【SpringCloud AlibabaSentinel实现熔断与限流】

本笔记内容为尚硅谷SpringCloud AlibabaSentinel部分 

目录

一、Sentinel

1、官网

2、Sentinel是什么

3、下载

4、特性

5、使用

二、安装Sentinel控制台 

1、sentinel组件由2部分构成

2、安装步骤

1.下载

2.运行命令

3.访问sentinel管理界面

三、初始化演示工程

四、流控规则

1、基本介绍

解释说明

2、流控模式

1.直接(默认)

2.关联

3.链路

3、流控效果

1.直接->快速失败(默认的流控处理)

2.预热

3.排队等待 

五、降级规则

1、基本介绍

2、降级策略实战

1.RT

2.异常比例

3.异常数

六、热点key限流

1、基本介绍

2、测试代码

3、配置

4、参数例外项

配置

七、系统规则 

各项配置参数说明 

八、@SentinelResource 

1、按资源名称限流+后续处理

2、按照Url地址限流+后续处理 

3、客户自定义限流处理逻辑 

4、更多注解属性说明

九、服务熔断功能 

1、Ribbon系列

2、Feign系列

3、熔断框架比较

十、规则持久化

步骤 


一、Sentinel


1、官网

https://github.com/alibaba/Sentinel

中文:https://github.com/alibaba/Sentinel/wiki/%E4%BB%8B%E7%BB%8D

2、Sentinel是什么

类似之前学过的Hystrix

【SpringCloud AlibabaSentinel实现熔断与限流】_第1张图片

3、下载

Releases · alibaba/Sentinel · GitHub

【SpringCloud AlibabaSentinel实现熔断与限流】_第2张图片

4、特性

【SpringCloud AlibabaSentinel实现熔断与限流】_第3张图片

5、使用

查看官网:Spring Cloud Alibaba Reference Documentation

服务使用中的各种问题

  • 服务雪崩
  • 服务降级
  • 服务熔断
  • 服务限流

二、安装Sentinel控制台 


1、sentinel组件由2部分构成

后台+前台8080

【SpringCloud AlibabaSentinel实现熔断与限流】_第4张图片

2、安装步骤

1.下载

Releases · alibaba/Sentinel · GitHub

下载到本地sentinel-dashboard-1.7.0.jar

2.运行命令

前提:java8环境正常,8080端口不能被占用

命令:java -jar sentinel-dashboard-1.7.0.jar

【SpringCloud AlibabaSentinel实现熔断与限流】_第5张图片

3.访问sentinel管理界面

http://localhost:8080,登录账号密码均为sentinel

【SpringCloud AlibabaSentinel实现熔断与限流】_第6张图片

三、初始化演示工程


1、启动Nacos8848成功

http://localhost:8848/nacos/#/login

2、Module

cloudalibaba-sentinel-service8401

3、POM

【SpringCloud AlibabaSentinel实现熔断与限流】_第7张图片



    
        cloud190805
        com.atguigu.springcloud
        1.0-SNAPSHOT
    
    4.0.0

    cloudalibaba-sentinel-service8401



    
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
        
            com.alibaba.csp
            sentinel-datasource-nacos
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-sentinel
        
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            cn.hutool
            hutool-all
            4.6.3
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        

    

4、YML

server:
  port: 8401

spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery:
        #Nacos服务注册中心地址
        server-addr: localhost:8848
    sentinel:
      transport:
        #配置Sentinel dashboard地址
        dashboard: localhost:8080
        #默认8719端口,假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口
        port: 8719

management:
  endpoints:
    web:
      exposure:
        include: '*'

5、主启动

package com.atguigu.springcloud.alibaba;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableDiscoveryClient
@SpringBootApplication
public class MainApp8401
{
    public static void main(String[] args) {
        SpringApplication.run(MainApp8401.class, args);
    }
}

6、业务类FlowLimitController

package com.atguigu.springcloud.alibaba.controller;

import com.atguigu.springcloud.alibaba.service.OrderService;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
public class FlowLimitController
{

    @GetMapping("/testA")
    public String testA()
    {
        return "------testA";
    }

    @GetMapping("/testB")
    public String testB()
    {
        return "------testB";
    }
}

启动Sentinel8080 cmd :java -jar sentinel-dashboard-1.7.0.jar

启动微服务8401

启动8401微服务后查看sentienl控制台,发现什么都没有

【SpringCloud AlibabaSentinel实现熔断与限流】_第8张图片

Sentinel采用的懒加载说明

执行一次访问即可(http://localhost:8401/testA 和 http://localhost:8401/testB)

