Sentinel流控与熔断

参考： https://thinkwon.blog.csdn.net/article/details/103770879

项目结构

com.guo     
├── guo-sentinel              // sentinel限流熔断学习
│       └── guo-sentinel-base                          // [9204]消费端，限流、熔断在这里体现
│       └── guo-sentinel-provider                      // [9205]接口提供端

安装Sentinel控制台

Sentinel控制台是一个轻量级的控制台应用，它可用于实时查看单机资源监控及集群资源汇总，并提供了一系列的规则管理功能，如流控规则、降级规则、热点规则等。

• 下载</br> 可以从https://github.com/alibaba/Sentinel/releases下载sentinel-dashboard-$version.jar包。我这里下载的是 sentinel-dashboard-1.8.0.jar 版本。可以从百度云盘下载 提取码：0708

• 启动控制台

  java -Dserver.port=8718 -Dcsp.sentinel.dashboard.server=localhost:8718 -Dproject.name=sentinel-dashboard -Dcsp.sentinel.api.port=8719 -jar D:gyinstall微服务sentinel-dashboard-1.8.0.jar

  其中-Dserver.port=8718用于指定Sentinel控制台端口为8718，D:gyinstall微服务sentinel-dashboard-1.8.0.jar为下载的包路径地址。

• 打开控制台</br> Sentinel提供了一个可视化的操作平台，安装好之后，在浏览器中输入(http://localhost:8718 (opens new window))就可以访问了，默认的用户名和密码都是sentinel（我使用的是1.8.0版本）

 

限流

添加依赖

<!-- 在guo-sentinel导入依赖 -->
<dependencyManagement>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-dependencies</artifactId>
            <version>${spring-cloud.alibaba}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencyManagement>
<!-- 在guo-sentinel-base添加依赖 -->
<dependencies>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
            <version>${spring-cloud.alibaba}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

添加bootstrap.yml配置

server:
  port: 9100
  address: localhost
  
  
spring:
  application:
    name: guo-sentinel-base
  cloud:
    sentinel:
      transport:
        dashboard: localhost:8718   #sentinel控制台的请求地址

按资源名称限流

• 在guo-sentinel-base编写需要限流的资源接口

​
import java.util.HashMap;
import java.util.Map;
​
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
​
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.guo.sentinel.handle.CustomBlockHandler;
​
import lombok.extern.slf4j.Slf4j;
​
@Slf4j
@RestController
@RequestMapping("/rateLimit")
public class RateLimitController {
​
    /**
     * 按资源名称限流，需要指定限流处理逻辑
     *
     * @return
     */
    @GetMapping("/byResource")
    @SentinelResource(value = "byResource", blockHandler = "handleException")
    public Map<String,Object> byResource() {
        log.info("/rateLimit/byResource");
        Map<String,Object> result = new HashMap<>();
        result.put("name","按资源名称限流");
        result.put("code",200);
        return result ;
    }
​
    /**
     * 按url限流，有默认的限流处理逻辑
     *
     * @return
     */
    @GetMapping("byUrl")
    @SentinelResource(value = "byUrl", blockHandler = "handleException")
    public Map<String,Object> byUrl() {
        log.info("/rateLimit/byResource");
        Map<String,Object> result = new HashMap<>();
        result.put("name","按url限流");
        result.put("code",200);
        return result ;
    }
​
    public Map<String,Object> handleException(BlockException exception) {
        Map<String,Object> result = new HashMap<>();
        result.put("name",exception.getClass().getCanonicalName());
        result.put("code",200);
        return result ;
    }
​
    @GetMapping("/customBlockHandler")
    @SentinelResource(value = "customBlockHandler", blockHandler = "handleException", blockHandlerClass = CustomBlockHandler.class)
    public Map<String,Object> blockHandler() {
        Map<String,Object> result = new HashMap<>();
        result.put("name","限流成功");
        result.put("code",200);
        return result ;
    }
​
​
}

