Resiliente Microservices mit Spring Boot und Failsafe

1. Resiliente Microservices mit Spring Boot und Failsafe JavaLand 2018 13.03.2018 Malte Pickhan @mpickhan Zalando Payments GmbH

2. WHOAMI > 5 years experience as Java Backend Engineer 3 years in Telco industry 2 years in E-Commerce Contributor to open source Project (Failsafe-Actuator) Published article in Java Magazin (10/17) 2

3. ZALANDO TECHNOLOGY help our brand to HOME-BREWED, CUTTING-EDGE & SCALABLE WIN ONLINE technology solutions 1,800 employees from 77 nations 6 3 tech locations + HQs in Berlin

4. HANDS ON EXPERIENCE ON HOW WE BUILD RESILIENT MICROSERVICES WITH SPRING BOOT AND FAILSAFE

5. BLACK FRIDAY 2017 R e q u e s t s TIME 5

6. RESILIENCE In computer networking: resilience is the ability to provide and maintain an acceptable level of service in the face of faults and challenges to normal operation. [0] 6

7. MICROSERVICES Accept failures instead of avoiding them • • • • 7 Latency Network More clients Maybe even unknown clients

8. SPRING BOOT Takes an opinionated view of building production-ready Spring applications. Spring Boot favors convention over configuration and is designed to get you up and running as quickly as possible. [1] 8

9. ACTUATOR Actuator endpoints allow you to monitor and interact with your application. Spring Boot includes a number of built-in endpoints and you can also add your own. For example the health endpoint provides basic application health information. [2] 9

10. FAILSAFE Failsafe is a lightweight, zero-dependency library for handling failures. It was designed to be as easy to use as possible, with a concise API for handling everyday use cases and the flexibility to handle everything else. [3] 10

11. FAILSAFE Execution Context Calls can be put to Lambda expressions or Callbacks 11 Supports retries out of the box Async execution can be observed via Listener API

12. EXAMPLE 12

13. CIRCUIT BREAKER ● ● ● 13 Fail fast Be excellent to others Three states ○ Closed ○ Open ○ Half Open

14. CIRCUIT BREAKER 14

15. THIS WAS GOOD, BUT WE CAN DO BETTER

16. FALLBACK ● ● 16 Call alternative service in case primary is unavailable Not only be available, but also deliver valid results

17. REAL WORLD EXAMPLE ● ● ● 17 Product detail page Customer might not be interested in details at all Why should we serve a 500 because of that and miss the sale?

18. FALLBACK EXAMPLE 18

19. RETRY ● ● ● 19 Retry call in case of transient errors Try to get as much through at possible Every request is a paying customer

20. RETRY EXAMPLE 20

21. RETRY delay = backoff + jitterFactor ● ● ● 21 backoff is growing exponentially with each retry (1 .. 5 seconds) jitterFactor is randomly picked in range (-10 .. 10 ms) retries will be equally distributed

22. MONITORING ● ● ● 22 Monitor Circuit Breaker to identify problems early Returns JSON containing the state of all registered Circuit Breaker Failsafe-Actuator provides this functionality ○ Spring Boot 2 support close to come

23. DEMO 23

24. QUESTIONS?

25. BIBLIOGRAPHY [0] https://en.wikipedia.org/wiki/Resilience_(n etwork) [1] https://projects.spring.io/spring-boot/ [2] https://docs.spring.io/spring-boot/docs/curr ent/reference/html/production-ready-endp oints.html [3] https://github.co/mjhalterman/failsafe 25