Module org.elasticsearch.server

Package org.elasticsearch.health

Class HealthPeriodicLogger

java.lang.Object

org.elasticsearch.common.component.AbstractLifecycleComponent

org.elasticsearch.health.HealthPeriodicLogger

All Implemented Interfaces:

Closeable, AutoCloseable, ClusterStateListener, LifecycleComponent, SchedulerEngine.Listener, Releasable

public class HealthPeriodicLogger
extends AbstractLifecycleComponent
implements ClusterStateListener, SchedulerEngine.Listener

This class periodically logs the results of the Health API to the standard Elasticsearch server log file. It a lifecycle aware component because it health depends on other lifecycle aware components. This means: - We do not schedule any jobs until the lifecycle state is STARTED - When the lifecycle state becomes STOPPED, do not schedule any more runs, but we do let the current one finish - When the lifecycle state becomes CLOSED, we will interrupt the current run as well.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	HealthPeriodicLogger.OutputMode	Valid modes of output for this logger

Field Summary

Fields

Modifier and Type	Field	Description
static final Setting<Boolean>	ENABLED_SETTING
static final String	HEALTH_FIELD_PREFIX
protected static final String	HEALTH_PERIODIC_LOGGER_JOB_NAME	Name constant for the job HealthService schedules
static final String	MESSAGE_FIELD
static final Setting<List<HealthPeriodicLogger.OutputMode>>	OUTPUT_MODE_SETTING
static final Setting<TimeValue>	POLL_INTERVAL_SETTING

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

lifecycle

Method Summary

Modifier and Type	Method	Description
void	clusterChanged(ClusterChangedEvent event)	Called when cluster state changes.
static HealthPeriodicLogger	create(Settings settings, ClusterService clusterService, Client client, HealthService healthService, TelemetryProvider telemetryProvider)	Creates a new HealthPeriodicLogger.
protected void	doClose()	Close this component.
protected void	doStart()	Start this component.
protected void	doStop()	Stopping means that the periodic health logger will not schedule any more runs.
void	triggered(SchedulerEngine.Event event)

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

HEALTH_FIELD_PREFIX

public static final String HEALTH_FIELD_PREFIX

See Also:

• Constant Field Values

MESSAGE_FIELD

public static final String MESSAGE_FIELD

See Also:

• Constant Field Values

POLL_INTERVAL_SETTING

public static final Setting<TimeValue> POLL_INTERVAL_SETTING

ENABLED_SETTING

public static final Setting<Boolean> ENABLED_SETTING

OUTPUT_MODE_SETTING

public static final Setting<List<HealthPeriodicLogger.OutputMode>> OUTPUT_MODE_SETTING

HEALTH_PERIODIC_LOGGER_JOB_NAME

protected static final String HEALTH_PERIODIC_LOGGER_JOB_NAME

Name constant for the job HealthService schedules

See Also:

• Constant Field Values

Method Details

create

public static HealthPeriodicLogger create(Settings settings,
 ClusterService clusterService,
 Client client,
 HealthService healthService,
 TelemetryProvider telemetryProvider)

Creates a new HealthPeriodicLogger. This creates a scheduled job using the SchedulerEngine framework and runs it on the current health node.

Parameters:

settings - the cluster settings, used to get the interval setting.

clusterService - the cluster service, used to know when the health node changes.

client - the client used to call the Health Service.

healthService - the Health Service, where the actual Health API logic lives.

telemetryProvider - used to get the meter registry for metrics

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

doStart

protected void doStart()

Description copied from class: AbstractLifecycleComponent

Start this component. Typically that means doing things like launching background processes and registering listeners on other components. Other components have been initialized by this point, but may not yet be started.

If this method throws an exception then the startup process will fail, but this component will not be stopped before it is closed.

This method is called while synchronized on AbstractLifecycleComponent.lifecycle. It is only called once in the lifetime of a component, although it may not be called at all if the startup process encountered some kind of fatal error, such as the failure of some other component to initialize or start.

Specified by:

doStart in class AbstractLifecycleComponent

doStop

protected void doStop()

Stopping means that the periodic health logger will not schedule any more runs. If the logger is currently running it will let this run finish, but it will cancel any future scheduling, and it will deregister the cluster state listener.

Specified by:

doStop in class AbstractLifecycleComponent

doClose

protected void doClose()
                throws IOException

Description copied from class: AbstractLifecycleComponent

Close this component. Typically that means doing the reverse of whatever happened during initialization, such as releasing resources acquired there.

This method is called while synchronized on AbstractLifecycleComponent.lifecycle. It is called once in the lifetime of a component. If the component was started then it will be stopped before it is closed, and once it is closed it will not be started or stopped.

Specified by:

doClose in class AbstractLifecycleComponent

Throws:

IOException

triggered

public void triggered(SchedulerEngine.Event event)

Specified by:

triggered in interface SchedulerEngine.Listener