[Spring-Cloud-Alibaba] Sentinel 规则持久化（Nacos configuration）

在之前的练习中，只要应用重启，就需要重新配置，这样在我们实际的项目是非常不实用的，那么有没有办法把我们配置的规则保存下来呢？答案是YES，那么接下来，给大家来介绍如何将Sentinel规则持久化。

Document: 传送门

• File Datasource(文件存储)
  • Pull 模式
  • Push 模式
• Nacos configuration
• Apollo

File Datasource

Pull 模式

原理：
扩展写数据源（WritableDataSource）， 客户端主动向某个规则管理中心定期轮询拉取规则，这个规则中心可以是 RDBMS、文件 等
pull 模式的数据源（如本地文件、RDBMS 等）一般是可写入的。使用时需要在客户端注册数据源：将对应的读数据源注册至对应的 RuleManager，将写数据源注册至 transport 的 WritableDataSourceRegistry 中。

过程如下：

Pull Demo

• Step 1: 添加配置

      <dependency>
          <groupId>com.alibaba.cspgroupId>
          <artifactId>sentinel-datasource-extensionartifactId>
      dependency>
  

• Step 2: 编写持久化代码，实现com.alibaba.csp.sentinel.init.InitFunc

  • 代码参考自：传送门

  import com.alibaba.csp.sentinel.command.handler.ModifyParamFlowRulesCommandHandler;
  import com.alibaba.csp.sentinel.datasource.*;
  import com.alibaba.csp.sentinel.init.InitFunc;
  import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRule;
  import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRuleManager;
  import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
  import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRuleManager;
  import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
  import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
  import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowRule;
  import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowRuleManager;
  import com.alibaba.csp.sentinel.slots.system.SystemRule;
  import com.alibaba.csp.sentinel.slots.system.SystemRuleManager;
  import com.alibaba.csp.sentinel.transport.util.WritableDataSourceRegistry;
  import com.alibaba.fastjson.JSON;
  import com.alibaba.fastjson.TypeReference;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.List;
  
  /**
   * FileDataSourceInit for : 自定义Sentinel存储文件数据源加载类
   *
   * @author Isaac.Zhang | 若初
   * @since 2019/7/21
   */
  public class FileDataSourceInit implements InitFunc {
      @Override
      public void init() throws Exception {
          // TIPS: 如果你对这个路径不喜欢，可修改为你喜欢的路径
          String ruleDir = System.getProperty("user.home") + "/sentinel/rules";
          String flowRulePath = ruleDir + "/flow-rule.json";
          String degradeRulePath = ruleDir + "/degrade-rule.json";
          String systemRulePath = ruleDir + "/system-rule.json";
          String authorityRulePath = ruleDir + "/authority-rule.json";
          String hotParamFlowRulePath = ruleDir + "/param-flow-rule.json";
  
          this.mkdirIfNotExits(ruleDir);
          this.createFileIfNotExits(flowRulePath);
          this.createFileIfNotExits(degradeRulePath);
          this.createFileIfNotExits(systemRulePath);
          this.createFileIfNotExits(authorityRulePath);
          this.createFileIfNotExits(hotParamFlowRulePath);
          // 流控规则
          ReadableDataSource<String, List<FlowRule>> flowRuleRDS = new FileRefreshableDataSource<>(
                  flowRulePath,
                  flowRuleListParser
          );
          // 将可读数据源注册至FlowRuleManager
          // 这样当规则文件发生变化时，就会更新规则到内存
          FlowRuleManager.register2Property(flowRuleRDS.getProperty());
          WritableDataSource<List<FlowRule>> flowRuleWDS = new FileWritableDataSource<>(
                  flowRulePath,
                  this::encodeJson
          );
          // 将可写数据源注册至transport模块的WritableDataSourceRegistry中
          // 这样收到控制台推送的规则时，Sentinel会先更新到内存，然后将规则写入到文件中
          WritableDataSourceRegistry.registerFlowDataSource(flowRuleWDS);
  
