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talevytalevy
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Skip Shrink when numberOfShards not changed
Previously, ShrinkAction would fail if it was executed on an index that had the same number of shards as the target shrunken number. This PR introduced a new BranchingStep that is used inside of ShrinkAction to branch which step to move to next, depending on the shard values. So no shrink will occur if the shard count is unchanged.
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8 files changed

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‎x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/indexlifecycle/BranchingStep.java‎

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/*
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* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
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* or more contributor license agreements. Licensed under the Elastic License;
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* you may not use this file except in compliance with the Elastic License.
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*/
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package org.elasticsearch.xpack.core.indexlifecycle;
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import org.apache.logging.log4j.LogManager;
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import org.apache.logging.log4j.Logger;
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import org.apache.lucene.util.SetOnce;
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import org.elasticsearch.cluster.ClusterState;
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import org.elasticsearch.cluster.metadata.IndexMetaData;
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import org.elasticsearch.index.Index;
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import java.util.Objects;
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import java.util.function.BiPredicate;
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public class BranchingStep extends ClusterStateActionStep {
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public static final String NAME = "branch";
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private static final Logger logger = LogManager.getLogger(BranchingStep.class);
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private StepKey nextStepKeyOnFalse;
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private StepKey nextStepKeyOnTrue;
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private BiPredicate<Index, ClusterState> predicate;
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private SetOnce<Boolean> predicateValue;
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/**
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* {@link BranchingStep} is a step whose next step is based on
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* the return value of a specific predicate.
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*
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* @param key the step's key
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* @param nextStepKeyOnFalse the key of the step to run if predicate returns false
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* @param nextStepKeyOnTrue the key of the step to run if predicate returns true
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* @param predicate the condition to check when deciding which step to run next
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*/
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public BranchingStep(StepKey key, StepKey nextStepKeyOnFalse, StepKey nextStepKeyOnTrue, BiPredicate<Index, ClusterState> predicate) {
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// super.nextStepKey is set to null since it is not used by this step
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super(key, null);
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this.nextStepKeyOnFalse = nextStepKeyOnFalse;
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this.nextStepKeyOnTrue = nextStepKeyOnTrue;
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this.predicate = predicate;
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this.predicateValue = new SetOnce<>();
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}
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@Override
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public ClusterState performAction(Index index, ClusterState clusterState) {
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IndexMetaData indexMetaData = clusterState.metaData().index(index);
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if (indexMetaData == null) {
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// Index must have been since deleted, ignore it
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logger.debug("[{}] lifecycle action for index [{}] executed but index no longer exists", getKey().getAction(), index.getName());
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return clusterState;
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}
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predicateValue.set(predicate.test(index, clusterState));
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return clusterState;
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}
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/**
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* This method returns the next step to execute based on the predicate. If
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* the predicate returned true, then nextStepKeyOnTrue is the key of the
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* next step to run, otherwise nextStepKeyOnFalse is.
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*
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* throws {@link UnsupportedOperationException} if performAction was not called yet
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*
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* @return next step to execute
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*/
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@Override
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public final StepKey getNextStepKey() {
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if (predicateValue.get() == null) {
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throw new UnsupportedOperationException("Cannot call getNextStepKey before performAction");
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}
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return predicateValue.get() ? nextStepKeyOnTrue : nextStepKeyOnFalse;
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}
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/**
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* @return the next step if {@code predicate} is false
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*/
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final StepKey getNextStepKeyOnFalse() {
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return nextStepKeyOnFalse;
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}
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/**
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* @return the next step if {@code predicate} is true
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*/
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final StepKey getNextStepKeyOnTrue() {
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return nextStepKeyOnTrue;
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}
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public final BiPredicate<Index, ClusterState> getPredicate() {
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return predicate;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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if (!super.equals(o)) return false;
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BranchingStep that = (BranchingStep) o;
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return super.equals(o)
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&& Objects.equals(nextStepKeyOnFalse, that.nextStepKeyOnFalse)
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&& Objects.equals(nextStepKeyOnTrue, that.nextStepKeyOnTrue);
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}
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@Override
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public int hashCode() {
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return Objects.hash(super.hashCode(), nextStepKeyOnFalse, nextStepKeyOnTrue);
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}
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}

‎x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/indexlifecycle/ShrinkAction.java‎

