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：
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="http://www.likecs.com/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