          // 降级规则
          ReadableDataSource<String, List<DegradeRule>> degradeRuleRDS = new FileRefreshableDataSource<>(
                  degradeRulePath,
                  degradeRuleListParser
          );
          DegradeRuleManager.register2Property(degradeRuleRDS.getProperty());
          WritableDataSource<List<DegradeRule>> degradeRuleWDS = new FileWritableDataSource<>(
                  degradeRulePath,
                  this::encodeJson
          );
          WritableDataSourceRegistry.registerDegradeDataSource(degradeRuleWDS);
  
          // 系统规则
          ReadableDataSource<String, List<SystemRule>> systemRuleRDS = new FileRefreshableDataSource<>(
                  systemRulePath,
                  systemRuleListParser
          );
          SystemRuleManager.register2Property(systemRuleRDS.getProperty());
          WritableDataSource<List<SystemRule>> systemRuleWDS = new FileWritableDataSource<>(
                  systemRulePath,
                  this::encodeJson
          );
          WritableDataSourceRegistry.registerSystemDataSource(systemRuleWDS);
  
          // 授权规则
          ReadableDataSource<String, List<AuthorityRule>> authorityRuleRDS = new FileRefreshableDataSource<>(
                  flowRulePath,
                  authorityRuleListParser
          );
          AuthorityRuleManager.register2Property(authorityRuleRDS.getProperty());
          WritableDataSource<List<AuthorityRule>> authorityRuleWDS = new FileWritableDataSource<>(
                  authorityRulePath,
                  this::encodeJson
          );
          WritableDataSourceRegistry.registerAuthorityDataSource(authorityRuleWDS);
  
          // 热点参数规则
          ReadableDataSource<String, List<ParamFlowRule>> hotParamFlowRuleRDS = new FileRefreshableDataSource<>(
                  hotParamFlowRulePath,
                  hotParamFlowRuleListParser
          );
          ParamFlowRuleManager.register2Property(hotParamFlowRuleRDS.getProperty());
          WritableDataSource<List<ParamFlowRule>> paramFlowRuleWDS = new FileWritableDataSource<>(
                  hotParamFlowRulePath,
                  this::encodeJson
          );
          ModifyParamFlowRulesCommandHandler.setWritableDataSource(paramFlowRuleWDS);
      }
  
      /**
       * 流控规则对象转换
       */
      private Converter<String, List<FlowRule>> flowRuleListParser = source -> JSON.parseObject(
              source,
              new TypeReference<List<FlowRule>>() {
              }
      );
      /**
       * 降级规则对象转换
       */
      private Converter<String, List<DegradeRule>> degradeRuleListParser = source -> JSON.parseObject(
              source,
              new TypeReference<List<DegradeRule>>() {
              }
      );
      /**
       * 系统规则对象转换
       */
      private Converter<String, List<SystemRule>> systemRuleListParser = source -> JSON.parseObject(
              source,
              new TypeReference<List<SystemRule>>() {
              }
      );
  
      /**
       * 授权规则对象转换
       */
      private Converter<String, List<AuthorityRule>> authorityRuleListParser = source -> JSON.parseObject(
              source,
              new TypeReference<List<AuthorityRule>>() {
              }
      );
  
      /**
       * 热点规则对象转换
       */
      private Converter<String, List<ParamFlowRule>> hotParamFlowRuleListParser = source -> JSON.parseObject(
              source,
              new TypeReference<List<ParamFlowRule>>() {
              }
      );
  
      /**
       * 创建目录
       *
       * @param filePath
       */
      private void mkdirIfNotExits(String filePath) {
          File file = new File(filePath);
          if (!file.exists()) {
              file.mkdirs();
          }
      }
  
      /**
       * 创建文件
       *
       * @param filePath
       * @throws IOException
       */
      private void createFileIfNotExits(String filePath) throws IOException {
          File file = new File(filePath);
          if (!file.exists()) {
              file.createNewFile();
          }
      }
  
      private <T> String encodeJson(T t) {
          return JSON.toJSONString(t);
      }
  }
  

