Going Reactive with Spring Data (JavaDay UA 2017)

Introduction to reactive streams, project Reactor and Spring 5 for building end to end reactive applications.

Transcript

1. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
   
   Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   Going with Data.
   Christoph Strobl

   Pivotal Software Inc.

   @stroblchristoph
   

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2. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
   
   Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   In a nutshell, reactive programming is about

   non-blocking, event-driven applications

   that scale with a small number of threads

   with back pressure as a key ingredient

   that aims to ensure producers to not overwhelm consumers.
   (Rossen Stoyanchev)
   

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3. The next 60 Minutes
   Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
   
   Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   - A bit of recent history.
   - Project Reactor / Spring Data Kay / Spring Framework 5.
   - Some Code.
   

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4. Sept 28
   5.0 GA
   Oct 2nd
   Kay GA
   Sept 25
   3.1 GA
   Sept 21
   9
   Nov 4th
   A bit of recent history.
   Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
   
   Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   2.0 GA
   5.0 M1
   Jul 2016
   Kay M1
   Sept 2016
   Nov 2016
   3.0 GA
   Sept 2015
   

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5. Imperative Applications
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6. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
   
   Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
   @RestController

   static class PersonController {

   

   PersonRepository repository;

   

   

   

   

   

   

   }
   @GetMapping("/")

   List listPersons(String name) {

   return repository.findAllByName(name);

   }

   

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7. Total Control
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   {…}
   

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8. Batching
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   {…}
   

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9. Async
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   {…}
   Dispatcher
   Thread: Worker A
   Thread: Worker B
   Thread: Worker C
   

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10. Reactive
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    {…}
    Subscriber Publisher
    Stream
    

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11. Iterator.next()
    Future.get()
    Subscriber.onNext(t)
    Remember
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    vs
    

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12. Reactor 3.1
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13. Reactive Streams
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    Provider of a potentially unbounded number of sequenced elements.
    Publisher
    Subscriber
    A processing stage - actually both a Subscriber and a Publisher.
    Processor
    One-to-one lifecycle of a Subscriber subscribing to a Publisher.
    Subscription
    

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14. Flux findAllByLastname(String lastname)
    Mono findByEmail(String email)
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    Mono (0…1)
    Flux (0…n)
    #jürgenized
    

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15. Reactive Applications with Spring
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    Spring Framework

    5
    Project Reactor

    3.1
    Spring Data

    Kay
    

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16. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
    
    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Apply familiar concepts

    to an new way of expressing functionality.

    With minimal fluff and surprise!
    

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17. Spring WebFlux
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    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    @RestController

    static class PersonController {

    

    PersonRepository repository;

    

    

    

    

    

    

    }
    @GetMapping("/")

    Flux fluxPersons(String name) {

    return repository.findAllByName(name);

    }

    

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18. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
    
    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    

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19. Spring WebFlux
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    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    @RestController

    static class PersonController {

    

    PersonRepository repository;

    

    

    

    

    

    

    }
    @GetMapping("/")

    Flux fluxPersons(String name) {

    return repository.findAllByName(name);

    }

    

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20. Spring Data Reactive
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    interface Repo extends ReactiveCrudRepository {
    }
    Flux findAllByLastname(String lastname);
    Flux findAllByLastname(Mono lastname);
    Flux customQuery(String lastname);
    @Query("{lastname : ?0}");
    Flux findAllByLastname(String ln, Pageable page);
    

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21. Reactive Repository
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    Mono save(S entity);
    Mono save(Mono entity);
    Flux saveAll(Iterable entities);
    Flux saveAll(Publisher entities);
    Mono existsById(Mono id);
    Flux findAll();
    Mono count();
    Mono deleteById(ID id);
    

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22. Reactive Template (MongoDB)
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    /**

    * Query for a {@link Flux} of objects of type T from the specified collection.

    *

    * @param entityClass the parametrized type of the returned {@link Flux}.

    * @param collectionName name of the collection to retrieve the objects from

    * @return the converted collection

    */

    Flux findAll(Class entityClass, String collectionName);
    /**

    * Map the results of an ad-hoc query on the collection for the entity class to a 

    * single instance of an object of the

    * specified type.
    *

    * @param query the query class that specifies the criteria 

    * @param entityClass the parametrized type of the returned {@link Mono}.

    * @return the converted object

    */

    Mono findOne(Query query, Class entityClass);
    

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23. Reactive Streams MongoDB Java Driver
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    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    /**
    * Counts the number of documents in the collection according to the given options.
    *
    * @param filter the query filter
    * @return a publisher with a single element indicating the number of documents
    */
    Publisher count(Bson filter);
    /**
    * Finds all documents in the collection.
    *
    * @param filter the query filter
    * @return the fluent find interface
    */
    FindPublisher find(Bson filter);
    

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24. Publisher
    Subscriber
    Processor
    Subscription
    .subscribe(Subscriber)
    .onSubscribe(Subscription)
    .request(long)
    .onNext(T)
    Reactive Streams
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    1
    2
    3
    4
    5
    

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25. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
    
    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    It’s Demo Time
    https://github.com/christophstrobl/going-reactive-with-spring-data
    

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26. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
    
    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Reactive is about efficient resource usage.
    Even if backed with familiar concepts and framework support, 

    it is no free lunch.
    The price is complexity.
    

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27. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
    
    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    More Spring / Reactive at
    15:00 Spring Boot 2.0 Web Applications (Stéphane Nicoll)
    16:10 The API Gateway is dead! Long live the API Gateway! (Spencer Gibb)
    17:30 Reactive Mythbusters With Reactor (Simon Basle)
    18:40 Refactor to Reactive with Spring 5 and Project Reactor (Oleh Dokuka)
    12:30 Spring Cloud Stream - a new rick and Morty adventure (Dieter Hubau)
    12:30 Advanced Client Load Balancing with Spring Cloud (Alejsandr Tarasov)
    13:50 A Day in a Life of a Traveling Open Source Developer (Spencer Gibb)
    14:30 Boot yourself, Spring is coming (Evgeniy Borisov, Kirill Tolkachev)
    17:00 Data Microservices with Spring Cloud (Orkhan Gasimov)
    Today
    Tomorrow
    

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28. Unless otherwise indicated, these slides are © 2013-2017 Pivotal Software, Inc. and licensed under a
    
    Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
    Spring Framework

    5
    Project Reactor

    3.1
    Spring Data

    Kay
    Questions ?
    

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