net.sf.basedb.clients.jobagent.slotmanager
Class MasterSlotManager

java.lang.Object
  net.sf.basedb.clients.jobagent.slotmanager.InternalSlotManager
      net.sf.basedb.clients.jobagent.slotmanager.MasterSlotManager

All Implemented Interfaces:

SlotManager

public class MasterSlotManager
extends InternalSlotManager

An extension to the internal slot manager which also accepts slot assignment from remote job agents. A custom request handler (MasterSlotManager.RemoteSlotRequestHandler) is installed to take care of the communication. Remotely assigned slots has a time-out (30 seconds) associated with them. This means that if the connection with the remote host is lost, the assigned slots are re-cycled.

The requst handler uses a simple protocol with the following actions:

• slotmanager://host:port/get-slot?TIME: Get a new slot for the TIME estimated execution time. TIME is a name from the Job.ExecutionTime enumeration. If succcessful, the request handler answers with OK on the first line and then Id:slot-id and Slot:TIME on the following lines. It is recommended that the answer is parsed with JobAgentConnection.parseSimpleAnswer(String).
• slotmanger://slot-id@host:port/release-slot: Release the slot with the given id.
• slotmanager://slot-id@host:port/ping-slot: Ping the slot with the given id to indicate that the job is still running on the remote job agent. A remote slot has a timeout of 30 seconds so the remote job agent has to send a ping at least at that interval or the slot will be returned to the pool.

If a request fails, the request handler returns FAILED followed with an explanation.

Since:

2.16

Author:

Nicklas

Last modified

$Date: 2010-10-19 13:02:17 +0200 (Tue, 19 Oct 2010) $

Nested Class Summary

(package private) static class	MasterSlotManager.RemoteSlot A remote slot is a slot with some information about when it was created and last updated.
(package private) static class	MasterSlotManager.RemoteSlotRequestHandler Request handler implementation that accepts requests for slots from remote hosts.
(package private) static class	MasterSlotManager.RemoteSlotTimeoutChecker Task that is scheduled at regular intervals to check for timed out slots.

Field Summary

private static Logger	log
private MasterSlotManager.RemoteSlotRequestHandler	remoteRequestHandler
private Map<String,MasterSlotManager.RemoteSlot>	remoteSlots
private TimerTask	timeoutChecker

Constructor Summary

MasterSlotManager()

Method Summary

(package private) int	checkTimeoutOnRemoteSlots() Check the remote slots to see if they have timed out.
void	close() This method is called when the job agent is shutting down.
(package private) MasterSlotManager.RemoteSlot	getRemoteSlot(Job.ExecutionTime estimated) Create a slot for a job on a remote job agent with the specified estimated execution time.
(package private) MasterSlotManager.RemoteSlot	getRemoteSlot(String slotId) Get the remote slot with the given id.
void	init(Agent agent) Initialize the slot manager.
(package private) MasterSlotManager.RemoteSlot	releaseRemoteSlot(String slotId) Release the remote slot with the given id.

Methods inherited from class net.sf.basedb.clients.jobagent.slotmanager.InternalSlotManager

getAgent, getSlot, getSlot, releaseSlot

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final Logger log

remoteSlots

private Map<String,MasterSlotManager.RemoteSlot> remoteSlots

remoteRequestHandler

private MasterSlotManager.RemoteSlotRequestHandler remoteRequestHandler

timeoutChecker

private TimerTask timeoutChecker

Constructor Detail

MasterSlotManager

public MasterSlotManager()

Method Detail

init

public void init(Agent agent)

Description copied from interface: SlotManager

Initialize the slot manager. This method is called once when the job agent is starting up. The slot manager may read configuration settings, and intialize local resources.

Specified by:

init in interface SlotManager

Overrides:

init in class InternalSlotManager

Parameters:

agent - The job agent

close

public void close()

Description copied from interface: SlotManager

This method is called when the job agent is shutting down. The slot manager should clean up any resources it is using.

Specified by:

close in interface SlotManager

Overrides:

close in class InternalSlotManager

getRemoteSlot

MasterSlotManager.RemoteSlot getRemoteSlot(Job.ExecutionTime estimated)

Create a slot for a job on a remote job agent with the specified estimated execution time. This method will call the InternalSlotManager.getSlot(net.sf.basedb.core.Job.ExecutionTime) and then wrap the slot in a MasterSlotManager.RemoteSlot instance.

Returns:

A remote slot, or null if not slot is available

getRemoteSlot

MasterSlotManager.RemoteSlot getRemoteSlot(String slotId)

Get the remote slot with the given id.

Parameters:

slotId - The id of the slot

Returns:

A remote slot or null if no slot with the given id exists

releaseRemoteSlot

MasterSlotManager.RemoteSlot releaseRemoteSlot(String slotId)

Release the remote slot with the given id.

Parameters:

slotId - The id of the slot

Returns:

A remote slot or null if no slot with the given id exists

checkTimeoutOnRemoteSlots

int checkTimeoutOnRemoteSlots()

Check the remote slots to see if they have timed out. If so, release them.

Returns:

The number of timed out slots