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* Licensed to Elasticsearch under one or more contributor
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* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.index.shard;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.Index;
import org.elasticsearch.index.IndexService;
import org.elasticsearch.index.IndexSettings;
import org.elasticsearch.indices.cluster.IndicesClusterStateService.AllocatedIndices.IndexRemovalReason;
/**
* An index event listener is the primary extension point for plugins and build-in services
* to react / listen to per-index and per-shard events. These listeners are registered per-index
* via {@link org.elasticsearch.index.IndexModule#addIndexEventListener(IndexEventListener)}. All listeners have the same
* lifecycle as the {@link IndexService} they are created for.
* <p>
* An IndexEventListener can be used across multiple indices and shards since all callback methods receive sufficient
* local state via their arguments. Yet, if an instance is shared across indices they might be called concurrently and should not
* modify local state without sufficient synchronization.
* </p>
*/
public interface IndexEventListener {
/**
* Called when the shard routing has changed state.
*
* @param indexShard The index shard
* @param oldRouting The old routing state (can be null)
* @param newRouting The new routing state
*/
default void shardRoutingChanged(IndexShard indexShard, @Nullable ShardRouting oldRouting, ShardRouting newRouting) {}
/**
* Called after the index shard has been created.
*/
default void afterIndexShardCreated(IndexShard indexShard) {}
/**
* Called after the index shard has been started.
*/
default void afterIndexShardStarted(IndexShard indexShard) {}
/**
* Called before the index shard gets closed.
*
* @param indexShard The index shard
*/
default void beforeIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {}
/**
* Called after the index shard has been closed.
*
* @param shardId The shard id
*/
default void afterIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {}
/**
* Called after a shard's {@link org.elasticsearch.index.shard.IndexShardState} changes.
* The order of concurrent events is preserved. The execution must be lightweight.
*
* @param indexShard the shard the new state was applied to
* @param previousState the previous index shard state if there was one, null otherwise
* @param currentState the new shard state
* @param reason the reason for the state change if there is one, null otherwise
*/
default void indexShardStateChanged(IndexShard indexShard, @Nullable IndexShardState previousState, IndexShardState currentState, @Nullable String reason) {}
/**
* Called when a shard is marked as inactive
*
* @param indexShard The shard that was marked inactive
*/
default void onShardInactive(IndexShard indexShard) {}
/**
* Called before the index gets created. Note that this is also called
* when the index is created on data nodes
*/
default void beforeIndexCreated(Index index, Settings indexSettings) {
}
/**
* Called after the index has been created.
*/
default void afterIndexCreated(IndexService indexService) {
}
/**
* Called before the index get closed.
*
* @param indexService The index service
* @param reason the reason for index removal
*/
default void beforeIndexRemoved(IndexService indexService, IndexRemovalReason reason) {
}
/**
* Called after the index has been removed.
*
* @param index The index
* @param reason the reason for index removal
*/
default void afterIndexRemoved(Index index, IndexSettings indexSettings, IndexRemovalReason reason) {
}
/**
* Called before the index shard gets created.
*/
default void beforeIndexShardCreated(ShardId shardId, Settings indexSettings) {
}
/**
* Called before the index shard gets deleted from disk
* Note: this method is only executed on the first attempt of deleting the shard. Retries are will not invoke
* this method.
* @param shardId The shard id
* @param indexSettings the shards index settings
*/
default void beforeIndexShardDeleted(ShardId shardId, Settings indexSettings) {
}
/**
* Called after the index shard has been deleted from disk.
*
* Note: this method is only called if the deletion of the shard did finish without an exception
*
* @param shardId The shard id
* @param indexSettings the shards index settings
*/
default void afterIndexShardDeleted(ShardId shardId, Settings indexSettings) {
}
/**
* Called on the Master node only before the {@link IndexService} instances is created to simulate an index creation.
* This happens right before the index and it's metadata is registered in the cluster state
*/
default void beforeIndexAddedToCluster(Index index, Settings indexSettings) {
}
/**
* Called when the given shards store is closed. The store is closed once all resource have been released on the store.
* This implies that all index readers are closed and no recoveries are running.
*
* @param shardId the shard ID the store belongs to
*/
default void onStoreClosed(ShardId shardId) {}
}