Sentinel 熔断限流
Sentinel控制台搭建
我这里为了方便使用docker-compose方式搭建
version: '3.1'
services:
sentinel-dashboard:
image: 'bladex/sentinel-dashboard:latest'
environment:
- AUTH_PASSWORD=cwljxf1025.
- AUTH_USERNAME=admin
container_name: sentinel-dashboard
ports:
- '8858:8858'
- '8719:8719'
新建cloud-sentinel-demo�模块
- pom文件,添加web、sentinel、nacos-discovery相关依赖
<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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>cn.unuuc.cwl</groupId>
<artifactId>cwl-spring-cloud-alibaba</artifactId>
<version>1.0</version>
</parent>
<artifactId>cloud-sentinel-demo</artifactId>
<version>1.0</version>
<description>nacos-discovery注册</description>
<dependencies>
<!-- sentinel -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<!-- springboot-web -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- nacos-discovery -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
</dependencies>
<build>
<finalName>${project.artifactId}</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
<configuration>
<fork>true</fork>
</configuration>
</plugin>
</plugins>
</build>
</project>
- bootstrap.yml
server:
port: 7001
spring:
application:
name: cloud-sentinel-demo
cloud:
sentinel:
enabled: true #开启Sentinel
eager: true # 取消控制台懒加载,项目启动即连接Sentinel
transport:
port: 8719
dashboard: 192.168.101.104:8858
nacos:
discovery:
# 命名空间,用于区分不同的项目
namespace: cwl
# 服务注册地址
server-addr: 192.168.101.104:8848
username: nacos
password: nacos
# 是否注册服务到nacos
enabled: true
ps: 这里也注册到nacos中,注意 namespace:cwl
添加注解
@SentinelResource(value = "sayHello")
注解解释详情 : 注解支持
@Service
public class SentinelService {
@SentinelResource(value = "sayHello", blockHandler = "exceptionHandler", fallback = "helloFallback")
public String helloSentinel(long s){
return "hello sentinel";
}
// Fallback 函数,函数签名与原函数一致或加一个 Throwable 类型的参数.
public String helloFallback(long s) {
return String.format("Halooooo %d", s);
}
// Block 异常处理函数,参数最后多一个 BlockException,其余与原函数一致.
public String exceptionHandler(long s, BlockException ex) {
// Do some log here.
ex.printStackTrace();
return "Oops, error occurred at " + s;
}
}
@SentinelResource 还提供了其它额外的属性如 blockHandler,blockHandlerClass,fallback 用于表示限流或降级的操作(注意有方法签名要求),更多内容可以参考 Sentinel 注解支持文档。若不配置 blockHandler、fallback 等函数,则被流控降级时方法会直接抛出对应的 BlockException;若方法未定义 throws BlockException 则会被 JVM 包装一层 UndeclaredThrowableException。
测试流量控制
这里设置2qps,一秒钟内最多处理2次请求 ps: 如果没有找到这个资源,可以先访问一次接口
多次高频访问时