![Spring boot example
@EnableAutoConfiguration
@RestController
@ComponentScan
public class TimeStarter {
@Autowired
TimeService timerService;
@RequestMapping("/now")
public Date now() {
return timerService.now();
}
public static void main(String[] args) {
SpringApplication.run(TimeStarter.class, args);
}
}](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-12-320.jpg)
![Spring Cloud + Zuul example
@EnableAutoConfiguration
@ComponentScan
@EnableEurekaClient
@EnableZuulProxy
public class ApiGatewayStarter {
public static void main(String[] args) {
SpringApplication.run(ApiGatewayStarter.class, args);
}
}](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-17-320.jpg)
![Eureka server
@SpringBootApplication
@EnableEurekaServer
public class EurekaStarter {
public static void main(String[] args) {
new SpringApplicationBuilder(EurekaStarter.class).web(true).run(args);
}
}](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-22-320.jpg)
![Eureka client
@EnableAutoConfiguration
@RestController
@ComponentScan
@EnableEurekaClient
public class TimeStarter {
@Autowired
TimeService tttService;
@RequestMapping("/now")
public Date now() {return tttService.now();}
public static void main(String[] args) {
SpringApplication.run(TimeStarter.class, args);
}
}](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-23-320.jpg)
![Config server
@SpringBootApplication
@EnableConfigServer
@EnableEurekaClient
public class ConfigServer {
public static void main(String[] args) {
new SpringApplicationBuilder(ConfigServer.class).run(args);
}
}](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-28-320.jpg)
![Config repository
elek@sc /tmp/config-repo [master] > ls -lah
drwxr-xr-x 3 elek elek 100 Dec 14 14:32 .
drwxrwxrwt 57 root root 1.8K Dec 14 14:37 ..
-rw-r--r-- 1 elek elek 55 Dec 14 14:16 application.properties
drwxr-xr-x 8 elek elek 260 Dec 14 14:40 .git
-rw-r--r-- 1 elek elek 12 Dec 14 14:32 timer.properties](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-29-320.jpg)
![Advantages of microservices
● Modular, loosely coupled
● Easily scalable to multiple machines
● Separated, modular development lifecycle
● Partial deploy without restart [like OSGi]
● Supports heterogeneous architecture (tech stack
migration)](https://image.slidesharecdn.com/microservicesandmodularitywithjava2-151216083523/85/Microservices-and-modularity-with-java-45-320.jpg)
Microservices and modularity with java
- 1. Microservices and modularity with Java Elek Márton @anzix 2015 December DPC Consulting
- 2. Agenda ● Microservice definition ● Core implementation patterns
- 3. People need modularity not microservices
- 4. Microservices is one way to achieve modularity. Other ways: OSGi, SPI, java9 jigsaw
- 5. What are microservices? The fire making rule: ● Use more sticks than you think they would be enough ● Use a little bit smaller sticks than you think would be enough
- 6. Informal definition Microservices when you have smaller, separated services as usual ● Many times they are not micro (group of services) ● Many times REST is used (but not always) ● Separated means different process/JVM instances
- 7. More formal definition ● “an approach to developing a single application as a suite of small services, ● each running in its own process ● and communicating with lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities and independently deployable by fully automated deployment machinery.” Lewis, Fowler
- 8. Microservices and REST REST is just one solution to communicate ● between services ● or call any of the service
- 9. Microservices vs SOA Even if the “Microservices != SOA” a very common statement there are a lot of shared concept. ● Usually we have new tools (using existing solutions differently) not totally new concept
- 12. Spring boot example @EnableAutoConfiguration @RestController @ComponentScan public class TimeStarter { @Autowired TimeService timerService; @RequestMapping("/now") public Date now() { return timerService.now(); } public static void main(String[] args) { SpringApplication.run(TimeStarter.class, args); } }
- 13. Modular monolith
- 15. API gateway
- 16. API gateway Goals: ● Hide available microservices behind a service facade pattern – Routing, Authorization – Deployment handling, Canary testing – Logging, SLA Implementations: ● Spring cloud: Netflix Zuul ● Netflix Zuul based implementation ● Twitter Finagle based implementation ● Amazon API gateway ● Simple Nginx reverse proxy configuration
