Package org.elasticsearch.persistent

Class PersistentTasksExecutor<Params extends PersistentTaskParams>

java.lang.Object

org.elasticsearch.persistent.PersistentTasksExecutor<Params>

public abstract class PersistentTasksExecutor<Params extends PersistentTaskParams>
extends Object

An executor of tasks that can survive restart of requesting or executing node. These tasks are using cluster state rather than only transport service to send requests and responses.

Field Summary

Fields

Modifier and Type	Field	Description
static PersistentTasksCustomMetadata.Assignment	NO_NODE_FOUND

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PersistentTasksExecutor(String taskName, String executor)

Method Summary

Modifier and Type	Method	Description
protected AllocatedPersistentTask	createTask(long id, String type, String action, TaskId parentTaskId, PersistentTasksCustomMetadata.PersistentTask<Params> taskInProgress, Map<String,String> headers)	Creates a AllocatedPersistentTask for communicating with task manager
PersistentTasksCustomMetadata.Assignment	getAssignment(Params params, Collection<DiscoveryNode> candidateNodes, ClusterState clusterState)	Returns the node id where the params has to be executed,
protected String	getDescription(PersistentTasksCustomMetadata.PersistentTask<Params> taskInProgress)	Returns task description that will be available via task manager
String	getExecutor()
String	getTaskName()
protected abstract void	nodeOperation(AllocatedPersistentTask task, Params params, PersistentTaskState state)	This operation will be executed on the executor node.
protected DiscoveryNode	selectLeastLoadedNode(ClusterState clusterState, Collection<DiscoveryNode> candidateNodes, Predicate<DiscoveryNode> selector)	Finds the least loaded node from amongs the candidate node collection that satisfies the selector criteria
void	validate(Params params, ClusterState clusterState)	Checks the current cluster state for compatibility with the params

Methods inherited from class java.lang.Object

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

Field Details

NO_NODE_FOUND

public static final PersistentTasksCustomMetadata.Assignment NO_NODE_FOUND

Constructor Details

PersistentTasksExecutor

protected PersistentTasksExecutor(String taskName,
 String executor)

Method Details

getTaskName

public String getTaskName()

getAssignment

public PersistentTasksCustomMetadata.Assignment getAssignment(Params params,
 Collection<DiscoveryNode> candidateNodes,
 ClusterState clusterState)

Returns the node id where the params has to be executed,

The default implementation returns the least loaded data node from amongst the collection of candidate nodes

selectLeastLoadedNode

protected DiscoveryNode selectLeastLoadedNode(ClusterState clusterState,
 Collection<DiscoveryNode> candidateNodes,
 Predicate<DiscoveryNode> selector)

Finds the least loaded node from amongs the candidate node collection that satisfies the selector criteria

validate

public void validate(Params params,
 ClusterState clusterState)

Checks the current cluster state for compatibility with the params

Throws an exception if the supplied params cannot be executed on the cluster in the current state.

createTask

protected AllocatedPersistentTask createTask(long id,
 String type,
 String action,
 TaskId parentTaskId,
 PersistentTasksCustomMetadata.PersistentTask<Params> taskInProgress,
 Map<String,String> headers)

Creates a AllocatedPersistentTask for communicating with task manager

getDescription

protected String getDescription(PersistentTasksCustomMetadata.PersistentTask<Params> taskInProgress)

Returns task description that will be available via task manager

nodeOperation

protected abstract void nodeOperation(AllocatedPersistentTask task,
 Params params,
 @Nullable
 PersistentTaskState state)

This operation will be executed on the executor node.

NOTE: The nodeOperation has to throw an exception, trigger task.markAsCompleted() or task.completeAndNotifyIfNeeded() methods to indicate that the persistent task has finished.

getExecutor

public String getExecutor()