效果

【SpringCloud AlibabaSentinel实现熔断与限流】_第9张图片

结论:sentinel8080正在监控微服务8401

四、流控规则


1、基本介绍

【SpringCloud AlibabaSentinel实现熔断与限流】_第10张图片

解释说明

【SpringCloud AlibabaSentinel实现熔断与限流】_第11张图片

2、流控模式

1.直接(默认)

直接->快速失败(系统默认)

配置及说明

【SpringCloud AlibabaSentinel实现熔断与限流】_第12张图片

2.关联

当关联的资源达到阈值时,就限流自己

当与A关联的资源B达到阀值后,就限流A自己、B惹事,A挂了

配置A

【SpringCloud AlibabaSentinel实现熔断与限流】_第13张图片

postman模拟并发密集访问testB

访问testB成功

【SpringCloud AlibabaSentinel实现熔断与限流】_第14张图片

postman里新建多线程集合组

【SpringCloud AlibabaSentinel实现熔断与限流】_第15张图片

将访问地址添加进新新线程组

【SpringCloud AlibabaSentinel实现熔断与限流】_第16张图片

Run(大批量线程高并发访问B,导致A失效了)

【SpringCloud AlibabaSentinel实现熔断与限流】_第17张图片

运行后发现testA挂了,点击访问http://localhost:8401/testA,结果Blocked by Sentinel (flow limiting)

3.链路

多个请求调用了同一个微服务(可以想象当作VIP通道)

【SpringCloud AlibabaSentinel实现熔断与限流】_第18张图片

3、流控效果

1.直接->快速失败(默认的流控处理)

2.预热

公式:阈值除以coldFactor(默认值为3),经过预热时长后才会达到阈值

官网:流量控制 · alibaba/Sentinel Wiki · GitHub

【SpringCloud AlibabaSentinel实现熔断与限流】_第19张图片

默认coldFactor为3,即请求 QPS 从 threshold / 3 开始,经预热时长逐渐升至设定的 QPS 阈值。

限流 冷启动:限流 冷启动 · alibaba/Sentinel Wiki · GitHub

WarmUp配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第20张图片

多次点击http://localhost:8401/testB、刚开始不行,后续慢慢OK

应用场景

如:秒杀系统在开启的瞬间,会有很多流量上来,很有可能把系统打死,预热方式就是把为了保护系统,可慢慢的把流量放进来,慢慢的把阀值增长到设置的阀值。

3.排队等待 

【SpringCloud AlibabaSentinel实现熔断与限流】_第21张图片

官网:https://github.com/alibaba/Sentinel/wiki/%E6%B5%81%E9%87%8F%E6%8E%A7%E5%88%B6

【SpringCloud AlibabaSentinel实现熔断与限流】_第22张图片

测试

【SpringCloud AlibabaSentinel实现熔断与限流】_第23张图片

五、降级规则


官网:熔断降级 · alibaba/Sentinel Wiki · GitHub

1、基本介绍

RT(平均响应时间,秒级)

      平均响应时间   超出阈值  且   在时间窗口内通过的请求>=5,两个条件同时满足后触发降级

      窗口期过后关闭断路器

      RT最大4900(更大的需要通过-Dcsp.sentinel.statistic.max.rt=XXXX才能生效)

 

异常比列(秒级)

    QPS >= 5 且异常比例(秒级统计)超过阈值时,触发降级;时间窗口结束后,关闭降级

 

异常数(分钟级)

     异常数(分钟统计)超过阈值时,触发降级;时间窗口结束后,关闭降级

【SpringCloud AlibabaSentinel实现熔断与限流】_第24张图片

Sentinel 熔断降级会在调用链路中某个资源出现不稳定状态时(例如调用超时或异常比例升高),对这个资源的调用进行限制,让请求快速失败,避免影响到其它的资源而导致级联错误。

当资源被降级后,在接下来的降级时间窗口之内,对该资源的调用都自动熔断(默认行为是抛出 DegradeException)。

Sentinel的断路器是没有半开状态的

半开的状态系统自动去检测是否请求有异常,没有异常就关闭断路器恢复使用,有异常则继续打开断路器不可用。具体可以参考Hystrix

2、降级策略实战

1.RT

【SpringCloud AlibabaSentinel实现熔断与限流】_第25张图片

【SpringCloud AlibabaSentinel实现熔断与限流】_第26张图片 

测试

@GetMapping("/testD")
public String testD()
{
    //暂停几秒钟线程
    try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); }
    log.info("testD 测试RT");
    return "------testD";
}

