SpringCloud Alibaba Sentinel 使用

sentinel 是面向分布式微服务架构的流量控制组件，主要以流量为切入点，从流量控制、熔断降级、系统自适应保护等多个维度保障微服务的稳定性。

使用sentinel限流

pom配置

<dependencies>
        <!-- 创建工程需要的两个依赖 -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!-- Sentinel 适配了 Feign, 可以实现服务间调用的保护 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!-- Sentinel 使用 Nacos 存储规则 -->
        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-datasource-nacos</artifactId>
        </dependency>
        <!-- web 工程 -->
        <dependency>
            <groupId>com.imooc.ecommerce</groupId>
            <artifactId>e-commerce-mvc-config</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

yml配置

  sentinel:
      # 配置 sentinel dashboard 地址
      transport:
        dashboard: 127.0.0.1:7777
        port: 8719 # 会在应用对应的机器上启动一个 Http Server, 该 Server 会与 Sentinel 控制台做交互

流控规则硬编码

public class FlowRuleCodeController {

    /**
     * <h2>初始化流控规则</h2>
     * */
    @PostConstruct
    public void init() {

        // 流控规则集合
        List<FlowRule> flowRules = new ArrayList<>();
        // 创建流控规则
        FlowRule flowRule = new FlowRule();
        // 设置流控规则 QPS, 限流阈值类型 (QPS, 并发线程数)
        flowRule.setGrade(RuleConstant.FLOW_GRADE_QPS);
        // 流量控制手段
        flowRule.setControlBehavior(RuleConstant.CONTROL_BEHAVIOR_DEFAULT);
        // 设置受保护的资源
        flowRule.setResource("flowRuleCode");
        // 设置受保护的资源的阈值
        flowRule.setCount(1);
        flowRules.add(flowRule);

        // 加载配置好的规则
        FlowRuleManager.loadRules(flowRules);
    }

    /**
     * <h2>采用硬编码限流规则的 Controller 方法</h2>
     * */
    @GetMapping("/flow-rule")
//    @SentinelResource(value = "flowRuleCode")
//    @SentinelResource(value = "flowRuleCode", blockHandler = "handleException")
    @SentinelResource(
            value = "flowRuleCode", blockHandler = "qinyiHandleBlockException",
            blockHandlerClass = QinyiBlockHandler.class
    )
    public CommonResponse<String> flowRuleCode() {
        log.info("request flowRuleCode");
        return new CommonResponse<>(0, "", "imooc-qinyi-ecommerce");
    }

    /**
     * <h2>当限流异常抛出时, 指定调用的方法</h2>
     * 是一个兜底策略
     * */
    public CommonResponse<String> handleException(BlockException exception) {
        log.error("has block exception: [{}]", JSON.toJSONString(exception.getRule()));
        return new CommonResponse<>(
                -1,
                "flow rule exception",
                exception.getClass().getCanonicalName()
        );
    }
}