soul网关入门 第六章 admin推送元数据到bootstrap流程梳理

admin 跟 bootstrap 通信通过websocket协议，首先看下admin如何引入websocket，以及是如何把数据推送出去的，领略设计的精妙之处。

首先看admin关键代码

<dependency><!-- 引入websocket  -->
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

soul:
  sync:
    websocket:
      enabled: true   # 开启websocket

    @Configuration
    @ConditionalOnProperty(name = "soul.sync.websocket.enabled", havingValue = "true", matchIfMissing = true)
    @EnableConfigurationProperties(WebsocketSyncProperties.class)
    static class WebsocketListener {

        @Bean
        @ConditionalOnMissingBean(WebsocketDataChangedListener.class)
        public DataChangedListener websocketDataChangedListener() {
          // 创建数据change 事件的各种处理器，类名有listener，事实跟监听没关系
            return new WebsocketDataChangedListener();
        }
        @Bean
        @ConditionalOnMissingBean(WebsocketCollector.class)
        public WebsocketCollector websocketCollector() {
            // 初始化WebsocketCollector
            /* 主要作用创建websocket服务端点
               建立连接，等待客户端连上来
               如发现有链接连上，同步所有数据给对方，
               下面贴出WebsocketCollector代码，一目了然
            */
            return new WebsocketCollector();
        }
        @Bean
        @ConditionalOnMissingBean(ServerEndpointExporter.class)
        public ServerEndpointExporter serverEndpointExporter() {
            // 作用未知
            return new ServerEndpointExporter();
        }
    }

@ServerEndpoint("/websocket")  // 暴露端点
public class WebsocketCollector {

    private static final Set<Session> SESSION_SET = new CopyOnWriteArraySet<>();
    private static final String SESSION_KEY = "sessionKey";
    // 创建会话
    @OnOpen
    public void onOpen(final Session session) {
        log.info("websocket on open successful....");
        SESSION_SET.add(session);
    }
// 接收对方发过来的数据
    @OnMessage
    public void onMessage(final String message, final Session session) {        // 当网关发来的message 等于 MYSELF 时，同步所有数据过去
        if (message.equals(DataEventTypeEnum.MYSELF.name())) {
            try {
                ThreadLocalUtil.put(SESSION_KEY, session);
              // 同步所有数据给对方
                SpringBeanUtils.getInstance().getBean(SyncDataService.class).syncAll(DataEventTypeEnum.MYSELF);
            } finally {
                ThreadLocalUtil.clear();
            }
        }
    }
    @OnClose
    public void onClose(final Session session) {
        SESSION_SET.remove(session);
        ThreadLocalUtil.clear();
    }
    @OnError
    public void onError(final Session session, final Throwable error) {
        SESSION_SET.remove(session);
        ThreadLocalUtil.clear();
        log.error("websocket collection error: ", error);
    }

    // 发送数据工具方法
    public static void send(final String message, final DataEventTypeEnum type) {
        if (StringUtils.isNotBlank(message)) {
            if (DataEventTypeEnum.MYSELF == type) {
                try {
                    Session session = (Session) ThreadLocalUtil.get(SESSION_KEY);
                    if (session != null) {
                        session.getBasicRemote().sendText(message);
                    }
                } catch (IOException e) {
                    log.error("websocket send result is exception: ", e);
                }
                return;
            }
            for (Session session : SESSION_SET) {
                try {
                    session.getBasicRemote().sendText(message);
                } catch (IOException e) {
                    log.error("websocket send result is exception: ", e);
                }
            }
        }
    }
}

全部数据同步到bootstrap 方法

@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();
  // 推送数据事件，观察者接受到事件执行推送，看类DataChangedEventDispatcher
    eventPublisher.publishEvent(new DataChangedEvent(ConfigGroupEnum.RULE, type, ruleDataList));
    metaDataService.syncData();
    return true;
}

DataChangedEventDispatcher 实现接口 ApplicationListener，spring容器即可代为实现观察者模式

@Component
public class DataChangedEventDispatcher implements ApplicationListener<DataChangedEvent>, InitializingBean {

    private ApplicationContext applicationContext;

    private List<DataChangedListener> listeners;

    public DataChangedEventDispatcher(final ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }
    // 执行推送
    @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());
            }
        }
    }

    @Override
    public void afterPropertiesSet() {
        Collection<DataChangedListener> listenerBeans = applicationContext.getBeansOfType(DataChangedListener.class).values();
        this.listeners = Collections.unmodifiableList(new ArrayList<>(listenerBeans));
    }

}

以上只介绍了admin是如果推送信息的，暂且打住，下一编将讲解网关bootstrap是如何接受数据然后存储到jvm的。