一、简介
前面几篇，我们对http长轮询数据同步方式进行了分析，这一讲，开始分析soul使用zookeeper的方式进行数据同步是如何实现的。
二、运行例子
1、修改soul-admin配置文件application.yml，打开zookeeper数据同步开关，如下：
soul:
sync:
zookeeper:
url: localhost:2181
sessionTimeout: 5000
connectionTimeout: 2000
2、修改soul-bootstrap配置文件pom.xml，加上如下配置：
<!--soul data sync start use zookeeper-->
<dependency>
<groupId>org.dromara</groupId>
<artifactId>soul-spring-boot-starter-sync-data-zookeeper</artifactId>
<version>${project.version}</version>
</dependency>
application-local.yml,打开zookeeper数据同步开关，如下：
soul :
sync:
zookeeper:
url: localhost:2181
sessionTimeout: 5000
connectionTimeout: 2000
3、启动zookeeper 运行本地目录:D:\Software\apache-zookeeper-3.6.2-bin\bin下的zkServer.cmd
4、soul-admin 网关后台服务启动，服务启动后可以看到发起的ZooKeeper请求调用
2021-01-30 01:22:33.510 INFO 3076 --- [-localhost:2181] org.I0Itec.zkclient.ZkEventThread : Starting ZkClient event thread.
2021-01-30 01:22:42.593 INFO 3076 --- [ main] org.apache.zookeeper.ClientCnxn : zookeeper.request.timeout value is 0. feature enabled=
2021-01-30 01:22:42.593 INFO 3076 --- [ main] org.I0Itec.zkclient.ZkClient : Waiting for keeper state SyncConnected
2021-01-30 01:22:42.601 INFO 3076 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error)
2021-01-30 01:22:42.603 INFO 3076 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Socket connection established, initiating session, client: /0:0:0:0:0:0:0:1:52208, server: localhost/0:0:0:0:0:0:0:1:2181
2021-01-30 01:22:42.641 INFO 3076 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Session establishment complete on server localhost/0:0:0:0:0:0:0:1:2181, sessionid = 0x100001059be0001, negotiated timeout = 5000
2021-01-30 01:22:42.644 INFO 3076 --- [ain-EventThread] org.I0Itec.zkclient.ZkClient : zookeeper state changed (SyncConnected)
5、soul-bootstrap 网关服务启动，服务启动后可以看到发起的ZooKeeper请求调用
2021-01-30 01:33:31.070 INFO 15332 --- [ main] s.b.s.d.z.ZookeeperSyncDataConfiguration : you use zookeeper sync soul data.......
2021-01-30 01:33:31.082 INFO 15332 --- [-localhost:2181] org.I0Itec.zkclient.ZkEventThread : Starting ZkClient event thread.
2021-01-30 01:33:40.148 INFO 15332 --- [ main] org.apache.zookeeper.ClientCnxn : zookeeper.request.timeout value is 0. feature enabled=
2021-01-30 01:33:40.148 INFO 15332 --- [ main] org.I0Itec.zkclient.ZkClient : Waiting for keeper state SyncConnected
2021-01-30 01:33:40.156 INFO 15332 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2021-01-30 01:33:40.158 INFO 15332 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Socket connection established, initiating session, client: /127.0.0.1:52634, server: localhost/127.0.0.1:2181
2021-01-30 01:33:40.199 INFO 15332 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x100001059be0002, negotiated timeout = 5000
2021-01-30 01:33:40.206 INFO 15332 --- [ain-EventThread] org.I0Itec.zkclient.ZkClient : zookeeper state changed (SyncConnected)
6、启动zookeeper客户端ZooInspector查看 zookeeper 上的soul网关同步的注册信息，如下图：
三、源码分析
在 soul-admin 启动后在控制台中看到了 org.I0Itec.zkclient.ZkClient，以此为入口进行跟踪调试。
1、ZookeeperConfiguration 作用：注册 zkClient 到Spring容器，如下：
// EnableConfigurationProperties 作用：使用 @ConfigurationProperties 注解的类生效。如果一个配置类只配置@ConfigurationProperties注解，而没有使用@Component，那么在IOC容器中是获取不到properties 配置文件转化的bean。@EnableConfigurationProperties 相当于把使用@ConfigurationProperties 的类进行了一次注入。
// @ConditionalOnMissingBean 容器中没有指定的类，就进行注入，@ConditionalOnBean与之相反
/**
* ZookeeperConfiguration .
