cloud foundy java client v 2.0 #cf_tokyo

Cloud Foundry Java Client 2.0Toshiaki Maki (@making) Cloud Foundry Tokyo Meetup #1 2016-03-31

Who am I ?• Toshiaki Maki (@making)

•Sr. Solutions Architect

•Spring Framework enthusiast

Spring Framework 徹底入門

(Coming Soon)

Perfect Java EE

(Coming Soon)

Agenda•How CF Java Client V1 was 😟

•How CF Java Client V2 looks 😎

Cloud Foundry Java Client V1CloudCredentials credentials = new CloudCredentials("username", "password"); CloudFoundryClient client = new CloudFoundryClient(credentials, URI.create("https://api.run.pivotal.io").toURL()); client.login();// cf appsList<CloudApplication> apps = client.getApplications();// cf app helloCloudApplication app = client.getApplication("hello");

Cloud Foundry Java Client V1// cf push hello -p foo.jar -m 512m -i 2client.createApplication("hello", new Staging(), 512, singletonList("hello.cfapps.io"), emptyList()); client.uploadApplication("hello", new File("foo.jar")); client.updateApplicationInstances("hello", 2); client.startApplication("hello");// cf logsclient.streamLogs("hello", new ApplicationLogListener() { public void onMessage(ApplicationLog log) { System.out.println(log.getMessage()); } public void onComplete() {} public void onError(Throwable exception) {} });

Problems in V1•Monolithic implementation •No separation between API and Command

•Dependency on Spring Framework (RestTemplate)

•Blocking, Inefficient use of CC API

CF Java Client 2.0 design

Too many overloading…😫

130+ methods…😫

I don’t need MVC…😫

Cloud Foundry Java Client V1

// cf appsclient.getApplications();// cf app helloclient.getApplication("hello");// cf pushclient.createApplication(...); client.uploadApplication(...); client.updateApplicationInstances(...); client.startApplication(...);

Blocking 😫

Cloud Foundry Java Client V2

https://lists.cloudfoundry.org/archives/list/cf-dev@lists.cloudfoundry.org/thread/W4455NML53LLSUSP25J2OXIYP2FNWUI4/

Project Structure in V2

cloudfoundry-client

cloudfoundry-operations

cloudfoundry-client-spring

Implements

CLI (cf ...)

REST API (CC API)

low level

high level

Class DiagramCloudFoundryOperations

DefaultCloudFoundryOperations

CloudFoundryClient

SpringCloudFoundryClient

LoggingClient

SpringLoggingClient

In Future?

CloudFoundryClient

SpringCloudFoundryClient

RetrofitCloudFoundryClient

AndroidCloudFoundryClient

for non-Spring user

for Android user

SpringCloudFoundryClient cloudfoundryClient = SpringCloudFoundryClient.builder() .host("api.run.pivotal.io") .username("user") .password("password") .build();

LoggingClient loggingClient = SpringLoggingClient.builder() .cloudFoundryClient(cloudFoundryClient) .build();

CloudFoundryOperations operations = new CloudFoundryOperationsBuilder() .cloudFoundryClient(cloudFoundryClient) .target("org", "space") .loggingClient(loggingClient) .build();

Builder Pattern

// cf appsoperations.applications().list();// cf app hellooperations.applications() .get(GetApplicationRequest.builder() .name("hello").build());// cf push hello -p foo.jar -m 512m -i 2operations.applications() .push(PushApplicationRequest.builder() .name("hello").path("foo.jar") .memory(512).instances(2).build());// cf logs hellooperations.applications().logs(LogsRequest.builder() .name("hello").build());

Problems in V1•Monolithic implementation •No separation between API and Command

•Dependency on Spring Framework (RestTemplate)

•Blocking, Inefficient use of CC API

CF Java Client 2.0 design

😄😄😄

What about this?

Non-Blocking!! Non-Blocking!!•Go reactive! 😎 •Move imperative logic to async, event-driven,

functional-style code

Why Reactive?

http://www.slideshare.net/SpringCentral/reactive-web-applications-53170985

http://www.slideshare.net/SpringCentral/introduction-to-reactive-programming

Why Reactive?

https://spring.io/blog/2016/03/11/reactor-core-2-5-becomes-a-unified-reactive-foundation-on-java-8#comment-2564120598

V2 supports Reactive Streams!!•Non-Blocking APIs

// cf appsPublisher<ApplicationSummary> apps = operations.applications().list();

Reactive Streams•Standard interfaces for asynchronous stream

processing with non-blocking back pressure •De facto standard for interop between reactive

libraries •Implemented by •Akka Streams •Reactor •RxJava • etc…

http://www.reactive-streams.org/

Reactive Streams has 4 interfacespublic interface Publisher<T> { public void subscribe(Subscriber<? super T> s);}public interface Subscription { public void request(long n); public void cancel();}public interface Subscriber<T> { public void onSubscribe(Subscription s); public void onNext(T t); public void onError(Throwable t); public void onComplete();}public interface Processor<T, R> extends Publisher<T>, Subscriber<R> {}