• Step 3: 启用上述代码

  resource 目录下创建 resources/META-INF/services 目录并创建文件com.alibaba.csp.sentinel.init.InitFunc ，内容为：

  com.sxzhongf.sharedcenter.configuration.sentinel.datasource.FileDataSourceInit
  

Pull 优缺点

• 优点
  1. 简单，无任何依赖
  2. 没有额外依赖
• 缺点
  1. 不保证一致性（规则是使用FileRefreshableDataSource定时更新，会有延迟）
  2. 实时性不保证（规则是使用FileRefreshableDataSource定时更新）
  3. 拉取过于频繁也可能会有性能问题
  4. 由于文件存储于本地，容易丢失
• 参考资料：
  1. ITMUCH
  2. Sentinel WIKI

Push 模式

推荐通过控制台设置规则后将规则推送到统一的规则中心，客户端实现 ReadableDataSource接口端监听规则中心实时获取变更，流程如下：

• 实现原理

  1. 控制台推送规则到Nacos/远程配置中心
  2. Sentinel client 舰艇Nacos配置变化，更新本地缓存

• shared_center service 加工

  1. 添加依赖

    <dependency>
        <groupId>com.alibaba.cspgroupId>
        <artifactId>sentinel-datasource-nacosartifactId>
    dependency>
  

  2. 添加配置

  spring:
    cloud:
      sentinel:
        datasource:
          sxzhongf_flow:
            nacos:
              server-addr: localhost:8848
              dataId: ${spring.application.name}-flow-rules
              groupId: SENTINEL_GROUP
              # 规则类型，取值见：org.springframework.cloud.alibaba.sentinel.datasource.RuleType
              rule_type: flow
          sxzhongf_degrade:
            nacos:
              server-addr: localhost:8848
              dataId: ${spring.application.name}-degrade-rules
              groupId: SENTINEL_GROUP
              rule-type: degrade
  

• Sentinel dashboard 加工

  Dashboard 规则改造主要通过2个接口：

  com.alibaba.csp.sentinel.dashboard.rule.DynamicRuleProvider & com.alibaba.csp.sentinel.dashboard.rule.DynamicRulePublisher

  • Download Sentinel Source Code

  • 修改原sentinel-dashboard项目下的POM文件

        
        <dependency>
            <groupId>com.alibaba.cspgroupId>
            <artifactId>sentinel-datasource-nacosartifactId>
            
            
        dependency>
    

  • 偷懒模式：复制sentinel-dashboard项目下test下的nacos包（

    src/test/java/com/alibaba/csp/sentinel/dashboard/rule/nacos到 src/main/java/com/alibaba/csp/sentinel/dashboard/rule下

  • 修改controller中的默认provider & publisher

    com.alibaba.csp.sentinel.dashboard.controller.v2.FlowControllerV2中

        @Autowired
        // @Qualifier("flowRuleDefaultProvider")
            @Qualifier("flowRuleNacosProvider")
        private DynamicRuleProvider<List<FlowRuleEntity>> ruleProvider;
        @Autowired
            // @Qualifier("flowRuleDefaultPublisher")
        @Qualifier("flowRuleNacosPublisher")
        private DynamicRulePublisher<List<FlowRuleEntity>> rulePublisher;
    

  • 打开 /Sentinel-1.6.2/sentinel-dashboard/src/main/webapp/resources/app/scripts/directives/sidebar/sidebar.html文件，修改代码：

    
                
                  
    
    
    ---
    
    改为
    
      <li ui-sref-active="active">
        <a ui-sref="dashboard.flow({app: entry.app})">
          <i class="glyphicon glyphicon-filter">i>  NACOS 流控规则 V1a>
      li>
    

  Dashboard中要修改的代码已经好了。

• 重新启动 Sentinel-dashboard mvn clean package -DskipTests

• 测试效果

  Sentinel 添加流控规则：

  

  Nacos 查看同步的配置：

---