SpringCloud：服务保护——通过Future机制自定义服务保护

水深无声 2022-04-23 01:46 213阅读 0赞

一，上一篇通过[Hystrix对服务保护][Hystrix]进行了分析；这一篇基于Future，分版本由浅入深对服务降级和服务隔离机制进行说明

二，服务端代码，线程随机沉睡200MS以内，客户端调用100MS超时，制造可能超时场景

package com.gupao.member.service.impl;
    
    import com.gupao.api.service.IMemberServier;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * @author pj_zhang
     * @create 2019-01-09 23:48
     **/
    @RestController
    public class MemberService implements IMemberServier {
    
        @Value("${server.port}")
        private Integer serverPort;
    
       @Override
        @RequestMapping("/getMember_1")
        public String getMember_1() throws InterruptedException {
            int sleepTime = new Random().nextInt(200);
            System.out.println("getMember_1, thread sleep : " + sleepTime);
            Thread.sleep(sleepTime);
            System.out.println("getMember_1 Thread Name : " + Thread.currentThread().getName());
            return "MemberService.getMember_1, serverPort : " + serverPort;
        }
    }

三，客户端自定义接口处理

1，初级版本——容错实现

\* 代码实现

package com.gupao.order.self;
    
    import com.gupao.order.feign.IMemberServiceFeign;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.concurrent.*;
    
    /**
     * @author pj_zhang
     * @create 2019-01-22 22:55
     **/
    @RestController
    public class SelfCircuitBreaker {
    
        // 创建一个线程池
        private final ExecutorService executorService = Executors.newSingleThreadExecutor();
    
        @Autowired
        private IMemberServiceFeign memberServiceFeign;
    
        @RequestMapping("/low")
        public String getMember() {
            // 通过Callable发起异步线程, 获取回调结果
            long startTime = System.currentTimeMillis();
            Future<String> future = executorService.submit(new Callable<String>() {
                @Override
                public String call() throws Exception {
                    return memberServiceFeign.getMember_1();
                }
            });
    
            // future阻塞获取回调结果
            String returnValue = null;
            long endTime = 0L;
            try {
                returnValue = future.get(100, TimeUnit.MILLISECONDS);
            } catch (Exception e) {
                // 报错后取消执行服务
                future.cancel(true);
                returnValue = "服务调用超时...";
            }
            System.out.println("returnValue : " + returnValue + ", costTime : " + (System.currentTimeMillis() - startTime));
            return returnValue;
        }
    
    }

\* 服务端控制台输出

![20190122231030919.png][]

\* 客户端控制台输出

![20190122231048303.png][]

2，中级版本——拦截器实现

\* Rest接口

@RequestMapping("/middle")
        public String middle() throws InterruptedException {
            return memberServiceFeign.getMember_1();
        }

\* 拦截器实现

package com.gupao.order.interceptor;
    
    import com.alibaba.fastjson.JSONObject;
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.springframework.stereotype.Component;
    
    import javax.annotation.PreDestroy;
    import java.util.concurrent.*;
    
    /**
     * @author pj_zhang
     * @create 2019-01-22 23:11
     **/
    @Aspect
    @Component
    public class SelfServerInterceptor {
    
        private ExecutorService executorService = Executors.newSingleThreadExecutor();
    
        @Around("execution(public * com.gupao.order.self.SelfCircuitBreaker.middle(..))")
        public String getMember(final ProceedingJoinPoint proceedingJoinPoint) {
            return doServer(proceedingJoinPoint, 100L);
        }
    
        private String doServer(final ProceedingJoinPoint proceedingJoinPoint, Long timeOut) {
            long startTime = System.currentTimeMillis();
            // 通过Callable发起异步线程, 获取回调结果
            Future<String> future = executorService.submit(new Callable<String>() {
                @Override
                public String call() throws Exception {
                    try {
                        // 执行目标方法
                        return JSONObject.toJSONString(proceedingJoinPoint.proceed());
                    } catch (Throwable throwable) {
                        return "服务调用失败";
                    }
                }
            });
    
            // 阻塞等待方法执行完成
            String returnValue = null;
            try {
                returnValue = future.get(100, TimeUnit.MILLISECONDS);
            } catch (Exception e) {
                future.cancel(true);
                returnValue = "服务请求超时...";
            }
    
            System.out.println("returnValue : " + returnValue + ", costTime : " + (System.currentTimeMillis() - startTime));
            return returnValue;
        }
    
    
        @PreDestroy
        public void destory() {
            executorService.shutdown();
        }
    
    }

\* 运行结果

![20190122232328340.png][]

3，高级版本——拦截器+注解实现

\* 添加注解

package com.gupao.order.annotation;
    
    import java.lang.annotation.*;
    
    /**
     * @author pj_zhang
     * @create 2019-01-22 23:24
     **/
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface CircuitBreakder {
    
        long outTime() default 100;
    }

\* 服务调用接口

@RequestMapping("/high")
        @CircuitBreakder(outTime = 100L)
        public String high() throws InterruptedException {
            return memberServiceFeign.getMember_1();
        }

