hadoop之yarn状态机模型

状态机一般和事件驱动结合在一起用的，我们继续上一篇的例子。

1.定时task的任务状态

package com.eg2;public enum TaskStateInternal {RUN,END}

2.定义状态机

package com.eg2;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;import org.apache.hadoop.yarn.event.EventHandler;import org.apache.hadoop.yarn.state.SingleArcTransition;import org.apache.hadoop.yarn.state.StateMachine;import org.apache.hadoop.yarn.state.StateMachineFactory;import com.eg1.TaskEvent;import com.eg1.TaskEventType;public class TaskStateMachine implements EventHandler<TaskEvent> {private final String taskID;private EventHandler eventHandler;private final Lock writeLock;private final Lock readLock;protected static finalStateMachineFactory<TaskStateMachine,TaskStateInternal,TaskEventType,TaskEvent>stateMachineFactory=new StateMachineFactory<TaskStateMachine,TaskStateInternal,TaskEventType,TaskEvent>(TaskStateInternal.RUN).addTransition(TaskStateInternal.RUN, TaskStateInternal.END, TaskEventType.T_KILL,new KillTransition()).addTransition(TaskStateInternal.RUN, TaskStateInternal.END, TaskEventType.T_SCHEDULE,new ScheduleTransition()).installTopology();private final StateMachine<TaskStateInternal, TaskEventType, TaskEvent> stateMachine;public StateMachine<TaskStateInternal, TaskEventType, TaskEvent> getStateMachine() {return stateMachine;}public TaskStateMachine(String taskID,EventHandler eventHandler){//单独观察状态机,EventHandler都应该可以不用传吧this.taskID=taskID;ReadWriteLock readWriteLock = new ReentrantReadWriteLock();this.readLock=readWriteLock.readLock();this.writeLock=readWriteLock.writeLock();this.eventHandler =eventHandler;stateMachine=stateMachineFactory.make(this);}public static class KillTransition implements SingleArcTransition<TaskStateMachine, TaskEvent>{@Overridepublic void transition(TaskStateMachine arg0, TaskEvent arg1) {System.out.println("KillTransition");arg0.eventHandler.handle(new TaskEvent("task1",TaskEventType.T_KILL));}}public static class ScheduleTransition implements SingleArcTransition<TaskStateMachine, TaskEvent>{@Overridepublic void transition(TaskStateMachine arg0, TaskEvent arg1) {System.out.println("ScheduleTransition");arg0.eventHandler.handle(new TaskEvent("task1",TaskEventType.T_SCHEDULE));}}@Overridepublic void handle(TaskEvent arg0) {try{writeLock.lock();TaskStateInternal oldstate = getInternalState();System.out.println("machine handler start ,state:"+oldstate);getStateMachine().doTransition(arg0.getType(), arg0);System.out.println("machine handler end ,  state:"+getInternalState());}finally{writeLock.unlock();}}public TaskStateInternal getInternalState(){try{readLock.lock();return getStateMachine().getCurrentState();}finally{readLock.unlock();}}}

3.测试类，我们将一个类copy一份简单修改，因为构造的时候需要传EventHandler，我们直接用上一例的TaskEventDisptacher

【private class TaskEventDisptacher implements EventHandler<TaskEvent>】

package com.eg2;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.service.CompositeService;import org.apache.hadoop.service.Service;import org.apache.hadoop.yarn.event.AsyncDispatcher;import org.apache.hadoop.yarn.event.Dispatcher;import org.apache.hadoop.yarn.event.EventHandler;import com.eg1.TaskEvent;import com.eg1.TaskEventType;public class SimpleMRAppMaster extends CompositeService {private Dispatcher dispatcher;public Dispatcher getDispatcher() {return dispatcher;}public SimpleMRAppMaster(String name) {super(name);}@Overrideprotected void serviceInit(Configuration arg0) throws Exception {dispatcher = new AsyncDispatcher();dispatcher.register(TaskEventType.class, new TaskEventDisptacher());addService((Service)dispatcher);super.serviceInit(arg0);}private class TaskEventDisptacher implements EventHandler<TaskEvent>{@Overridepublic void handle(TaskEvent arg0) {//TaskStateMachine machine = new TaskStateMachine("TaskStateMachine",this);//machine.handle(arg0);//以上代码是可以调用状态机去发送事件，但是状态机器handle的时候又发送了本事件，造成死循环。所以这里暂时不这样使用if(arg0.getType() == TaskEventType.T_KILL){System.out.println("run kill");}else if(arg0.getType() == TaskEventType.T_SCHEDULE){System.out.println("run schedule");}}}//测试入口public static void main(String[] args) throws Exception {//因为没有TaskEventDisptacher中handle()调用状态机，所以也不需要启动service之类的，我们直接在下面new状态机测试TaskStateMachine machine = new TaskStateMachine("TaskStateMachine",new SimpleMRAppMaster("SimpleMRAppMaster").new TaskEventDisptacher());machine.handle(new TaskEvent("task1",TaskEventType.T_KILL));//machine.handle(new TaskEvent("task1",TaskEventType.T_SCHEDULE));//如果连续执行，抛出异常，因为kill后状态为END无法执行schedule事件}}