配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第27张图片

jmeter压测

【SpringCloud AlibabaSentinel实现熔断与限流】_第28张图片

结论:

永远一秒钟打进来10个线程(大于5个了)调用testD,我们希望200毫秒处理完本次任务,

如果超过200毫秒还没处理完,在未来1秒钟的时间窗口内,断路器打开(保险丝跳闸)微服务不可用,保险丝跳闸断电了

后续我停止jmeter,没有这么大的访问量了,断路器关闭(保险丝恢复),微服务恢复OK

2.异常比例

【SpringCloud AlibabaSentinel实现熔断与限流】_第29张图片

测试

@GetMapping("/testD")
public String testD()
{
    log.info("testD 测试RT");
    int age = 10/0;
    return "------testD";
}

配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第30张图片

jmeter

【SpringCloud AlibabaSentinel实现熔断与限流】_第31张图片

结论

【SpringCloud AlibabaSentinel实现熔断与限流】_第32张图片

3.异常数

【SpringCloud AlibabaSentinel实现熔断与限流】_第33张图片

【SpringCloud AlibabaSentinel实现熔断与限流】_第34张图片

异常数是按照分钟统计的

测试

@GetMapping("/testE")
public String testE()
{
    log.info("testE 测试异常比例");
    int age = 10/0;
    return "------testE 测试异常比例";
}

配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第35张图片

jmeter

【SpringCloud AlibabaSentinel实现熔断与限流】_第36张图片

六、热点key限流


1、基本介绍

【SpringCloud AlibabaSentinel实现熔断与限流】_第37张图片

官网:https://github.com/alibaba/Sentinel/wiki/热点参数限流

【SpringCloud AlibabaSentinel实现熔断与限流】_第38张图片

2、测试代码

@SentinelResource

@GetMapping("/testHotKey")
@SentinelResource(value = "testHotKey",blockHandler = "dealHandler_testHotKey")
public String testHotKey(@RequestParam(value = "p1",required = false) String p1, 

                         @RequestParam(value = "p2",required = false) String p2){
    return "------testHotKey";
}
public String dealHandler_testHotKey(String p1,String p2,BlockException exception)
{
    return "-----dealHandler_testHotKey";
}

3、配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第39张图片

限流模式只支持QPS模式,固定写死了。(这才叫热点)

@SentinelResource注解的方法参数索引,0代表第一个参数,1代表第二个参数,以此类推

单机阀值以及统计窗口时长表示在此窗口时间超过阀值就限流。

上面的抓图就是第一个参数有值的话,1秒的QPS为1,超过就限流,限流后调用dealHandler_testHotKey支持方法。

测试

4、参数例外项

上述案例演示了第一个参数p1,当QPS超过1秒1次点击后马上被限流

配置

 【SpringCloud AlibabaSentinel实现熔断与限流】_第40张图片

【SpringCloud AlibabaSentinel实现熔断与限流】_第41张图片

@SentinelResource

处理的是Sentinel控制台配置的违规情况,有blockHandler方法配置的兜底处理;

 

RuntimeException

int age = 10/0,这个是java运行时报出的运行时异常RunTimeException,@SentinelResource不管

总结

 @SentinelResource主管配置出错,运行出错该走异常走异常

七、系统规则 


官网:系统自适应限流 · alibaba/Sentinel Wiki · GitHub

各项配置参数说明 

【SpringCloud AlibabaSentinel实现熔断与限流】_第42张图片

八、@SentinelResource 


1、按资源名称限流+后续处理

启动Nacos成功:http://localhost:8848/nacos/#/login

启动Sentinel成功:java -jar sentinel-dashboard-1.7.0.jar

Module

1.新建cloudalibaba-sentinel-service8401

2.POM



    
        mscloud03
        com.atguigu.springcloud
        1.0-SNAPSHOT
    
    4.0.0

    cloudalibaba-sentinel-service8401


    
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
            com.atguigu.springcloud
            cloud-api-commons
            ${project.version}
        
        
        
            com.alibaba.csp
            sentinel-datasource-nacos
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-sentinel
        
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            cn.hutool
            hutool-all
            4.6.3
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        

    

3.YML

server:
  port: 8401

spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #Nacos服务注册中心地址
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard地址
        port: 8719

management:
  endpoints:
    web:
      exposure:
        include: '*'

