
Controller + Reactive client
Async Servlet
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Tomcat, Jetty, … Netty Tomcat, Jetty, … Servlet API Blocking I/O
Servlet 3.1 Non-blocking I/O Reactor, Reactive Streams Reactor Netty
Spring Web API
Controller + Reactive client
Async Servlet
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Tomcat, Jetty, … Netty Tomcat, Jetty, … Servlet API Blocking I/O Spring WebFlux Spring MVC Non-blocking I/O
Reactor, Reactive Streams
Spring Web API
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Reactive, non-blocking back pressure
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Blocking expected
Filter Servlet Filter
Tomcat, Jetty, …
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Blocking not expected
WebFilter WebHandler
Tomcat, Jetty, … Netty Even Loop
WebFilter
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WebFilter, WebHandler Mono<Void>
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Request Flux<DataBuffer> getBody()
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Response writeWith(Flux<DataBuffer>)
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Codecs Flux<DataBuffer> Flux<T>
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WebFilter WebHandler WebFilter
Mono Mono Mono Mono
- nNext(T)
request(n)
A B C D E A B C D E
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HTTP Server Reactive Adapter Flux Spring WebFlux Flux Controller Flux Web Client
Non-blocking write
WebFlux Response
request(n) request(n) request(n)
- nNext(T)
- nNext(T)
- nNext(T)
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Server Reactive Adapter Flux Spring WebFlux Flux Controller Flux Data Repo
Non-blocking read
WebFlux Request
request(n) request(n) request(n)
- nNext(T)
- nNext(T)
- nNext(T)
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Server Servlet API Spring MVC Flux Controller Flux Web Client
Blocking write Spring MVC thread request(1) request(1)
- nNext(T)
- nNext(T)
Spring MVC Response
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Demo
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Choosing
The right stack for the job at hand
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Spring MVC
If it ain’t broken, don’t fix it Imperative logic is the easiest to write and debug Check application dependencies (JDBC, JPA)
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Spring MVC + Reactive Client
Compose remote service calls Reactive data (Mongo, Cassandra, Redis) Response stream
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Spring WebFlux
Use cases → easy to stream up or down Scale → efficient at I/O Programming model → functional endpoints
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Spring WebFlux Performance
Efficient scale with less hardware resources It’s not about speed Latency is key to exhibit differences
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