序
本文主要研究一下nacos的ConfigDataChangeEvent
Event
nacos-1.1.3/config/src/main/java/com/alibaba/nacos/config/server/utils/event/EventDispatcher.java
public interface Event {
}- Event是个空接口，仅仅用于标名事件
ConfigDataChangeEvent
nacos-1.1.3/config/src/main/java/com/alibaba/nacos/config/server/service/ConfigDataChangeEvent.java
public class ConfigDataChangeEvent implements Event {
final public boolean isBeta;
final public String dataId;
final public String group;
final public String tenant;
final public String tag;
final public long lastModifiedTs;
public ConfigDataChangeEvent(String dataId, String group, long gmtModified) {
this(false, dataId, group, gmtModified);
}
public ConfigDataChangeEvent(boolean isBeta, String dataId, String group, String tenant, long gmtModified) {
if (null == dataId || null == group) {
throw new IllegalArgumentException();
}
this.isBeta = isBeta;
this.dataId = dataId;
this.group = group;
this.tenant = tenant;
this.tag = null;
this.lastModifiedTs = gmtModified;
}
public ConfigDataChangeEvent(boolean isBeta, String dataId, String group, long gmtModified) {
this(isBeta, dataId, group, StringUtils.EMPTY, gmtModified);
}
public ConfigDataChangeEvent(boolean isBeta, String dataId, String group, String tenant, String tag,
long gmtModified) {
if (null == dataId || null == group) {
throw new IllegalArgumentException();
}
this.isBeta = isBeta;
this.dataId = dataId;
this.group = group;
this.tenant = tenant;
this.tag = tag;
this.lastModifiedTs = gmtModified;
}
}- ConfigDataChangeEvent实现了Event接口，它包含有isBeta、dataId、group、tenant、tag、lastModifiedTs属性
AbstractEventListener
nacos-1.1.3/config/src/main/java/com/alibaba/nacos/config/server/utils/event/EventDispatcher.java
static public abstract class AbstractEventListener {
public AbstractEventListener() {
/**
* automatic register
*/
EventDispatcher.addEventListener(this);
}
/**
* 感兴趣的事件列表
*
* @return event list
*/
abstract public List> interest();
/**
* 处理事件
*
* @param event event
*/
abstract public void onEvent(Event event);
} - AbstractEventListener接口定义了interest、onEvent两个抽象方法
AsyncNotifyService
nacos-1.1.3/config/src/main/java/com/alibaba/nacos/config/server/service/notify/AsyncNotifyService.java
@Service
public class AsyncNotifyService extends AbstractEventListener {
@Override
public List> interest() {
List> types = new ArrayList>();
// 触发配置变更同步通知
types.add(ConfigDataChangeEvent.class);
return types;
}
@Override
public void onEvent(Event event) {
// 并发产生 ConfigDataChangeEvent
if (event instanceof ConfigDataChangeEvent) {
ConfigDataChangeEvent evt = (ConfigDataChangeEvent) event;
long dumpTs = evt.lastModifiedTs;
String dataId = evt.dataId;
String group = evt.group;
String tenant = evt.tenant;
String tag = evt.tag;
List ipList = serverListService.getServerList();
// 其实这里任何类型队列都可以
Queue queue = new LinkedList();
for (int i = 0; i < ipList.size(); i++) {
queue.add(new NotifySingleTask(dataId, group, tenant, tag, dumpTs, (String) ipList.get(i), evt.isBeta));
}
EXECUTOR.execute(new AsyncTask(httpclient, queue));
}
}
@Autowired
public AsyncNotifyService(ServerListService serverListService) {
this.serverListService = serverListService;
httpclient.start();
}
//......