4.业务类RateLimitController

package com.atguigu.springcloud.alibaba.controller;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class RateLimitController
{
    @GetMapping("/byResource")
    @SentinelResource(value = "byResource",blockHandler = "handleException")
    public CommonResult byResource()
    {
        return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
    }
    public CommonResult handleException(BlockException exception)
    {
        return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
    }
}

5.主启动

package com.atguigu.springcloud.alibaba;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableDiscoveryClient
@SpringBootApplication
public class MainApp8401
{
    public static void main(String[] args) {
        SpringApplication.run(MainApp8401.class, args);
    }
}

配置流控规则

【SpringCloud AlibabaSentinel实现熔断与限流】_第43张图片

图形配置和代码关系(表示1秒钟内查询次数大于1,就跑到我们自定义的处流,限流)

【SpringCloud AlibabaSentinel实现熔断与限流】_第44张图片

额外问题:此时关闭问服务8401看看,Sentinel控制台,流控规则消失了-临时(见第十的规则持久化)

2、按照Url地址限流+后续处理 

通过访问的URL来限流,会返回Sentinel自带默认的限流处理信息

业务类RateLimitController

package com.atguigu.springcloud.alibaba.controller;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class RateLimitController
{
    @GetMapping("/byResource")
    @SentinelResource(value = "byResource",blockHandler = "handleException")
    public CommonResult byResource()
    {
        return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
    }
    public CommonResult handleException(BlockException exception)
    {
        return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
    }

    @GetMapping("/rateLimit/byUrl")
    @SentinelResource(value = "byUrl")
    public CommonResult byUrl()
    {
        return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
    }
}

访问:http://localhost:8401/rateLimit/byUrl

Sentinel控制台配置 

【SpringCloud AlibabaSentinel实现熔断与限流】_第45张图片

【SpringCloud AlibabaSentinel实现熔断与限流】_第46张图片

上面兜底方案面临的问题

  1. 系统默认的,没有体现我们自己的业务要求。
  2. 依照现有条件,我们自定义的处理方法又和业务代码耦合在一块,不直观。
  3. 每个业务方法都添加一个兜底的,那代码膨胀加剧。
  4. 全局统一的处理方法没有体现。

3、客户自定义限流处理逻辑 

创建CustomerBlockHandler类用于自定义限流处理逻辑

1.自定义限流处理类CustomerBlockHandler

package com.atguigu.springcloud.alibaba.myhandler;

import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.alibaba.entities.CommonResult;
import org.springframework.stereotype.Component;

public class CustomerBlockHandler
{
    public static CommonResult handleException(BlockException exception){
        return new CommonResult(2020,"自定义的限流处理信息......CustomerBlockHandler");
    }
}

【SpringCloud AlibabaSentinel实现熔断与限流】_第47张图片

2.RateLimitController

【SpringCloud AlibabaSentinel实现熔断与限流】_第48张图片

启动微服务后先调用一次http://localhost:8401/rateLimit/customerBlockHandler

3.Sentinel控制台配置 

【SpringCloud AlibabaSentinel实现熔断与限流】_第49张图片

测试后我们自定义的出来了

【SpringCloud AlibabaSentinel实现熔断与限流】_第50张图片

4、更多注解属性说明

【SpringCloud AlibabaSentinel实现熔断与限流】_第51张图片

【SpringCloud AlibabaSentinel实现熔断与限流】_第52张图片

 

九、服务熔断功能 


sentinel整合ribbon+openFeign+fallback

1、Ribbon系列

1.启动nacos和sentinel

2.提供者9003/9004

新建cloudalibaba-provider-payment9003/9004两个一样的做法

POM



    
        mscloud03
        com.atguigu.springcloud
        1.0-SNAPSHOT
    
    4.0.0

    cloudalibaba-provider-payment9003



    
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
            com.atguigu.springcloud
            cloud-api-commons
            ${project.version}
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

YML(记得修改不同的端口号)

server:
  port: 9003

spring:
  application:
    name: nacos-payment-provider
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #配置Nacos地址

management:
  endpoints:
    web:
      exposure:
        include: '*'

主启动

package com.atguigu.springcloud.alibaba;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class PaymentMain9003
{
    public static void main(String[] args) {
            SpringApplication.run(PaymentMain9003.class, args);
    }
}

