首页 » 漏洞 » Zookeeper实现参数的集中式管理

Zookeeper实现参数的集中式管理

 

前言

应用项目中都会有一些参数,一般的做法通常可以选择将其存储在本地配置文件或者内存变量中;对于集群机器规模不大、配置变更不是特别频繁的情况下,这两种方式都能很好的解决;但是一旦集群机器规模变大,且配置信息越来越频繁,依靠这两种方式就越来越困难;我们希望能够快速的做到全局参数的变更,因此需要一种参数的集中式管理,下面利用Zookeeper的一些特性来实现简单的参数管理。

准备

jdk:1.7.0_80 zookeeper:3.4.3 curator:2.6.0 spring:3.1.2

Maven引入

<dependency>  <groupId>org.springframework</groupId>  <artifactId>spring-core</artifactId>  <version>3.1.2.RELEASE</version> </dependency> <dependency>  <groupId>org.springframework</groupId>  <artifactId>spring-context</artifactId>  <version>3.1.2.RELEASE</version> </dependency> <dependency>  <groupId>org.springframework</groupId>  <artifactId>spring-beans</artifactId>  <version>3.1.2.RELEASE</version> </dependency> <dependency>  <groupId>org.apache.zookeeper</groupId>  <artifactId>zookeeper</artifactId>  <version>3.4.3</version>  <exclusions>   <exclusion>    <groupId>com.sun.jmx</groupId>    <artifactId>jmxri</artifactId>   </exclusion>   <exclusion>    <groupId>com.sun.jdmk</groupId>    <artifactId>jmxtools</artifactId>   </exclusion>   <exclusion>    <groupId>javax.jms</groupId>    <artifactId>jms</artifactId>   </exclusion>  </exclusions> </dependency> <dependency>  <groupId>org.apache.curator</groupId>  <artifactId>curator-framework</artifactId>  <version>2.6.0</version> </dependency> <dependency>  <groupId>org.apache.curator</groupId>  <artifactId>curator-recipes</artifactId>  <version>2.6.0</version> </dependency>

目标

1.可以同时配置监听多个节点如/app1,/app2;

2.希望只需要配置如/app1,就能够监听其子节点如/app1/modual1以及子节点的子节点如/app1/modual1/xxx/…;

3.服务器启动能获取当前指定父节点下的所有子节点数据;

4.在添加节点或者在更新节点数据的时候能够动态通知,这样代码中就能够实时获取最新的数据;

5.spring配置中可以从Zookeeper中读取参数进行初始化。

实现

提供ZKWatcher类主要用来和Zookeeper建立连接,监听节点,初始化节点数据,更新节点数据,存储节点数据等

1.同时配置监听多个节点

提供一个字符串数组给用户用来添加需要监听的节点:

private String[] keyPatterns;

2.能够监听其子节点以及子节点的子节点

使用递归的方式用来获取指定监听节点的子节点:

private List<String> listChildren(String path) throws Exception {  List<String> pathList = new ArrayList<String>();  pathList.add(path);  List<String> list = client.getChildren().forPath(path);  if (list != null && list.size() > 0) {   for (String cPath : list) {    String temp = "";    if ("/".equals(path)) {     temp = path + cPath;    } else {     temp = path + "/" + cPath;    }    pathList.addAll(listChildren(temp));   }  }  return pathList; }

3.服务器启动初始化节点数据

上面已经递归获取了所有的节点,所有可以遍历获取所有节点数据,并且存储在Map中:

private Map<String, String> keyValueMap = new ConcurrentHashMap<String, String>();  if (pathList != null && pathList.size() > 0) {  for (String path : pathList) {   keyValueMap.put(path, readPath(path));   watcherPath(path);  } }  private String readPath(String path) throws Exception {  byte[] buffer = client.getData().forPath(path);  String value = new String(buffer);  logger.info("readPath:path = " + path + ",value = " + value);  return value; }

4.监听节点数据的变更

使用PathChildrenCache用来监听子节点的CHILD_ADDED,CHILD_UPDATED,CHILD_REMOVED事件:

private void watcherPath(String path) {   PathChildrenCache cache = null;   try {    cache = new PathChildrenCache(client, path, true);    cache.start(StartMode.POST_INITIALIZED_EVENT);    cache.getListenable().addListener(new PathChildrenCacheListener() {      @Override     public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {      switch (event.getType()) {      case CHILD_ADDED:       logger.info("CHILD_ADDED," + event.getData().getPath());       watcherPath(event.getData().getPath());       keyValueMap.put(event.getData().getPath(), new String(event.getData().getData()));       break;      case CHILD_UPDATED:       logger.info("CHILD_UPDATED," + event.getData().getPath());       keyValueMap.put(event.getData().getPath(), new String(event.getData().getData()));       break;      case CHILD_REMOVED:       logger.info("CHILD_REMOVED," + event.getData().getPath());       break;      default:       break;      }     }    });   } catch (Exception e) {    if (cache != null) {     try {      cache.close();     } catch (IOException e1) {     }    }    logger.error("watch path error", e);   }  }

5.spring配置中可以从Zookeeper中读取参数进行初始化

实现自定义的PropertyPlaceholderConfigurer类ZKPropPlaceholderConfigurer:

public class ZKPropPlaceholderConfigurer extends PropertyPlaceholderConfigurer {   private ZKWatcher zkwatcher;   @Override  protected Properties mergeProperties() throws IOException {   return loadPropFromZK(super.mergeProperties());  }   /**   * 从zk中加载配置的常量   *    * @param result   * @return   */  private Properties loadPropFromZK(Properties result) {   zkwatcher.watcherKeys();   zkwatcher.fillProperties(result);   return result;  }         ...... }