Lines changed: 7 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -85,6 +85,7 @@ public boolean isSafeAction() {
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public List<Step> toSteps(Client client, String phase, Step.StepKey nextStepKey) {
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Settings readOnlySettings = Settings.builder().put(IndexMetaData.SETTING_BLOCKS_WRITE, true).build();
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StepKey branchingKey = new StepKey(phase, NAME, BranchingStep.NAME);
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StepKey readOnlyKey = new StepKey(phase, NAME, ReadOnlyAction.NAME);
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StepKey setSingleNodeKey = new StepKey(phase, NAME, SetSingleNodeAllocateStep.NAME);
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StepKey allocationRoutedKey = new StepKey(phase, NAME, CheckShrinkReadyStep.NAME);
@@ -94,6 +95,8 @@ public List<Step> toSteps(Client client, String phase, Step.StepKey nextStepKey)
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StepKey aliasKey = new StepKey(phase, NAME, ShrinkSetAliasStep.NAME);
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StepKey isShrunkIndexKey = new StepKey(phase, NAME, ShrunkenIndexCheckStep.NAME);
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BranchingStep conditionalSkipShrinkStep = new BranchingStep(branchingKey, readOnlyKey, nextStepKey,
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(index, clusterState) -> clusterState.getMetaData().index(index).getNumberOfShards() == numberOfShards);
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UpdateSettingsStep readOnlyStep = new UpdateSettingsStep(readOnlyKey, setSingleNodeKey, client, readOnlySettings);
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SetSingleNodeAllocateStep setSingleNodeStep = new SetSingleNodeAllocateStep(setSingleNodeKey, allocationRoutedKey, client);
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CheckShrinkReadyStep checkShrinkReadyStep = new CheckShrinkReadyStep(allocationRoutedKey, shrinkKey);
@@ -102,12 +105,13 @@ public List<Step> toSteps(Client client, String phase, Step.StepKey nextStepKey)
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CopyExecutionStateStep copyMetadata = new CopyExecutionStateStep(copyMetadataKey, aliasKey, SHRUNKEN_INDEX_PREFIX);
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ShrinkSetAliasStep aliasSwapAndDelete = new ShrinkSetAliasStep(aliasKey, isShrunkIndexKey, client, SHRUNKEN_INDEX_PREFIX);
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ShrunkenIndexCheckStep waitOnShrinkTakeover = new ShrunkenIndexCheckStep(isShrunkIndexKey, nextStepKey, SHRUNKEN_INDEX_PREFIX);
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return Arrays.asList(readOnlyStep, setSingleNodeStep, checkShrinkReadyStep, shrink, allocated, copyMetadata,
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aliasSwapAndDelete, waitOnShrinkTakeover);
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return Arrays.asList(conditionalSkipShrinkStep, readOnlyStep, setSingleNodeStep, checkShrinkReadyStep, shrink, allocated,
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copyMetadata, aliasSwapAndDelete, waitOnShrinkTakeover);
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}
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@Override
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public List<StepKey> toStepKeys(String phase) {
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StepKey conditionalSkipKey = new StepKey(phase, NAME, BranchingStep.NAME);
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StepKey readOnlyKey = new StepKey(phase, NAME, ReadOnlyAction.NAME);
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StepKey setSingleNodeKey = new StepKey(phase, NAME, SetSingleNodeAllocateStep.NAME);
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StepKey checkShrinkReadyKey = new StepKey(phase, NAME, CheckShrinkReadyStep.NAME);
@@ -116,7 +120,7 @@ public List<StepKey> toStepKeys(String phase) {
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StepKey copyMetadataKey = new StepKey(phase, NAME, CopyExecutionStateStep.NAME);
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StepKey aliasKey = new StepKey(phase, NAME, ShrinkSetAliasStep.NAME);
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StepKey isShrunkIndexKey = new StepKey(phase, NAME, ShrunkenIndexCheckStep.NAME);
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return Arrays.asList(readOnlyKey, setSingleNodeKey, checkShrinkReadyKey, shrinkKey, enoughShardsKey,
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return Arrays.asList(conditionalSkipKey, readOnlyKey, setSingleNodeKey, checkShrinkReadyKey, shrinkKey, enoughShardsKey,
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copyMetadataKey, aliasKey, isShrunkIndexKey);
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}
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‎x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/indexlifecycle/Step.java‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -34,7 +34,7 @@ public final StepKey getKey() {
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return key;
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}
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public final StepKey getNextStepKey() {
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public StepKey getNextStepKey() {
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return nextStepKey;
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}
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‎x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/indexlifecycle/BranchingStepTests.java‎

