Going Reactive - High Performance JVM Code with Reactor

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1 Going Reac+ve High Performance JVM Code with Reactor Michael Nitschinger

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2 Who is that guy? •  Developer Advocate at Couchbase   Java SDK Maintainer   Spring-‐Data-‐Couchbase and more •  @daschl •  Contribu+ng to Reactor, NeGy,... •  Living here in Vienna

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3 Reac+ve?

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4 The Manifesto •  hGp://www.reac+vemanifesto.org/ h>p://www.reacCvemanifesto.org/images/full-‐[email protected]

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5 The Manifesto •  Event-‐Driven   Loosely coupled components   Sharing resources   Async execuCon •  Scalable •  Resilient   IsolaCng failure   Build supervision hierachies •  Responsive

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6 Yo dawg, I heard you like ships events!

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7 Meet Reactor.

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8 What is Reactor? •  A founda+onal library to build reac+ve applica+ons. •  Gray area between user-‐ and low-‐level code. •  Build your applica+on cores on top of it. •  Helps: drivers, servers, libraries, evented architectures. •  Maintained by, but no dependency on Spring. •  Currently in RC state! (hGps://github.com/reactor/reactor)

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9 Landscape

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10 A ﬁrst look

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11 Dispatchers •  Created on an Environment-‐basis. •  Dispatchers manage Task Execu+on.   ThreadPoolExecutorDispatcher execuCng tasks in a thread pool   BlockingQueueDispatcher event-‐loop style   RingBufferDispatcher uses the LMAX Disruptor RingBuﬀer   SynchronousDispatcher for tesCng

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12 Selectors •  LeY-‐hand side of an equality comparison. •  Can be created from any object.   $(object)   Selectors.object(obj) •  Can extract data from the matched key.

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13 Selectors -‐ Regex •  A RegexSelector will match a String by execu+ng the regex.

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14 Selectors -‐ Templates •  A UriTemplateSelector will match a String by extrac+ng bits from a URI.

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15 Func+ons •  Perform work on T. public interface Consumer { void accept(T t); } •  Supply the caller with T. public interface Supplier { T get(); } •  Perform work on T and return V. public interface Function { V apply(T t); } •  Check if the input matches the criteria. public interface Predicate { boolean test(T t); }

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16 Promises •  Promises allow for composi+on of func+ons   Shares common funcCons with a Stream

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17 Streams •  Streams allow the composi+on of func+ons   Callback++   NeYlix RxJava Observable, JDK 8 Stream

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18 Processor •  Thin wrapper around the Disruptor RingBuﬀer   Converts Disruptor API to Reactor API   Really fast!

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19 Integra+on: Spring •  Helpers to integrate Reactor into ApplicationContext   @EnableReactor   Wiring annotated handlers •  DispatcherTaskExecutor   Not intended for “high scale”   Used to get Spring components running in the same thread as Reactor consumers.

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20 Integra+on: Groovy •  First class ci+zen language implementa+on   @CompileStaCc ready   Prominent use of Closure as Consumers, FuncCons and more   Operator overloading   Full Reactor system Builder

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21 Integra+on: Clojure •  Meltdown: A Clojure binding by @michaelklishin and @ifesdjeen   h>ps://github.com/clojurewerkz/meltdown

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22 What else? •  Too much to show today!   TCP Client/Server based on Ne>y 4   Buﬀer tooling   Sequencing for event ordering   Work Queue support on top of Java Chronicle   Logback Appender   Language Constructs (Composables, Tuples,…)