业务类

package com.atguigu.springcloud.alibaba.controller;

import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
@RestController
public class PaymentController
{
    @Value("${server.port}")
    private String serverPort;

    public static HashMap hashMap = new HashMap<>();
    static
    {
        hashMap.put(1L,new Payment(1L,"28a8c1e3bc2742d8848569891fb42181"));
        hashMap.put(2L,new Payment(2L,"bba8c1e3bc2742d8848569891ac32182"));
        hashMap.put(3L,new Payment(3L,"6ua8c1e3bc2742d8848569891xt92183"));
    }

    @GetMapping(value = "/paymentSQL/{id}")
    public CommonResult paymentSQL(@PathVariable("id") Long id)
    {
        Payment payment = hashMap.get(id);
        CommonResult result = new CommonResult(200,"from mysql,serverPort:  "+serverPort,payment);
        return result;
    }


}

测试地址:http://localhost:9003/paymentSQL/1

3.消费者84

新建cloudalibaba-consumer-nacos-order84

POM

【SpringCloud AlibabaSentinel实现熔断与限流】_第53张图片



    
        mscloud03
        com.atguigu.springcloud
        1.0-SNAPSHOT
    
    4.0.0

    cloudalibaba-consumer-nacos-order84

    
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-sentinel
        
        
        
            com.atguigu.springcloud
            cloud-api-commons
            ${project.version}
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

YML

server:
  port: 84


spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    sentinel:
      transport:
        #配置Sentinel dashboard地址
        dashboard: localhost:8080
        #默认8719端口,假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口
        port: 8719


#消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者)
service-url:
  nacos-user-service: http://nacos-payment-provider

主启动

package com.atguigu.springcloud.alibaba;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClient
@SpringBootApplication
public class OrderNacosMain84
{
    public static void main(String[] args) {
            SpringApplication.run(OrderNacosMain84.class, args);
    }
}

业务类

ApplicationContextConfig

package com.atguigu.springcloud.alibaba.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;


@Configuration
public class ApplicationContextConfig
{
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }
}

CircleBreakerController​

 

fallback和blockHandler都配置

编码

package com.atguigu.springcloud.alibaba.controller;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;
import java.sql.SQLException;
import java.util.concurrent.Executors;

@RestController
@Slf4j
public class CircleBreakerController
{
    public static final String SERVICE_URL = "http://nacos-payment-provider";

    @Resource
    private RestTemplate restTemplate;

    @RequestMapping("/consumer/fallback/{id}")
     @SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler")
    public CommonResult fallback(@PathVariable Long id)
    {
        CommonResult result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);
        if (id == 4) {
            throw new IllegalArgumentException ("非法参数异常....");
        }else if (result.getData() == null) {
            throw new NullPointerException ("NullPointerException,该ID没有对应记录");
        }
        return result;
    }
    public CommonResult handlerFallback(@PathVariable  Long id,Throwable e) {
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(444,"fallback,无此流水,exception  "+e.getMessage(),payment);
    }
    public CommonResult blockHandler(@PathVariable  Long id,BlockException blockException) {
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(445,"blockHandler-sentinel限流,无此流水: blockException  "+blockException.getMessage(),payment);
    }

}

【SpringCloud AlibabaSentinel实现熔断与限流】_第54张图片

sentinel需配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第55张图片

结果 

【SpringCloud AlibabaSentinel实现熔断与限流】_第56张图片

忽略属性

【SpringCloud AlibabaSentinel实现熔断与限流】_第57张图片

程序异常打到前台了,对用户不友好 

【SpringCloud AlibabaSentinel实现熔断与限流】_第58张图片

2、Feign系列

2.POM



    
        mscloud03
        com.atguigu.springcloud
        1.0-SNAPSHOT
    
    4.0.0

    cloudalibaba-consumer-nacos-order84




    
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-sentinel
        
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
        
            com.atguigu.springcloud
            cloud-api-commons
            ${project.version}
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

3.YML(激活Sentinel对Feign的支持)

server:
  port: 84


spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        #Nacos服务注册中心地址
        server-addr: localhost:8848
    sentinel:
      transport:
        #配置Sentinel dashboard地址
        dashboard: localhost:8080
        #默认8719端口,假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口
        port: 8719

management:
  endpoints:
    web:
      exposure:
        include: '*'
# 激活Sentinel对Feign的支持
feign:
  sentinel:
    enabled: true  

4.业务类

带@FeignClient注解的业务接口(定义接口)

package com.atguigu.springcloud.alibaba.service;

import com.atguigu.springcloud.alibaba.entities.CommonResult;
import com.atguigu.springcloud.alibaba.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

