Experiments and prototypes with reactive application design using service-oriented architecture concepts.
Start server using EdgeServer.java or Gradle:
./gradlew startEdge
Simulation of middle-tier RPC/RESTful services exposing endpoints over HTTP.
Start several services on different ports using StartMiddleTierServices.java or Gradle:
./gradlew startServices
See how Netty and RxJava are used as an HTTP server in EdgeServer
Basics are:
RxNetty.createHttpServer(8080, (request, response) -> {
System.out.println("Server => Request: " + request.getPath());
... handle requests here ...
}).startAndWait();Clients using Netty and RxJava can be seen in the clients package.
Basic example:
return RxNetty.createHttpClient("localhost", 9100)
.submit(HttpClientRequest.createGet("/mock.json?id=" + id));Here is a batch request using SSE inside a HystrixObservableCommand for fault-tolerance: BookmarksCommand.
A HystrixObservableCollapser can be put in front of that command to allow automated batching: BookmarkCommand.
Nested, parallel execution of network requests can be composed using RxJava and Hystrix as demonstrated in RouteForDeviceHome which is the example running at the /device/home endpoint.
Here is a portion of the code to show the composition:
return new UserCommand(userId).observe().flatMap(user -> {
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);
});
});
});
Observable<Map<String, Object>> social = new SocialCommand(user).observe().map(s -> {
return s.getDataAsMap();
});
return Observable.merge(catalog, social);
}).flatMap(data -> {
return response.writeAndFlush(new ServerSentEvent("", "data", SimpleJson.mapToJson(data)), EdgeServer.SSE_TRANSFORMER);
});This results in 7 network calls being made, and multiple bookmark requests are automatically collapsed into 1 network call. Here is the HystrixRequestLog that results from the code above being executed:
Server => Hystrix Log [/device/home] => UserCommand[SUCCESS][191ms], PersonalizedCatalogCommand[SUCCESS][50ms], SocialCommand[SUCCESS][53ms], RatingsCommand[SUCCESS][65ms]x6, VideoMetadataCommand[SUCCESS][73ms]x6, BookmarksCommand[SUCCESS, COLLAPSED][25ms], BookmarksCommand[SUCCESS, COLLAPSED][24ms]