spring cloud alibaba sentinel使用详解

/**
  *  在spring-cloud-alibaba v2.1.1.RELEASE及前，sentinel1.7.0及后，关闭URL PATH聚合需要通过该方式
  *  在spring-cloud-alibaba v2.1.1.RELEASE后，可以配置关闭：spring.cloud.sentinel.web-context-unify=false
  *  手动注入Sentinel的过滤器，关闭Sentinel注入CommonFilter实例，
  *  修改配置文件中的 spring.cloud.sentinel.filter.enabled=false
  */
@Bean
public FilterRegistrationBean sentinelFilterRegistration() {
  FilterRegistrationBean registration = new FilterRegistrationBean();
  registration.setFilter(new CommonFilter());
  registration.addUrlPatterns("/*");
  // 入口资源关闭聚合
  registration.addInitParameter(CommonFilter.WEB_CONTEXT_UNIFY, "false");
  registration.setName("sentinelFilter");
  registration.setOrder(1);
  return registration;
}

/**
 * 解析流控应用表示
 */
@Component
public class CustomRequestOriginParser implements RequestOriginParser {

  // 获取调用方标识信息并返回
  @Override
  public String parseOrigin(HttpServletRequest request) {
    String serviceName = request.getParameter("serviceName");
    StringBuffer url = request.getRequestURL();
    if (url.toString().endsWith("favicon.ico")) {
      // 浏览器会向后台请求favicon.ico图标
      return serviceName;
    }

    if (StringUtils.isEmpty(serviceName)) {
      throw new IllegalArgumentException("serviceName must not be null");
    }

    return serviceName;
  }
}

/**
 * 拉模式规则持久化	
 */
public class FileDataSourceInit implements InitFunc {
  @Override	
  public void init() throws Exception {	
    // 存放路径
    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<>(
      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>> 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) {
    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);	
  }	
}

/**
 * 自定义sentinel报错信息
 */
@Component
public class CustomBlockExceptionHandler implements BlockExceptionHandler {

  private ObjectMapper objectMapper = new ObjectMapper();

  @Override
  public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception {
    response.setContentType(MediaType.APPLICATION_JSON_VALUE);
    response.setCharacterEncoding(CharEncoding.UTF_8);
    PrintWriter writer = response.getWriter();
    // 触发限流
    if(e instanceof FlowException) {
      response.setStatus(2001);
      writer.print(objectMapper.writeValueAsString(CommentResult.failed("触发限流")));
    }
    // 授权规则不通过
    else if(e instanceof AuthorityException) {
      response.setStatus(2002);
      writer.print(objectMapper.writeValueAsString(CommentResult.failed("授权规则不通过")));
    }
    // 服务降级
    else if(e instanceof DegradeException) {
      response.setStatus(2003);
      writer.print(objectMapper.writeValueAsString(CommentResult.failed("服务降级")));
    }
    // 热点参数限流
    else if(e instanceof ParamFlowException) {
      response.setStatus(2004);
      writer.print(objectMapper.writeValueAsString(CommentResult.failed("触发热点限流")));
    }
    // 系统保护
    else if(e instanceof SystemBlockException) {
      response.setStatus(2005);
      writer.print(objectMapper.writeValueAsString(CommentResult.failed("触发系统保护规则")));
    }
    // 兜底
    else {
      response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());
      writer.print(objectMapper.writeValueAsString(CommentResult.failed("发生未知错误")));
    }
    writer.flush();
    writer.close();
  }
}