Sentinel 系列教程-使用Sentinel限流
前言： Sentinel 是由alibaba出品的，针对于系统负载保护的组件，其有丰富的流量防护手段和多样化的流量整型策略而被广大使用。 以下是转自Sentinel官方的介绍： 随着微服务的流行，服务和服务之间的稳定性变得越来越重要。Sentinel 是面向分布式服务架构的轻量级流量控制组件，主要以流量为切入点，从限流、流量整形、熔断降级、系统负载保护等多个维度来帮助您保障微服务的稳定性。 Sentinel-wiki Sentinel GitHub wiki 有兴趣的童鞋可以去了解。
本文以Sentinel 1.6.3 为例；
引入sentinel-core
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-core</artifactId>
<version>1.6.3</version>
</dependency>
加载规则信息
private static final String RESOURCE_NAME = "hello";
/**
* 加载限流规则
*/
public static void loadRules(){
List<FlowRule> rules = new ArrayList<FlowRule>();
FlowRule flowRule = new FlowRule();
flowRule.setResource(RESOURCE_NAME); //资源名
flowRule.setLimitApp("default");//default 代表对所有应用生效
flowRule.setGrade(RuleConstant.FLOW_GRADE_QPS); //限流阈值类型
flowRule.setCount(10); //阈值
rules.add(flowRule);
FlowRuleManager.loadRules(rules);
}
添加资源入口处理限流异常
/**
* 执行方法
* @param hello
*/
public static void hello(String hello){
Entry entry = null;
try {
entry = SphU.entry(RESOURCE_NAME);
log.info("args hello value is {}",hello);
}catch (Exception e){
if(FlowException.isBlockException(e)){
log.error("block resourceName: {}",RESOURCE_NAME);
}
}finally {
if(entry !=null){
entry.exit();
}
}
}
模拟调用测试
public static void main(String[] args) {
loadRules();
for(int i=0;i<20;i++){
hello("hello"+i);
}
}
运行记录
15:26:08.453 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello0
15:26:08.458 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello1
15:26:08.458 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello2
15:26:08.458 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello3
15:26:08.459 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello4
15:26:08.459 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello5
15:26:08.459 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello6
15:26:08.459 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello7
15:26:08.459 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello8
15:26:08.459 [main] INFO com.example.sentinel.sentineldemo.SampleFlowDemo - args hello value is hello9
15:26:08.492 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.492 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.493 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
15:26:08.494 [main] ERROR com.example.sentinel.sentineldemo.SampleFlowDemo - block resourceName: hello