• 在项目guo-sentinel-provider编写远程测试接口

controller

​
import java.util.List;
import java.util.Map;
​
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.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
​
import com.guo.sentinel.service.UserService;
​
@RestController
@RequestMapping("/user")
public class UserController {
​
    @Autowired
    private UserService userService;
​
    @PostMapping("/insert")
    public Map<String,Object> insert(@RequestBody Map<String,Object> user) {
        return userService.insert(user);
    }
​
    @GetMapping("/{id}")
    public Map<String,Object> getUser(@PathVariable Long id) {
        return userService.getUser(id);
    }
​
    @GetMapping("/listUsersByIds")
    public Map<String,Object> listUsersByIds(@RequestParam List<Long> ids) {
        return userService.listUsersByIds(ids);
    }
​
    @GetMapping("/getByUsername")
    public Map<String,Object> getByUsername(@RequestParam String username) {
        return userService.getByUsername(username);
    }
​
    @PostMapping("/update")
    public Map<String,Object> update(@RequestBody Map<String,Object> user) {
        return userService.update(user);
    }
​
    @PostMapping("/delete/{id}")
    public Map<String,Object> delete(@PathVariable Long id) {
        return userService.delete(id);
    }
    
}

service

import java.util.List;
import java.util.Map;
​
public interface UserService {
​
    Map<String,Object> insert(Map<String,Object> user);
​
    Map<String,Object> getUser(Long id);
​
    Map<String,Object> listUsersByIds(List<Long> ids);
​
    Map<String,Object> getByUsername(String username);
​
    Map<String,Object> update(Map<String,Object> user);
​
    Map<String,Object> delete(Long id);
    
}

service.impl

import java.util.HashMap;
import java.util.List;
import java.util.Map;
​
import org.springframework.stereotype.Service;
​
import com.guo.sentinel.service.UserService;
​
import lombok.extern.slf4j.Slf4j;
​
@Slf4j
@Service
public class UserServiceImpl implements UserService {
​
    @Override
    public Map<String, Object> insert(Map<String, Object> user) {
        log.info("新增：{}", user);
        return null;
    }
​
    @Override
    public Map<String, Object> getUser(Long id) {
        log.info("获取：{}", id);
        if(Long.valueOf("1").equals(id)) {
            throw new RuntimeException("remote func is fail");
        }
​
        Map<String,Object> result = new HashMap<>();
        result.put("reqData",id);
        result.put("code","200");
​
        return result ;
    }
​
    @Override
    public Map<String, Object> listUsersByIds(List<Long> ids) {
        log.info("获取集合：{}", ids);
        return null;
    }
​
    @Override
    public Map<String, Object> getByUsername(String username) {
        log.info("根据用户名获取：{}", username);
        if(1==1) throw new RuntimeException("模拟异常");
        return null;
    }
​
    @Override
    public Map<String, Object> update(Map<String, Object> user) {
        log.info("更新：{}", user);
        return null;
    }
​
    @Override
    public Map<String, Object> delete(Long id) {
        log.info("删除：{}", id);
        return null;
    }
​
}
​

• 在nacos配置guo-sentinel-base-dev.yml中添加远程调用接口地址

service-url:
  user-service: http://localhost:9205

 

• 在sentinel控制台给资源添加限流规则

资源名称必须与流量控制定义的资源名称一致

 

 

• 快速访问接口发现资源被限流， 设置1QPS,连续访问2次以上发现，远程服务并未被调用，直接走了限流逻辑

##按url限流

• 在sentinel控制台给资源添加限流规则

资源名称必须与流量控制定义的资源访问全路径一致

 

 

自定义限流逻辑

用blockHandlerClass = CustomBlockHandler.class指定限流逻辑

import com.alibaba.csp.sentinel.slots.block.BlockException;
​
import java.util.HashMap;
import java.util.Map;
​
public class CustomBlockHandler {
​
    public static Map<String,Object> handleException(BlockException exception) {
​
        Map<String,Object> result = new HashMap<>();
        result.put("name","自定义限流信息");
        result.put("code",200);
        return result ;
    }
​
}

