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• [display] ProductRemoteServiceImp에 Fallback Method 에 Throwable추가
  

  • Code Block

    @Service public class ProductRemoteServiceImpl implements ProductRemoteService { private static final String url = "http://localhost:8082/products/"; private final RestTemplate restTemplate; public ProductRemoteServiceImpl(RestTemplate restTemplate) { this.restTemplate = restTemplate; } @Override @HystrixCommand(fallbackMethod = "getProductInfoFallback") public String getProductInfo(String productId) { return this.restTemplate.getForObject(url + productId, String.class); } public String getProductInfoFallback(String productId, Throwable t) { System.out.println("t = " + t); return "[ this product is sold out ]"; } }

• Display 호출 확인

  • http://localhost:8081/displays/11111

    Code Block

    2020-02-25 11:32:22.068 INFO 69092 --- [io-8081-exec-10] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring FrameworkServlet 'dispatcherServlet' 2020-02-25 11:32:22.068 INFO 69092 --- [io-8081-exec-10] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization started 2020-02-25 11:32:22.174 INFO 69092 --- [io-8081-exec-10] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 106 ms t = org.springframework.web.client.HttpServerErrorException: 500 null

• 정리

  • Info
    Hystrix에서 Fallback의 실행 여부는 Exception이 발생 했는가 여부 Fallback의 정의 여부는 Circuit Breaker Open과 무관. Throwable 파래매터의 추가로. Fallback 원인을 알 수 있다.

03. Hystrix로 Timeout 처리하기

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• [product] ProductController의 throw Exception을 Thread.sleep(2000)로 수정

  • Code Block
    @RestController @RequestMapping("/products") public class ProductController { @GetMapping(path = "{productId}") public String getProductInfo(@PathVariable String productId) { try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } return "[product id = " + productId + " at " + System.currentTimeMillis() + "]"; //throw new RuntimeException("I/O Exception"); } }

• [display] application.yml 수정하여 Hystrix Timeout 시간 조정하기

  • Code Block
    hystrix: command: default: # command key. use 'default' for global setting. execution: isolation: thread: timeoutInMilliseconds: 30001000

• Display → Product 호출 하기

  • Info
    icon false
    http://localhost:8082/products/22222 http://localhost:8081/displays/11111

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