16、OpenFeign和Sentinel集成实现fallback服务降级

发布于：2024-03-28 ⋅ 阅读:(14) ⋅ 点赞:(0)

注：本篇文章主要参考周阳老师讲解的cloud进行整理的！

1、需求说明

cloudalibaba-consumer-nacos-order83 通过OpenFeign调用 cloudalibaba-provider-payment9001

1、 83 通过OpenFeign调用 9001微服务，正常访问OK
2、 83 通过OpenFeign调用 9001微服务，异常访问error
访问者要有fallback服务降级的情况，不要持续访问9001加大微服务负担，但是通过feign接口调用的又方法各自不同，如果每个不同方法都加一个fallback配对方法，会导致代码膨胀不好管理，工程埋雷…/(ㄒoㄒ)/~~
3、 public @interface FeignClient
通过fallback属性进行统一配置，feign接口里面定义的全部方法都走统一的服务降级，一个搞定即可。
4、 9001微服务自身还带着sentinel内部配置的流控规则，如果满足也会被触发，也即本例有2个Case
4.1、 OpenFeign接口的统一fallback服务降级处理
4.2、 Sentinel访问触发了自定义的限流配置,在注解@SentinelResource里面配置的blockHandler方法。

2、程序解耦

2.1、前述参考

在这里插入图片描述

2.2、本例说明

在这里插入图片描述

3、编码步骤

3.1、启动nacos服务器8848

startup.cmd -m standalone

3.2、启动Sentinel服务

java -jar sentinel-dashboard-1.8.6.jar

3.3、修改服务提供方cloudalibaba-provider-payment9001

3.3.1、改POM

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.mui.cloud</groupId>
        <artifactId>cloud2024</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.mui.cloud</groupId>
    <artifactId>cloudalibaba-provider-payment9001</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--alibaba-sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--nacos-discovery-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- 引入自己定义的api通用包 -->
        <dependency>
            <groupId>com.mui.cloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--SpringBoot通用依赖模块-->
        <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>
        <!--hutool-->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.28</version>
            <scope>provided</scope>
        </dependency>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

3.3.2、修改YML

server:
  port: 9002

spring:
  application:
    name: nacos-payment-provider
  cloud:
    nacos:
      discovery:
        # 配置Nacos地址
        server-addr: localhost:8848
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard控制台服务地址
        port: 8719 #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

3.3.3、主启动

package com.mui.cloud;

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

@SpringBootApplication
@EnableDiscoveryClient
public class Main9001 {
    public static void main(String[] args) {
        SpringApplication.run(Main9001.class, args);
    }
}

3.3.4、PayAlibabaController

package com.mui.cloud.controller;

import cn.hutool.core.util.IdUtil;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.dashun.cloud.entities.PayDTO;
import com.dashun.cloud.enums.ReturnCodeEnum;
import com.dashun.cloud.resp.ResultData;
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.math.BigDecimal;

@RestController
public class PayAlibabaController {

    @Value("${server.port}")
    private String serverPort;


    @GetMapping("/pay/nacos/{id}")
    public String getPayInfo(@PathVariable("id") Integer id) {
        return "nacos registry, serverport:" + serverPort + "\t id:" + id;
    }

    @GetMapping("/pay/nacos/get/{orderNo}")
    @SentinelResource(value = "getPayByOrderNo", blockHandler = "handlerBlockHandler")
    public ResultData getPayByOrderNo(@PathVariable("orderNo") String orderNo) {
        // 模拟从数据库查询出数据并赋值给DTO
        PayDTO payDTO = new PayDTO();

        payDTO.setId(1024);
        payDTO.setOrderNo(orderNo);
        payDTO.setAmount(BigDecimal.valueOf(9.9));
        payDTO.setPayNo("pay:" + IdUtil.fastUUID());
        payDTO.setUserId(1);

        return ResultData.success("查询返回值：" + payDTO);
    }

    public ResultData handlerBlockHandler(@PathVariable("orderNo") String orderNo, BlockException exception) {
        return ResultData.fail(ReturnCodeEnum.RC500.getCode(), "getPayByOrderNo服务不可用，触发sentinel流控配置规则" + "\t" + "o(╥﹏╥)o");
    }

}

3.3.5、测试

启动9001微服务测试
http://localhost:9001/pay/nacos/get/ord1024

3.4、修改cloud-api-commons

3.4.1、POM

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.mui.cloud</groupId>
        <artifactId>cloud2024</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>cloud-api-commons</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--alibaba-sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--SpringBoot通用依赖模块-->
        <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.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--hutool-->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
        </dependency>
    </dependencies>

