基于时间的断路器

1 新建一个微服务模块

我们在cloud-payment-service模块中新增一个controller以提供给其它微服务模块调用。

@RestController
public class PayCircuitController {

    @GetMapping("/pay/circuit/{id}")
    public String myCircuit(@PathVariable("id") Integer id){
        if(id == -4) {
            throw new RuntimeException("ID不能为负数");
        }
        if(id == 999) {
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        return "Hello Circuit! InputId: " + id + " \t" + IdUtil.simpleUUID();
    }
}

根据ID返回一段字符串，当ID为负数或者999使用特殊处理，其它情况直接返回字符串。

2 编写OpenFeign访问接口

@FeignClient(value = "cloud-payment-service", path = "/pay")
@RestController
public interface PayFeignApi {

    @GetMapping("/circuit/{id}")
    public String myCircuit(@PathVariable("id") Integer id);
}

3 引入依赖

<!-- Circuit断路器       -->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
</dependency>
<!--   断路器保护需要AOP实现     -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

4 配置文件

resilience4j:
  timelimiter:
    configs:
      default:
        timeout-duration: 10s #
  circuitbreaker:
    configs:
      default:
        failure-rate-threshold: 50 # 设置50%失败打开断路器，超过失败百分比的circuitBreaker变为OPEN状态
        slow-call-duration-threshold: 2s # 慢调用时间阀值
        slow-call-rate-threshold: 30 # 慢调用百分比峰值，断路器时间大于slow-call-duration-threshold就是慢调用，当达到峰值就打开断路器
        sliding-window-type: TIME_BASED # 滑动窗口类型
        sliding-window-size: 2 # 滑动窗口大小配置COUNT_BASED表示6个请求 配置为TIME_BASED表示6s
        minimum-number-of-calls: 2 # 断路器计算失败率或者慢调用率之前所需要的最小样本
        automatic-transition-from-open-to-half-open-enabled: true # 是否开启自动从开启状态过渡到半开状态。默认为true
        wait-duration-in-open-state: 5s # 从OPEN到HALF_OPEN需要等待时间
        permitted-number-of-calls-in-half-open-state: 2 # 半开状态最大请求数
        record-exceptions:
          - java.lang.Exception
    instances:
      cloud-payment-service:
        base-config: default

5 编写业务

@RestController
public class OrderCircuitController {
    @Resource
    private PayFeignApi payFeignApi;

    @GetMapping("/feign/pay/circuit/{id}")
    @CircuitBreaker(name = "cloud-payment-service" , fallbackMethod = "myCircuitFullBack")
    public String myCircuitBreaker(@PathVariable("id") Integer id){
        return payFeignApi.myCircuit(id);
    }

    @Operation(summary = "服务降级后的处理方法")
    public String myCircuitFullBack(Integer id,Throwable e){
        return "系统繁忙，请稍后再试！！";
    }
}

6 测试