} - AsyncNotifyService继承了AbstractEventListener接口，其interest返回的列表包含了ConfigDataChangeEvent；其onEvent方法判断是ConfigDataChangeEvent，则会通过serverListService.getServerList()获取ipList，然后遍历该列表往queue添加NotifySingleTask，然后使用该queue创建AsyncTask并提交线程池执行
AsyncTask
nacos-1.1.3/config/src/main/java/com/alibaba/nacos/config/server/service/notify/AsyncNotifyService.java
class AsyncTask implements Runnable {
public AsyncTask(CloseableHttpAsyncClient httpclient, Queue queue) {
this.httpclient = httpclient;
this.queue = queue;
}
@Override
public void run() {
executeAsyncInvoke();
}
private void executeAsyncInvoke() {
while (!queue.isEmpty()) {
NotifySingleTask task = queue.poll();
String targetIp = task.getTargetIP();
if (serverListService.getServerList().contains(
targetIp)) {
// 启动健康检查且有不监控的ip则直接把放到通知队列，否则通知
if (serverListService.isHealthCheck()
&& ServerListService.getServerListUnhealth().contains(targetIp)) {
// target ip 不健康，则放入通知列表中
ConfigTraceService.logNotifyEvent(task.getDataId(), task.getGroup(), task.getTenant(), null,
task.getLastModified(),
LOCAL_IP, ConfigTraceService.NOTIFY_EVENT_UNHEALTH, 0, task.target);
// get delay time and set fail count to the task
asyncTaskExecute(task);
} else {
HttpGet request = new HttpGet(task.url);
request.setHeader(NotifyService.NOTIFY_HEADER_LAST_MODIFIED,
String.valueOf(task.getLastModified()));
request.setHeader(NotifyService.NOTIFY_HEADER_OP_HANDLE_IP, LOCAL_IP);
if (task.isBeta) {
request.setHeader("isBeta", "true");
}
httpclient.execute(request, new AsyncNotifyCallBack(httpclient, task));
}
}
}
}
private Queue queue;
private CloseableHttpAsyncClient httpclient;
} - AsyncTask实现了Runnable接口，其run方法执行executeAsyncInvoke方法；该方法会不断从queue取出NotifySingleTask，然后判断目标ip是否健康不健康则延迟再次执行该task；如果是健康的话则使用httpclient向目标地址发送get请求，然后注册AsyncNotifyCallBack
AsyncNotifyCallBack
nacos-1.1.3/config/src/main/java/com/alibaba/nacos/config/server/service/notify/AsyncNotifyService.java
class AsyncNotifyCallBack implements FutureCallback {
public AsyncNotifyCallBack(CloseableHttpAsyncClient httpClient, NotifySingleTask task) {
this.task = task;
this.httpClient = httpClient;
}
@Override
public void completed(HttpResponse response) {
long delayed = System.currentTimeMillis() - task.getLastModified();
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
ConfigTraceService.logNotifyEvent(task.getDataId(),
task.getGroup(), task.getTenant(), null, task.getLastModified(),
LOCAL_IP,
ConfigTraceService.NOTIFY_EVENT_OK, delayed,
task.target);
} else {
log.error("[notify-error] target:{} dataId:{} group:{} ts:{} code:{}",
task.target, task.getDataId(), task.getGroup(), task.getLastModified(), response.getStatusLine().getStatusCode());
ConfigTraceService.logNotifyEvent(task.getDataId(),
task.getGroup(), task.getTenant(), null, task.getLastModified(),
LOCAL_IP,
ConfigTraceService.NOTIFY_EVENT_ERROR, delayed,
task.target);
//get delay time and set fail count to the task
asyncTaskExecute(task);
LogUtil.notifyLog.error("[notify-retry] target:{} dataId:{} group:{} ts:{}",
task.target, task.getDataId(), task.getGroup(), task.getLastModified());
MetricsMonitor.getConfigNotifyException().increment();
}
HttpClientUtils.closeQuietly(response);
}
@Override
public void failed(Exception ex) {
long delayed = System.currentTimeMillis() - task.getLastModified();
log.error("[notify-exception] target:{} dataId:{} group:{} ts:{} ex:{}",
task.target, task.getDataId(), task.getGroup(), task.getLastModified(), ex.toString());
ConfigTraceService.logNotifyEvent(task.getDataId(),
task.getGroup(), task.getTenant(), null, task.getLastModified(),
LOCAL_IP,
ConfigTraceService.NOTIFY_EVENT_EXCEPTION, delayed,
task.target);
//get delay time and set fail count to the task
asyncTaskExecute(task);
LogUtil.notifyLog.error("[notify-retry] target:{} dataId:{} group:{} ts:{}",
task.target, task.getDataId(), task.getGroup(), task.getLastModified());
MetricsMonitor.getConfigNotifyException().increment();
}
@Override
public void cancelled() {
LogUtil.notifyLog.error("[notify-exception] target:{} dataId:{} group:{} ts:{} method:{}",
task.target, task.getDataId(), task.getGroup(), task.getLastModified(), "CANCELED");
//get delay time and set fail count to the task
asyncTaskExecute(task);
LogUtil.notifyLog.error("[notify-retry] target:{} dataId:{} group:{} ts:{}",
task.target, task.getDataId(), task.getGroup(), task.getLastModified());
MetricsMonitor.getConfigNotifyException().increment();
}
private NotifySingleTask task;
private CloseableHttpAsyncClient httpClient;
} - AsyncNotifyCallBack实现了FutureCallback接口，其completed方法判断请求是否是HttpStatus.SC_OK，不是的话会再次延迟调度该任务；其failed、cancelled方法也是会再次延时调度该任务
小结
ConfigDataChangeEvent实现了Event接口，它包含有isBeta、dataId、group、tenant、tag、lastModifiedTs属性；AsyncNotifyService继承了AbstractEventListener接口，其interest返回的列表包含了ConfigDataChangeEvent；其onEvent方法判断是ConfigDataChangeEvent，则会通过serverListService.getServerList()获取ipList，然后遍历该列表往queue添加NotifySingleTask，然后使用该queue创建AsyncTask并提交线程池执行
doc
- ConfigDataChangeEvent