Reactive Microservices with Java and Java EERodrigo Cândido da Silva @rcandidosilva Israel Boza Rodriguez @IsraKaos

Agenda• Monolithic vs. Microservices • Reactive Manifesto • Resilience • Message-driven • Demo • Q&A

Monolithic vs. Microservices

Microservices

• Small components • Isolated deployment • Independent technology • Separate infrastructure

"Small independent component with well-defined boundaries that’s doing one thing, but

doing it well"

Reactive Manifesto

Resilient• How to support it on microservices?

• Central point of configuration • Service registry and discovery • Routing features • Load balancing • Failover • Monitoring

Spring BootSpring Cloud

Spring Cloud + Netflix OSS

Spring Cloud + Netflix OSS“Nice match to build resilient microservices with

Java"

Configuration Management Spring Cloud Config + Bus

Service Registration and Discovery Netflix Eureka

Load Balacing Netflix Ribbon

Circuit Breaker Netflix Hystrix + Turbine

Proxy Server Netflix Zuul

Autenthication Spring Cloud Security

Spring Cloud Config

Netflix Eureka

Netflix Ribbon

Netflix Hystrix• Circuit Breaker Pattern

Hystrix Dashboard

Netflix Zuul

Spring Cloud Security

Discovery

Client Relying Party

Resource Server

Get an access token

& an ID Token (JWT)

Use an access token

Authorization Server

Iden.tyProviderorIDPor

OpenIDProviderorOP

Authorization Endpoint

Token Endpoint

Important Stuff

Userinfo Endpoint

Registration Endpoint

JWKS Endpoint

JWKS Endpoint

Validate (JWT)

ID Token

/.well-known /webfinger /openid-configura.on

Check Session IFrame

End Session Endpoint

Message-Driven • How to support it on microservices?

• Asynchronous communication • Non blocking I/O • Distributed • Consistency • Event sourcing • CQRS

Reactive Programming• Asynchronous communication and data streams

• reactive-streams.org

Reactive Alternatives at Java EE

JMS EJB 3

Message-Driven Beans

Asynchronous Session Beans

CDIEvents

Observers

ServletAsynchronous

NIO

JAX-RSAsync on Server

Async on Client

WebSocket

Async Remote Endpoints Concurrency

Utilities

Project Reactor• Library for building non-blocking apps • Interacts with Java 8 functional API • Offers two reactive composable API

• Flux[N] and Mono[0|1] • Supports scalable in-memory routing with Bus extensions

• Ported to support microservices

REST Endpoint@RestControllerpublic class UserRestController {

private static final List<User> users = new ArrayList<>();

static { users.add(new User(1, "Rodrigo", "C", "da Silva")); users.add(new User(2, "Israel", "B", "Rodriguez")); users.add(new User(3, "Bruno", "", "Souza")); users.add(new User(4, "Edson", "", "Yanaga")); }

@RequestMapping(method = RequestMethod.GET, value = "/users") public List<User> getUsers() { return users; }

@RequestMapping(method = RequestMethod.GET, value = "/user/{id}") public User getUser(@PathVariable("id") Integer id) { return users.stream().filter(g -> g.getId() == id) .collect(Collectors.toList()).get(0); }

}

REST Proxy@Componentpublic class UserServiceProxy {

@Autowired UserService service;

@HystrixCommand(fallbackMethod = "defaultUsersObservable") public Observable<List<User>> getUsersObservable() { return new ObservableResult<List<User>>() { @Override public List<User> invoke() { return service.getUsers(); } }; }

public Observable<User> defaultUsersObservable() { return null; }} @FeignClient("USER-SERVICE")

public interface UserService {

@RequestMapping(value = "/users", method = RequestMethod.GET) List<User> getUsers();

@RequestMapping(value = "/user/{id}", method = RequestMethod.GET) User getUser(@PathVariable("id") Integer id);}

REST Async Client

@RestControllerpublic class APIController {

@Autowired GroupServiceProxy groupService;

@Autowired UserServiceProxy userService;

@RequestMapping(method = RequestMethod.GET, value = "/userGroups") public UserGroup getUserGroups() { Observable<List<Group>> groups = groupService.getGroupsObservable(); Observable<List<User>> users = userService.getUsersObservable();

Observable<UserGroup> userGroupObservable = Observable.zip(groups, users, (g, u) -> new UserGroup(u, g));

return userGroupObservable.toList().toBlocking().single().get(0); }

}

Demo• Reactive Microservices • https://github.com/rcandidosilva/reactive-microservices

Other Alternatives

Q&A

?

References• http://projects.spring.io/spring-boot/ • http://projects.spring.io/spring-cloud/ • https://netflix.github.io/ • http://www.reactive-streams.org/ • http://www.reactivemanifesto.org/ • https://github.com/reactivemanifesto/website-manifesto/tree/master/public/pdf • https://projectreactor.io/ • http://reactivex.io/ • http://www.kennybastani.com/2016/04/event-sourcing-microservices-spring-

cloud.html

Thank you! Obrigado!