Subscription SubscriberPublisher Application

subscribe(Subscriber)

onSubscribe(Subscription)

request(1)

onNext(●)

request(1)

onNext(●)

request(2)

request(1)

onNext(●)

request(2)

onNext(●)

request(1)

onNext(●)

request(2)

onNext(●)

request(1)

onNext(●)

request(2)

onNext(●)

request(4)

request(1)

onNext(●)

request(2)

onNext(●)

request(4)

onNext(●)

request(1)

onNext(●)

request(2)

onNext(●)

request(4)

onNext(●)

request(1)

onNext(●)

request(2)

onNext(●)

request(4)

onNext(●)

onComplete()

Reactive Streams with CF Java Client// cf appsPublisher<ApplicationSummary> apps = operations.applications() .list();

Reactive Streams with CF Java Client// cf appsPublisher<ApplicationSummary> apps = operations.applications() .list(); services.subscribe(new Subscriber<ServiceInstance>() { Subscription s; public void onSubscribe(Subscription subscription) { this.s = subscription; subscription.request(1); } public void onNext(ServiceInstance i) { System.out.println(i.getName() + " : " + i.getService()); this.s.request(1); // one by one } public void onError(Throwable throwable) {} public void onComplete() {} });

No higher level abstractions like composition

Reactive eXtensions •A pattern for composing potentially asynchronous and

event-based programs by using sequences or elements.

•On the JVM

•RxJava is the most used implementation

•Reactor Core is the main alternative

•Also for other languages, for example RxJava

•Some composition libraries doesn't follow closely RxPattern (Akka) https://speakerdeck.com/sdeleuze/a-lite-rx-api-for-the-jvm?slide=9

http://reactivex.io/

Reactor

•Yet Another Rx library on the JVM

•Natively built on top of Reactive Streams

•Developed by Pivotal

•Reactor Core provides lite Rx API

• Flux / Mono

•CF Java Client V2 embraces Reactor Core

https://projectreactor.io/

Flux / Mono•Both implement Publisher with Rx API

• Flux for 0..N elements

• Mono for 0..1 element

FluxFlux<Integer> stream1 = Flux.just(1, 2, 3) .map(x -> x * 2) .filter(x -> x > 2); // 4, 6Flux<String> stream2 = Flux.just("a", "b", "c");

Flux.zip(stream1, stream2) .consume(t -> System.out.println(t.t1 + ":" + t.t2));Flux.merge(stream1, stream2) .consume(x -> System.out.println(x));

FluxFlux<Integer> stream1 = Flux.just(1, 2, 3) .map(x -> x * 2) .filter(x -> x > 2); // 4, 6Flux<String> stream2 = Flux.just("a", "b", "c");

Flux.zip(stream1, stream2) .consume(t -> System.out.println(t.t1 + ":" + t.t2));Flux.merge(stream1, stream2) .consume(x -> System.out.println(x));

4:a6:b

MonoMono<Boolean> result = Mono.just(true); result.consume(x -> System.out.println("result=" + x)); Mono<String> delayed = Mono .delay(Duration.ofSeconds(1)) .after(() -> Mono.just("Hi")); delayed.consume(x -> System.out.println("result=" + x)); Mono<Void> noValue = Mono.empty(); noValue .doOnSuccess(x -> System.out.println("finished!")) .subscribe();

Type comparisonNo value Single value Multiple values

Sync (JDK)

void TFuture<T>

Iterable<T>Collection<T>java.util.stream.Stream<T>

Async (JDK)

CompletableFuture<Void> CompletableFuture<T> CompletableFuture<List<T>>

Reactive Streams

Publisher<Void> Publisher<T> Publisher<T>

RxJava Observable<Void>Completable

Single<T> Observable<T>

Reactor Mono<Void> Mono<T> Flux<T>

Reactor with CF Java Client// cf appsFlux<ApplicationSummary> apps = operations .applications().list();apps.map(app -> app.getName()) .consume(x -> System.out.println("name=" + x));

// cf appMono<ApplicationDetail> app = operations .applications().get(GetApplicationRequest.builder() .name("hello").build());app.map(app -> app.getName()) .consume(x -> System.out.println("name=" + x));

Reactor with CF Java Client// cf push hello -p foo.jar -m 512m -i 2Mono<Void> pushed = operations.applications() .push(PushApplicationRequest.builder() .name("hello").path("foo.jar") .memory(512).instances(2).build());pushed.doOnSuccess(x -> System.out.println("pushed!!")) .subscribe();

// cf logs helloFlux<LogMessage> logs = operations.applications() .logs(LogsRequest.builder() .name("hello").build());

logs.filter(log -> "RTR".equals(log.getSourceName())).map(LogMessage::getMessage).filter(msg -> msg.contains(" 500 ")) // 500 error.userTimer(Timer.create()).buffer(Duration.ofSeconds(10)).map(List::size).filer(x -> x.size() > 5) // 5 errors in 10 sec.consume(x -> { System.out.println(x +" errors in 10 seconds!"); // some alerts});

Simple log monitor

Prefer former simple one?

Going Non-Blocking is difficult

Blocking API Non-Blocking API

😭difficult

to Blocking is Easy

Mono<ApplicationDetail> app = ...;ApplicationDetail detail = app.get();

Flux<ApplicationSummary> apps = ...;Iterable<ApplicationSummary> summaries = apps.toIterable();

Enjoy Reactive Programming with CF Java Client V2

cloud foundy java client v 2.0 #cf_tokyo

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