- 17. Spring Cloud + Zuul example @EnableAutoConfiguration @ComponentScan @EnableEurekaClient @EnableZuulProxy public class ApiGatewayStarter { public static void main(String[] args) { SpringApplication.run(ApiGatewayStarter.class, args); } }
- 19. Service registry
- 20. Service registry Goal: ● Store the location and state of the available services – Health check – DNS interface Implementations: ● Spring cloud: Eureka ● Netflix eureka based implementation ● Consul.io ● etcd, zookeeper ● Simple: DNS or hosts file
- 21. Eureka
- 22. Eureka server @SpringBootApplication @EnableEurekaServer public class EurekaStarter { public static void main(String[] args) { new SpringApplicationBuilder(EurekaStarter.class).web(true).run(args); } }
- 23. Eureka client @EnableAutoConfiguration @RestController @ComponentScan @EnableEurekaClient public class TimeStarter { @Autowired TimeService tttService; @RequestMapping("/now") public Date now() {return tttService.now();} public static void main(String[] args) { SpringApplication.run(TimeStarter.class, args); } }
- 24. SIMPLE Discovery client @Service public class Client { @Autowired private DiscoveryClient discoveryClient; public void list() { for (ServiceInstance instance : discoveryClient.getInstances("BOOTSTRAP")) { System.out.println(instance.getHost()); System.out.println(instance.getPort()); System.out.println(instance.getUri()); } } }
- 25. Config service
- 26. Monolith configuration ● Store configuration outside of the project – Versioning? Who did what ● Store configuration in separated versioned project – Which binary version need which config version? ● Store configuration with the source code – Sensitive configuration?
- 27. Config Service Goals: ● One common place for all of the configuration – Versioning – Auditing – Multiple environment support Solutions: ● Spring Cloud config service ● Zookeeper ● Most of the service registry have key->value store ● Any persistence datastore
- 28. Config server @SpringBootApplication @EnableConfigServer @EnableEurekaClient public class ConfigServer { public static void main(String[] args) { new SpringApplicationBuilder(ConfigServer.class).run(args); } }
- 29. Config repository elek@sc /tmp/config-repo [master] > ls -lah drwxr-xr-x 3 elek elek 100 Dec 14 14:32 . drwxrwxrwt 57 root root 1.8K Dec 14 14:37 .. -rw-r--r-- 1 elek elek 55 Dec 14 14:16 application.properties drwxr-xr-x 8 elek elek 260 Dec 14 14:40 .git -rw-r--r-- 1 elek elek 12 Dec 14 14:32 timer.properties
- 30. Config client @Service public class TimeService { @Value("${version:Unknown}") String version; public Date now() { return new Date(); } public String version() { return version; } }
- 31. Monitoring
- 32. Monitoring Goal: ● Combined business log ● Health check, exceptions, what is running? ● Metrics Solutions (for one of the goals): ● Netflix Spectator, Servo, Atlas ● Spring cloud: Hystrix (circuit breaker) ● ELK: ElasticSearch + Logstash + Kibana ● Cloud based solutions (logentries...) ● Metrics: Dropwizard based implementations
- 34. Hystrix
- 35. Hystrix @Service public class TimeService { @HystrixCommand(fallbackMethod = "safeNow") public Date now() { return new Date(); } public Date safeNow() { return new Date(0); } }
- 38. Inter-module calls Goal: ● RPC calls between modules ● Protocol ● Usage of the Service Registry Solutions: ● Spring cloud/Netflix: ribbon ● Simple REST calls ● Message Oriented solutions: – Rabbit MQ, ZMQ, ...
- 41. Distributed tracing Goal: ● Global information about latency and errors – Service enter/exit point measurement – Transaction identification Implementations: ● Twitter’s Zipkin ● Apache (Cloudera) HTrace ● Spring cloud Sleuth
- 43. Summary
- 44. Advantages of monolith Modular monolith Microservices
- 45. Advantages of microservices ● Modular, loosely coupled ● Easily scalable to multiple machines ● Separated, modular development lifecycle ● Partial deploy without restart [like OSGi] ● Supports heterogeneous architecture (tech stack migration)
- 46. Summary ● Focus on modularity ● Be familiar with the microservice related tools: they could be useful even with monolith applications…
- 47. Start with monolith? Stefan Tilkov: http://martinfowler.com/articles/dont- start-monolith.html Martin Fowler: http://martinfowler.com/bliki/MonolithFirst. html
- 48. Q&A Márton Elek DPC consulting http://dpc.hu twitter: @anzix http://blog.dpc.hu, http://blog.anzix.net