benjchristensen

/**
 * Copyright 2014 Netflix, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software

benjchristensen

/**
 * Copyright 2014 Netflix, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software

benjchristensen

/**
 * Copyright 2014 Netflix, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software

benjchristensen

Problem Statement

A service layer (Java API in this case) is backed by dozens of services (over the network in an SOA) and used by dozens of clients, each using different subsets of the overall API. In our case all client interaction happens within a single JVM so we can know which clients are accessing what services, fields and keys (versus a RESTful API over HTTP where this would be unknown).

Principally the API is functionality focused rather than system focused. A client should request data to serve a given use case and not need to concern themselves with the underlying implementation details of what backend system the data is coming from.

Today this is achieved through static typing and Java object modeling. Types from underlying services are decoupled from clients so that backend systems can change their implementations without impacting clients.

This means (assuming Java language environment):

benjchristensen

/*
 * Copyright 2013 Netflix, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software

benjchristensen

public interface Observable<T> {
 
 public Subscription subscribe(Observer<T> observer);
 
}

benjchristensen

/**
 * Copyright 2013 Netflix, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software

benjchristensen

Example output of hystrix.stream that is consumed by the dashboard: https://github.com/Netflix/Hystrix/tree/master/hystrix-dashboard

The stream is an EventSource formatted stream of JSON: https://developer.mozilla.org/en-US/docs/Server-sent_events/EventSource

Content-Type: text/event-stream;charset=UTF-8

The b_run-hystrix-examples-webapp.sh file shows how to run the example Hystrix app that exposes a stream to play with.

benjchristensen

/**
 * Copyright 2013 Netflix, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software

benjchristensen

import rx.Observable;

import java.util.ArrayList;
import java.util.List;

public class RxUsingJava8 {

    public static void main(String args[]) {

        /*