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        <dependency>
            <groupId>io.github.resilience4j</groupId>
            <artifactId>resilience4j-feign</artifactId>
            <version>0.17.0</version>
        </dependency>
        <dependency>
            <groupId>io.github.resilience4j</groupId>
            <artifactId>resilience4j-circuitbreaker</artifactId>
            <version>0.17.0</version>
        </dependency>

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    @Configuration
    public class AAAClientConfig {
    
    @Value("${url}")
    private String url;

    CircuitBreakerConfig config = CircuitBreakerConfig.custom()
            .failureRateThreshold(50) // 실패 임계치 50% 로 설정
            .ringBufferSizeInClosedState(20) // 20번 시도 
            .ringBufferSizeInHalfOpenState(10) // 10초 후 10번 시도
            .waitDurationInOpenState(Duration.ofSeconds(3L)) // Open 후 3초 기다림
            .build();

    CircuitBreaker circuitBreaker = CircuitBreaker.of("AAAClientCB", config);

    FeignDecorators decorators =
            FeignDecorators.builder().withCircuitBreaker(circuitBreaker).build();

    @Bean
    public AAAClient aAAClient() {
        return Resilience4jFeign.builder(decorators)
                .client(new OkHttpClient())
                .encoder(new JacksonEncoder())
                .decoder(new JacksonDecoder())
                .options(new Request.Options(3000, 5000))
                .retryer(Retryer.NEVER_RETRY)
                .logger(new Slf4jLogger(AAAClient.class))
                .logLevel(Logger.Level.FULL)
                .target(AAAClient.class, url);
    }
}

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public class CBTest {
    @Rule
    public WireMockRule wireMockRule = new WireMockRule();
    
    private AAAClient client;
    
    @Before
    public void setUp() {
        
        CircuitBreakerConfig config = CircuitBreakerConfig.custom()
            .failureRateThreshold(50) // 실패 임계치 50% 로 설정
            .ringBufferSizeInClosedState(20) // 20번 시도 
            .ringBufferSizeInHalfOpenState(10) // 3초 후 10번 시도
            .waitDurationInOpenState(Duration.ofSeconds(3L)) // Open 후 3초 기다림
            .build();

        CircuitBreaker circuitBreaker = CircuitBreaker.of("AAAClientCB", config);

        FeignDecorators decorators =
              FeignDecorators.builder().withCircuitBreaker(circuitBreaker).build();
    
        aAAClient = Resilience4jFeign.builder(decorators)
                .client(new OkHttpClient())
                .encoder(new JacksonEncoder())
                .decoder(new JacksonDecoder())
                .options(new Request.Options(3000, 5000))
                .retryer(Retryer.NEVER_RETRY)
                .logger(new Slf4jLogger(AAAClient.class))
                .logLevel(Logger.Level.FULL)
                .target(AAAClient.class, "http://localhost:8080");
    }

    @Test
    public void 정상인경우_Test() {

        stubFor(
                get(urlPathMatching("/1"))
                        .willReturn(
                                aResponse()
                                        .withStatus(200)
                                        .withHeader("content-type", "application/json")
                                        .withBody("{}")
                        )
        );

        boolean allSuccess = IntStream.range(0, 40)
                .mapToObj(i -> Try.of(() -> client.getDetail(1)))
                .allMatch(t -> t.isSuccess());

        assertThat(allSuccess).isTrue();
    }
    
    @Test
    public void 서킷브레이커_Open_Close_Test() {

        stubFor(
                get(urlPathMatching("/71"))
                        .willReturn(
                                aResponse()
                                        .withStatus(200)
                                        .withHeader("content-type", "application/json")
                                        .withBody("{}")
                        )
        );

        stubFor(
                get(urlPathMatching("/72"))
                        .willReturn(
                                aResponse()
                                        .withStatus(500)
                                        .withHeader("content-type", "application/json")
                                        .withBody("{}")
                        )
        );

        // 에러 비율 50% 이상
        IntStream.range(0, 10).forEach(i -> Try.of(() -> client.getDetail(72)));

        // 3초간 오픈 상태에서 바로 에러
        sleep(1000);
        Try<ApiResponse> failFast1 = Try.of(() -> client.getDetail(71));
        sleep(1500);
        Try<ApiResponse> failFast2 = Try.of(() -> client.getDetail(71));

        // 3초 후 반 오픈
        sleep(1000);
        Try.of(() -> client.getDetail(71));
        Try<ApiResponse> realEx = Try.of(() -> client.getDetail(72));// 1개 실패로는 50% 비율 안 됨

        // 반 오픈 후 다시 열리지 않으면 모두 성공
        boolean allSuccess = IntStream.range(0, 40)
                .mapToObj(i -> Try.of(() -> client.getDetail(71)))
                .allMatch(t -> t.isSuccess());

        SoftAssertions.assertSoftly(softly -> {
            softly.assertThat(failFast1.getCause()).isInstanceOf(CallNotPermittedException.class);
            softly.assertThat(failFast2.getCause()).isInstanceOf(CallNotPermittedException.class);
            softly.assertThat(realEx.getCause()).isNotInstanceOf(CallNotPermittedException.class);
            softly.assertThat(allSuccess).isTrue();
        });
    }

    private void sleep(int sleepTime) {
        try {
            Thread.sleep(sleepTime);
        } catch (InterruptedException e) {
        }
    }
}