Module org.elasticsearch.server

Package org.elasticsearch.reservedstate.service

Class FileSettingsService

java.lang.Object

org.elasticsearch.common.component.AbstractLifecycleComponent

org.elasticsearch.reservedstate.service.FileSettingsService

All Implemented Interfaces:

Closeable, AutoCloseable, ClusterStateListener, LifecycleComponent, Releasable

public class FileSettingsService
extends AbstractLifecycleComponent
implements ClusterStateListener

File based settings applier service which watches an 'operator` directory inside the config directory.

The service expects that the operator directory will contain a single JSON file with all the settings that need to be applied to the cluster state. The name of the file is fixed to be settings.json. The operator directory name can be configured by setting the 'path.config.operator_directory' in the node properties.

The FileSettingsService is active always, but enabled only on the current master node. We register the service as a listener to cluster state changes, so that we can enable the file watcher thread when this node becomes a master node.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	FileSettingsService.FileSettingsStartupException	Error subclass that is thrown when we encounter a fatal error while applying the operator cluster state at Elasticsearch boot time.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAMESPACE
static final String	OPERATOR_DIRECTORY
static final String	SETTINGS_FILE_NAME

Fields inherited from class org.elasticsearch.common.component.AbstractLifecycleComponent

lifecycle

Constructor Summary

Constructors

Constructor	Description
FileSettingsService(ClusterService clusterService, ReservedClusterStateService stateService, Environment environment)	Constructs the FileSettingsService

Method Summary

Modifier and Type	Method	Description
void	clusterChanged(ClusterChangedEvent event)	Called when cluster state changes.
protected void	doClose()
protected void	doStart()
protected void	doStop()
void	handleSnapshotRestore(ClusterState clusterState, Metadata.Builder mdBuilder)	Used by snapshot restore service RestoreService to prepare the reserved state of the snapshot for the current cluster.

Methods inherited from class org.elasticsearch.common.component.AbstractLifecycleComponent

addLifecycleListener, close, lifecycleState, start, stop

Methods inherited from class java.lang.Object

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

Field Details

SETTINGS_FILE_NAME

public static final String SETTINGS_FILE_NAME

See Also:

• Constant Field Values

NAMESPACE

public static final String NAMESPACE

See Also:

• Constant Field Values

OPERATOR_DIRECTORY

public static final String OPERATOR_DIRECTORY

See Also:

• Constant Field Values

Constructor Details

FileSettingsService

public FileSettingsService(ClusterService clusterService,
 ReservedClusterStateService stateService,
 Environment environment)

Constructs the FileSettingsService

Parameters:

clusterService - so we can register ourselves as a cluster state change listener

stateService - an instance of the immutable cluster state controller, so we can perform the cluster state changes

environment - we need the environment to pull the location of the config and operator directories

Method Details

doStart

protected void doStart()

Specified by:

doStart in class AbstractLifecycleComponent

doStop

protected void doStop()

Specified by:

doStop in class AbstractLifecycleComponent

doClose

protected void doClose()

Specified by:

doClose in class AbstractLifecycleComponent

clusterChanged

public void clusterChanged(ClusterChangedEvent event)

Description copied from interface: ClusterStateListener

Called when cluster state changes.

Cluster states are applied one-by-one which means they can be a performance bottleneck. Implementations of this method should therefore be fast, so please consider forking work into the background rather than doing everything inline.

Specified by:

clusterChanged in interface ClusterStateListener

handleSnapshotRestore

public void handleSnapshotRestore(ClusterState clusterState,
 Metadata.Builder mdBuilder)

Used by snapshot restore service RestoreService to prepare the reserved state of the snapshot for the current cluster.

If the current cluster where we are restoring the snapshot into has any operator file based settings, we'll reset the reserved state version to 0.

If there's no file based settings file in this cluster, we'll remove all state reservations for file based settings from the cluster state.

Parameters:

clusterState - the cluster state before snapshot restore

mdBuilder - the current metadata builder for the new cluster state