The document discusses microservices architecture using the Spring Cloud framework. It provides an overview of Spring Cloud concepts like service discovery with Eureka, centralized configuration with Config Server, circuit breaking with Hystrix, and API routing with Zuul proxy. Examples are given of setting up Spring Cloud applications for configuration, discovery, and circuit breaking. The document aims to motivate microservices and demonstrate how to build them using Spring Cloud.

1. Construindo
Microservices com
Spring Cloud
Arquitetura Java
Claudio Eduardo
de Oliveira

2. About me
Claudio Eduardo de Oliveira
Java Developer @ ADTsys
Bacharel em Ciência da Computação
Cursando MBA em Arquitetura de Soluções em
Tecnologia (DeVry/Metrocamp)
Entusiasta Docker / Spring
Contatos:
Email: claudioed.oliveira@gmail.com
Linkedin: https://br.linkedin.com/in/claudioedoliveira
Twitter: @claudioed
Blog: www.claudioliveira.com

4. Eat your
own
Dog Food

5. Agenda
Motivação
Microservices
Spring Boot + Spring Cloud
Portifólio de projetos
Spring Cloud Config
Spring Cloud Eureka
Spring Cloud Bus

6. Motivação
http://www.infoworld.com/article/3075880/application-development/microservice-architecture-is-agile-
software-architecture.html
motivacao

7. The term "Microservice Architecture" has
sprung up over the last few years to describe
a particular way of designing software
applications as suites of independently
deployable services. While there is no
precise definition of this architectural style,
there are certain common characteristics
around organization around business
capability, automated deployment,
intelligence in the endpoints, and
decentralized control of languages and
data
http://martinfowler.com/articles/microservices.html
microservices

8. - Desacoplamento
- Agilidade na entrega de
Valor
- Deploy independente
- Diversidade tecnológica
Vantagens
http://martinfowler.com/articles/microservice-trade-offs.html
microservices

9. - Complexidade Operacional
- Comunicação
- Consistência Eventual
Desvantagens
http://martinfowler.com/articles/microservice-trade-offs.html
microservices

10. microservices
- Configurações Centralizadas
- Service Registry / Service
Discovery
- Circuit Breaker
- API Proxy

12. Spring Cloud
Netflix OSS
+

13. Advice

14. spring boot

15. spring boot
- criação de aplicações standalone
spring
- NO xml
- configuração automática
- métricas e health checks
- tomcat, jetty ou undertow embed
spring boot
features

16. spring cloud
spring cloud
=
spring boot
+
steroids

17. spring cloud
- spring cloud config
- spring cloud netflix
- spring cloud security
- spring cloud bus
- spring cloud consul
- spring cloud sleuth
- spring cloud stream
- spring cloud zookeeper
- ...
portifólio
http://projects.spring.io/spring-cloud/

18. spring cloud config
- Configurações Centralizadas
- Service Registry / Service
Discovery
- Circuit Breaker
- API Proxy

19. - HTTP resource based API
- encrypt / Decrypt
- integração Spring Boot
@EnableConfigServer
- suporte múltiplos ambiente
(dev, qa, prod)
- arquivos (github / filesystem)
spring cloud config

20. - spring cloud server
- spring cloud client
spring cloud config

21. spring cloud configConfig Server
Dependência
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-config-server</artifactId>
</dependency>

22. spring cloud configConfig Server
Setup
/**
* @author Claudio E. de Oliveira.
*/
@SpringCloudApplication
@EnableConfigServer
public class ConfigApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigApplication.class, args);
}
}

23. spring cloud configConfig Server
Setup (bootstrap.yml)
spring:
application:
name: configserver

24. spring cloud config
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
Config Client
Dependência

25. spring cloud configConfig Client
Setup (bootstrap.yml)
spring:
profiles: default
application:
name: predictors
cloud:
config:
uri: http://configserver:8001/
server:
port: 7003

26. Cloud Bus
spring cloud bus

27. - Push de configurações
- RabbitMQ
spring cloud busConfig Client Bus
Funcionamento

28. spring cloud busCloud Bus
Dependência
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-bus-amqp</artifactId>
</dependency>

29. spring cloud busConfig Client Bus
Setup
info:
component: Predictor MicroService
spring:
rabbitmq:
host: localhost
port: 5672
username: guest
password: guest

30. spring cloud busConfig Client Bus
Exemplo
@Service
@RefreshScope
public class ParticipantService {
@Autowired
private RestTemplate restTemplate;
@Value("${services.user.info}")
private String url;
}

31. spring cloud busConfig Client Bus
Exemplo
services:
user:
info: http://USERS/
event:
info: http://EVENTS/

32. spring cloud eureka
- Configurações Centralizadas
- Service Registry / Service
Discovery
- Circuit Breaker
- API Proxy

33. spring cloud eureka
Service Discovery
Conceito
● clientes se registram no
servidor
● servidor lista os clientes
● clientes conhecem são
reconhecidos por outros
clientes

34. spring cloud eureka
Service Discovery
Desafios
● # de chamadas a microservices
● configuração manual
impraticável
● # de instâncias de serviços
● resolver dependências em
runtime

35. - “lookup” de serviços
- clientes enviam heartbeats
- remoção de clientes não
funcionais
- testado em produção pelo
Netflix
spring cloud eureka

36. <dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
spring cloud eurekaEureka Server
Dependência

37. spring cloud eurekaEureka Server
Setup
@SpringBootApplication
@EnableEurekaServer
@EnableDiscoveryClient
public class DiscoveryApplication{
public static void main(String[] args) {
SpringApplication.run(DiscoveryApplication.class, args);
}
}

