Reactive Programming with Rx at NYTimes

Reactive programming in the form of RxJS and RxJava has been adopted at Netflix over the past couple years for both client-side and server-side programming. This talk summarizes why the Rx programming model was chosen and demonstrates how it is applied to a variety of use cases including web services, interprocess communication and stream processing.

Presented at New York Times: http://developers.nytimes.com/events/

Transcript

1. Ben Christensen Software Engineer – Edge Engineering at Netflix @benjchristensen http://www.linkedin.com/in/benjchristensen ! ! ! ! ! http://techblog.netflix.com/ New York Times - September 2014 Reactive Programming with Rx
2. Reactive Extensions for Async Programming RxJava http://github.com/ReactiveX/RxJava http://reactivex.io
3. Reactive Extensions for Async Programming RxJava http://github.com/ReactiveX/RxJava http://reactivex.io Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData()
4. Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData() Observable.create(subscriber -> { subscriber.onNext("Hello world!"); subscriber.onCompleted(); }).forEach(System.out::println); Synchronous single value
5. Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData() Observable.create(subscriber -> { subscriber.onNext("Hello"); subscriber.onNext("world"); subscriber.onNext("!"); subscriber.onCompleted(); }).forEach(System.out::println); Synchronous multi-value
6. Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData() Observable.create(subscriber -> { try { subscriber.onNext(doSomething()); subscriber.onCompleted(); } catch (Throwable e) { subscriber.onError(e); } }).subscribeOn(Schedulers.io()) .forEach(System.out::println); Asynchronous single value with error handling
7. Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData() Observable.create(subscriber -> { int i = 0; while (!subscriber.isUnsubscribed()) { subscriber.onNext(i++); } }).take(10).forEach(System.out::println); Synchronous multi-value with unsubscribe
8. Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData() Observable.create(subscriber -> { AtomicInteger i = new AtomicInteger(); AtomicLong requested = new AtomicLong(); subscriber.setProducer(r -> { if (requested.getAndAdd(r) == 0) { do { if (subscriber.isUnsubscribed()) { break; } subscriber.onNext(i.incrementAndGet()); } while (requested.decrementAndGet() > 0); } }); }).observeOn(Schedulers.newThread()) .take(10).forEach(System.out::println); Synchronous multi-valued source that thread-hops with “reactive pull” backpressure
9. Single Multiple Sync T getData() Iterable<T> getData() Async Future<T> getData() Observable<T> getData() Observable.from(iterable) .observeOn(Schedulers.newThread()) .take(10).forEach(System.out::println); Synchronous multi-valued source that thread-hops with “reactive pull” backpressure
13. Abstract Concurrency
14. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
15. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
16. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
17.  Observable<R>  b  =  Observable<T>.flatMap({  T  t  -­‐>            Observable<R>  r  =  ...  transform  t  ...          return  r;    }) flatMap
18.  Observable<R>  b  =  Observable<T>.flatMap({  T  t  -­‐>            Observable<R>  r  =  ...  transform  t  ...          return  r;    }) flatMap
19. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
20. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
21. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
22. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
23. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
24. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
25. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
26. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
27. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
28.        Observable.zip(a,  b,  {  a,  b,  -­‐>                ...  operate  on  values  from  both  a  &  b  ...              return  [a,  b];  //  i.e.  return  tuple          })
29. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
30. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
32. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
33. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
34. class  VideoService  {        def  VideoList  getPersonalizedListOfMovies(userId);        def  VideoBookmark  getBookmark(userId,  videoId);        def  VideoRating  getRating(userId,  videoId);        def  VideoMetadata  getMetadata(videoId);   } class  VideoService  {        def  Observable<VideoList>  getPersonalizedListOfMovies(userId);        def  Observable<VideoBookmark>  getBookmark(userId,  videoId);        def  Observable<VideoRating>  getRating(userId,  videoId);        def  Observable<VideoMetadata>  getMetadata(videoId);   } ... create an observable api: instead of a blocking api ...
35. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); } 1 2 3 4 5 6
36. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); } 1 2 3 4 5 6
37. Non-Opinionated Concurrency
39. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
44. public Observable<Void> handle(HttpServerRequest<ByteBuf> request, HttpServerResponse<ByteBuf> response) { // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }).flatMap(data -> { // output as SSE as we get back the data (no waiting until all is done) return response.writeAndFlush(new ServerSentEvent(SimpleJson.mapToJson(data))); }); }
46. Decouples Consumption from Production // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); })
47. Decouples Consumption from Production // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); })
48. Decouples Consumption from Production // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); })
49. Decouples Consumption from Production Event Loop API Request API Request API Request API Request API Request Dependency REST API new Command().observe() new Command(). observe() new Command(). observe() new Command(). observe() new Command(). observe() Collapser
50. Decouples Consumption from Production // first request User object return new UserCommand(request.getQueryParameters().get("userId")).observe().flatMap(user -> { // then fetch personal catalog Observable<Map<String, Object>> catalog = new PersonalizedCatalogCommand(user).observe() .flatMap(catalogList -> { return catalogList.videos().<Map<String, Object>> flatMap(video -> { Observable<Bookmark> bookmark = new BookmarkCommand(video).observe(); Observable<Rating> rating = new RatingsCommand(video).observe(); Observable<VideoMetadata> metadata = new VideoMetadataCommand(video).observe(); return Observable.zip(bookmark, rating, metadata, (b, r, m) -> { return combineVideoData(video, b, r, m); }); }); }); // and fetch social data in parallel Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> { return s.getDataAsMap(); }); // merge the results return Observable.merge(catalog, social); }) 1 2 3 4 5
51. class  VideoService  {        def  Observable<VideoList>  getPersonalizedListOfMovies(userId);        def  Observable<VideoBookmark>  getBookmark(userId,  videoId);        def  Observable<VideoRating>  getRating(userId,  videoId);        def  Observable<VideoMetadata>  getMetadata(videoId);   } Clear API Communicates Potential Cost
52. class  VideoService  {        def  Observable<VideoList>  getPersonalizedListOfMovies(userId);        def  Observable<VideoBookmark>  getBookmark(userId,  videoId);        def  Observable<VideoRating>  getRating(userId,  videoId);        def  Observable<VideoMetadata>  getMetadata(videoId);   } Implementation Can Differ BIO Network Call Local Cache Collapsed Network Call
53. class  VideoService  {        def  Observable<VideoList>  getPersonalizedListOfMovies(userId);        def  Observable<VideoBookmark>  getBookmark(userId,  videoId);        def  Observable<VideoRating>  getRating(userId,  videoId);        def  Observable<VideoMetadata>  getMetadata(videoId);   } Implementation Can Differ and Change Local Cache Collapsed Network Call Collapsed Network Call BIO NIO Network Call
54. Retrieval, Transformation, Combination all done in same declarative manner
55. Front Controller and Web Service Endpoints Service Layer Impl & Service Clients Observable APIs & Reactive Programming
56. Front Controller and Web Service Endpoints Service Layer Impl & Service Clients Imperative & Blocking Service Layer Impl & Service Clients
57. Front Controller and Web Service Endpoints Service Layer Impl & Service Clients Can we do better here? Service Layer Impl & Service Clients
58. Service Layer Impl & Service Clients RxNetty +
59. WSPerfLab https://github.com/Netflix-Skunkworks/WSPerfLab
60. Latency in Milliseconds 0 1,250 2,500 3,750 5,000 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s
61. Latency in Milliseconds 0 100 200 300 400 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s
62. Latency in Milliseconds 0 1,250 2,500 3,750 5,000 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s
63. Latency in Milliseconds 0 1,250 2,500 3,750 5,000 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s 458 1217
64. Latency in Milliseconds 0 150 300 450 600 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s Tomcat -c200: 969 r/s
65. Latency in Milliseconds 0 150 300 450 600 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s Tomcat -c200: 969 r/s