熔断

• 在guo-sentinel-base编写需要熔断的资源接口

​
import com.alibaba.csp.sentinel.annotation.SentinelResource;
​
import lombok.extern.slf4j.Slf4j;
​
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
​
import java.util.HashMap;
import java.util.Map;
​
​
@Slf4j
@RestController
@RequestMapping("/breaker")
public class CircleBreakerController {
​
    private static final Logger LOGGER = LoggerFactory.getLogger(CircleBreakerController.class);
​
    @Autowired
    private RestTemplate restTemplate;
​
    @Value("${service-url.user-service}")
    private String userServiceUrl;
​
    @GetMapping("/fallback/{id}")
     @SentinelResource(value = "fallback", fallback = "handleFallback")
    public Map<String,Object> fallback(@PathVariable Long id) {
        Map<String,Object> forObject = restTemplate.getForObject(userServiceUrl + "/user/{1}", Map.class, id);
        System.out.println(forObject);
        return forObject;
    }
​
    @GetMapping("/fallbackException/{id}")
    @SentinelResource(value = "fallbackException", fallback = "handleFallback2", exceptionsToIgnore = {NullPointerException.class})
    public Map<String,Object> fallbackException(@PathVariable Long id) {
        log.info("/breaker/fallbackException");
        if (id == 1) {
            throw new IndexOutOfBoundsException();
        } else if (id == 2) {
            throw new NullPointerException();
        }
​
        return restTemplate.getForObject(userServiceUrl + "/user/{1}", Map.class, id);
    }
​
    public Map<String,Object> handleFallback(Long id) {
        Map<String,Object> result = new HashMap<>();
        result.put("name","服务熔断");
        result.put("code",200);
        return result ;
    }
​
    public Map<String,Object> handleFallback2(Long id, Throwable e) {
        LOGGER.error("handleFallback2 id:{},throwable class:{}", id, e.getClass());
        Map<String,Object> result = new HashMap<>();
        result.put("name","服务熔断");
        result.put("code",200);
​
        return result ;
    }
}
​

在feign接口上的限流与熔断

guo-sentinel-base添加feign接口相关依赖

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

guo-sentinel-base中nacos添加配置项

# 打开sentinel对feign的支持
feign:
  sentinel:
    enabled: true

在应用启动类上添加启用feign的注解@EnableFeignClients

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
​
@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class SentinelBaseApplication {
​
    public static void main(String[] args) {
        SpringApplication.run(SentinelBaseApplication.class, args);
    }
}
​

创建feign接口

controller

​
import java.util.List;
import java.util.Map;
​
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.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
​
import com.guo.sentinel.service.UserService;
​
@RestController
@RequestMapping("/user")
public class UserFeignController {
​
    @Autowired
    private UserService userService;
​
    @PostMapping("/insert")
    public Map<String,Object> insert(@RequestBody Map<String,Object> user) {
        return userService.insert(user);
    }
​
    @GetMapping("/{id}")
    public Map<String,Object> getUser(@PathVariable Long id) {
        return userService.getUser(id);
    }
​
    @GetMapping("/listUsersByIds")
    public Map<String,Object> listUsersByIds(@RequestParam List<Long> ids) {
        return userService.listUsersByIds(ids);
    }
​
    @GetMapping("/getByUsername")
    public Map<String,Object> getByUsername(@RequestParam String username) {
        return userService.getByUsername(username);
    }
​
    @PostMapping("/update")
    public Map<String,Object> update(@RequestBody Map<String,Object> user) {
        return userService.update(user);
    }
​
    @PostMapping("/delete/{id}")
    public Map<String,Object> delete(@PathVariable Long id) {
        return userService.delete(id);
    }
​
}

service

import java.util.List;
import java.util.Map;
​
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestParam;
​
import com.guo.sentinel.service.impl.UserFallbackService;
​
// 注意value = "guo-sentinel-provider"值与服务提供方的服务注册名一致
@FeignClient(value = "guo-sentinel-provider", fallback = UserFallbackService.class)
public interface UserService {
​
    @PostMapping("/user/insert")
    Map<String,Object> insert(@RequestBody Map<String,Object> user);
​
    @GetMapping("/user/{id}")
    Map<String,Object> getUser(@PathVariable(value = "id") Long id);
​
    @GetMapping("/user/listUsersByIds")
    Map<String,Object> listUsersByIds(@RequestParam(value = "ids") List<Long> ids);
​
    @GetMapping("/user/getByUsername")
    Map<String,Object> getByUsername(@RequestParam(value = "username") String username);
​
    @PostMapping("/user/update")
    Map<String,Object> update(@RequestBody Map<String,Object> user);
​
    @PostMapping("/user/delete/{id}")
    Map<String,Object> delete(@PathVariable(value = "id") Long id);
​
}

fallback熔断逻辑UserFallbackService.java

​
import java.util.HashMap;
import java.util.List;
import java.util.Map;
​
import org.springframework.stereotype.Service;
​
import com.guo.sentinel.service.UserService;
​
@Service
public class UserFallbackService implements UserService {
    
