org.apache.ambari.server.serveraction

Class ServerActionExecutor

java.lang.Object

org.apache.ambari.server.serveraction.ServerActionExecutor

public class ServerActionExecutor
extends Object

Server Action Executor used to execute server-side actions (or tasks)

The ServerActionExecutor executes in its own thread, polling for AMBARI_SERVER_ACTION HostRoleCommands queued for execution. It is expected that this thread is managed by the ActionScheduler such that it is started when the ActionScheduler is started and stopped when the ActionScheduler is stopped.

Constructor Summary

Constructors

Constructor and Description
ServerActionExecutor(ActionDBAccessor db, long sleepTimeMS) Creates a new ServerActionExecutor

Method Summary

Modifier and Type	Method and Description
void	awake() Attempts to force this ServerActionExecutor to wake up and do work.
void	doWork() Execute the logic to handle each task in the queue in the order in which it was queued.
static void	init(com.google.inject.Injector injector) Statically initialize the Injector This should only be used for unit tests.
void	start() Starts this ServerActionExecutor's main thread.
void	stop() Attempts to stop this ServerActionExecutor's main thread.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ServerActionExecutor

public ServerActionExecutor(ActionDBAccessor db,
                            long sleepTimeMS)

Creates a new ServerActionExecutor

Parameters:

db - the ActionDBAccessor to use to read and update tasks

sleepTimeMS - the time (in milliseconds) to wait between polling the database for more tasks

Method Detail

init

public static void init(com.google.inject.Injector injector)

Statically initialize the Injector

This should only be used for unit tests.

Parameters:

injector - the Injector to (manually) statically inject

start

public void start()

Starts this ServerActionExecutor's main thread.

stop

public void stop()

Attempts to stop this ServerActionExecutor's main thread.

awake

public void awake()

Attempts to force this ServerActionExecutor to wake up and do work.

Should be called from another thread when we want scheduler to make a run ASAP (for example, to process desired configs of SCHs). The method is guaranteed to return quickly.

doWork

public void doWork()
            throws InterruptedException

Execute the logic to handle each task in the queue in the order in which it was queued.

A single task is executed at one time, allowing for a specified (ExecutionCommand.KeyNames.COMMAND_TIMEOUT) or the default timeout for it to complete before considering the task timed out.

Throws:

InterruptedException