Java tutorial
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See the License for the * specific language governing permissions and limitations * under the License. */ package org.elasticsearch.action.admin.indices.shrink; import org.apache.lucene.index.IndexWriter; import org.elasticsearch.action.ActionListener; import org.elasticsearch.action.admin.indices.create.CreateIndexClusterStateUpdateRequest; import org.elasticsearch.action.admin.indices.create.CreateIndexRequest; import org.elasticsearch.action.admin.indices.stats.IndexShardStats; import org.elasticsearch.action.admin.indices.stats.IndicesStatsResponse; import org.elasticsearch.action.support.ActionFilters; import org.elasticsearch.action.support.master.TransportMasterNodeAction; import org.elasticsearch.client.Client; import org.elasticsearch.cluster.ClusterState; import org.elasticsearch.cluster.block.ClusterBlockException; import org.elasticsearch.cluster.block.ClusterBlockLevel; import org.elasticsearch.cluster.metadata.IndexMetaData; import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver; import org.elasticsearch.cluster.metadata.MetaDataCreateIndexService; import org.elasticsearch.cluster.service.ClusterService; import org.elasticsearch.common.inject.Inject; import org.elasticsearch.common.settings.Settings; import org.elasticsearch.index.shard.DocsStats; import org.elasticsearch.index.shard.ShardId; import org.elasticsearch.threadpool.ThreadPool; import org.elasticsearch.transport.TransportService; import java.util.Set; import java.util.function.IntFunction; /** * Main class to initiate shrinking an index into a new index with a single shard */ public class TransportShrinkAction extends TransportMasterNodeAction<ShrinkRequest, ShrinkResponse> { private final MetaDataCreateIndexService createIndexService; private final Client client; @Inject public TransportShrinkAction(Settings settings, TransportService transportService, ClusterService clusterService, ThreadPool threadPool, MetaDataCreateIndexService createIndexService, ActionFilters actionFilters, IndexNameExpressionResolver indexNameExpressionResolver, Client client) { super(settings, ShrinkAction.NAME, transportService, clusterService, threadPool, actionFilters, indexNameExpressionResolver, ShrinkRequest::new); this.createIndexService = createIndexService; this.client = client; } @Override protected String executor() { // we go async right away return ThreadPool.Names.SAME; } @Override protected ShrinkResponse newResponse() { return new ShrinkResponse(); } @Override protected ClusterBlockException checkBlock(ShrinkRequest request, ClusterState state) { return state.blocks().indexBlockedException(ClusterBlockLevel.METADATA_WRITE, request.getShrinkIndexRequest().index()); } @Override protected void masterOperation(final ShrinkRequest shrinkRequest, final ClusterState state, final ActionListener<ShrinkResponse> listener) { final String sourceIndex = indexNameExpressionResolver .resolveDateMathExpression(shrinkRequest.getSourceIndex()); client.admin().indices().prepareStats(sourceIndex).clear().setDocs(true) .execute(new ActionListener<IndicesStatsResponse>() { @Override public void onResponse(IndicesStatsResponse indicesStatsResponse) { CreateIndexClusterStateUpdateRequest updateRequest = prepareCreateIndexRequest( shrinkRequest, state, (i) -> { IndexShardStats shard = indicesStatsResponse.getIndex(sourceIndex) .getIndexShards().get(i); return shard == null ? null : shard.getPrimary().getDocs(); }, indexNameExpressionResolver); createIndexService.createIndex(updateRequest, ActionListener.wrap( response -> listener.onResponse( new ShrinkResponse(response.isAcknowledged(), response.isShardsAcked())), listener::onFailure)); } @Override public void onFailure(Exception e) { listener.onFailure(e); } }); } // static for unittesting this method static CreateIndexClusterStateUpdateRequest prepareCreateIndexRequest(final ShrinkRequest shrinkReqeust, final ClusterState state, final IntFunction<DocsStats> perShardDocStats, IndexNameExpressionResolver indexNameExpressionResolver) { final String sourceIndex = indexNameExpressionResolver .resolveDateMathExpression(shrinkReqeust.getSourceIndex()); final CreateIndexRequest targetIndex = shrinkReqeust.getShrinkIndexRequest(); final String targetIndexName = indexNameExpressionResolver.resolveDateMathExpression(targetIndex.index()); final IndexMetaData metaData = state.metaData().index(sourceIndex); final Settings targetIndexSettings = Settings.builder().put(targetIndex.settings()) .normalizePrefix(IndexMetaData.INDEX_SETTING_PREFIX).build(); int numShards = 1; if (IndexMetaData.INDEX_NUMBER_OF_SHARDS_SETTING.exists(targetIndexSettings)) { numShards = IndexMetaData.INDEX_NUMBER_OF_SHARDS_SETTING.get(targetIndexSettings); } for (int i = 0; i < numShards; i++) { Set<ShardId> shardIds = IndexMetaData.selectShrinkShards(i, metaData, numShards); long count = 0; for (ShardId id : shardIds) { DocsStats docsStats = perShardDocStats.apply(id.id()); if (docsStats != null) { count += docsStats.getCount(); } if (count > IndexWriter.MAX_DOCS) { throw new IllegalStateException("Can't merge index with more than [" + IndexWriter.MAX_DOCS + "] docs - too many documents in shards " + shardIds); } } } targetIndex.cause("shrink_index"); Settings.Builder settingsBuilder = Settings.builder().put(targetIndexSettings); settingsBuilder.put("index.number_of_shards", numShards); targetIndex.settings(settingsBuilder); return new CreateIndexClusterStateUpdateRequest(targetIndex, "shrink_index", targetIndexName, true) // mappings are updated on the node when merging in the shards, this prevents race-conditions since all mapping must be // applied once we took the snapshot and if somebody fucks things up and switches the index read/write and adds docs we miss // the mappings for everything is corrupted and hard to debug .ackTimeout(targetIndex.timeout()).masterNodeTimeout(targetIndex.masterNodeTimeout()) .settings(targetIndex.settings()).aliases(targetIndex.aliases()).customs(targetIndex.customs()) .waitForActiveShards(targetIndex.waitForActiveShards()).shrinkFrom(metaData.getIndex()); } }