sentinel入门

本地测试需要本地启动本地sentinel

依赖

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<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<!--	持久化配置	-->
<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-datasource-nacos</artifactId>
</dependency>

注解

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@SentinelResource // d进去自己看
// fallback 后被隐藏能源
// blockhandler 不管了，开摆

配置文件

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server:
  port: 10000
spring:
  application:
    name: sentinel-service
  cloud:
    sentinel:
      transport:
        dashboard: localhost:8080 # 需要修改
      web-context-unify: false # 链路
      # 自动推送配置
      datasource:
        flow-rule: # 随便起名字
          nacos:
            serverAddr: sdadgz.cn:8849
            username: nacos
            password: sdadgz.cn
            namespase: test # 命名空间
            dataId: sentinel-service-flow-rule
            rule-type: flow
    nacos:
      username: nacos
      password: sdadgz.cn
      discovery:
        namespace: test
      server-addr: sdadgz.cn:8849
feign:
  sentinel:
    enabled: true # sentinel接管feign

整合gateway

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spring:
  cloud:
  	sentinel:
      transport:
        dashboard: localhost:8080

整合feign

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@FeignClient(value = "demo", path = "/test", fallback = DemoServiceFeignFallback.class)
// 写一个DemoServiceFeignFallback类继承当前类（DemoServiceFeign）

配置中心 限速咯

设置持久化配置

  1. 配置文件输入spring.cloud.sentinel.datasource
  2. datasource点进去，是个map
  3. map的value（DataSourcePropertiesConfiguration）点进去
  4. NacosDataSourceProperties点进去，若干配置可自定义
  5. 他的父类AbstractDataSourceProperties点进去
  6. RuleType点进去
  7. 规则名及其类得到了
  8. nacos创建配置 x-x-flow-rule ，内容：上一步获取的rule的对象数组
  9. 配置文件datasource写入对应 nacos创建的配置的dataId

例：FlowRule

狂点shift ，然后搜索FlowRule，下表不全

Field 说明 默认值
resource 资源名，资源名是限流规则的作用对象
count 限流阈值
grade 限流阈值类型，QPS 模式（1）或并发线程数模式（0） QPS 模式
limitApp 流控针对的调用来源 default，代表不区分调用来源
strategy 调用关系限流策略：直接、关联（1）、链路（2） 根据资源本身（直接）
controlBehavior 流控效果（直接拒绝/WarmUp/匀速+排队等待），不支持按调用关系限流 直接拒绝
clusterMode 是否集群限流 否

strtegy关联，链路

  • 关联：我关注的人限流了我也限 （1）
  • 链路：我达到阈值我关注的人限流（2）

例：匀速，5秒超时，qps1

  • warm up 需要额外增加 warmUpPeriodSec: [s]
  • 削峰填谷 需要额外增加 maxQueueingTimeMs: [ms]
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[
    {
        "resource": "/sentinel/feign",
        "controlBehavior": 2,
        "count": 1,
        "grade": 1,
        "limitApp": "default",
        "strategy": 0,
        "maxQueueingTimeMs": 5000
    }
]

全局捕获异常

你抄我，我抄你，这种谁都用的东西跟hello world一样

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package cn.sdadgz.exception;

import cn.sdadgz.common.Result;
import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowException;
import com.alibaba.fastjson.JSON;
import lombok.Cleanup;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * <p>
 * 废物本物
 * </p>
 *
 * @author sdadgz
 * @since 2023/2/16 00:52:36
 */
@Component
@Slf4j
public class DefaultBlockExceptionHandler implements BlockExceptionHandler {

    @Override
    public void handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws Exception {
        //getRule返回资源、规则的详细信息
        log.info("BlockExceptionHandler BlockException================" + e.getRule());

        Result r = null;
        if (e instanceof FlowException) {
            r = Result.error(100, "接口被限流了");
        } else if (e instanceof DegradeException) {
            r = Result.error(101, "服务降级了");
        } else if (e instanceof ParamFlowException) {
            r = Result.error(102, "热点参数限流了");
        } else if (e instanceof AuthorityException) {
            r = Result.error(104, "授权规则不通过");
        }

        //返回Json数据
        httpServletResponse.setStatus(500);
        httpServletResponse.setCharacterEncoding("UTF-8");
        httpServletResponse.setContentType(MediaType.APPLICATION_JSON_VALUE);
        try (PrintWriter writer = httpServletResponse.getWriter()) {
            writer.write(JSON.toJSONString(r));
            writer.flush();
        } catch (IOException ioException) {
            log.error("异常：{}", ioException.toString());
        }
    }
}