datax源码阅读四：TaskGroupContainer
根据前面源码阅读可以知道，JobContainer将所有的task分配到TaskGroup中执行，TaskGroup启动5个线程去消费所有的task的，具体实现为
public void start() {
try {
/**
* 状态check时间间隔，较短，可以把任务及时分发到对应channel中
*/
int sleepIntervalInMillSec = this.configuration.getInt(
CoreConstant.DATAX_CORE_CONTAINER_TASKGROUP_SLEEPINTERVAL, 100);
/**
* 状态汇报时间间隔，稍长，避免大量汇报
*/
long reportIntervalInMillSec = this.configuration.getLong(
CoreConstant.DATAX_CORE_CONTAINER_TASKGROUP_REPORTINTERVAL,
10000);
/**
* 2分钟汇报一次性能统计
*/
// 获取channel数目
int channelNumber = this.configuration.getInt(
CoreConstant.DATAX_CORE_CONTAINER_TASKGROUP_CHANNEL);
int taskMaxRetryTimes = this.configuration.getInt(
CoreConstant.DATAX_CORE_CONTAINER_TASK_FAILOVER_MAXRETRYTIMES, 1);
long taskRetryIntervalInMsec = this.configuration.getLong(
CoreConstant.DATAX_CORE_CONTAINER_TASK_FAILOVER_RETRYINTERVALINMSEC, 10000);
long taskMaxWaitInMsec = this.configuration.getLong(CoreConstant.DATAX_CORE_CONTAINER_TASK_FAILOVER_MAXWAITINMSEC, 60000);
List taskConfigs = this.configuration
.getListConfiguration(CoreConstant.DATAX_JOB_CONTENT);
if(LOG.isDebugEnabled()) {
LOG.debug("taskGroup[{}]'s task configs[{}]", this.taskGroupId,
JSON.toJSONString(taskConfigs));
}
int taskCountInThisTaskGroup = taskConfigs.size();
/*LOG.info(String.format(
"taskGroupId=[%d] start [%d] channels for [%d] tasks.",
this.taskGroupId, channelNumber, taskCountInThisTaskGroup));*/
this.containerCommunicator.registerCommunication(taskConfigs);
Map taskConfigMap = buildTaskConfigMap(taskConfigs); //taskId与task配置
List taskQueue = buildRemainTasks(taskConfigs); //待运行task列表
Map taskFailedExecutorMap = new HashMap(); //taskId与上次失败实例
List runTasks = new ArrayList(channelNumber); //正在运行task
Map taskStartTimeMap = new HashMap(); //任务开始时间
long lastReportTimeStamp = 0;
Communication lastTaskGroupContainerCommunication = new Communication();
while (true) {
//1.判断task状态
boolean failedOrKilled = false;
Map communicationMap = containerCommunicator.getCommunicationMap();
for(Map.Entry entry : communicationMap.entrySet()){
Integer taskId = entry.getKey();
Communication taskCommunication = entry.getValue();
if(!taskCommunication.isFinished()){
continue;
}
TaskExecutor taskExecutor = removeTask(runTasks, taskId);
//上面从runTasks里移除了，因此对应在monitor里移除
taskMonitor.removeTask(taskId);
//失败，看task是否支持failover，重试次数未超过最大限制
if(taskCommunication.getState() == State.FAILED){
taskFailedExecutorMap.put(taskId, taskExecutor);
if(taskExecutor.supportFailOver() && taskExecutor.getAttemptCount() < taskMaxRetryTimes){
taskExecutor.shutdown(); //关闭老的executor
containerCommunicator.resetCommunication(taskId); //将task的状态重置
Configuration taskConfig = taskConfigMap.get(taskId);
taskQueue.add(taskConfig); //重新加入任务列表
}else{
failedOrKilled = true;
break;
}
}else if(taskCommunication.getState() == State.KILLED){
failedOrKilled = true;
break;
}else if(taskCommunication.getState() == State.SUCCEEDED){
Long taskStartTime = taskStartTimeMap.get(taskId);
if(taskStartTime != null){
Long usedTime = System.currentTimeMillis() - taskStartTime;
/*LOG.info("taskGroup[{}] taskId[{}] is successed, used[{}]ms",
this.taskGroupId, taskId, usedTime);*/
//usedTime*1000*1000 转换成PerfRecord记录的ns，这里主要是简单登记，进行最长任务的打印。因此增加特定静态方法
PerfRecord.addPerfRecord(taskGroupId, taskId, PerfRecord.PHASE.TASK_TOTAL,taskStartTime, usedTime * 1000L * 1000L);
taskStartTimeMap.remove(taskId);
taskConfigMap.remove(taskId);
}
}
}
// 2.发现该taskGroup下taskExecutor的总状态失败则汇报错误
