Talk from Sydney JVM Community Meetup S04E01 : Microservice Frameworks http://www.meetup.com/Sydney-JVM-Community/

1. JAVA MICROSERVICES WITH
NETFLIX OSS & SPRING
CONOR SVENSSON

4. SPRING BOOT
SPRING BOOT
▸ Stand-alone Spring-based applications
▸ Tomcat embedded container (supports Jetty & JBoss
Undertow too)
▸ Starter POMs
▸ Annotation driven

5. SPRING BOOT
DEPLOYMENT
▸ Self contained jar
▸ Web application archive
▸ Build targets
▸ $ mvn spring-boot:run
▸ $ gradle bootRun

6. SPRING BOOT

7. ACME HOME LOANS

8. ACME HOME LOANS
LOAN APPLICATION
EXTERNAL
CREDIT
SERVICE
WEBSITE
SERVICE
SUBMISSION
SERVICE
1
2 3

9. ACME HOME LOANS

10. ACME HOME LOANS

11. ACME HOME LOANS

12. SPRING BOOT
TESTING
▸ spring-boot-starter-test starter POM provides:
▸ Spring Test
▸ Unit
▸ Hamcrest + Assert4J (v1.4)
▸ Mockito
▸ MockMvc
▸ @WebIntegrationTest

15. SPRING BOOT
CONFIGURATION BEANS

17. SPRING CLOUD
SPRING CLOUD
▸ Microservice friendly components
▸ Distributed & versioned configuration
▸ Service discovery
▸ Dynamic routing
▸ Circuit breakers
▸ Distributed messaging
▸ Getting started:

18. SPRING CLOUD
SPRING CLOUD
▸ Config
▸ Netflix
▸ Bus
▸ Cloud Foundry
▸ Cluster
▸ Consul
▸ Security
▸ Sleuth
▸ Data Flow
▸ Stream
▸ Modules
▸ Task
▸ Zookeeper
▸ AWS
▸ Connectors
▸ CLI

19. SPRING CLOUD
CONFIG SERVER
▸ Git hosted configuration repository
▸ SVN & filesystem also supported (see implementations
of
org.springframework.cloud.config.server.EnvironmentR
epository)
▸ Multiple security options w/Spring Security (HTTP Basic ->
OAuth bearer tokens)
▸ Push updates via Spring Cloud Bus

20. SPRING CLOUD
CONFIG SERVER

21. SPRING CLOUD
CONFIG SERVER CONFIGURATION
application.yml:

22. SPRING CLOUD
CLIENT CONFIGURATION FILE
website.yml:

23. SPRING CLOUD
RESOURCE FORMAT
/{application}/{profile}[/{label}]
/{application}-{profile}.yml
/{label}/{application}-{profile}.yml
/{application}-{profile}.properties
/{label}/{application}-{profile}.properties
(label: master by default)

24. SPRING CLOUD
RESOLVED CONFIGURATION

25. SPRING CLOUD
SHARED RESOURCES
▸ Place in application.yml in root of configuration repo
▸ Profile specific configuration always takes precedence
over shared
▸ E.g. Eureka server (more on this shortly)

26. SPRING CLOUD
CLIENT CONFIGURATION
bootstrap.yml:

27. SPRING CLOUD
CLIENT PROFILES
▸ Annotate classes to associate with a profile
▸ @Profile(“…”)
▸ Configuration (bootstrap/application properties)
▸ spring.profiles.active = …
▸ Command line
▸ -Dspring.profiles.active=…
▸ Environment variable
▸ SPRING_PROFILES_ACTIVE=…

28. SPRING CLOUD
RESOLVED CLIENT CONFIGURATION

29. SPRING CLOUD
CONFIG SERVER GOTCHAS
▸ Client’s don’t fail on Config Server failure - boot with
defaults (e.g. port 8080)
▸ To enable use spring.cloud.config.failFast=true
▸ Enable retries:
▸ Add spring-retry and spring-boot-starter-aop
▸ spring.cloud.config.retry.

