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Day11-SpringCloud alibaba服务降级熔断框架Sentinel （笔记全）

GG_lyf 2022-01-07 阅读 28
微服务javaspring cloud

文章目录

Sentinel介绍及下载安装

Sentinel-features-overview

下载安装可视端

启动

创建项目

  • pom.xml

            <!--SpringCloud ailibaba nacos -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--SpringCloud ailibaba sentinel-datasource-nacos 后续做持久化用到-->
        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-datasource-nacos</artifactId>
        </dependency>
        <!--SpringCloud ailibaba 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>

  • yaml

    server:
  port: 8401

spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery: # http://1.116.182.96:8888/files
        server-addr: localhost:8848 #Nacos服务注册中心地址
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard地址
        port: 8719
      datasource:
        ds1:
          nacos:
            server-addr: localhost:8848
            dataId: cloudalibaba-sentinel-service
            groupId: DEFAULT_GROUP
            data-type: json
            rule-type: flow

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

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

  • 主启动类

    @EnableDiscoveryClient
@SpringBootApplication
public class MainApp8401
{
    public static void main(String[] args) {
        SpringApplication.run(MainApp8401.class, args);
    }
}

  • Controller测试类

    package com.atguigu.springcloud.alibaba.controller;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.util.concurrent.TimeUnit;

/**
 * @auther zzyy
 * @create 2020-02-24 16:26
 */
@RestController
@Slf4j
public class FlowLimitController
{
    @GetMapping("/testA")
    public String testA()
    {
        return "------testA";
    }

    @GetMapping("/testB")
    public String testB()
    {
        log.info(Thread.currentThread().getName()+"\t"+"...testB");
        return "------testB";
    }


    @GetMapping("/testD")
    public String testD()
    {
//        try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); }
//        log.info("testD 测试RT");

        log.info("testD 异常比例");
        int age = 10/0;
        return "------testD";
    }

    @GetMapping("/testE")
    public String testE()
    {
        log.info("testE 测试异常数");
        int age = 10/0;
        return "------testE 测试异常数";
    }

    @GetMapping("/testHotKey")
    @SentinelResource(value = "testHotKey",blockHandler = "deal_testHotKey")
    public String testHotKey(@RequestParam(value = "p1",required = false) String p1,
                             @RequestParam(value = "p2",required = false) String p2)
    {
        //int age = 10/0;
        return "------testHotKey";
    }
    public String deal_testHotKey (String p1, String p2, BlockException exception)
    {
        return "------deal_testHotKey,o(╥﹏╥)o";  //sentinel系统默认的提示：Blocked by Sentinel (flow limiting)
    }

}

  • 访问 http://localhost:8401/testB 看看控制台实时监控

image-20220106113510870

Sentinel流控规则

image-20220106114105601

image-20220106114428849

流控模式-----直接

image-20220106114617589

image-20220106114642362

每秒三下触发默认限流规则 抛出异常

流控模式-----关联

image-20220106115313850

测试：

image-20220106115534159

PostMan中新建多线程集合组

image-20220106164744324

后台运行 /testB 前台访问 /testA

效果： (被限流)

image-20220106164828302

流控模式—–链路

image-20220106165030947

Sentinel降级规则

熔断策略

Sentinel热点规则

返回自定义异常显示

    @GetMapping("/testHotKey")
    @SentinelResource(value = "testHotKey",blockHandler = "deal_testHotKey")
    public String testHotKey(@RequestParam(value = "p1",required = false) String p1,
                             @RequestParam(value = "p2",required = false) String p2)
    {
        //int age = 10/0;
        return "------testHotKey";
    }
    public String deal_testHotKey (String p1, String p2, BlockException exception)
    {
        return "------deal_testHotKey,o(╥﹏╥)o";  //sentinel系统默认的提示：Blocked by Sentinel (flow limiting)
    }

设定热点规则

image-20220106170458989

image-20220106171507571

关于该资源内部出错

Sentinel系统规则（了解即可）

image-20220106171728394

@SentinelResource

关键属性：

  • value：资源名称，必需项（不能为空）

  • fallback：fallback函数名称，可选项，用于在抛出异常的时候提供 fallback处理逻辑。fallback函数可以针对所有类型的异常（除了exceptionsToIgnore里面排除掉的异常类型）进行处理。fallback函数签名和位置要求： 返回值类型必须与原函数返回值类型一致；方法参数列表需要和原函数一致，或者可以额外多一个 Throwable类型的参数用于接收对应的异常。

