【SpringCloud AlibabaSentinel实现熔断与限流】
本笔记内容为尚硅谷SpringCloud AlibabaSentinel部分
目录
一、Sentinel
1、官网
2、Sentinel是什么
3、下载
4、特性
5、使用
二、安装Sentinel控制台
1、sentinel组件由2部分构成
2、安装步骤
1.下载
2.运行命令
3.访问sentinel管理界面
三、初始化演示工程
四、流控规则
1、基本介绍
解释说明
2、流控模式
1.直接(默认)
2.关联
3.链路
3、流控效果
1.直接->快速失败(默认的流控处理)
2.预热
3.排队等待
五、降级规则
1、基本介绍
2、降级策略实战
1.RT
2.异常比例
3.异常数
六、热点key限流
1、基本介绍
2、测试代码
3、配置
4、参数例外项
配置
七、系统规则
各项配置参数说明
八、@SentinelResource
1、按资源名称限流+后续处理
2、按照Url地址限流+后续处理
3、客户自定义限流处理逻辑
4、更多注解属性说明
九、服务熔断功能
1、Ribbon系列
2、Feign系列
3、熔断框架比较
十、规则持久化
步骤
一、Sentinel
1、官网
https://github.com/alibaba/Sentinel
中文:https://github.com/alibaba/Sentinel/wiki/%E4%BB%8B%E7%BB%8D
2、Sentinel是什么
类似之前学过的Hystrix
3、下载
Releases · alibaba/Sentinel · GitHub
4、特性
5、使用
查看官网：Spring Cloud Alibaba Reference Documentation
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
二、安装Sentinel控制台
1、sentinel组件由2部分构成
后台+前台8080
2、安装步骤
1.下载
Releases · alibaba/Sentinel · GitHub
下载到本地sentinel-dashboard-1.7.0.jar
2.运行命令
前提：java8环境正常，8080端口不能被占用
命令：java -jar sentinel-dashboard-1.7.0.jar
3.访问sentinel管理界面
http://localhost:8080，登录账号密码均为sentinel
三、初始化演示工程
1、启动Nacos8848成功
http://localhost:8848/nacos/#/login
2、Module
cloudalibaba-sentinel-service8401
3、POM
cloud190805
com.atguigu.springcloud
1.0-SNAPSHOT
4.0.0
cloudalibaba-sentinel-service8401
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
4、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: '*'5、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);
}
}
6、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 cmd ：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，发现什么都没有
Sentinel采用的懒加载说明
执行一次访问即可（http://localhost:8401/testA 和 http://localhost:8401/testB）
效果
结论：sentinel8080正在监控微服务8401
四、流控规则
1、基本介绍
解释说明
2、流控模式
1.直接(默认)
直接->快速失败（系统默认）
配置及说明
2.关联
当关联的资源达到阈值时，就限流自己
当与A关联的资源B达到阀值后，就限流A自己、B惹事，A挂了
配置A
postman模拟并发密集访问testB
访问testB成功
postman里新建多线程集合组
将访问地址添加进新新线程组
Run（大批量线程高并发访问B，导致A失效了）
运行后发现testA挂了，点击访问http://localhost:8401/testA，结果Blocked by Sentinel (flow limiting)
3.链路
多个请求调用了同一个微服务（可以想象当作VIP通道）
3、流控效果
1.直接->快速失败(默认的流控处理)
2.预热
公式：阈值除以coldFactor(默认值为3),经过预热时长后才会达到阈值
官网：流量控制 · alibaba/Sentinel Wiki · GitHub
默认coldFactor为3，即请求 QPS 从 threshold / 3 开始，经预热时长逐渐升至设定的 QPS 阈值。
限流 冷启动：限流 冷启动 · alibaba/Sentinel Wiki · GitHub
WarmUp配置
多次点击http://localhost:8401/testB、刚开始不行，后续慢慢OK
应用场景
如：秒杀系统在开启的瞬间，会有很多流量上来，很有可能把系统打死，预热方式就是把为了保护系统，可慢慢的把流量放进来，慢慢的把阀值增长到设置的阀值。
3.排队等待
官网：https://github.com/alibaba/Sentinel/wiki/%E6%B5%81%E9%87%8F%E6%8E%A7%E5%88%B6
测试
五、降级规则
官网：熔断降级 · alibaba/Sentinel Wiki · GitHub
1、基本介绍
RT（平均响应时间，秒级）
平均响应时间 超出阈值 且 在时间窗口内通过的请求>=5，两个条件同时满足后触发降级
窗口期过后关闭断路器
RT最大4900（更大的需要通过-Dcsp.sentinel.statistic.max.rt=XXXX才能生效）
异常比列（秒级）
QPS >= 5 且异常比例（秒级统计）超过阈值时，触发降级；时间窗口结束后，关闭降级
异常数（分钟级）
异常数（分钟统计）超过阈值时，触发降级；时间窗口结束后，关闭降级
Sentinel 熔断降级会在调用链路中某个资源出现不稳定状态时（例如调用超时或异常比例升高），对这个资源的调用进行限制，让请求快速失败，避免影响到其它的资源而导致级联错误。
当资源被降级后，在接下来的降级时间窗口之内，对该资源的调用都自动熔断（默认行为是抛出 DegradeException）。
Sentinel的断路器是没有半开状态的
半开的状态系统自动去检测是否请求有异常，没有异常就关闭断路器恢复使用，有异常则继续打开断路器不可用。具体可以参考Hystrix
2、降级策略实战
1.RT
测试
@GetMapping("/testD")
public String testD()
{
//暂停几秒钟线程
try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); }
log.info("testD 测试RT");
return "------testD";
}配置
jmeter压测
结论：
永远一秒钟打进来10个线程（大于5个了）调用testD，我们希望200毫秒处理完本次任务，
如果超过200毫秒还没处理完，在未来1秒钟的时间窗口内，断路器打开(保险丝跳闸)微服务不可用，保险丝跳闸断电了
后续我停止jmeter，没有这么大的访问量了，断路器关闭(保险丝恢复)，微服务恢复OK
2.异常比例
测试
@GetMapping("/testD")
public String testD()
{
log.info("testD 测试RT");
int age = 10/0;
return "------testD";
}配置
jmeter
结论
3.异常数
异常数是按照分钟统计的
测试
@GetMapping("/testE")
public String testE()
{
log.info("testE 测试异常比例");
int age = 10/0;
return "------testE 测试异常比例";