* @author xiaoyu(Myth)
*/
@EnableConfigurationProperties(ZookeeperProperties.class)
public class ZookeeperConfiguration {
/**
* register zkClient in spring ioc.
*
* @param zookeeperProp the zookeeper configuration
* @return ZkClient {@linkplain ZkClient}
*/
@Bean
@ConditionalOnMissingBean(ZkClient.class)
public ZkClient zkClient(final ZookeeperProperties zookeeperProp) {
return new ZkClient(zookeeperProp.getUrl(), zookeeperProp.getSessionTimeout(), zookeeperProp.getConnectionTimeout());
}
}
soul-admin 启动后，会实读取 zookeeper 配置信息，向容器中注入 zkClient 和 zookeeper建立连接。
2、实例化 ZkClient 的调用栈中会调用 DataChangedEventDispatcher 的 afterPropertiesSet 方法。
- org.dromara.soul.admin.listener.DataChangedEventDispatcher：事件转发器，将更改的事件转发到每个ConfigEventListener，此类实现了 InitializingBean，在DataChangedEventDispatcher初始化过程中，会执行afterPropertiesSet方法;
- afterPropertiesSet 方法会在容器中查找类型是 DataChangedListener.class 的bean，如下所示：
@Component
public class DataChangedEventDispatcher implements ApplicationListener<DataChangedEvent>, InitializingBean {
private ApplicationContext applicationContext;
private List<DataChangedListener> listeners;
public DataChangedEventDispatcher(final ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
}
@Override
@SuppressWarnings("unchecked")
public void onApplicationEvent(final DataChangedEvent event) {
for (DataChangedListener listener : listeners) {
switch (event.getGroupKey()) {
case APP_AUTH:
listener.onAppAuthChanged((List<AppAuthData>) event.getSource(), event.getEventType());
break;
.......
default:
throw new IllegalStateException("Unexpected value: " + event.getGroupKey());
}
}
......
@Override
public void afterPropertiesSet() {
Collection<DataChangedListener> listenerBeans = applicationContext.getBeansOfType(DataChangedListener.class).values();
this.listeners = Collections.unmodifiableList(new ArrayList<>(listenerBeans));
}
}
3、afterPropertiesSet 方法的执行会查找 DataChangedListener.class 相关类的实例化。
-
org.dromara.soul.admin.config.DataSyncConfiguration：数据同步配置类。
-
ZookeeperDataChangedListener：数据变化监听器，监听元数据变化，然后同步到zookeeper。
-
ZookeeperDataInit：向zookeeper同步初始化数据。
/**
* The type Zookeeper listener.
*/
@Configuration
@ConditionalOnProperty(prefix = "soul.sync.zookeeper", name = "url")
@Import(ZookeeperConfiguration.class)
static class ZookeeperListener {
/**
* Config event listener data changed listener.
* @param zkClient the zk client
* @return the data changed listener
*/
@Bean
@ConditionalOnMissingBean(ZookeeperDataChangedListener.class)
public DataChangedListener zookeeperDataChangedListener(final ZkClient zkClient) {
return new ZookeeperDataChangedListener(zkClient);
}
/**
* Zookeeper data init zookeeper data init
* @param zkClient the zk client
* @param syncDataService the sync data service
* @return the zookeeper data init
*/
@Bean
@ConditionalOnMissingBean(ZookeeperDataInit.class)
public ZookeeperDataInit zookeeperDataInit(final ZkClient zkClient, final SyncDataService syncDataService) {
return new ZookeeperDataInit(zkClient, syncDataService);
}
}
4、org.dromara.soul.admin.listener.zookeeper.ZookeeperDataInit：负责向zookeeper同步初始化数据。此类实现了 CommandLineRunner。
-
CommandLineRunner：SpringBoot在项目启动后会遍历所有实现CommandLineRunner的实体类并执行run方法，如果需要按照一定的顺序去执行，那么就需要在实体类上使用一个@Order注解（或者实现Order接口）来表明顺序。
-
run 方法会调用 syncDataService.syncAll方法。
public class ZookeeperDataInit implements CommandLineRunner {
private final ZkClient zkClient;
private final SyncDataService syncDataService;
/**
* Instantiates a new Zookeeper data init.