if (failedOrKilled) {
lastTaskGroupContainerCommunication = reportTaskGroupCommunication(
lastTaskGroupContainerCommunication, taskCountInThisTaskGroup);
throw DataXException.asDataXException(
FrameworkErrorCode.PLUGIN_RUNTIME_ERROR, lastTaskGroupContainerCommunication.getThrowable());
}
//3.有任务未执行，且正在运行的任务数小于最大通道限制
Iterator iterator = taskQueue.iterator();
while(iterator.hasNext() && runTasks.size() < channelNumber){
Configuration taskConfig = iterator.next();
Integer taskId = taskConfig.getInt(CoreConstant.TASK_ID);
int attemptCount = 1;
TaskExecutor lastExecutor = taskFailedExecutorMap.get(taskId);
if(lastExecutor!=null){
attemptCount = lastExecutor.getAttemptCount() + 1;
long now = System.currentTimeMillis();
long failedTime = lastExecutor.getTimeStamp();
if(now - failedTime < taskRetryIntervalInMsec){ //未到等待时间，继续留在队列
continue;
}
if(!lastExecutor.isShutdown()){ //上次失败的task仍未结束
if(now - failedTime > taskMaxWaitInMsec){
markCommunicationFailed(taskId);
reportTaskGroupCommunication(lastTaskGroupContainerCommunication, taskCountInThisTaskGroup);
throw DataXException.asDataXException(CommonErrorCode.WAIT_TIME_EXCEED, "task failover等待超时");
}else{
lastExecutor.shutdown(); //再次尝试关闭
continue;
}
}else{
/*LOG.info("taskGroup[{}] taskId[{}] attemptCount[{}] has already shutdown",
this.taskGroupId, taskId, lastExecutor.getAttemptCount());*/
}
}
Configuration taskConfigForRun = taskMaxRetryTimes > 1 ? taskConfig.clone() : taskConfig;
TaskExecutor taskExecutor = new TaskExecutor(taskConfigForRun, attemptCount);
taskStartTimeMap.put(taskId, System.currentTimeMillis());
taskExecutor.doStart();
iterator.remove();
runTasks.add(taskExecutor);
//上面，增加task到runTasks列表，因此在monitor里注册。
taskMonitor.registerTask(taskId, this.containerCommunicator.getCommunication(taskId));
taskFailedExecutorMap.remove(taskId);
/*LOG.info("taskGroup[{}] taskId[{}] attemptCount[{}] is started",
this.taskGroupId, taskId, attemptCount);*/
}
//4.任务列表为空，executor已结束, 搜集状态为success--->成功
if (taskQueue.isEmpty() && isAllTaskDone(runTasks) && containerCommunicator.collectState() == State.SUCCEEDED) {
// 成功的情况下，也需要汇报一次。否则在任务结束非常快的情况下，采集的信息将会不准确
lastTaskGroupContainerCommunication = reportTaskGroupCommunication(
lastTaskGroupContainerCommunication, taskCountInThisTaskGroup);
/*LOG.info("taskGroup[{}] completed it's tasks.", this.taskGroupId);*/
break;
}
// 5.如果当前时间已经超出汇报时间的interval，那么我们需要马上汇报
long now = System.currentTimeMillis();
if (now - lastReportTimeStamp > reportIntervalInMillSec) {
lastTaskGroupContainerCommunication = reportTaskGroupCommunication(
lastTaskGroupContainerCommunication, taskCountInThisTaskGroup);
lastReportTimeStamp = now;
//taskMonitor对于正在运行的task，每reportIntervalInMillSec进行检查
for(TaskExecutor taskExecutor:runTasks){
taskMonitor.report(taskExecutor.getTaskId(),this.containerCommunicator.getCommunication(taskExecutor.getTaskId()));
if(DATX_LOG_ENABLE){
LOG.info("Running queue capacity is :[{}], current length is:[{}]", taskExecutor.channel.getCapacity(), taskExecutor.channel.size());
}
}
}
Thread.sleep(sleepIntervalInMillSec);
}
//6.最后还要汇报一次
reportTaskGroupCommunication(lastTaskGroupContainerCommunication, taskCountInThisTaskGroup);
} catch (Throwable e) {
Communication nowTaskGroupContainerCommunication = this.containerCommunicator.collect();
if (nowTaskGroupContainerCommunication.getThrowable() == null) {
nowTaskGroupContainerCommunication.setThrowable(e);
}