通过以上的处理,可以使用如下简单的配置来达到目标:

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"  xmlns:tx="http://www.springframework.org/schema/tx"  xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd   http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd   http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">   <bean id="zkwatcher" class="zh.maven.DynamicConf.ZKWatcher">   <property name="keyPatterns" value="/a2,/a3/m1" />  </bean>   <bean id="propertyConfigurer" class="zh.maven.DynamicConf.ZKPropPlaceholderConfigurer">   <property name="zkwatcher" ref="zkwatcher"></property>  </bean>   <bean id="person" class="zh.maven.DynamicConf.Person">   <property name="name">    <value>${/a2/m1}</value>   </property>   <property name="address">    <value>${/a3/m1/v2}</value>   </property>   <property name="company">    <value>${/a3/m1/v2/t2}</value>   </property>  </bean> </beans>

详细代码svn地址: http://code.taobao.org/svn/temp-pj/DynamicConf

测试

1.首先启动Zookeeper

zkServer.cmd

2.初始化需要使用的节点

public class Create_Node {   static String path = "/a3/m1/v2/t2";  static CuratorFramework client = CuratorFrameworkFactory.builder()    .connectString("127.0.0.1:2181").sessionTimeoutMs(5000)    .retryPolicy(new ExponentialBackoffRetry(1000, 3)).build();   public static void main(String[] args) throws Exception {   client.start();   client.create().creatingParentsIfNeeded()     .withMode(CreateMode.PERSISTENT)     .forPath(path, "init".getBytes());  } }

创建需要的节点方便ZKWatcher来监听,这里根据以上的配置,分别初始化/a3/m1/v2/t2和/a2/m1/v1/t1

3.启动Main,分别验证配置文件中的初始化以及代码动态获取参数

public class Main {   public static void main(String[] args) throws Exception {   ApplicationContext context = new ClassPathXmlApplicationContext(new String[] { "spring-config.xml" });   Person person = (Person) context.getBean("person");   System.out.println(person.toString());    ZKWatcher zkwatcher = (ZKWatcher) context.getBean("zkwatcher");   while (true) {    Person p = new Person(zkwatcher.getKeyValue("/a2/m1"), zkwatcher.getKeyValue("/a3/m1/v2"),      zkwatcher.getKeyValue("/a3/m1/v2/t2"));    System.out.println(p.toString());     Thread.sleep(1000);   }  } }

4.观察日志同时更新参数:

public class Set_Data {   static String path = "/a3/m1/v2/t2";  static CuratorFramework client = CuratorFrameworkFactory.builder().connectString("127.0.0.1:2181")    .sessionTimeoutMs(5000).retryPolicy(new ExponentialBackoffRetry(1000, 3)).build();   public static void main(String[] args) throws Exception {   client.start();   Stat stat = new Stat();   System.out.println(stat.getVersion());   System.out.println("Success set node for :" + path + ",new version:"     + client.setData().forPath(path, "codingo_v2".getBytes()).getVersion());  } }

部分日志如下:

2017-08-05 18:04:57 - watcher path : [/a2, /a2/m1, /a2/m1/v1, /a2/m1/v1/t2, /a3/m1, /a3/m1/v2, /a3/m1/v2/t2] 2017-08-05 18:04:57 - readPath:path = /a2,value =  2017-08-05 18:04:57 - readPath:path = /a2/m1,value = zhaohui 2017-08-05 18:04:57 - readPath:path = /a2/m1/v1,value =  2017-08-05 18:04:57 - readPath:path = /a2/m1/v1/t2,value = init 2017-08-05 18:04:57 - readPath:path = /a3/m1,value =  2017-08-05 18:04:57 - readPath:path = /a3/m1/v2,value = nanjing 2017-08-05 18:04:57 - readPath:path = /a3/m1/v2/t2,value = codingo_v10 2017-08-05 18:04:57 - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@182f4aea: defining beans [zkwatcher,propertyConfigurer,person]; root of factory hierarchy name = zhaohui,address = nanjing,company = codingo_v10 name = zhaohui,address = nanjing,company = codingo_v10 2017-08-05 18:04:57 - CHILD_ADDED,/a2/m1 2017-08-05 18:04:57 - CHILD_ADDED,/a3/m1/v2 2017-08-05 18:04:57 - CHILD_ADDED,/a2/m1/v1 2017-08-05 18:04:57 - CHILD_ADDED,/a2/m1/v1/t2 2017-08-05 18:04:57 - CHILD_ADDED,/a3/m1/v2/t2 name = zhaohui,address = nanjing,company = codingo_v10 name = zhaohui,address = nanjing,company = codingo_v10 name = zhaohui,address = nanjing,company = codingo_v10 2017-08-05 18:05:04 - CHILD_UPDATED,/a3/m1/v2/t2 name = zhaohui,address = nanjing,company = codingo_v11 name = zhaohui,address = nanjing,company = codingo_v11

总结

通过Zookeeper实现了一个简单的参数化平台,当然想在生产中使用还有很多需要优化的地方,本文在于提供一个思路;当然除了Zookeeper还可以使用MQ,分布式缓存等来实现参数化平台。

原文链接:Zookeeper实现参数的集中式管理,转载请注明来源!

0