[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。

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：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 <a href="mailto:magicianisaac@gmail.com">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

添加依赖

  <dependency>

      <groupId>com.alibaba.csp</groupId>

      <artifactId>sentinel-datasource-nacos</artifactId>

  </dependency>

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：