nowTaskGroupContainerCommunication.setState(State.FAILED);
this.containerCommunicator.report(nowTaskGroupContainerCommunication);
throw DataXException.asDataXException(
FrameworkErrorCode.RUNTIME_ERROR, e);
}finally {
if(!PerfTrace.getInstance().isJob()){
//最后打印cpu的平均消耗，GC的统计
VMInfo vmInfo = VMInfo.getVmInfo();
if (vmInfo != null) {
vmInfo.getDelta(false);
LOG.info(vmInfo.totalString());
}
LOG.info(PerfTrace.getInstance().summarizeNoException());
}
}
}
上述实现主要分为以下几个步骤：
1、初始化task执行相关的状态信息，分别是taskId->Congifuration的map、待运行的任务队列taskQueue、运行失败任务taskFailedExecutorMap、运行中的任务runTasks、任务开始时间taskStartTimeMap
2、循环检测所有任务的执行状态
1）判断是否有失败的task，如果有则放入失败对立中，并查看当前的执行是否支持重跑和failOver，如果支持则重新放回执行队列中；如果没有失败，则标记任务执行成功，并从状态轮询map中移除
2）如果发现有失败的任务，则汇报当前TaskGroup的状态，并抛出异常
3）查看当前执行队列的长度，如果发现执行队列还有通道，则构建TaskExecutor加入执行队列，并从待运行移除
4）检查执行队列和所有的任务状态，如果所有的任务都执行成功，则汇报taskGroup的状态并从循环中退出
5）检查当前时间是否超过汇报时间检测，如果是，则汇报当前状态
6）当所有的执行完成从while中退出之后，再次全局汇报当前的任务状态 至此，taskGroup中的所有执行完成，上述taskGroup的运行队列只是将负责对task任务进行调度，具体的执行还是TaskExecutor负责实现，下面看看TaskExecutor的执行，代码实现如下
public TaskExecutor(Configuration taskConf, int attemptCount) {
// 获取该taskExecutor的配置
this.taskConfig = taskConf;
Validate.isTrue(null != this.taskConfig.getConfiguration(CoreConstant.JOB_READER)
&& null != this.taskConfig.getConfiguration(CoreConstant.JOB_WRITER),
"[reader|writer]的插件参数不能为空!");
// 得到taskId
this.taskId = this.taskConfig.getInt(CoreConstant.TASK_ID);
this.attemptCount = attemptCount;
/**
* 由taskId得到该taskExecutor的Communication
* 要传给readerRunner和writerRunner，同时要传给channel作统计用
*/
this.taskCommunication = containerCommunicator
.getCommunication(taskId);
Validate.notNull(this.taskCommunication,
String.format("taskId[%d]的Communication没有注册过", taskId));
this.channel = ClassUtil.instantiate(channelClazz,
Channel.class, configuration);
this.channel.setCommunication(this.taskCommunication);
/**
* 获取transformer的参数
*/
List transformerInfoExecs = TransformerUtil.buildTransformerInfo(taskConfig);
/**
* 生成writerThread
*/
writerRunner = (WriterRunner) generateRunner(PluginType.WRITER);
this.writerThread = new Thread(writerRunner,
String.format("%d-%d-%d-writer",
jobId, taskGroupId, this.taskId));
//通过设置thread的contextClassLoader，即可实现同步和主程序不通的加载器
this.writerThread.setContextClassLoader(LoadUtil.getJarLoader(
PluginType.WRITER, this.taskConfig.getString(
CoreConstant.JOB_WRITER_NAME)));
/**
* 生成readerThread
*/
readerRunner = (ReaderRunner) generateRunner(PluginType.READER,transformerInfoExecs);
this.readerThread = new Thread(readerRunner,
String.format("%d-%d-%d-reader",
jobId, taskGroupId, this.taskId));
/**
* 通过设置thread的contextClassLoader，即可实现同步和主程序不通的加载器
*/
this.readerThread.setContextClassLoader(LoadUtil.getJarLoader(
PluginType.READER, this.taskConfig.getString(
CoreConstant.JOB_READER_NAME)));
}
public void doStart() {
this.writerThread.start();
// reader没有起来，writer不可能结束
if (!this.writerThread.isAlive() || this.taskCommunication.getState() == State.FAILED) {
throw DataXException.asDataXException(
FrameworkErrorCode.RUNTIME_ERROR,
this.taskCommunication.getThrowable());
}
this.readerThread.start();
// 这里reader可能很快结束
if (!this.readerThread.isAlive() && this.taskCommunication.getState() == State.FAILED) {
// 这里有可能出现Reader线上启动即挂情况 对于这类情况 需要立刻抛出异常
throw DataXException.asDataXException(
FrameworkErrorCode.RUNTIME_ERROR,
this.taskCommunication.getThrowable());
}
}
TaskExecutor构建的时候，生成一个reader、channel和writer，并启动两个线程，reader生产数据写入channel，writer从channel中读数据，任务执行完毕时，通过wirter将任务状态置为成功