springcloud(12)SentinelResource注解配置应用及其他

本篇接上篇的sentinel，主要介绍sentinelResource注解和兜底的方法fallback的各种参数和使用。
1.配置服务提供者集群。

pom文件

<dependencies>
        <!-- SpringCloud ailibaba nacos-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- SpringCloud ailibaba sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <dependency>
            <groupId>com.bai</groupId>
            <artifactId>cloud-api-common</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--监控-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--热部署-->
        <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文件

server:
  port: 9004

spring:
  application:
    name: nacos-payment-provider
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848

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

controller加入集合数据充当数据库进行测试

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

    public static HashMap<Long, PayMent > map = new HashMap<>();
    static {
        map.put(1L,new PayMent(1L,"1111"));
        map.put(2L,new PayMent(2L,"2222"));
        map.put(3L,new PayMent(3L,"3333"));
    }

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

主启动类还是常规配置注解两个

另一个服务提供者配置同上，只需要改一下端口即可。

2.消费者配置

pom文件

<dependencies>
        <!-- SpringCloud ailibaba nacos-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- SpringCloud ailibaba sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <dependency>
            <groupId>com.bai</groupId>
            <artifactId>cloud-api-common</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--监控-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--热部署-->
        <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文件

server:
  port: 84
spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    sentinel:
      transport:
        dashboard: localhost:8080
        port: 8719

#消费者将去访问的微服务名称
server-url:
  nacos-user-service: http://nacos-payment-provider

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

本次采用的有restTemplate所以添加配置类

@Configuration
public class ApplicationConfig {
    @Bean
    @LoadBalanced
    public RestTemplate gettemple(){
        return new RestTemplate();
    }
}

主启动类

@EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
public class Consumer84 {
    public static void main(String[] args) {
        SpringApplication.run(Consumer84.class,args);
    }
}

controller

@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")
//    @SentinelResource(value = "fallback",fallback ="handlerFallback")
    @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);
        //设置特定参数报错，进行降级
        if(id == 4){
            throw new IllegalArgumentException("IllegalArgument ,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,"异常handlerFallback，exception内容： " + e.getMessage(), payment);
    }

    public CommonResult blockHandler(@PathVariable Long id, BlockException e) {
        PayMent payment = new PayMent(id,"null");
        return new CommonResult(444,"blockHandler-sentinel 限流，BlockException： " + e.getMessage(), payment);
    }

    @Resource
    private PaymentFeign paymentFeign;

    @GetMapping(value = "/consumer/paymentSQL/{id}")
    public CommonResult<PayMent> paymentSQLC(@PathVariable("id") Long id){
        return paymentFeign.paymentSQL(id);
    }
}

创建feign接口

@FeignClient(value ="nacos-payment-provider",fallback = PaymentFallback.class)
public interface PaymentFeign {
    @GetMapping(value = "/paymentSQL/{id}")
    public CommonResult<PayMent> paymentSQL(@PathVariable("id") Long id);
 }

兜底的fallback

@Component
public class PaymentFallback implements PaymentFeign{
    @Override
    public CommonResult<PayMent> paymentSQL(Long id) {
        return new CommonResult<>(444,"服务降级返回，---PaymentFallbackService",new PayMent(id,"ErrorSerial"));
    }
}

3.sentenelResource注解参数分析

 @SentinelResource(value = "fallback",fallback ="handlerFallback",blockHandler = "blockHandler")
   

其中有两个比较重要的参数，fallback和blockHandler这两个都是兜底的方法，不过处理的情况却不相同。

blockhandler处理的是sentinel工具出现的限制级错误，本身方法自己出现的错误不属于block管，若是方法出现自身的错误等，该报错还是报错。

fallback则是正常的降级策略，方法出现各种报错的信息都会有fallback来兜底。

4.sentinel熔断

从controller中调用的PaymentFeign接口，实现了openfeign的功能，同时也为接口中配置了兜底的fallback方法，所以sentinel的熔断和之前的没有区别，都是一样的配置。

5.规则持久化。

在学习的过程中 可能发现了随着每次重启应用，后台sentinel中的配置规则所有的 都消失了。下面介绍配合nacos进行持久化规则，避免每次重启都进行复制的配置。

之前的sentinel测试项目yml配置datasource进行持久化

server:
  port: 8401

spring:
  application:
    name: cloudalibaba-sentinal-service
  cloud:
    nacos:
      discovery:
        #Nacos服务注册中心地址
        server-addr: localhost:8848
    sentinel:
      transport:
        #配置Sentin dashboard地址
        dashboard: localhost:8080
        # 默认8719端口，假如被占用了会自动从8719端口+1进行扫描，直到找到未被占用的 端口
        port: 8719
      datasource:   #配置流控规则持久化
        ds1:
          nacos:
            server-addr: localhost:8848
            dataId: cloudalibaba-sentinel-service
            groupId: DEFAULT_GROUP
            data-type: json
            rule-type: flow
management:
  endpoints:
    web:
      exposure:
        include: '*'

里面的参数在之前的nacos文章中有介绍，其实就是在nacos的配置列表中创建记录的对应信息。

还需要在nacos配置列表中新建想要配置的规则持久化。大致如下。

配置的内容参数含义，可以从sentinel的界面用开发者工具进行查看内部名称，决定填写对应的参数名的值。 

6.版本冲突

openfeign和sentinel在整合的时候出现的版本问题报错。提供解决方案，推荐选择第二种添加额外的类。

https://blog.csdn.net/qq_29860591/article/details/108139270

 本篇所有代码均在GitHub：

https://github.com/MaTsukun/springcloud2020