}配置
jmeter
六、热点key限流
1、基本介绍
官网：https://github.com/alibaba/Sentinel/wiki/热点参数限流
2、测试代码
@SentinelResource
@GetMapping("/testHotKey")
@SentinelResource(value = "testHotKey",blockHandler = "dealHandler_testHotKey")
public String testHotKey(@RequestParam(value = "p1",required = false) String p1,
@RequestParam(value = "p2",required = false) String p2){
return "------testHotKey";
}
public String dealHandler_testHotKey(String p1,String p2,BlockException exception)
{
return "-----dealHandler_testHotKey";
}3、配置
限流模式只支持QPS模式，固定写死了。（这才叫热点）
@SentinelResource注解的方法参数索引，0代表第一个参数，1代表第二个参数，以此类推
单机阀值以及统计窗口时长表示在此窗口时间超过阀值就限流。
上面的抓图就是第一个参数有值的话，1秒的QPS为1，超过就限流，限流后调用dealHandler_testHotKey支持方法。
测试
4、参数例外项
上述案例演示了第一个参数p1，当QPS超过1秒1次点击后马上被限流
配置
@SentinelResource
处理的是Sentinel控制台配置的违规情况，有blockHandler方法配置的兜底处理；
RuntimeException
int age = 10/0,这个是java运行时报出的运行时异常RunTimeException，@SentinelResource不管
总结
@SentinelResource主管配置出错，运行出错该走异常走异常
七、系统规则
官网：系统自适应限流 · alibaba/Sentinel Wiki · GitHub
各项配置参数说明
八、@SentinelResource
1、按资源名称限流+后续处理
启动Nacos成功：http://localhost:8848/nacos/#/login
启动Sentinel成功：java -jar sentinel-dashboard-1.7.0.jar
Module
1.新建cloudalibaba-sentinel-service8401
2.POM
mscloud03
com.atguigu.springcloud
1.0-SNAPSHOT
4.0.0
cloudalibaba-sentinel-service8401
com.alibaba.cloud
spring-cloud-starter-alibaba-nacos-discovery
com.atguigu.springcloud
cloud-api-commons
${project.version}
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
3.YML
server:
port: 8401
spring:
application:
name: cloudalibaba-sentinel-service
cloud:
nacos:
discovery:
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
management:
endpoints:
web:
exposure:
include: '*'4.业务类RateLimitController
package com.atguigu.springcloud.alibaba.controller;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class RateLimitController
{
@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");
}
}5.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);
}
}配置流控规则
图形配置和代码关系（表示1秒钟内查询次数大于1，就跑到我们自定义的处流，限流）
额外问题：此时关闭问服务8401看看，Sentinel控制台，流控规则消失了-临时（见第十的规则持久化）
2、按照Url地址限流+后续处理
通过访问的URL来限流，会返回Sentinel自带默认的限流处理信息
业务类RateLimitController
package com.atguigu.springcloud.alibaba.controller;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class RateLimitController
{
@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");
}
@GetMapping("/rateLimit/byUrl")
@SentinelResource(value = "byUrl")
public CommonResult byUrl()
{
return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
}
}访问：http://localhost:8401/rateLimit/byUrl
Sentinel控制台配置
上面兜底方案面临的问题
- 系统默认的，没有体现我们自己的业务要求。
- 依照现有条件，我们自定义的处理方法又和业务代码耦合在一块，不直观。
- 每个业务方法都添加一个兜底的，那代码膨胀加剧。
- 全局统一的处理方法没有体现。
3、客户自定义限流处理逻辑
创建CustomerBlockHandler类用于自定义限流处理逻辑
1.自定义限流处理类CustomerBlockHandler
package com.atguigu.springcloud.alibaba.myhandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.alibaba.entities.CommonResult;
import org.springframework.stereotype.Component;
public class CustomerBlockHandler
{
public static CommonResult handleException(BlockException exception){
return new CommonResult(2020,"自定义的限流处理信息......CustomerBlockHandler");
}
}
2.RateLimitController
启动微服务后先调用一次http://localhost:8401/rateLimit/customerBlockHandler
3.Sentinel控制台配置
测试后我们自定义的出来了
4、更多注解属性说明
九、服务熔断功能
sentinel整合ribbon+openFeign+fallback
1、Ribbon系列
1.启动nacos和sentinel
2.提供者9003/9004
新建cloudalibaba-provider-payment9003/9004两个一样的做法
POM
mscloud03
com.atguigu.springcloud
1.0-SNAPSHOT
4.0.0
cloudalibaba-provider-payment9003
com.alibaba.cloud
spring-cloud-starter-alibaba-nacos-discovery
com.atguigu.springcloud
cloud-api-commons
${project.version}
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-actuator
