Spring Cloud Alibaba整合Sentinel

1.引入依赖

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

spring-boot-starter-actuator是微服务监控的,sentinel需要这个

2.添加yml配置，为微服务设置sentinel控制台地址
添加Sentinel后，需要暴露/actuator/sentinel端点,而Springboot默认是没有暴露该端点的，所以需要设置，测试http://localhost:8800/actuator/sentinel

server:
  port: 8800

spring:
  application:
    name: mall-user-sentinel-demo
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

    sentinel:
      transport:
        # 添加sentinel的控制台地址
        dashboard: 127.0.0.1:8080
        # 指定应用与Sentinel控制台交互的端口，应用本地会起一个该端口占用的HttpServer
        # port: 8719

#暴露actuator端点   
management:
  endpoints:
    web:
      exposure:
        include: '*'

3.在sentinel控制台中设置流控规则

• 资源名: 接口的API
• 针对来源: 默认是default，当多个微服务都调用这个资源时，可以配置微服务名来对指定的微服务设置阈值
• 阈值类型: 分为QPS和线程数 假设阈值为10
• QPS类型: 只得是每秒访问接口的次数>10就进行限流
• 线程数: 为接受请求该资源分配的线程数>10就进行限流

测试： 因为QPS是1，所以1秒内多次访问会出现如下情形：

访问http://localhost:8800/actuator/sentinel， 可以查看flowRules

微服务和Sentinel Dashboard通信原理
Sentinel控制台与微服务端之间，实现了一套服务发现机制，集成了Sentinel的微服务都会将元数据传递给Sentinel控制台，架构图如下所示：

浏览器访问: http://localhost:8719/api

[
    {
        "url": "/cnode",
        "desc": "get clusterNode metrics by id, request param: id={resourceName}"
    },
    {
        "url": "/setParamFlowRules",
        "desc": "Set parameter flow rules, while previous rules will be replaced."
    },
    {
        "url": "/origin",
        "desc": "get origin clusterNode by id, request param: id={resourceName}"
    },
    {
        "url": "/cluster/server/flowRules",
        "desc": "get cluster flow rules"
    },
    {
        "url": "/cluster/server/modifyFlowConfig",
        "desc": "modify cluster server flow config"
    },
    {
        "url": "/cluster/server/modifyTransportConfig",
        "desc": "modify cluster server transport config"
    },
    {
        "url": "/basicInfo",
        "desc": "get sentinel config info"
    },
    {
        "url": "/getClusterMode",
        "desc": "get cluster mode status"
    },
    {
        "url": "/cluster/client/modifyConfig",
        "desc": "modify cluster client config"
    },
    {
        "url": "/setClusterMode",
        "desc": "set cluster mode, accept param: mode={0|1} 0:client mode 1:server mode"
    },
    {
        "url": "/getRules",
        "desc": "get all active rules by type, request param: type={ruleType}"
    },
    {
        "url": "/api",
        "desc": "get all available command handlers"
    },
    {
        "url": "/setRules",
        "desc": "modify the rules, accept param: type={ruleType}&data={ruleJson}"
    },
    {
        "url": "/cluster/server/modifyNamespaceSet",
        "desc": "modify server namespace set"
    },
    {
        "url": "/cluster/client/fetchConfig",
        "desc": "get cluster client config"
    },
    {
        "url": "/cluster/server/paramRules",
        "desc": "get cluster server param flow rules"
    },
    {
        "url": "/tree",
        "desc": "get metrics in tree mode, use id to specify detailed tree root"
    },
    {
        "url": "/cluster/server/fetchConfig",
        "desc": "get cluster server config"
    },
    {
        "url": "/version",
        "desc": "get sentinel version"
    },
    {
        "url": "/clusterNode",
        "desc": "get all clusterNode VO, use type=notZero to ignore those nodes with totalRequest <=0"
    },
    {
        "url": "/jsonTree",
        "desc": "get tree node VO start from root node"
    },
    {
        "url": "/getParamFlowRules",
        "desc": "Get all parameter flow rules"
    },
    {
        "url": "/cluster/server/modifyParamRules",
        "desc": "modify cluster param flow rules"
    },
    {
        "url": "/metric",
        "desc": "get and aggregate metrics, accept param: startTime={startTime}&endTime={endTime}&maxLines={maxLines}&identify={resourceName}"
    },
    {
        "url": "/systemStatus",
        "desc": "get system status"
    },
    {
        "url": "/cluster/server/modifyFlowRules",
        "desc": "modify cluster flow rules"
    },
    {
        "url": "/cluster/server/metricList",
        "desc": "get cluster server metrics"
    },
    {
        "url": "/getSwitch",
        "desc": "get sentinel switch status"
    },
    {
        "url": "/setSwitch",
        "desc": "set sentinel switch, accept param: value={true|false}"
    },
    {
        "url": "/clusterNodeById",
        "desc": "get clusterNode VO by id, request param: id={resourceName}"
    },
    {
        "url": "/cluster/server/info",
        "desc": "get cluster server info"
    }
]