38. spring cloud eurekaEureka Server
Exemplo

39. <dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
spring cloud eurekaEureka Client
Dependência

40. spring cloud eurekaEureka Client
Setup
info:
component: Ranking MicroService
server:
port: 7002
eureka:
client:
serviceUrl:
defaultZone: http://discovery:8761/eureka/

41. spring cloud eurekaEureka Client
Setup
@SpringCloudApplication
public class RankingApplication {
public static void main(String[] args) throws Exception {
SpringApplication.run(RankingApplication.class, args);
}
}

42. spring cloud eurekaEureka Client
Setup
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootApplication
@EnableDiscoveryClient
@EnableCircuitBreaker
public @interface SpringCloudApplication {
}

43. spring cloud hystrix
- Configurações Centralizadas
- Service Registry / Service
Discovery
- Circuit Breaker
- API Proxy

44. Falácias da Computação
Distribuída
spring cloud hystrix
1. A rede é confíavel
2. A latência é zero
3. A largura da banda é infinita
4. A rede é segura
5. A topologia não se altera
6. Existe apenas um administrador
7. Custo de transporte é zero
8. A rede é homogênea

45. spring cloud hystrix
Cascading Failures
Problema
● # número de dependências pode levar ao “cascading failures”
● sistemas distribuídos por padrão tem mais chances de falhar

46. Circuit Breaker
Conceito
spring cloud hystrix
● Mesmo comportamento de um circuito elétrico
● “Aberto” falha na operação e a mesma não deve
ser chamada
● “Fechado” funcionamento normal, a operação
pode ser chamada
● “Parcialmente Aberto” pode haver chamada mas
serão auditadas para ver se o problema ainda
persiste

47. Netflix Hystrix
spring cloud hystrix
● provê mecanismo de “fallback”
● “fallbacks” podem ser encadeados (cuidado!!!)
● fácil integração com Spring (via annotations)
● fechamento automático do circuito

48. spring cloud hystrix
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
Cloud Hystrix
Dependência

49. spring cloud hystrixCloud Hystrix
Setup
@SpringCloudApplication
@EnableHystrix
public class PredictorApplication {
public static void main(String[] args) throws Exception {
SpringApplication.run(PredictorApplication.class, args);
}
}

50. spring cloud hystrixCloud Hystrix
Exemplo (command)
@Service
@RefreshScope
public class ParticipantService {
@HystrixCommand(fallbackMethod = "getParticipantInCache")
public Participant getUserInfo(String participantId){
log.info("[REQUEST-PARTICIPANT-INFO] Request event info ");
ResponseEntity<Participant> response = this.restTemplate.getForEntity(this.url +
participantId, Participant.class);
final Participant participant = response.getBody();
cache.put(participant.getId(),participant);
return participant;
}
}

51. spring cloud hystrixCloud Hystrix
Exemplo (fallback)
@Service
@RefreshScope
public class ParticipantService {
public Participant getParticipantInCache(String participantId){
Participant cachedParticipant = cache.getIfPresent(participantId);
if(Objects.isNull(cachedParticipant)){
log.error(String.format("[REQUEST-PARTICIPANT-INFO] CACHE - Error on
retrieve participant %s information", participantId));
throw new InvalidParticipant(participantId);
}
return cachedParticipant;
}
}

52. spring cloud hystrix
● microservices sem monitoramento torna-se
impraticável
● hystrix provê dashboards
● @EnableHystrixDashboard
Cloud Hystrix
Monitoramento

53. spring cloud zuul
- Configurações Centralizadas
- Service Registry / Service
Discovery
- Circuit Breaker
- API Proxy

54. spring cloud zuulAPI Proxy
Problemas
● API internas “expostas”
● segurança
● CORS
● Roteamento
● Versionamento
● Cache
● # excessivo de chamadas remotas

55. spring cloud zuulAPI Proxy
Spring Cloud Zuul
● filtros (pre/pos)
● roteamento para serviços
● versionamento de APIs
● CORS
● integração Eureka (service name)

56. spring cloud zuul
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zuul</artifactId>
</dependency>
Cloud Zuul
Dependência

57. spring cloud zuulCloud Zuul
Setup
@SpringCloudApplication
@Controller
@EnableZuulProxy
public class GatewayApplication {
public static void main(String[] args) {
SpringApplication.run(GatewayApplication.class, args);
}
}

58. spring cloud zuulCloud Zuul
Setup
info:
component: API Gateway (Zull Proxy)
eureka:
registryFetchIntervalSeconds: 5
serviceUrl:
defaultZone: http://${eureka.host:localhost}:${eureka.port:8761}/eureka/
zuul:
routes:
users:
path: /api/v1/users/**
serviceId: users

59. spring cloud zuulCloud Zuul
Exemplo (client)
@SpringCloudApplication
@EnableZuulProxy
public class EventApplication {
public static void main(String[] args) throws Exception {
SpringApplication.run(EventApplication.class, args);
}
}

60. #tip

62. email: claudioed.oliveira@gmail.com
linkedin: https://br.linkedin.com/in/claudioedoliveira
twitter: @claudioed
blog: www.claudioliveira.com
github: https://github.com/claudioed
Claudio Eduardo de Oliveira

63. Referências
http://martinfowler.com/articles/microservices.html
http://microservices.io/
http://microservices.io/patterns/apigateway.html
http://projects.spring.io/spring-boot/
https://cloud.spring.io/spring-cloud-netflix/
http://callistaenterprise.se/blogg/teknik/2015/04/10/building-microservices-with-spring-cloud-and-netflix-oss-
part-1/