* @param zkClient the zk client
* @param syncDataService the sync data service
*/
public ZookeeperDataInit(final ZkClient zkClient, final SyncDataService syncDataService) {
this.zkClient = zkClient;
this.syncDataService = syncDataService;
}
@Override
public void run(final String... args) {
String pluginPath = ZkPathConstants.PLUGIN_PARENT;
String authPath = ZkPathConstants.APP_AUTH_PARENT;
String metaDataPath = ZkPathConstants.META_DATA;
if (!zkClient.exists(pluginPath) && !zkClient.exists(authPath) && !zkClient.exists(metaDataPath)) {
syncDataService.syncAll(DataEventTypeEnum.REFRESH);
}
}
}
5、org.dromara.soul.admin.service.sync.SyncDataServiceImpl
- syncAll 方法会调用事件发布器进行事件发布，事件类型是 DataEventTypeEnum.REFRESH
/**
* The type sync data service.
* @author xiaoyu(Myth)
*/
@Service("syncDataService")
public class SyncDataServiceImpl implements SyncDataService {
// 发布事件，也就是把某个事件告诉的所有与这个事件相关的监听器
private final ApplicationEventPublisher eventPublisher;
......
@Override
public boolean syncAll(final DataEventTypeEnum type) {
appAuthService.syncData();
List<PluginData> pluginDataList = pluginService.listAll();
eventPublisher.publishEvent(new DataChangedEvent(ConfigGroupEnum.PLUGIN, type, pluginDataList));
List<SelectorData> selectorDataList = selectorService.listAll();
eventPublisher.publishEvent(new DataChangedEvent(ConfigGroupEnum.SELECTOR, type, selectorDataList));
List<RuleData> ruleDataList = ruleService.listAll();
eventPublisher.publishEvent(new DataChangedEvent(ConfigGroupEnum.RULE, type, ruleDataList));
metaDataService.syncData();
return true;
}
......
}
6、事件发布后 org.dromara.soul.admin.listener.DataChangedEventDispatcher 类的onApplicationEvent 方法会监听事件变化，遍历所有的监听者进行数据同步处理，这里的监听者实现类是 ZookeeperDataChangedListener，根据对应的事件类型通过 zkClient 向zookeeper 同步数据。
@Component
public class DataChangedEventDispatcher implements ApplicationListener<DataChangedEvent>, InitializingBean {
@Override
@SuppressWarnings("unchecked")
public void onApplicationEvent(final DataChangedEvent event) {
for (DataChangedListener listener : listeners) {
switch (event.getGroupKey()) {
case APP_AUTH:
listener.onAppAuthChanged((List<AppAuthData>) event.getSource(), event.getEventType());
break;
case PLUGIN:
listener.onPluginChanged((List<PluginData>) event.getSource(), event.getEventType());
break;
case RULE:
listener.onRuleChanged((List<RuleData>) event.getSource(), event.getEventType());
break;
case SELECTOR:
listener.onSelectorChanged((List<SelectorData>) event.getSource(), event.getEventType());
break;
case META_DATA:
listener.onMetaDataChanged((List<MetaData>) event.getSource(), event.getEventType());
break;
default:
throw new IllegalStateException("Unexpected value: " + event.getGroupKey());
}
}
}
}
四、总结
soul-admin 启动就会同步网关数据 rule、metaData、selector、plugin 等到 zookeeper。数据变化会发布 DataChangedEvent事件，监听事件将数据同步至zookeeper。