Lines changed: 85 additions & 0 deletions
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/*
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* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
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* or more contributor license agreements. Licensed under the Elastic License;
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* you may not use this file except in compliance with the Elastic License.
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*/
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package org.elasticsearch.xpack.core.indexlifecycle;
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import org.apache.lucene.util.SetOnce;
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import org.elasticsearch.Version;
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import org.elasticsearch.cluster.ClusterName;
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import org.elasticsearch.cluster.ClusterState;
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import org.elasticsearch.cluster.metadata.IndexMetaData;
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import org.elasticsearch.cluster.metadata.MetaData;
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import org.elasticsearch.index.Index;
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import org.elasticsearch.xpack.core.indexlifecycle.Step.StepKey;
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import java.util.function.BiPredicate;
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import static org.hamcrest.Matchers.equalTo;
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public class BranchingStepTests extends AbstractStepTestCase<BranchingStep> {
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public void testPredicateNextStepChange() {
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String indexName = randomAlphaOfLength(5);
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ClusterState state = ClusterState.builder(ClusterName.DEFAULT).metaData(MetaData.builder()
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.put(IndexMetaData.builder(indexName).settings(settings(Version.CURRENT))
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.numberOfShards(1).numberOfReplicas(0))).build();
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StepKey stepKey = new StepKey(randomAlphaOfLength(5), randomAlphaOfLength(5), BranchingStep.NAME);
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StepKey nextStepKey = new StepKey(randomAlphaOfLength(6), randomAlphaOfLength(6), BranchingStep.NAME);
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StepKey nextSkipKey = new StepKey(randomAlphaOfLength(7), randomAlphaOfLength(7), BranchingStep.NAME);
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{
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BranchingStep step = new BranchingStep(stepKey, nextStepKey, nextSkipKey, (i, c) -> true);
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expectThrows(UnsupportedOperationException.class, step::getNextStepKey);
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step.performAction(state.metaData().index(indexName).getIndex(), state);
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assertThat(step.getNextStepKey(), equalTo(step.getNextStepKeyOnTrue()));
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expectThrows(SetOnce.AlreadySetException.class, () -> step.performAction(state.metaData().index(indexName).getIndex(), state));
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}
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{
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BranchingStep step = new BranchingStep(stepKey, nextStepKey, nextSkipKey, (i, c) -> false);
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expectThrows(UnsupportedOperationException.class, step::getNextStepKey);
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step.performAction(state.metaData().index(indexName).getIndex(), state);
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assertThat(step.getNextStepKey(), equalTo(step.getNextStepKeyOnFalse()));
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expectThrows(SetOnce.AlreadySetException.class, () -> step.performAction(state.metaData().index(indexName).getIndex(), state));
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}
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}
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@Override
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public BranchingStep createRandomInstance() {
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StepKey stepKey = new StepKey(randomAlphaOfLength(5), randomAlphaOfLength(5), BranchingStep.NAME);
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StepKey nextStepKey = new StepKey(randomAlphaOfLength(6), randomAlphaOfLength(6), BranchingStep.NAME);
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StepKey nextSkipKey = new StepKey(randomAlphaOfLength(7), randomAlphaOfLength(7), BranchingStep.NAME);
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return new BranchingStep(stepKey, nextStepKey, nextSkipKey, (i, c) -> randomBoolean());
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}
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@Override
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public BranchingStep mutateInstance(BranchingStep instance) {
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StepKey key = instance.getKey();
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StepKey nextStepKey = instance.getNextStepKeyOnFalse();
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StepKey nextSkipStepKey = instance.getNextStepKeyOnTrue();
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BiPredicate<Index, ClusterState> predicate = instance.getPredicate();
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switch (between(0, 2)) {
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case 0:
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key = new StepKey(key.getPhase(), key.getAction(), key.getName() + randomAlphaOfLength(5));
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break;
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case 1:
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nextStepKey = new StepKey(nextStepKey.getPhase(), nextStepKey.getAction(), nextStepKey.getName() + randomAlphaOfLength(5));
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break;
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case 2:
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nextSkipStepKey = new StepKey(nextSkipStepKey.getPhase(), nextSkipStepKey.getAction(),
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nextSkipStepKey.getName() + randomAlphaOfLength(5));
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break;
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default:
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throw new AssertionError("Illegal randomisation branch");
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}
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return new BranchingStep(key, nextStepKey, nextSkipStepKey, predicate);
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}
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@Override
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public BranchingStep copyInstance(BranchingStep instance) {
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return new BranchingStep(instance.getKey(), instance.getNextStepKeyOnFalse(), instance.getNextStepKeyOnTrue(),
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instance.getPredicate());
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}
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}

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