/**
 * 使用 fallback 方式是无法获取异常信息的,
 * 如果想要获取异常信息,可以使用 fallbackFactory参数
 */
@FeignClient(value = "nacos-payment-provider",fallback = PaymentFallbackService.class)//调用中关闭9003服务提供者
public interface PaymentService
{
    @GetMapping(value = "/paymentSQL/{id}")
    public CommonResult paymentSQL(@PathVariable("id") Long id);
}

fallback = PaymentFallbackService.class(实现类)

package com.atguigu.springcloud.alibaba.service;

import com.atguigu.springcloud.alibaba.entities.CommonResult;
import com.atguigu.springcloud.alibaba.entities.Payment;
import org.springframework.stereotype.Component;

@Component
public class PaymentFallbackService implements PaymentService
{
    @Override
    public CommonResult paymentSQL(Long id)
    {
        return new CommonResult<>(444,"服务降级返回,没有该流水信息",new Payment(id, "errorSerial......"));
    }
}

5.Controller

【SpringCloud AlibabaSentinel实现熔断与限流】_第59张图片

package com.atguigu.springcloud.alibaba.controller;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

@RestController
@Slf4j
public class CircleBreakerController
{
    public static final String SERVICE_URL = "http://nacos-payment-provider";

    @Resource
    private RestTemplate restTemplate;

    @RequestMapping("/consumer/fallback/{id}")
    //@SentinelResource(value = "fallback") //没有配置
    //@SentinelResource(value = "fallback",fallback = "handlerFallback") //fallback只负责业务异常
    //@SentinelResource(value = "fallback",blockHandler = "blockHandler") //blockHandler只负责sentinel控制台配置违规
    @SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler",
            exceptionsToIgnore = {IllegalArgumentException.class})
    public CommonResult fallback(@PathVariable Long id)
    {
        CommonResult result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);

        if (id == 4) {
            throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常....");
        }else if (result.getData() == null) {
            throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常");
        }

        return result;
    }
    //本例是fallback
    public CommonResult handlerFallback(@PathVariable  Long id,Throwable e) {
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(444,"兜底异常handlerFallback,exception内容  "+e.getMessage(),payment);
    }
    //本例是blockHandler
    public CommonResult blockHandler(@PathVariable  Long id,BlockException blockException) {
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(445,"blockHandler-sentinel限流,无此流水: blockException  "+blockException.getMessage(),payment);
    }

    //==================OpenFeign
    @Resource
    private PaymentService paymentService;

    @GetMapping(value = "/consumer/openfeign/{id}")
    public CommonResult paymentSQL(@PathVariable("id") Long id)
    {
        if(id == 4)
        {
            throw new RuntimeException("没有该id");
        }
        return paymentService.paymentSQL(id);
    }

}

6.主启动

添加@EnableFeignClients启动Feign的功能

package com.atguigu.springcloud.alibaba;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
public class OrderNacosMain84
{
    public static void main(String[] args) {
            SpringApplication.run(OrderNacosMain84.class, args);
    }
}

3、熔断框架比较

【SpringCloud AlibabaSentinel实现熔断与限流】_第60张图片

十、规则持久化


一旦我们重启应用,sentinel规则将消失,生产环境需要将配置规则进行持久化

将限流配置规则持久化进Nacos保存,只要刷新8401某个rest地址,sentinel控制台的流控规则就能看到,只要Nacos里面的配置不删除,针对8401上sentinel上的流控规则持续有效

步骤 

1.修改cloudalibaba-sentinel-service8401

2.POM引入持久化依赖



    com.alibaba.csp
    sentinel-datasource-nacos

3.YML

添加Nacos数据源配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第61张图片

server:
  port: 8401

spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #Nacos服务注册中心地址
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard地址
        port: 8719
      datasource:
        ds1:
          nacos:
            server-addr: localhost:8848
            dataId: cloudalibaba-sentinel-service
            groupId: DEFAULT_GROUP
            data-type: json
            rule-type: flow

management:
  endpoints:
    web:
      exposure:
        include: '*'

feign:
  sentinel:
    enabled: true # 激活Sentinel对Feign的支持

4.添加Nacos业务规则配置

【SpringCloud AlibabaSentinel实现熔断与限流】_第62张图片

【SpringCloud AlibabaSentinel实现熔断与限流】_第63张图片

5.启动8401后刷新sentinel发现业务规则有了

【SpringCloud AlibabaSentinel实现熔断与限流】_第64张图片

6.快速访问测试接口

7.停止8401再看sentinel

【SpringCloud AlibabaSentinel实现熔断与限流】_第65张图片

 结束!

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