\* 拦截器实现

@Around("execution(public * com.gupao.order.self.SelfCircuitBreaker.high(..))")
        public String getMemberByHigh(final ProceedingJoinPoint proceedingJoinPoint) {
            // 通过注解获取超时时间
            long outTime = 100L;
            if (proceedingJoinPoint instanceof MethodInvocationProceedingJoinPoint) {
                MethodInvocationProceedingJoinPoint methodPoint = (MethodInvocationProceedingJoinPoint) proceedingJoinPoint;
                MethodSignature signature = (MethodSignature) methodPoint.getSignature();
                Method method = signature.getMethod();
                CircuitBreakder circuitBreaker = method.getAnnotation(CircuitBreakder.class);
                outTime = circuitBreaker.outTime();
            }
            return doServer(proceedingJoinPoint, outTime);
        }

\* 运行结果

![20190122233425532.png][]

4，通过信号灯实现单机版限流方案

\* 注意暂时去掉Feign客户端的Hystrix服务保护，此处在原项目上实现，受超时时间影响

@FeignClient(name = "app-itmayiedu-member")
    public interface IMemberServiceFeign extends IMemberServier {
    }

\* Hystrix超时时间默认1S，进行修改

###服务启动端口号
    server:
      port: 8100
    ###服务名称(服务注册到eureka名称)
    spring:
        application:
            name: app-itmayiedu-order
    ###服务注册到eureka地址
    eureka:
      client:
        service-url:
               defaultZone: http://localhost:8000/eureka
    
        ###因为该应用为注册中心，不会注册自己
        register-with-eureka: true
        ###是否需要从eureka上获取注册信息
        fetch-registry: true
    ###设置feign客户端超时时间
    ribbon:
    ###指的是建立连接所用的时间，适用于网络状况正常的情况下，两端连接所用的时间。
      ReadTimeout: 50000
    ###指的是建立连接后从服务器读取到可用资源所用的时间。
      ConnectTimeout: 50000
    
    ### 开启hystrix断路器
    feign:
      hystrix:
        enabled: true
    
    ### hystrix超时时间
    hystrix:
      command:
        default:
          execution:
            isolation:
              thread:
                timeoutInMilliseconds : 100000

\* 修改服务端睡眠时间，睡眠5S

@Override
        @RequestMapping("/getMember_1")
        public String getMember_1() throws InterruptedException {
            Thread.sleep(5000);
            System.out.println("getMember_1 Thread Name : " + Thread.currentThread().getName());
            return "MemberService.getMember_1, serverPort : " + serverPort;
        }

\* 自定义注解添加限流属性

package com.gupao.order.annotation;
    
            import java.lang.annotation.*;
    
    /**
     * @author pj_zhang
     * @create 2019-01-22 23:24
     **/
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface CircuitBreakder {
    
        long outTime() default 100;
    
        int value() default 5;
    }

\* 定义REST接口

@RequestMapping("/limit")
        public String limit() throws InterruptedException {
            return memberServiceFeign.getMember_1();
        }

\* 拦截器实现

@Around("execution(public * com.gupao.order.self.SelfCircuitBreaker.limit(..))")
        public String limit(final ProceedingJoinPoint proceedingJoinPoint) {
            // 通过注解获取超时时间
            Integer limitValue = 5;
            if (proceedingJoinPoint instanceof MethodInvocationProceedingJoinPoint) {
                MethodInvocationProceedingJoinPoint methodPoint = (MethodInvocationProceedingJoinPoint) proceedingJoinPoint;
                MethodSignature signature = (MethodSignature) methodPoint.getSignature();
                Method method = signature.getMethod();
                CircuitBreakder circuitBreaker = method.getAnnotation(CircuitBreakder.class);
                limitValue = circuitBreaker.value();
            }
            // 初始化信号量
            if (semaphore == null) {
                semaphore = new Semaphore(limitValue);
            }
            String returnValue = null;
            try {
                // 获取到可用信号, 执行方法
                if (semaphore.tryAcquire()) {
                    returnValue = JSONObject.toJSONString(proceedingJoinPoint.proceed());
                // 未获取到可用信号, 返回错误提示
                } else {
                    returnValue = "Semaphore 限流...";
                }
            } catch (Throwable throwable) {
                returnValue = "执行异常";
            } finally {
                semaphore.release();
            }
            System.out.println("returnValue : " + returnValue);
            return returnValue;
        }

\* 频繁刷新页面数次，直到刷新出预期结果

![20190122235518680.png][]

![20190122235503210.png][]

[Hystrix]: https://mp.csdn.net/postedit/86602280
[20190122231030919.png]: /images/20220323/1ed1552ebd9c497b9319328ecd5a92ba.png
[20190122231048303.png]: /images/20220323/9779601ab99445eea3029f88d1f25045.png
[20190122232328340.png]: /images/20220323/c451a64d5472463bab7358ee805e2cb4.png
[20190122233425532.png]: /images/20220323/ae841ad93420433da7964a42a132e201.png
[20190122235518680.png]: /images/20220323/3acf98c5f84646ceac265ae6732e8068.png
[20190122235503210.png]: /images/20220323/9e49cdaaadbd4b99af625894d868e44b.png