sentinel源码分析第二篇一sentinel-dashboard控制台启动与配置

| 工作原理|| push模式工作原理

控制台配置规则应用程序监听规则 ||| 源码分析

A 控制台

控制台配置控制台推送

apiAddFlowRulepublishRules B 客户端程序

客户端改造客户端监听与更新

更新实现 总结

应用程序启动时需配置控制台地址,使得应用程序与控制台进行交互应用程序负责向控制台注册控制台负责配置规则信息应用程序通过监听等方式拉取rule到本地,等待流量到达依据配置进行限流 || push模式工作原理 控制台配置规则

控制台模块是一个轻量级springboot模块用户通过FlowControllerV2配置规则并且推送zk等配置中心
控制台配置

按照类型修改DynamicRuleProvider和DynamicRulePublisher为zk,nacos等

@RestController
@RequestMapping(value = "/v2/flow")
public class FlowControllerV2 {

    private final Logger logger = LoggerFactory.getLogger(FlowControllerV2.class);

    @Autowired
    private InMemoryRuleRepositoryAdapter repository;

    @Autowired
    @Qualifier("flowRuleDefaultProvider")
    private DynamicRuleProvider> ruleProvider;
    @Autowired
    @Qualifier("flowRuleDefaultPublisher")
    private DynamicRulePublisher> rulePublisher;
}

持久化于内存推送zk

 @PostMapping("/rule")
 @AuthAction(value = AuthService.PrivilegeType.WRITE_RULE)
 public Result apiAddFlowRule(@RequestBody FlowRuleEntity entity) {

     Result checkResult = checkEntityInternal(entity);
     if (checkResult != null) {
         return checkResult;
     }
     entity.setId(null);
     Date date = new Date();
     entity.setGmtCreate(date);
     entity.setGmtModified(date);
     entity.setLimitApp(entity.getLimitApp().trim());
     entity.setResource(entity.getResource().trim());
     try {
         持久化于内存
         entity = repository.save(entity);
         推送zk
         publishRules(entity.getApp());
     } catch (Throwable throwable) {
         logger.error("Failed to add flow rule", throwable);
         return Result.ofThrowable(-1, throwable);
     }
     return Result.ofSuccess(entity);
 }

获取所有的规则并且推送zk

private void publishRules( String app) throws Exception {
     List rules = repository.findAllByApp(app);
     // FlowRuleApiPublisher
     // FlowRuleApolloPublisher
     // FlowRuleNacosPublisher
     // FlowRuleZookeeperPublisher
     rulePublisher.publish(app, rules);
 }

Sentinel 针对 ZooKeeper 作了相应适配，底层可以采用 ZooKeeper 作为规则配置数据源。使用时只需添加以下依赖：

    com.alibaba.csp
    sentinel-datasource-zookeeper
    x.y.z

然后创建 ZookeeperDataSource 并将其注册至对应的 RuleManager 上即可

// remoteAddress 代表 ZooKeeper 服务端的地址
// path 对应 ZK 中的数据路径
ReadableDataSource> flowRuleDataSource = new ZookeeperDataSource<>(remoteAddress, path, source -> JSON.parseObject(source, new TypeReference>() {}));
FlowRuleManager.register2Property(flowRuleDataSource.getProperty());

通过zklistener 监听规则变更全量覆盖更新规则

public class ZookeeperDataSource extends AbstractDataSource {
    ...... 删除大量代码
    private void initZookeeperListener(final String serverAddr, final List authInfos) {
        ...... 删除大量代码
       this.listener = new NodeCacheListener() {
            @Override
            public void nodeChanged() {
                zk变更
                try {
                    newValue也就是配置的rule信息 比如限流 熔断 等
                    T newValue = loadConfig();
                    RecordLog.info(String.format("[ZookeeperDataSource] New property value received for (%s, %s): %s",
                            serverAddr, path, newValue));
                    
                    更新时同时更新ruleManager的相关规则信息
                    Property对应也存在与ruleManager中
                    getProperty().updatevalue(newValue);
                } catch (Exception ex) {
                    RecordLog.warn("[ZookeeperDataSource] loadConfig exception", ex);
                }
            }
        };
    }
}

getProperty().updatevalue(newValue);更新实现

Property注册到FlowRuleManager

FlowRuleManager.register2Property(flowRuleDataSource.getProperty());

修改currentProperty规则信息为zk监听器的property

 public class FlowRuleManager {
    限流规则信息
    private static SentinelProperty> currentProperty = new DynamicSentinelProperty>();

    public static void register2Property(SentinelProperty> property) {
    AssertUtil.notNull(property, "property cannot be null");
    synchronized (LISTENER) {
        currentProperty.removeListener(LISTENER);
        property.addListener(LISTENER);
        修改currentProperty规则信息为zk监听器的property
        currentProperty = property;
    }
}   

生成环境一般采用注册中心保障规则持久化,不会因为宕机丢失本文概述push模式的实现,sentinel还有pull,内存直接推送模式