     @GetMapping("/rateLimit/byUrl")
    @SentinelResource(value = "byUrl",fallback ="runTimeException")
    public CommonResult byUrl()
    {

        int age = 10/0;

        return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
    }
    public CommonResult runTimeException(Throwable exception) //这里不能用Exception
    {

        return new CommonResult(666,exception.getClass().getCanonicalName()+"\t 运行时异常");
    }

  • blockHandler:实现处理函数，该函数的传参必须与资源点的传参一样，并且最后加上BlockException异常参数；同时，返回类型也必须一样。

        @GetMapping("/byResource")
    @SentinelResource(value = "byResource",blockHandler = "handleException" )
    public CommonResult byResource()
    {
        return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001"));
    }

    public CommonResult handleException(BlockException exception)
    {
        return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
    }

  • blockHandlerClass: 自定义限流处理类

  • fallbackClass： 自定义异常类

同时启用blockHander 和 fallback

整合Ribbon+openFeign+fallback实现服务熔断

  • 客户端引入依赖

            <!--SpringCloud openfeign -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--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>

  • 主启动类

    @EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
public class OrderNacosMain84
{
    public static void main(String[] args) {
        SpringApplication.run(OrderNacosMain84.class, args);
    }
}

  • 配置RestTemplate 负载均衡

    @Configuration
public class ApplicationContextConfig
{
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }
}
@Configuration
public class ApplicationContextConfig
{
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }
}

  • Controller测试

    //测试RestTemplate
    @Value("${service-url.nacos-user-service}")
    public String SERVICE_URL;

    @GetMapping("/consumer2/paymentSQL/{id}")
    public CommonResult<Payment> paymentSQ2(@PathVariable("id") Long id)
    {
        return restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class);
    }

image-20220107022504883

image-20220107022518753

可以看见是轮询访问服务端

 ```java
 //测试OpenFeign
    //==================OpenFeign
     @Resource
     private PaymentService paymentService;
 
     @GetMapping(value = "/consumer/paymentSQL/{id}")
     public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id)
     {
         return paymentService.paymentSQL(id);
 
     }
 =============================================================================
     //service
    @FeignClient(value = "${service-url.nacos-user-service}",fallback = PaymentFallbackService.class)
 public interface PaymentService
 {
     @GetMapping(value = "/paymentSQL/{id}")
     public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id);
 }
  
 ```

这里就不截图了 同样效果

  • 实现熔断

       @RequestMapping("/consumer/fallback/{id}")
    //@SentinelResource(value = "fallback") //没有配置
    //@SentinelResource(value = "fallback",fallback = "handlerFallback") //fallback只负责业务异常
    //@SentinelResource(value = "fallback",blockHandler = "blockHandler") //blockHandler只负责sentinel控制台配置违规
    @SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler",
            exceptionsToIgnore = {IllegalArgumentException.class})
    public CommonResult<Payment> fallback(@PathVariable Long id)
    {
        CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);

        if (id == 4) {
            throw new IllegalArgumentException ("IllegalArgumentException,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;
    }
    //本例是fallback
    public CommonResult handlerFallback(@PathVariable  Long id,Throwable e) {
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(444,"兜底异常handlerFallback,exception内容  "+e.getMessage(),payment);
    }
    //本例是blockHandler
    public CommonResult blockHandler(@PathVariable  Long id,BlockException blockException) {
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(445,"blockHandler-sentinel限流,无此流水: blockException  "+blockException.getMessage(),payment);
    }

  • 关闭远程服务试试

    image-20220107023947406

持久化配置

image-20220107024214451

实现步骤

  • <!--SpringCloud ailibaba sentinel-datasource-nacos -->
<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-datasource-nacos</artifactId>
</dependency>

  • yaml

    spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery:
        server-addr: IP:8848 #Nacos服务注册中心地址
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard地址
        port: 8719
      datasource:
        ds1:
          nacos:
            server-addr: IP:8848
            dataId: cloudalibaba-sentinel-service
            groupId: DEFAULT_GROUP
            data-type: json
            rule-type: flow

  • 在Nacos可视化面板添加规则

  • [

    {

        "resource": "/rateLimit/byUrl",

        "limitApp": "default",

        "grade": 1,

        "count": 1,

        "strategy": 0,

        "controlBehavior": 0,

        "clusterMode": false

    }

]

image-20220107024706012

image-20220107025355371

成功！

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