Alibaba Sentinel规则持久化-拉模式-手把手教程【基于文件】

淩亂°似流年 2023-01-17 08:44 70阅读 0赞

### 文章目录 ###

*   *   *   *   *  一、拉模式架构
                 *  二、原理简述
                 *  三、编写
                 *   *  3.1 加依赖
                     *  3.2 写代码
                     *  3.3 配置
                 *  四、优缺点分析
                 *  五、你可能会有的疑问
                 *  六、参考文档
                 *  七、案例测试
                 *   *  7.1. 添加流控规则
                     *  7.2. 服务停止
                     *  7.3. 重新启动服务
                     *  7.4. 调用接口
                     *  7.5. 查看流控规则

本文实现基于拉模式的Alibaba Sentinel规则持久化。

##### 一、拉模式架构 #####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDgxNjczOA_size_16_color_FFFFFF_t_70]

> 图片来自官方。  
> 引用自 https://github.com/alibaba/Sentinel/wiki/在生产环境中使用-Sentinel

##### 二、原理简述 #####

FileRefreshableDataSource 定时从指定文件中读取规则JSON文件【图中的本地文件】，如果发现文件发生变化，就更新规则缓存。  
FileWritableDataSource 接收控制台规则推送，并根据配置，修改规则JSON文件【图中的本地文件】。

##### 三、编写 #####

修改Spring Cloud Alibaba微服务。

###### 3.1 加依赖 ######

<dependency>
      <groupId>com.alibaba.csp</groupId>
      <artifactId>sentinel-datasource-extension</artifactId>
    </dependency>

###### 3.2 写代码 ######

package com.itmuch.contentcenter.sentinel;
    
    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;
    
    /**
     * 拉模式规则持久化
     *
     * @author itmuch.com
     */
    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 paramFlowRulePath = ruleDir + "/param-flow-rule.json";
    
            this.mkdirIfNotExits(ruleDir);
            this.createFileIfNotExits(flowRulePath);
            this.createFileIfNotExits(degradeRulePath);
            this.createFileIfNotExits(systemRulePath);
            this.createFileIfNotExits(authorityRulePath);
            this.createFileIfNotExits(paramFlowRulePath);
    
            // 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<>(
                authorityRulePath,
                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>> paramFlowRuleRDS = new FileRefreshableDataSource<>(
                paramFlowRulePath,
                paramFlowRuleListParser
            );
            ParamFlowRuleManager.register2Property(paramFlowRuleRDS.getProperty());
            WritableDataSource<List<ParamFlowRule>> paramFlowRuleWDS = new FileWritableDataSource<>(
                paramFlowRulePath,
                this::encodeJson
            );
            ModifyParamFlowRulesCommandHandler.setWritableDataSource(paramFlowRuleWDS);
        }
    
        private Converter<String, List<FlowRule>> flowRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<FlowRule>>() { 
            }
        );
        private Converter<String, List<DegradeRule>> degradeRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<DegradeRule>>() { 
            }
        );
        private Converter<String, List<SystemRule>> systemRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<SystemRule>>() { 
            }
        );
    
        private Converter<String, List<AuthorityRule>> authorityRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<AuthorityRule>>() { 
            }
        );
    
        private Converter<String, List<ParamFlowRule>> paramFlowRuleListParser = source -> JSON.parseObject(
            source,
            new TypeReference<List<ParamFlowRule>>() { 
            }
        );
    
        private void mkdirIfNotExits(String filePath) throws IOException { 
            File file = new File(filePath);
            if (!file.exists()) { 
                file.mkdirs();
            }
        }
    
        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);
        }
    }

###### 3.3 配置 ######

在项目的 `resources/META-INF/services` 目录下创建文件，名为 `com.alibaba.csp.sentinel.init.InitFunc` ，内容为：

# 改成上面FileDataSourceInit的包名类名全路径即可。
    com.itmuch.contentcenter.sentinel.FileDataSourceInit

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDgxNjczOA_size_16_color_FFFFFF_t_70 1]

##### 四、优缺点分析 #####

> 优点:  
> 简单易懂  
> 没有多余依赖（比如配置中心、缓存等）  
> 缺点:  
> 由于规则是用 FileRefreshableDataSource 定时更新的，所以规则更新会有延迟。如果FileRefreshableDataSource定时时间过大，可能长时间延迟；如果FileRefreshableDataSource过小，又会影响性能；  
> 规则存储在本地文件，如果有一天需要迁移微服务，那么需要把规则文件一起迁移，否则规则会丢失。

##### 五、你可能会有的疑问 #####

Spring Cloud Alibaba不是提供了如下配置了吗？为什么要全部自己写呢？

spring.cloud.sentinel.datasource.ds1.file.file=classpath: degraderule.json
    spring.cloud.sentinel.datasource.ds1.file.rule-type=flow
    
    #spring.cloud.sentinel.datasource.ds1.file.file=classpath: flowrule.json
    #spring.cloud.sentinel.datasource.ds1.file.data-type=custom
    #spring.cloud.sentinel.datasource.ds1.file.converter-class=com.alibaba.cloud.examples.JsonFlowRuleListConverter
    #spring.cloud.sentinel.datasource.ds1.file.rule-type=flow

关于这个问题，可以参考提的Issue[https://github.com/alibaba/spring-cloud-alibaba/issues/756)][https_github.com_alibaba_spring-cloud-alibaba_issues_756]：

##### 六、参考文档 #####

https://github.com/alibaba/Sentinel/wiki/在生产环境中使用-Sentinel#pull模式

##### 七、案例测试 #####

###### 7.1. 添加流控规则 ######

簇点链路-流控  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDgxNjczOA_size_16_color_FFFFFF_t_70 2]

###### 7.2. 服务停止 ######

停止内容中心和Sentinel控制台

###### 7.3. 重新启动服务 ######

重新启动Sentinel控制台和内容中心

###### 7.4. 调用接口 ######

> 由于Sentinel控制台采用的是懒加载策略，因此，需要请求一次接口，再刷新

http://localhost:8010/shares/1

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDgxNjczOA_size_16_color_FFFFFF_t_70 3]

###### 7.5. 查看流控规则 ######

刷新Sentinel控制台，查看流控规则  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDgxNjczOA_size_16_color_FFFFFF_t_70 4]

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[https_github.com_alibaba_spring-cloud-alibaba_issues_756]: https://github.com/alibaba/spring-cloud-alibaba/issues/756
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