</project>

3.4.2、新增PayFeignSentinelApi接口

package com.mui.cloud.api;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.mui.cloud.resp.ResultData;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@FeignClient(value = "nacos-payment-provider", fallback = PayFeignSentinelApiFallBack.class)
public interface PayFeignSentinelApi {

    @GetMapping("/pay/nacos/get/{orderNo}")
    public ResultData getPayByOrderNo(@PathVariable("orderNo") String orderNo);
    
}

3.4.3、为远程调用新建全局统一服务降级类

package com.mui.cloud.api;

import com.mui.cloud.enums.ReturnCodeEnum;
import com.mui.cloud.resp.ResultData;
import org.springframework.stereotype.Component;

@Component
public class PayFeignSentinelApiFallBack implements PayFeignSentinelApi {
    
    @Override
    public ResultData getPayByOrderNo(String orderNo) {
        return ResultData.fail(ReturnCodeEnum.RC500.getCode(), "对方服务宕机或不可用，FallBack服务降级o(╥﹏╥)o");
    }
    
}

3.5、修改cloudalibaba-consumer-nacos-order83

3.5.1、POM

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.dashun.cloud</groupId>
        <artifactId>cloud2024</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.mui.cloud</groupId>
    <artifactId>cloudalibaba-consumer-nacos-order83</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!-- 引入自己定义的api通用包 -->
        <dependency>
            <groupId>com.mui.cloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--alibaba-sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--nacos-discovery-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--loadbalancer-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-loadbalancer</artifactId>
        </dependency>
        <!--web + actuator-->
        <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>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

3.5.2、YML

server:
  port: 83

spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
#消费者将要去访问的微服务名称(nacos微服务提供者叫什么你写什么)
service-url:
  nacos-user-service: http://nacos-payment-provider

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

3.5.3、主启动

package com.mui.cloud;

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 Main83 {
    public static void main(String[] args) {
        SpringApplication.run(Main83.class, args);
    }
}

3.5.4、业务类

package com.mui.cloud.controller;

import com.mui.cloud.api.PayFeignSentinelApi;
import com.mui.cloud.resp.ResultData;
import jakarta.annotation.Resource;
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 org.springframework.web.client.RestTemplate;

@RestController
public class OrderNacosController {

    @Resource
    private RestTemplate restTemplate;

    @Resource
    private PayFeignSentinelApi payFeignSentinelApi;

    @Value("${service-url.nacos-user-service}")
    private String serverURL;

    @GetMapping("/consumer/pay/nacos/{id}")
    public String paymentInfo(@PathVariable("id") Integer id) {
        String result = restTemplate.getForObject(serverURL + "/pay/nacos/" + id, String.class);
        return result + "\t" + "    我是OrderNacosController83调用者。。。。。。";
    }

    @GetMapping(value = "/consumer/pay/nacos/get/{orderNo}")
    public ResultData getPayByOrderNo(@PathVariable("orderNo") String orderNo) {
        return payFeignSentinelApi.getPayByOrderNo(orderNo);
    }
    
}

3.5.5、启动83微服务第一次

3.5.5.1、故障现象

在这里插入图片描述

3.5.5.2、导致原因

springboot + springcloud版本太高导致和阿里巴巴Sentinel不兼容

3.5.5.3、解决方案

总体父工程，boot + cloud降低版本
<spring.boot.version>3.2.0</spring.boot.version>
<spring.cloud.version>2023.0.0</spring.cloud.version>
上面的配置暂时为本案例注释掉，版本降级一下。
讲解完后请恢复上述高版本保持前后配置一致，请用下面的版本替代上述
<spring.boot.version>3.0.9</spring.boot.version>
<spring.cloud.version>2022.0.2</spring.cloud.version>

再次启动成功

4、测试

  • 9001正常启动后，再启动83通过feign调用

  • 测试地址

    • http://localhost:83/consumer/pay/nacos/get/1024
      在这里插入图片描述

  • sentinel流控为例，进行配置在这里插入图片描述

  • http://localhost:83/consumer/pay/nacos/get/1024

  • 频繁访问后触发了Sentinel的流控规则在这里插入图片描述

  • 9001宕机了，83通过feign调用

    • 测试83调用9001，此时故意关闭9001微服务提供者，看83消费侧自动降级，不会被耗死
    • 降级效果在这里插入图片描述

  • 最后一步

    • 恢复父工程版本号，升在这里插入图片描述
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