Going Reactive - High Performance JVM code with Reactor

I gave this talk at JAX 2014. It is an introduction into reactive programming, why its needed and how the Reactor framework can help you achieve those goals.

Transcript

1. Michael  Nitschinger  (@daschl)  
   JVM  Engineer  @  Couchbase,  Inc.  
   Going  Reac6ve  
   High  Performance  JVM  Code  with  Reactor  
   

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2. 2  
   Reac6ve?  
   

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3. 3  
   4  Traits  of  Reac6ve  Systems  
   •  h?p://www.reac6vemanifesto.org/  
    
   h9p://www.reac>vemanifesto.org/images/full-­‐reac>ve@2x.png  
   

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4. 4  
   Scalable  &  Event-­‐Driven  
   •  Message-­‐Passing  
   •  Asynchronous  
   •  Non-­‐Blocking  
   •  Immutability  
   •  Avoiding  
   Synchroniza6on  
   h9p://www.reac>vemanifesto.org/images/amdahl@2x.png  
   

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5. 5  
   Resilient  
   •  Isola6ng  Failure  
   •  Supervision  Hierachies  
   •  Self-­‐Healing  Components  
   h9p://www.reac>vemanifesto.org/images/tank@2x.png  
   

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6. 6  
   Responsive  
   •  Use  Bounded  Queues  &  Backpressure  
   •  Apply  Batching  under  Traffic  Bursts  
   •  Don‘t  forget  the  Big  O!  
   0  
   20  
   40  
   60  
   80  
   100  
   120  
   Hockey  S>ck  
   Linear  
   Leveling  Off  
   

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7. 7  
   Meet  Reactor.  
   

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8. 8  
   What  is  Reactor?  
   •  Founda6onal  library  
   •  Lives  between  user  and  low-­‐level  code.  
   •  Suite  for:  drivers,  libraries,  event-­‐driven  systems  
   •  Part  of  Spring  IO  
   •  1.1.0  Released  (h?ps://github.com/reactor/reactor)  
   

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9. 9  
   Landscape  
   

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10. 10  
    A  first  look  
    

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11. 11  
    Dispatchers  
    •  Per  Environment  
    •  Manage  Task  Execu6on.  
     
    ­  ThreadPoolExecutorDispatcher  
    execu>ng  tasks  in  a  thread  pool  
    ­  EventLoopDispatcher  
    mul>ple  event  loops  dispatching  tasks  
    ­  RingBufferDispatcher  
    uses  the  LMAX  Disruptor  RingBuffer  
    ­  ActorDispatcher  
    to  pin  keys  to  threads  
    ­  SynchronousDispatcher  
    for  tes>ng  
    

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12. 12  
    Selectors  
    •  Lea-­‐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. 13  
    Selectors  -­‐  Regex  
    •  A  RegexSelector  will  match  a  String  by  execu6ng  the  
    regex.  
    

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14. 14  
    Selectors  -­‐  Templates  
    •  A  UriTemplateSelector  will  match  a  String  by  extrac6ng  
    bits  from  a  URI.  
    

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15. 15  
    Selectors  –  Class  Types  
    •  A  ClassSelector  will  match  the  same  or  a  supertype  of  
    the  given  class.  
    

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16. 16  
    Func6ons  
    •  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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17. 17  
    Promises  
    •  Promises  allow  for  composi6on  of  func6ons  
    ­  Shares  common  func>ons  with  a  Stream  
    

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18. 18  
    Streams  
    •  Streams  allow  the  composi6on  of  func6ons  
    ­  Callbacks  on  steroids  
    ­  Akka  Streams,  RxJava  Observables,  JDK  8  Stream  
    

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19. 19  
    Processor  
    •  Thin  wrapper  around  the  Disruptor  RingBuffer  
    ­  Converts  Disruptor  API  to  Reactor  API  
    ­  Really  fast!  
    

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20. 20  
    Integra6on:  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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21. 21  
    Integra6on:  Groovy  
    •  First  class  ci6zen  language  implementa6on  
     
    ­  @CompileSta>c  ready  
    ­  Prominent  use  of  Closure  as  Consumers,  Func>ons  and  more  
    ­  Operator  overloading  
    ­  Full  Reactor  system  Builder  
    

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22. 22  
    Integra6on:  Clojure  
    •  Meltdown:  A  Clojure  binding  by  @michaelklishin  and  
    @ifesdjeen  
    ­  h9ps://github.com/clojurewerkz/meltdown    
    

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23. 23  
    Wait  –  there  is  more!  
    

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24. 24  
    Networking  
    •  TCP  and  UDP  Support  
    •  ZeroMQ,  SSL,  Codecs,...  
    

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25. 25  
    Networking  -­‐  Server  
    

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26. 26  
    Allocators  
    •  Control  Memory  Usage  (RingBuffer,  Refcoun>ng)  
    

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27. 27  
    What  else?  
    •  Too  much  to  show  today!  
     
    ­  Buffer  tooling  
    ­  Sequencing/EventOrdering  
    ­  Work  Queue  support  on  top  of  Java  Chronicle  
    ­  Logback  Appender  
    ­  Language  Constructs  (i.e.  Tuples,…)  
    

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28. 28  
    Demo  
    

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29. 29  
    Ques6ons?  
    

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