31. NETFLIX OSS + SPRING
SPRING CLOUD NETFLIX
▸ Service discovery (Eureka)
▸ Client side load balancing (Ribbon)
▸ Dynamic routing (Zuul)
▸ Circuit breaker (Hystrix)
▸ + a few others…

32. NETFLIX OSS + SPRING
EUREKA
▸ Service discovery client & server
▸ Maintains registry of clients with metadata
▸ Host/port
▸ Health indicator URL
▸ Client heartbeats (30 sec default - changing not encouraged)
▸ Lease renewed with server
▸ Service available when client & server(s) metadata cache all in sync
▸ Can take up to 3 heart beats

33. NETFLIX OSS + SPRING
EUREKA SERVER

34. NETFLIX OSS + SPRING
EUREKA SERVER DASHBOARD

35. NETFLIX OSS + SPRING
EUREKA CLIENT SETUP
@EnableEurekaClient annotation
application.yml in Config Server repo

36. NETFLIX OSS + SPRING
RIBBON
▸ Client side loan balancer
▸ Can delegate to Eureka for server lists
▸ Or list servers
▸ stores.ribbon.listOfServers=… +
ribbon.eureka.enabled=false

37. NETFLIX OSS + SPRING
RIBBON USAGE
▸ Via RestTemplate
▸ No different to normal usage - Spring Cloud Commons
abstraction
▸ Qualifier’s required if using regular & Ribbon enabled
RestTemplate

38. NETFLIX OSS + SPRING
ZUUL
▸ JVM based router & load balancer
▸ Provides single point of entry to services
▸ Including single point of authentication
▸ By default creates route for every service in Eureka
▸ Refer to http://localhost/credit-service routes to http://credit-
service
▸ Filters provide limited entry points to system

39. NETFLIX OSS + SPRING
ZUUL SERVER CREATION
‣ Include dependency spring-cloud-starter-zuul
‣ @EnableZuulProxy application annotation
‣ E.g. Allow access only to credit-service

40. NETFLIX OSS + SPRING
SIDECAR
▸ Non-JVM access to components via Zuul proxy
▸ Setup Spring Boot application with @EnableSidecar
▸ Configure for your service:
▸ sidecar.port=… + sidecar.health-ui=…
▸ Access all services by Zuul URL (Sidecar running on port
80)
▸ http://localhost/config-server

41. NETFLIX OSS + SPRING
HYSTRIX
▸ Circuit breaker
▸ Threshold breached (20 failures in 5 seconds) => breaker
kicks in
▸ Default timeout threshold 1 second
▸ Per dependency thread pools
▸ Async command support (not Spring @Async)
▸ Sync or async fallback

42. NETFLIX OSS + SPRING
HYSTRIX CLIENT
▸ @EnableCircuitBreaker application annotation
▸ @HystrixCommand on applicable methods

43. NETFLIX OSS + SPRING

44. NETFLIX OSS + SPRING
HYSTRIX STREAM - PRE-REQUESTS

45. NETFLIX OSS + SPRING
HYSTRIX STREAM - POST-REQUESTS

46. NETFLIX OSS + SPRING
HYSTRIX DASHBOARD

47. NETFLIX OSS + SPRING
HYSTRIX STREAM

48. NETFLIX OSS + SPRING
HYSTRIX DASHBOARD

49. NETFLIX OSS + SPRING
TURBINE - AGGREGATE MULTIPLE HYSTRIX CLIENTS

50. NETFLIX OSS + SPRING
MONITORING
▸ Add dependency spring-boot-actuator
▸ Makes available various application metrics via /metrics
endpoint
▸ Integration also available with DropWizard metrics (add
dependency)
▸ Spring Cloud
▸ Spectator (supersedes Servo) - metrics collection
▸ Atlas - metrics backend

51. NETFLIX OSS + SPRING

52. NETFLIX OSS + SPRING
LOGGING
▸ Logback is the default choice
▸ Alternative starters are provided
▸ Using alternatives (such as log4j2) requires exclusions
throughout the starter POMs

53. NETFLIX OSS + SPRING
DOWNSIDES
▸ A lot of magic - e.g. CORS filters
▸ ADD (Annotation driven development)
▸ Dependency management
▸ RestTemplates - Ribbon enabled != Standard HTTP
▸ Lack of proper polygot support - libraries are in Java
(Sidecar is OK as a middle ground)
▸ Spring Hystrix documentation is pretty light

54. NETFLIX OSS + SPRING
ALTHOUGH…

55. NETFLIX OSS + SPRING
RESOURCES
▸ Spring Cloud documentation - http://projects.spring.io/spring-cloud/spring-cloud.html
▸ Spring Boot sample projects - https://github.com/spring-projects/spring-boot/tree/
master/spring-boot-samples
▸ Spring Cloud sample projects - https://github.com/spring-cloud-samples
▸ Hystrix annotations - https://github.com/Netflix/Hystrix/tree/master/hystrix-contrib/
hystrix-javanica
▸ Useful demonstration of Spring Cloud usage - http://callistaenterprise.se/blogg/teknik/
2015/05/20/blog-series-building-microservices/
▸ Spring project dependency selector - http://start.spring.io/
▸ Code to accompany this talk - https://github.com/conor10/homeloans
▸ https://www.huffle.com.au

56. NETFLIX OSS + SPRING
THANKS
conor@huffle.com.au