Sentinel服务熔断功能（sentinel整合ribbon+openFeign+fallback）

蔚落 2023-10-11 20:46 6阅读 0赞

**目录**

1、Sentinel服务熔断功能

一、Ribbon系列

（一）提供者9003/9004

（二）消费者84

二、OpenFeign系列

三、熔断框架比较

2、规则持久化

--------------------

## 1、Sentinel服务熔断功能 ##

## 一、Ribbon系列 ##

### （一）提供者9003/9004 ###

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

Pom

<dependencies>
            
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            </dependency>
            <dependency>
                <groupId>com.atguigu.springcloud</groupId>
                <artifactId>cloud-api-commons</artifactId>
                <version>${project.version}</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <scope>runtime</scope>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

YML

server:
      port: 9003 #9004
    
    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

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

业务类

@RestController
    public class PaymentController
    {
        @Value("${server.port}")
        private String serverPort;
    
        public static HashMap<Long,Payment> 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<Payment> paymentSQL(@PathVariable("id") Long id)
        {
            Payment payment = hashMap.get(id);
            CommonResult<Payment> result = new CommonResult(200,"from mysql,serverPort:  "+serverPort,payment);
            return result;
        }
    
    
    
    }

测试地址：[http://localhost:9003/paymentSQL/1][http_localhost_9003_paymentSQL_1]

### （二）消费者84 ###

新建cloudalibaba-consumer-nacos-order84

POM

<dependencies>
            
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            </dependency>
            
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
            </dependency>
            
            <dependency>
                <groupId>com.atguigu.springcloud</groupId>
                <artifactId>cloud-api-commons</artifactId>
                <version>${project.version}</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <scope>runtime</scope>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

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

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

业务类

ApplicationContextConfig

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

CircleBreakerController

@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") 
         public CommonResult<Payment> fallback(@PathVariable Long id)
        {
            CommonResult<Payment> 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;
        }
    }

**只配置fallback**

@RequestMapping("/consumer/fallback/{id}")
        @SentinelResource(value = "fallback", fallback = "handlerFallback")
        public CommonResult<Payment> fallback(@PathVariable Long id)
        {
            CommonResult<Payment> 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;
        }
    
        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);
        }

如果在自定义的异常之前就出现了异常，那么输出的就会是那个异常

![6d0c3906f73048c598599aa0dea70b0f.png][]

**只配置blockhandler**

@RequestMapping("/consumer/fallback/{id}")
    //    @SentinelResource(value = "fallback", fallback = "handlerFallback")
        @SentinelResource(value = "fallback", blockHandler = "blockHandler")
        public CommonResult<Payment> fallback(@PathVariable Long id)
        {
            CommonResult<Payment> 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;
        }
    
        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);
        }

异常超过2次后，断路器打开，断电跳闸，系统被保护

![9627801d3f3e4a3c89036046c989c90f.png][]

**配置fallback和blockhandler**

@RequestMapping("/consumer/fallback/{id}")
    //    @SentinelResource(value = "fallback", fallback = "handlerFallback")
    //    @SentinelResource(value = "fallback", blockHandler = "blockHandler")
        @SentinelResource(value = "fallback", fallback = "handlerFallback",blockHandler = "blockHandler")
        public CommonResult<Payment> fallback(@PathVariable Long id)
        {
            CommonResult<Payment> 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;
        }
    
        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);
        }
    
        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);
        }

![beee4a32d0e64ac4a9a94932fd77c789.png][]

如果次数没有超过sentinel配置的流控规则的时候出现异常，那么是调用了fallback方法。

当超过次数后无论是否出现异常，都是调用blockhandler。

![3d2b8a61d01a4c1b8fe80aca281b7d40.png][]

![62a7e76086ca4017bb96aa1da632a67a.png][]

## 二、OpenFeign系列 ##

修改84模块，Feign组件一般是用于消费侧

POM文件添加依赖

<dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>

激活Sentinel对Feign的支持

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

带@FeignClient注解的业务接口

@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<Payment> paymentSQL(@PathVariable("id") Long id);
    }

PaymentFallbackService

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

Controller

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

主启动类上添加**@EnableFeignClients**

测试84调用9003，此时故意关闭9003微服务提供者，看84消费侧自动降级，不会被耗死

![8b948a0e751c4a7ab93decc23b8917b4.png][]

## 三、熔断框架比较 ##

![63659b82c0204fdf937d2f51637c6352.png][]

## 2、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

修改cloudalibaba-sentinel-service8401

POM文件添加依赖

<dependency>
        <groupId>com.alibaba.csp</groupId>
        <artifactId>sentinel-datasource-nacos</artifactId>
    </dependency>

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
          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

即添加了添加Nacos数据源配置

spring:
      cloud:
        sentinel:
          datasource:
            ds1:
              nacos:
                server-addr: localhost:8848
                dataId: ${spring.application.name}
                groupId: DEFAULT_GROUP
                data-type: json
                rule-type: flow

添加Nacos业务规则配置

![bd4bd3e1ced34daa93bd62187696cf6f.png][]

[
        {
            "resource": "/rateLimit/byUrl",
            "limitApp": "default",
            "grade": 1,
            "count": 1,
            "strategy": 0,
            "controlBehavior": 0,
            "clusterMode": false
        }
    ]
    resource：资源名称；
    limitApp：来源应用；
    grade：阈值类型，0表示线程数，1表示QPS；
    count：单机阈值；
    strategy：流控模式，0表示直接，1表示关联，2表示链路；
    controlBehavior：流控效果，0表示快速失败，1表示Warm Up，2表示排队等待；
    clusterMode：是否集群。

此时停止8401服务后再次启动后就能看到流控规则了，但可能需要先访问几次网址，流控规则才会出现在sentinel控制台

[http_localhost_9003_paymentSQL_1]: http://localhost:9003/paymentSQL/1
[6d0c3906f73048c598599aa0dea70b0f.png]: https://img-blog.csdnimg.cn/6d0c3906f73048c598599aa0dea70b0f.png
[9627801d3f3e4a3c89036046c989c90f.png]: https://img-blog.csdnimg.cn/9627801d3f3e4a3c89036046c989c90f.png
[beee4a32d0e64ac4a9a94932fd77c789.png]: https://img-blog.csdnimg.cn/beee4a32d0e64ac4a9a94932fd77c789.png
[3d2b8a61d01a4c1b8fe80aca281b7d40.png]: https://img-blog.csdnimg.cn/3d2b8a61d01a4c1b8fe80aca281b7d40.png
[62a7e76086ca4017bb96aa1da632a67a.png]: https://img-blog.csdnimg.cn/62a7e76086ca4017bb96aa1da632a67a.png
[8b948a0e751c4a7ab93decc23b8917b4.png]: https://img-blog.csdnimg.cn/8b948a0e751c4a7ab93decc23b8917b4.png
[63659b82c0204fdf937d2f51637c6352.png]: https://img-blog.csdnimg.cn/63659b82c0204fdf937d2f51637c6352.png
[bd4bd3e1ced34daa93bd62187696cf6f.png]: https://img-blog.csdnimg.cn/bd4bd3e1ced34daa93bd62187696cf6f.png