    @Override
    public Map<String, Object> insert(Map<String, Object> user) {
        return this.installFallBack();
    }
​
    @Override
    public Map<String, Object> getUser(Long id) {
        return this.installFallBack();
    }
​
    @Override
    public Map<String, Object> listUsersByIds(List<Long> ids) {
        return this.installFallBack();
    }
​
    @Override
    public Map<String, Object> getByUsername(String username) {
        return this.installFallBack();
    }
​
    @Override
    public Map<String, Object> update(Map<String, Object> user) {
        return this.installFallBack();
    }
​
    @Override
    public Map<String, Object> delete(Long id) {
        return this.installFallBack();
    }
​
    private Map<String, Object> installFallBack() {
        Map<String, Object> r = new HashMap<>();
        r.put("code", 500);
        r.put("msg", "调用失败，服务被降级");
        return r;
    }
​
}

在sentinel控制台配置熔断逻辑

 

统一限流处理

参考： https://zhuanlan.zhihu.com/p/150058613

 

使用nacos存储限流、熔断规则

默认情况下，当我们在Sentinel控制台中配置规则时，控制台推送规则方式是通过API将规则推送至客户端并直接更新到内存中。一旦我们重启应用，规则将消失。下面我们介绍下如何将配置规则进行持久化，以存储到Nacos为例。

先在guo-sentinel-base pom.xml中添加相关依赖：

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-datasource-nacos</artifactId>
</dependency>

修改bootstrap.yml添加规则配置

server:
  port: 9204
  
spring:
  application:
    name: guo-sentinel-base
  profiles:
    active: dev    
  cloud:
    sentinel:
      transport:
        # 配置Sentinel dashborad地址
        dashboard: http://localhost:8718
        port: 8719
      # 添加Nacos数据源配置
      datasource:
        - nacos:
            server-addr: localhost:8848
            # guo-sentinel-base-flow-rules.json
            data-id: ${spring.application.name}-flow-rules
            group-id: DEFAULT_GROUP
            data-type: json
            rule-type: flow
    nacos:
      discovery:
        server-addr: localhost:8848
      config:
        server-addr: localhost:8848
        file-extension: yml
        ext-config:
        # guo-sentinel-base-dev.yml
          - data-id: ${spring.application.name}-${spring.profiles.active}.${spring.cloud.nacos.config.file-extension}
            group: DEFAULT_GROUP
            refresh: true
            

在nacos中新建配置guo-sentinel-base-flow-rules.json

[
    {
        "resource": "/rateLimit/byUrl",
        "limitApp": "default",
        "grade": 1,
        "count": 1,
        "strategy": 0,
        "controlBehavior": 0,
        "clusterMode": false
    }
]

限流相关参数解释：

• resource：资源名称；

• limitApp：来源应用；

• grade：阈值类型，0表示线程数，1表示QPS；

• count：单机阈值；

• strategy：流控模式，0表示直接，1表示关联，2表示链路；

• controlBehavior：流控效果，0表示快速失败，1表示Warm Up，2表示排队等待；

• clusterMode：是否集群。

熔断相关参数解释

• resource：资源名，即规则的作用对象

• grade：熔断策略，支持慢调用比例/异常比例/异常数策略，默认为 慢调用比例

• count：慢调用比例模式下为慢调用临界 RT（超出该值计为慢调用）；异常比例/异常数模式下为对应的阈值

• timeWindow：熔断时长，单位为 s

• minRequestAmount：熔断触发的最小请求数，请求数小于该值时即使异常比率超出阈值也不会熔断（1.7.0 引入），默认为5

• statIntervalMs：统计时长（单位为 ms），如 60*1000 代表分钟级（1.8.0 引入），默认为1000ms

• slowRatioThreshold:慢调用比例阈值，仅慢调用比例模式有效（1.8.0 引入）

 

代码地址

https://gitee.com/laiba_yun/test20210702