66. Latency in Milliseconds 0 150 300 450 600 Latency Percentile 50th 66th 75th 80th 90th 95th 98th 99th 100th Tomcat -c200: 969 r/s Tomcat -c400: 1142 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s Tomcat -c400: 1142 r/s Tomcat -c200: 969 r/s RxNetty -c200: 1264 r/s RxNetty -c400: 2077 r/s 458 1217
67. Current status … moving on to production testing with Netty-based IPC
69. Note: This is a mockup
70. Note: This is a mockup
71. private static Observable<GroupedObservable<TypeAndNameKey, Map<String, Object>>> aggregateUsingPivot(Observable<GroupedObservable<InstanceKey, Map<String, Object>>> instanceStreams) { return instanceStreams.map(instanceStream -> { return createGroupedObservable(instanceStream.getKey(), instanceStream .groupBy((Map<String, Object> json) -> { return TypeAndNameKey.from(String.valueOf(json.get("type")), String.valueOf(json.get("name"))); })); }).lift(OperatorPivot.create()).map(commandGroup -> { // merge all instances per group into a single stream of deltas and sum them return createGroupedObservable(commandGroup.getKey(), commandGroup.flatMap(instanceGroup -> { return instanceGroup.startWith(Collections.<String, Object> emptyMap()) .buffer(2, 1) .map(StreamAggregator::previousAndCurrentToDelta) .filter(data -> data != null && !data.isEmpty()); }).scan(new HashMap<String, Object>(), StreamAggregator::sumOfDelta) .skip(1)); }); }
72. private static Observable<GroupedObservable<TypeAndNameKey, Map<String, Object>>> aggregateUsingPivot(Observable<GroupedObservable<InstanceKey, Map<String, Object>>> instanceStreams) { return instanceStreams.map(instanceStream -> { return createGroupedObservable(instanceStream.getKey(), instanceStream .groupBy((Map<String, Object> json) -> { return TypeAndNameKey.from(String.valueOf(json.get("type")), String.valueOf(json.get("name"))); })); }).lift(OperatorPivot.create()).map(commandGroup -> { // merge all instances per group into a single stream of deltas and sum them return createGroupedObservable(commandGroup.getKey(), commandGroup.flatMap(instanceGroup -> { return instanceGroup.startWith(Collections.<String, Object> emptyMap()) .buffer(2, 1) .map(StreamAggregator::previousAndCurrentToDelta) .filter(data -> data != null && !data.isEmpty()); }).scan(new HashMap<String, Object>(), StreamAggregator::sumOfDelta) .skip(1)); }); }
73. private static Observable<GroupedObservable<TypeAndNameKey, Map<String, Object>>> aggregateUsingPivot(Observable<GroupedObservable<InstanceKey, Map<String, Object>>> instanceStreams) { return instanceStreams.map(instanceStream -> { return createGroupedObservable(instanceStream.getKey(), instanceStream .groupBy((Map<String, Object> json) -> { return TypeAndNameKey.from(String.valueOf(json.get("type")), String.valueOf(json.get("name"))); })); }).lift(OperatorPivot.create()).map(commandGroup -> { // merge all instances per group into a single stream of deltas and sum them return createGroupedObservable(commandGroup.getKey(), commandGroup.flatMap(instanceGroup -> { return instanceGroup.startWith(Collections.<String, Object> emptyMap()) .buffer(2, 1) .map(StreamAggregator::previousAndCurrentToDelta) .filter(data -> data != null && !data.isEmpty()); }).scan(new HashMap<String, Object>(), StreamAggregator::sumOfDelta) .skip(1)); }); }
74. private static Observable<GroupedObservable<TypeAndNameKey, Map<String, Object>>> aggregateUsingPivot(Observable<GroupedObservable<InstanceKey, Map<String, Object>>> instanceStreams) { return instanceStreams.map(instanceStream -> { return createGroupedObservable(instanceStream.getKey(), instanceStream .groupBy((Map<String, Object> json) -> { return TypeAndNameKey.from(String.valueOf(json.get("type")), String.valueOf(json.get("name"))); })); }).lift(OperatorPivot.create()).map(commandGroup -> { // merge all instances per group into a single stream of deltas and sum them return createGroupedObservable(commandGroup.getKey(), commandGroup.flatMap(instanceGroup -> { return instanceGroup.startWith(Collections.<String, Object> emptyMap()) .buffer(2, 1) .map(StreamAggregator::previousAndCurrentToDelta) .filter(data -> data != null && !data.isEmpty()); }).scan(new HashMap<String, Object>(), StreamAggregator::sumOfDelta) .skip(1)); }); }
75. http://ReactiveX.io
76. ! Reactive Programming in the Netflix API with RxJava http://techblog.netflix.com/2013/02/rxjava-netflix-api.html ! Optimizing the Netflix API http://techblog.netflix.com/2013/01/optimizing-netflix-api.html ! ! ! ! Ben Christensen @benjchristensen http://www.linkedin.com/in/benjchristensen RxJava https://github.com/ReactiveX/RxJava @RxJava RxJS http://reactive-extensions.github.io/RxJS/ @ReactiveX jobs.netflix.com