org.springframework.boot
spring-boot-devtools
runtime
true
org.projectlombok
lombok
true
org.springframework.boot
spring-boot-starter-test
test
YML（记得修改不同的端口号）
server:
port: 9003
spring:
application:
name: nacos-payment-provider
cloud:
nacos:
discovery:
server-addr: localhost:8848 #配置Nacos地址
management:
endpoints:
web:
exposure:
include: '*'主启动
package com.atguigu.springcloud.alibaba;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@SpringBootApplication
@EnableDiscoveryClient
public class PaymentMain9003
{
public static void main(String[] args) {
SpringApplication.run(PaymentMain9003.class, args);
}
}业务类
package com.atguigu.springcloud.alibaba.controller;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
@RestController
public class PaymentController
{
@Value("${server.port}")
private String serverPort;
public static HashMap hashMap = new HashMap<>();
static
{
hashMap.put(1L,new Payment(1L,"28a8c1e3bc2742d8848569891fb42181"));
hashMap.put(2L,new Payment(2L,"bba8c1e3bc2742d8848569891ac32182"));
hashMap.put(3L,new Payment(3L,"6ua8c1e3bc2742d8848569891xt92183"));
}
@GetMapping(value = "/paymentSQL/{id}")
public CommonResult paymentSQL(@PathVariable("id") Long id)
{
Payment payment = hashMap.get(id);
CommonResult result = new CommonResult(200,"from mysql,serverPort: "+serverPort,payment);
return result;
}
} 测试地址：http://localhost:9003/paymentSQL/1
3.消费者84
新建cloudalibaba-consumer-nacos-order84
POM
mscloud03
com.atguigu.springcloud
1.0-SNAPSHOT
4.0.0
cloudalibaba-consumer-nacos-order84
com.alibaba.cloud
spring-cloud-starter-alibaba-nacos-discovery
com.alibaba.cloud
spring-cloud-starter-alibaba-sentinel
com.atguigu.springcloud
cloud-api-commons
${project.version}
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-actuator
org.springframework.boot
spring-boot-devtools
runtime
true
org.projectlombok
lombok
true
org.springframework.boot
spring-boot-starter-test
test
YML
server:
port: 84
spring:
application:
name: nacos-order-consumer
cloud:
nacos:
discovery:
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
#消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者)
service-url:
nacos-user-service: http://nacos-payment-provider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;
@EnableDiscoveryClient
@SpringBootApplication
public class OrderNacosMain84
{
public static void main(String[] args) {
SpringApplication.run(OrderNacosMain84.class, args);
}
}业务类
ApplicationContextConfig
package com.atguigu.springcloud.alibaba.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class ApplicationContextConfig
{
@Bean
@LoadBalanced
public RestTemplate getRestTemplate()
{
return new RestTemplate();
}
}CircleBreakerController
fallback和blockHandler都配置
编码
package com.atguigu.springcloud.alibaba.controller;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import javax.annotation.Resource;
import java.sql.SQLException;
import java.util.concurrent.Executors;
@RestController
@Slf4j
public class CircleBreakerController
{
public static final String SERVICE_URL = "http://nacos-payment-provider";
@Resource
private RestTemplate restTemplate;
@RequestMapping("/consumer/fallback/{id}")
@SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler")
public CommonResult fallback(@PathVariable Long id)
{
CommonResult result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);
if (id == 4) {
throw new IllegalArgumentException ("非法参数异常....");
}else if (result.getData() == null) {
throw new NullPointerException ("NullPointerException,该ID没有对应记录");
}
return result;
}
