[Spring-Cloud-Alibaba] Sentinel 规则持久化

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

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：

• Step 1: 添加配置

          com.alibaba.csp      sentinel-datasource-extension  

• 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> 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> 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> degradeRuleRDS = new FileRefreshableDataSource<>(              degradeRulePath,              degradeRuleListParser      );      DegradeRuleManager.register2Property(degradeRuleRDS.getProperty());      WritableDataSource> degradeRuleWDS = new FileWritableDataSource<>(              degradeRulePath,              this::encodeJson      );      WritableDataSourceRegistry.registerDegradeDataSource(degradeRuleWDS);      // 系统规则      ReadableDataSource> systemRuleRDS = new FileRefreshableDataSource<>(              systemRulePath,              systemRuleListParser      );      SystemRuleManager.register2Property(systemRuleRDS.getProperty());      WritableDataSource> systemRuleWDS = new FileWritableDataSource<>(              systemRulePath,              this::encodeJson      );      WritableDataSourceRegistry.registerSystemDataSource(systemRuleWDS);      // 授权规则      ReadableDataSource> authorityRuleRDS = new FileRefreshableDataSource<>(              flowRulePath,              authorityRuleListParser      );      AuthorityRuleManager.register2Property(authorityRuleRDS.getProperty());      WritableDataSource> authorityRuleWDS = new FileWritableDataSource<>(              authorityRulePath,              this::encodeJson      );      WritableDataSourceRegistry.registerAuthorityDataSource(authorityRuleWDS);      // 热点参数规则      ReadableDataSource> hotParamFlowRuleRDS = new FileRefreshableDataSource<>(              hotParamFlowRulePath,              hotParamFlowRuleListParser      );      ParamFlowRuleManager.register2Property(hotParamFlowRuleRDS.getProperty());      WritableDataSource> paramFlowRuleWDS = new FileWritableDataSource<>(              hotParamFlowRulePath,              this::encodeJson      );      ModifyParamFlowRulesCommandHandler.setWritableDataSource(paramFlowRuleWDS);  }  /**   * 流控规则对象转换   */  private Converter> flowRuleListParser = source -> JSON.parseObject(          source,          new TypeReference>() {          }  );  /**   * 降级规则对象转换   */  private Converter> degradeRuleListParser = source -> JSON.parseObject(          source,          new TypeReference>() {          }  );  /**   * 系统规则对象转换   */  private Converter> systemRuleListParser = source -> JSON.parseObject(          source,          new TypeReference>() {          }  );  /**   * 授权规则对象转换   */  private Converter> authorityRuleListParser = source -> JSON.parseObject(          source,          new TypeReference>() {          }  );  /**   * 热点规则对象转换   */  private Converter> hotParamFlowRuleListParser = source -> JSON.parseObject(          source,          new TypeReference>() {          }  );  /**   * 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  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

• 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

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

          com.alibaba.csp      sentinel-datasource-nacos  

  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

                  com.alibaba.csp        sentinel-datasource-nacos                    

  • 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> ruleProvider;    @Autowired        // @Qualifier("flowRuleDefaultPublisher")    @Qualifier("flowRuleNacosPublisher")    private DynamicRulePublisher> 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  
              NACOS 流控规则 V1  

  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：