Sentinel生产环境实践

来自杨三超wiki

1、功能描述

API 限流

sentinel默认会探测所有API，但需要注意，Sentinel 会在客户端首次调用时候进行初始化，开始向控制台发送心跳包。因此需要确保客户端有访问量，才能在控制台上看到监控数据。

RPC限流粒度

可以是服务接口和服务方法两种粒度：

• 服务接口：resourceName 为 接口全限定名，如 com.alibaba.csp.sentinel.demo.dubbo.FooService
• 服务方法：resourceName 为 接口全限定名:方法签名，如 com.alibaba.csp.sentinel.demo.dubbo.FooService:sayHello(java.lang.String)

存在问题

1、规则持久化

支持基于 ZooKeeper / Nacos / Apollo 的数据源规则持久化，但需要改造；

2、统一异常处理；

需要自己改造；

3、监控数据持久化；

需要自己改造；

2、Dashboard改造部署

1、修改路由规则

第一步：修改dashboad.flowV1为dashboad.flow；

第二步：FlowServiceV1修改为FlowServiceV2；

2、支持规则持久化

sentinel支持限流、降级、热点、系统、授权五种规则，目前常用的功能是限流和降级、基于zookeeper实现持久化规则；

dashboad默认规则都是内存，同时需要修改对应的Controller；

 

3、监控日志持久化    

默认监控日志仅在内容保留5分钟

 

4、部署

• 编译jar包：https://github.com/alibaba/Sentinel/releases
• 启动：java -Dserver.port=8100 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard-1.6.2.jar 

  • -Dserver.port=8080 用于指定 Sentinel 控制台端口为 8100。

• 扩展阅读 Sentinel 控制台： https://github.com/alibaba/Sentinel/wiki/%E6%8E%A7%E5%88%B6%E5%8F%B0

3、服务如何使用

1、添加相关pom

1.1 springboot2.x添加pom

<dependency>     <groupId>com.alibaba.cloudgroupId>     <artifactId>spring-cloud-starter-alibaba-sentinelartifactId>     <version>2.1.0.RELEASEversion>     <exclusions>         <exclusion>             <artifactId>sentinel-coreartifactId>             <groupId>com.alibaba.cspgroupId>         exclusion>         <exclusion>             <artifactId>fastjsonartifactId>             <groupId>com.alibabagroupId>         exclusion>     exclusions> dependency>   <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-datasource-zookeeperartifactId>     <version>1.6.3version>     <exclusions>         <exclusion>             <artifactId>sentinel-datasource-extensionartifactId>             <groupId>com.alibaba.cspgroupId>         exclusion>         <exclusion>             <artifactId>zookeeperartifactId>             <groupId>org.apache.zookeepergroupId>         exclusion>     exclusions> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-dubbo-adapterartifactId>     <version>1.6.3version> dependency>   <dependency>     <groupId>org.apache.curatorgroupId>     <artifactId>curator-frameworkartifactId>     <version>2.11.0version> dependency> <dependency>     <groupId>org.apache.curatorgroupId>     <artifactId>curator-clientartifactId>     <version>2.11.0version> dependency> <dependency>     <groupId>org.apache.curatorgroupId>     <artifactId>curator-recipesartifactId>     <version>2.11.0version> dependency>

 

1.2 springboot1.5.x添加pom

 折叠源码

<dependency>     <groupId>com.alibaba.cloudgroupId>     <artifactId>spring-cloud-starter-alibaba-sentinelartifactId>     <version>1.5.1.RELEASEversion> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-cluster-client-defaultartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-cluster-common-defaultartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-cluster-server-defaultartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-datasource-extensionartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-parameter-flow-controlartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-transport-commonartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-transport-simple-httpartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-web-servletartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-coreartifactId>     <version>1.5.1version> dependency> <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-annotation-aspectjartifactId>     <version>1.5.1version> dependency>   <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-datasource-zookeeperartifactId>     <version>1.5.1version>     <exclusions>         <exclusion>             <artifactId>zookeeperartifactId>             <groupId>org.apache.zookeepergroupId>         exclusion>     exclusions> dependency>   <dependency>     <groupId>com.alibaba.cspgroupId>     <artifactId>sentinel-dubbo-adapterartifactId>     <version>1.5.1version> dependency>

 

2、添加配置

添加配置： cloud:   sentinel:     transport:       port: 8731       dashboard: http://127.0.0.1:9001     datasource:       ds:         zk:           path: /           serverAddr: zookeeper:2181           groupId: SENTINEL_GROUP           dataId: ${spring.application.name}-flow-rules           ruleType: FLOW       ds1:         zk:           path: /           serverAddr: zookeeper:2181           groupId: SENTINEL_GROUP           dataId: ${spring.application.name}-degrade-rules           ruleType: DEGRADE

3、添加统一异常

API统一异常

@Configuration public class MyFallbackAPIConfig {     /**      * URL block handler.      */     private static volatile UrlBlockHandler urlBlockHandler = new DefaultUrlBlockHandler();       static {         WebCallbackManager.setUrlBlockHandler(urlBlockHandler);     }       public static class DefaultUrlBlockHandler implements UrlBlockHandler {           private static void writeDefaultBlockedPage(HttpServletResponse response) throws IOException {             response.setCharacterEncoding("UTF-8");             response.setHeader("Content-Type", "application/json; charset=utf-8");               Map responseObject = new HashMap<>(3);             responseObject.put("code",10001);             responseObject.put("message","系统繁忙，请稍后再试！");             responseObject.put("body",new Object());             JSONObject responseJSONObject = (JSONObject)JSONObject.toJSON(responseObject);               PrintWriter out = response.getWriter();             out.write(responseJSONObject.toString());             out.flush();             out.close();         }           @Override         public void blocked(HttpServletRequest request, HttpServletResponse response, BlockException ex)                 throws IOException {             // Directly redirect to the default flow control (blocked) page or customized block page.             blockRequest(request, response);         }           public static void blockRequest(HttpServletRequest request, HttpServletResponse response) throws IOException {             StringBuffer url = request.getRequestURL();               if ("GET".equals(request.getMethod()) && StringUtil.isNotBlank(request.getQueryString())) {                 url.append("?").append(request.getQueryString());             }               if (StringUtil.isBlank(WebServletConfig.getBlockPage())) {                 writeDefaultBlockedPage(response);             } else {                 String redirectUrl = WebServletConfig.getBlockPage() + "?http_referer=" + url.toString();                 // Redirect to the customized block page.                 response.sendRedirect(redirectUrl);             }         }     } }

 

dubbo统一异常

@Component public class MyFallbackDubboConfig  {     /**      * URL block handler.      */     private static volatile DefaultDubboBlockHandler dubboFallback = new DefaultDubboBlockHandler();       static {         DubboFallbackRegistry.setConsumerFallback(dubboFallback);     }       public static class DefaultDubboBlockHandler implements DubboFallback {           @Override         public Result handle(Invoker invoker, Invocation invocation, BlockException e) {             return new RpcResult(null);         }     }   }