SpringCloud第十八章AlibabaSentinel实现熔断与限流（安装Sentinel控制台）

十八、SpringCloud AlibabaSentinel实现熔断与限流

1、Sentinel

• 官网

  https://github.com/alibaba/Sentinel

  中文：https://github.com/alibaba/Sentinel/wiki/%E4%BB%8B%E7%BB%8D

• 是什么

  

  

• 去哪下

  https://github.com/alibaba/Sentinel/releases

  

• 能干嘛

  

• 怎么玩

  • https://spring-cloud-alibaba-group.github.io/github-pages/greenwich/spring-cloud-alibaba.html#_spring_cloud_alibaba_sentinel

  • 服务使用中的各种问题

    • 服务雪崩
    • 服务降级
    • 服务熔断
    • 服务限流

2、安装Sentinel控制台

• sentinel组件由2部分构成

  

  • 后台
  • 前台8080

• 安装步骤

  • 下载 https://github.com/alibaba/Sentinel/releases 下载到本地sentinel-dashboard-1.7.0.jar

  • 运行命令

    • 前提

      • java8环境OK
      • 8080端口不能被占用

    • 命令

      

  java -jar sentinel-dashboard-1.7.0.jar

  • 访问sentinel管理界面

    • http://localhost:8080

      

  • 登录账号密码均为sentinel

3、初始化演示工程

• 启动Nacos8848成功 http://localhost:8848/nacos/#/login

• Module

  • cloudalibaba-sentinel-service8401

  • POM

    
    <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">
        <parent>
            <artifactId>cloud190805artifactId>
            <groupId>com.atguigu.springcloudgroupId>
            <version>1.0-SNAPSHOTversion>
        parent>
        <modelVersion>4.0.0modelVersion>
    
        <artifactId>cloudalibaba-sentinel-service8401artifactId>
    

    
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
        
            com.alibaba.csp
            sentinel-datasource-nacos
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-sentinel
        
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            runtime
            true
        
        
            cn.hutool
            hutool-all
            4.6.3
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    
    
    

  • YML

    server:
      port: 8401
    
    spring:
      application:
        name: cloudalibaba-sentinel-service
      cloud:
        nacos:
          discovery:
            #Nacos服务注册中心地址
            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
    
    management:
      endpoints:
        web:
          exposure:
            include: '*'
    
    

  • 主启动

    package com.atguigu.springcloud.alibaba;
    
    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
    public class MainApp8401
    {
    public static void main(String[] args) {
    SpringApplication.run(MainApp8401.class, args);
    }
    }

  • 业务类FlowLimitController

    package com.atguigu.springcloud.alibaba.controller;
    
    import com.atguigu.springcloud.alibaba.service.OrderService;
    import org.springframework.stereotype.Service;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.annotation.Resource;
    
    
    @RestController
    public class FlowLimitController
    {
    
        @GetMapping("/testA")
        public String testA()
        {
            return "------testA";
        }
    
        @GetMapping("/testB")
        public String testB()
        {
            return "------testB";
        }
    }
    
    

• 启动Sentinel8080 java -jar sentinel-dashboard-1.7.0.jar

• 启动微服务8401

• 启动8401微服务后查看sentienl控制台

  • 空空如也，啥都没有

    

  • Sentinel采用的懒加载说明

    执行一次访问即可

    http://localhost:8401/testA

    http://localhost:8401/testB

    效果

    

  • 结论

    sentinel8080正在监控微服务8401