Sentinel dashboard的使用；Nacos保存Sentinel限流规则

Sentinel dashboard的使用

往期文章

1. Nacos环境搭建
2. Nacos注册中心的使用
3. Nacos配置中心的使用
4. Sentinel 容灾中心的使用

参考文档

Sentinel · alibaba/spring-cloud-alibaba Wiki · GitHub

限流结果

下载sentinel-dashboard

github地址：Sentinel/sentinel-dashboard at master · alibaba/Sentinel · GitHub

启动脚本

创建sentinel-dashboard的启动脚本，并添加如下信息：

java -jar -Dserver.port=8350 -Dcsp.sentinel.dashboard.server=localhost:8350 -Dproject.name=sentinel-dashboard --add-exports=java.base/sun.net.util=ALL-UNNAMED sentinel-dashboard-1.8.4.jar

目录：

Jar（客户端）

<!-- 一定要放在前面 -->
<!--Sentinel -->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<!-- sentinel-dashboard -->
<dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-transport-simple-http</artifactId>
</dependency>
<!--Spring Cloud Alibaba Nacos Discovery-->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--Spring Cloud Alibaba Nacos Config-->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>
<!--LoadBalancer-->
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

yml

注意：sentinel-dashboard默认会在8720端口接收注册服务的数据，所以dashboard使用的端口和接收数据的端口不要一样。

消费者

server:port: 8581
spring:application:name: nacos-consumercloud:nacos:config:group: DEFAULT_GROUPserver-addr: localhost:8848sentinel:transport:port: 8720dashboard: localhost:8350eager: trueconfig:import:# 父类配置要放在前面，相同的项会被后面的配置覆盖- optional:nacos:nacos-discovery.yaml
management:endpoints:web:exposure:include: '*'

nacos-discovery.yml

spring:cloud:nacos:discovery:server-addr: localhost:8848username: devilvanpassword: 741258963hjklfailure-tolerance-enabled: true

Sentinel Dashboard的使用

1. 关闭服务端硬编码的限流规则

服务端的代码参考：Sentinel 容灾中心的使用

2. 在dashboard中设置限流规则（不推荐）

不推荐的原因，客户端、服务端重启后规则不会保存

3. 限流效果：

Nacos配置并保存Sentinel限流规则

步骤

1. 引入sentinel和sentinel dashboard相关依赖
2. 服务端给对应controller添加@SentinelResource注解，并定义一个限流/熔断处理类负责处理该resource的限流/熔断逻辑（注：方法必须有static修饰）。
3. Nacos配置中心保存sentinel resource的配置信息，即限流规则

Jar（服务端）

<!-- 一定要放在前面 -->
<!--Sentinel -->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<!-- SpringCloud Alibaba CircuitBreaker Sentinel-->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-circuitbreaker-sentinel</artifactId>
</dependency>
<!-- sentinel-dashboard -->
<dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-transport-simple-http</artifactId>
</dependency>
<dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-datasource-nacos</artifactId><version>${sentinel-version}</version>
</dependency>
<dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-spring-webmvc-adapter</artifactId><version>${sentinel-version}</version>
</dependency>
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<!--Spring Cloud Alibaba Nacos Discovery-->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--Spring Cloud Alibaba Nacos Config-->
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>

yml（服务端）

server:port: 8481
spring:application:name: nacos-providercloud:nacos:config:group: DEFAULT_GROUPserver-addr: localhost:8848discovery:server-addr: localhost:8848username: devilvanpassword: 741258963hjklsentinel:transport:port: 8720dashboard: localhost:8350eager: truedatasource:echo:nacos:server-add: ${spring.cloud.nacos.config.server-addr}groupId: ${spring.cloud.nacos.config.group}dataId: ${spring.application.name}-rulesrule-type: flowdata-type: jsonconfig:import:# 父类配置要放在前面，相同的项会被后面的配置覆盖- optional:nacos:nacos-discovery.yaml
management:endpoints:web:exposure:include: '*'

