[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

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.csp</groupid>
          <artifactid>sentinel-datasource-extension</artifactid>
      </dependency>

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

  • 代码参考自：

  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 <a href="mailto:[e-mail]">isaac.zhang | 若初</a>
   * @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.csp</groupid>
        <artifactid>sentinel-datasource-nacos</artifactid>
    </dependency>

  1. 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

        <!-- for nacos rule publisher sample -->
        <dependency>
            <groupid>com.alibaba.csp</groupid>
            <artifactid>sentinel-datasource-nacos</artifactid>
            <!--注释掉原文件中的scope，让其不仅在test的时候生效-->
            <!--<scope>test</scope>-->
        </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：

    <!--<li ui-sref-active="active">-->
                <!--<a ui-sref="dashboard.flow({app: entry.app})">-->
                  <!--<i class="glyphicon glyphicon-filter"></i>&nbsp;&nbsp;流控规则 v1</a>-->
    <!--</li>-->
    
    ---
    
    改为
    
      <li ui-sref-active="active">
        <a ui-sref="dashboard.flow({app: entry.app})">
          <i class="glyphicon glyphicon-filter"></i>&nbsp;&nbsp;nacos 流控规则 v1</a>
      </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：

  

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