[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

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

  <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);
}
}

resources/META-INF/services

com.alibaba.csp.sentinel.init.InitFunc

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

• 优点
  简单，无任何依赖
  1. 没有额外依赖
• 缺点
  不保证一致性（规则是使用

  FileRefreshableDataSource

  定时更新，会有延迟）
  1. 实时性不保证（规则是使用

     FileRefreshableDataSource

     定时更新）
  2. 拉取过于频繁也可能会有性能问题
  3. 由于文件存储于本地，容易丢失
• 参考资料：
  ITMUCH
  1. 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：

<img src="https://user-images.githubusercontent.com/9434884/45406233-645e8380-b698-11e8-8199-0c917403238f.png" width="500" />

• 实现原理

  控制台推送规则到Nacos/远程配置中心
  1. 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>

  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

src/main/java/com/alibaba/csp/sentinel/dashboard/rule

• 修改controller中的默认provider & publisher

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

@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>  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>  NACOS 流控规则 V1</a>
</li>

Dashboard中要修改的代码已经好了。

mvn clean package -DskipTests