public CommonResult handlerFallback(@PathVariable Long id,Throwable e) {
Payment payment = new Payment(id,"null");
return new CommonResult<>(444,"fallback,无此流水,exception "+e.getMessage(),payment);
}
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);
}
} 
sentinel需配置
结果
忽略属性
程序异常打到前台了，对用户不友好
2、Feign系列
2.POM
mscloud03
com.atguigu.springcloud
1.0-SNAPSHOT
4.0.0
cloudalibaba-consumer-nacos-order84
com.alibaba.cloud
spring-cloud-starter-alibaba-nacos-discovery
com.alibaba.cloud
spring-cloud-starter-alibaba-sentinel
org.springframework.cloud
spring-cloud-starter-openfeign
com.atguigu.springcloud
cloud-api-commons
${project.version}
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-actuator
org.springframework.boot
spring-boot-devtools
runtime
true
org.projectlombok
lombok
true
org.springframework.boot
spring-boot-starter-test
test
3.YML（激活Sentinel对Feign的支持）
server:
port: 84
spring:
application:
name: nacos-order-consumer
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: '*'
# 激活Sentinel对Feign的支持
feign:
sentinel:
enabled: true 4.业务类
带@FeignClient注解的业务接口（定义接口）
package com.atguigu.springcloud.alibaba.service;
import com.atguigu.springcloud.alibaba.entities.CommonResult;
import com.atguigu.springcloud.alibaba.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
/**
* 使用 fallback 方式是无法获取异常信息的，
* 如果想要获取异常信息，可以使用 fallbackFactory参数
*/
@FeignClient(value = "nacos-payment-provider",fallback = PaymentFallbackService.class)//调用中关闭9003服务提供者
public interface PaymentService
{
@GetMapping(value = "/paymentSQL/{id}")
public CommonResult paymentSQL(@PathVariable("id") Long id);
} fallback = PaymentFallbackService.class（实现类）
package com.atguigu.springcloud.alibaba.service;
import com.atguigu.springcloud.alibaba.entities.CommonResult;
import com.atguigu.springcloud.alibaba.entities.Payment;
import org.springframework.stereotype.Component;
@Component
public class PaymentFallbackService implements PaymentService
{
@Override
public CommonResult paymentSQL(Long id)
{
return new CommonResult<>(444,"服务降级返回,没有该流水信息",new Payment(id, "errorSerial......"));
}
} 5.Controller
package com.atguigu.springcloud.alibaba.controller;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import javax.annotation.Resource;
@RestController
@Slf4j
public class CircleBreakerController
{
public static final String SERVICE_URL = "http://nacos-payment-provider";
@Resource
private RestTemplate restTemplate;
@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 fallback(@PathVariable Long id)
{
CommonResult 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);
}
//==================OpenFeign
@Resource
private PaymentService paymentService;
@GetMapping(value = "/consumer/openfeign/{id}")
public CommonResult paymentSQL(@PathVariable("id") Long id)
{
if(id == 4)
{
throw new RuntimeException("没有该id");
}
return paymentService.paymentSQL(id);
}
} 6.主启动
添加@EnableFeignClients启动Feign的功能
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
@EnableFeignClients
public class OrderNacosMain84
{
public static void main(String[] args) {
SpringApplication.run(OrderNacosMain84.class, args);
}
}
3、熔断框架比较
十、规则持久化
一旦我们重启应用，sentinel规则将消失，生产环境需要将配置规则进行持久化
将限流配置规则持久化进Nacos保存，只要刷新8401某个rest地址，sentinel控制台的流控规则就能看到，只要Nacos里面的配置不删除，针对8401上sentinel上的流控规则持续有效
步骤
1.修改cloudalibaba-sentinel-service8401
2.POM引入持久化依赖
com.alibaba.csp
sentinel-datasource-nacos
3.YML
添加Nacos数据源配置
server:
port: 8401
spring:
application:
name: cloudalibaba-sentinel-service
cloud:
nacos:
discovery:
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4.添加Nacos业务规则配置
5.启动8401后刷新sentinel发现业务规则有了
6.快速访问测试接口
7.停止8401再看sentinel
结束！