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【SpringCloud】06-Sentinel

article 2024/10/31 5:31:49

1. 雪崩问题

一个微服务出现问题导致一系列微服务都不可以正常工作。
服务保护方案：

请求限流。
线程隔离。
服务熔断

2. Sentinel

启动Sentinel

java -Dserver.port=8090 -Dcsp.sentinel.dashboard.server=localhost:8090 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard.jar

依赖

<!--sentinel-->
<dependency>
    <groupId>com.alibaba.cloud</groupId> 
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>

配置

spring:
  cloud: 
    sentinel:
      transport:
        dashboard: localhost:8090
      http-method-specify: true # 将请求方式也作为簇点链路

簇点链路： Controller中的Rest接口

3. Fallback

配置openfeign使之能够成为簇点链路

feign:
  okhttp:
    enabled: true # 开启OKHttp功能
  sentinel: # 让feign可以成为簇点链路
    enabled: true

设置FallbackFactory

package com.hmall.api.client.fallback;

import com.hmall.api.client.ItemClient;
import com.hmall.api.dto.ItemDTO;
import com.hmall.api.dto.OrderDetailDTO;
import com.hmall.common.utils.CollUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.openfeign.FallbackFactory;

import java.util.Collection;
import java.util.List;

@Slf4j
public class ItemClientFallbackFactory implements FallbackFactory<ItemClient> {
    @Override
    public ItemClient create(Throwable cause) {
        return new ItemClient() {
            @Override
            public List<ItemDTO> queryItemByIds(Collection<Long> ids) {
                log.info("查询商品失败！", cause);
                return CollUtils.emptyList();
            }

            @Override
            public void deductStock(List<OrderDetailDTO> items) {
                log.info("扣减商品库存失败!", cause);
                throw new RuntimeException(cause);
            }
        };
    }
}

注册Bean

package com.hmall.api.config;

import com.hmall.api.client.fallback.ItemClientFallbackFactory;
import com.hmall.common.utils.UserContext;
import feign.Logger;
import feign.RequestInterceptor;
import feign.RequestTemplate;
import org.springframework.context.annotation.Bean;

public class DefaultFeignConfig {
    @Bean
    public Logger.Level feignLogLevel() {
        return Logger.Level.FULL;
    }

    @Bean
    public RequestInterceptor userInfoRequestInterceptor() {
        return new RequestInterceptor() {
            @Override
            public void apply(RequestTemplate requestTemplate) {
                Long userId = UserContext.getUser();
                if (userId!=null) {
                    requestTemplate.header("user-info", userId.toString());
                }
            }
        };
    }

    @Bean
    public ItemClientFallbackFactory itemClientFallbackFactory() {
        return new ItemClientFallbackFactory();
    }
}

配置Bean

@FeignClient(value = "item-service", fallbackFactory = ItemClientFallbackFactory.class)
public interface ItemClient {
    @GetMapping("/items")
    List<ItemDTO> queryItemByIds(@RequestParam("ids") Collection<Long> ids);

    @PutMapping("/items/stock/deduct")
    void deductStock(@RequestBody List<OrderDetailDTO> items);
}