Nacos配置并保存Sentinel限流规则

1. Nacos配置中心添加配置文件

注：建议单独起resource的名字，不要将路由信息当做resource

[{"resource": "echo","limitApp": "default","grade": 1,"count": 1,"strategy": 0,"controlBehavior": 0,"clusterMode": false},{"resource": "echo2","limitApp": "default","grade": 1,"count": 1,"strategy": 0,"controlBehavior": 0,"clusterMode": false}
]

2. 服务端后台代码

注意：echo2()方法是通过代码层面的try catch来进行限流/熔断的，在nacos配置中定义的echo2的resource不能在该处添加@SentinelResource注解

/*** @Description Nacos生产者 控制层*/
@RestController
@RequestMapping(value = "nacosProviderController")
public class NacosProviderController {@Resource(name = "nacosProviderServiceImpl")private NacosProviderService nacosProviderService;@GetMapping(value = "/echo/{str}")@SentinelResource(value = "echo", fallback = "echoFallback", fallbackClass = EchoFallback.class,blockHandler = "echoBlockHandler", blockHandlerClass = EchoFallback.class)public ResultMessage<String> echo(@PathVariable String str) {return nacosProviderService.echo(str);}@GetMapping(value = "/echo2/{str}")public ResultMessage<String> echo2(@PathVariable String str) {return nacosProviderService.echo2(str);}
}

3. 限流/熔断处理类

注意：该类中的限流/熔断方法必须static修饰

/*** @Description echo方法 异常回调类*/
public class EchoFallback {/*** 遇到异常走的逻辑** @param str 原方法的参数* @param e   异常信息* @return 异常回调方法返回值，和原方法返回值一致*/public static ResultMessage<String> echoFallback(String str, Throwable e) {ResultMessage<String> resultMessage = new ResultMessage<>();String message = "熔断-echo方法调用异常，str: " + str + "\n" + e;resultMessage.setMessage(message);return resultMessage;}/*** 方法限流逻辑** @param str 原方法的参数* @param e   异常信息* @return 限流回调方法返回值，和原方法返回值一致*/public static ResultMessage<String> echoBlockHandler(String str, BlockException e) {ResultMessage<String> resultMessage = new ResultMessage<>();String message = "限流-echo方法进行 限流，str: " + str + "\n" + e;resultMessage.setMessage(message);return resultMessage;}
}

4. 生产者业务逻辑代码

注：echo2()方法中使用的是sentinel的api实现限流，高亮的部分需要指定配置文件中已存在，或在代码中定义限流规则的resource，即"echo2"资源需要对应上方Nacos配置文件中的resource。

/*** @Description Nacos生产者 业务逻辑实现类*/
@Service
public class NacosProviderServiceImpl implements NacosProviderService {/*** 测试限流/熔断的方法** @param str 原方法的参数* @return 回调*/@Overridepublic ResultMessage<String> echo(String str) {ResultMessage<String> resultMessage = new ResultMessage<>();if ("devilvan".equals(str)) {String msg = "Hello Nacos Discovery " + str;resultMessage.setMessage(msg);} else {throw new RuntimeException();}return resultMessage;}/*** 测试sentinel设置资源并使用的方法** @param str 入参字符串* @return 回调*/@Overridepublic ResultMessage<String> echo2(String str) {String resource = "echo2";ResultMessage<String> resultMessage = new ResultMessage<>();Entry entry = null;try {entry = SphU.entry(resource);if ("devilvan".equals(str)) {String msg = "Hello Nacos Discovery " + str;resultMessage.setMessage(msg);} else {throw new RuntimeException();}} catch (BlockException e) {String msg = "限流-echo2方法调用异常，str: " + str + "\n" + e;resultMessage.setMessage(msg);} catch (Exception e) {String msg = "熔断-echo2方法调用异常，str: " + str + "\n" + e;resultMessage.setMessage(msg);} finally {if (entry != null) {entry.exit();}}return resultMessage;}
}