Add size-based condition to the index rollover API (#27160)

This is to add a max_size condition to the index rollover API. We use
a totalSizeInBytes from DocsStats to evaluate this condition.

Closes #27004

core/src/main/java/org/elasticsearch/action/admin/indices/rollover/Condition.java

@@ -19,8 +19,10 @@
 
 package org.elasticsearch.action.admin.indices.rollover;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.io.stream.NamedWriteable;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ObjectParser;
 
@@ -38,6 +40,9 @@ public abstract class Condition<T> implements NamedWriteable {
             new ParseField(MaxAgeCondition.NAME));
         PARSER.declareLong((conditions, value) ->
             conditions.add(new MaxDocsCondition(value)), new ParseField(MaxDocsCondition.NAME));
+        PARSER.declareString((conditions, s) ->
+                conditions.add(new MaxSizeCondition(ByteSizeValue.parseBytesSizeValue(s, MaxSizeCondition.NAME))),
+            new ParseField(MaxSizeCondition.NAME));
     }
 
     protected T value;
@@ -49,6 +54,14 @@ public abstract class Condition<T> implements NamedWriteable {
 
     public abstract Result evaluate(Stats stats);
 
+    /**
+     * Checks if this condition is available in a specific version.
+     * This makes sure BWC when introducing a new condition which is not recognized by older versions.
+     */
+    boolean includedInVersion(Version version) {
+        return true;
+    }
+
     @Override
     public final String toString() {
         return "[" + name + ": " + value + "]";
@@ -60,10 +73,12 @@ public abstract class Condition<T> implements NamedWriteable {
     public static class Stats {
         public final long numDocs;
         public final long indexCreated;
+        public final ByteSizeValue indexSize;
 
-        public Stats(long numDocs, long indexCreated) {
+        public Stats(long numDocs, long indexCreated, ByteSizeValue indexSize) {
             this.numDocs = numDocs;
             this.indexCreated = indexCreated;
+            this.indexSize = indexSize;
         }
     }
 

core/src/main/java/org/elasticsearch/action/admin/indices/rollover/MaxSizeCondition.java

@@ -0,0 +1,66 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * 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.action.admin.indices.rollover;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.unit.ByteSizeUnit;
+import org.elasticsearch.common.unit.ByteSizeValue;
+
+import java.io.IOException;
+
+/**
+ * A size-based condition for an index size.
+ * Evaluates to <code>true</code> if the index size is at least {@link #value}.
+ */
+public class MaxSizeCondition extends Condition<ByteSizeValue> {
+    public static final String NAME = "max_size";
+
+    public MaxSizeCondition(ByteSizeValue value) {
+        super(NAME);
+        this.value = value;
+    }
+
+    public MaxSizeCondition(StreamInput in) throws IOException {
+        super(NAME);
+        this.value = new ByteSizeValue(in.readVLong(), ByteSizeUnit.BYTES);
+    }
+
+    @Override
+    public Result evaluate(Stats stats) {
+        return new Result(this, stats.indexSize.getBytes() >= value.getBytes());
+    }
+
+    @Override
+    boolean includedInVersion(Version version) {
+        return version.onOrAfter(Version.V_7_0_0_alpha1);
+    }
+
+    @Override
+    public String getWriteableName() {
+        return NAME;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(value.getBytes());
+    }
+}

core/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverRequest.java

@@ -27,6 +27,7 @@ import org.elasticsearch.action.support.master.AcknowledgedRequest;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ObjectParser;
 
@@ -106,7 +107,9 @@ public class RolloverRequest extends AcknowledgedRequest<RolloverRequest> implem
         out.writeBoolean(dryRun);
         out.writeVInt(conditions.size());
         for (Condition condition : conditions) {
-            out.writeNamedWriteable(condition);
+            if (condition.includedInVersion(out.getVersion())) {
+                out.writeNamedWriteable(condition);
+            }
         }
         createIndexRequest.writeTo(out);
     }
@@ -155,6 +158,13 @@ public class RolloverRequest extends AcknowledgedRequest<RolloverRequest> implem
         this.conditions.add(new MaxDocsCondition(numDocs));
     }
 
+    /**
+     * Adds a size-based condition to check if the index size is at least <code>size</code>.
+     */
+    public void addMaxIndexSizeCondition(ByteSizeValue size) {
+        this.conditions.add(new MaxSizeCondition(size));
+    }
+
     /**
      * Sets rollover index creation request to override index settings when
      * the rolled over index has to be created

core/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverRequestBuilder.java

@@ -23,6 +23,7 @@ import org.elasticsearch.action.support.ActiveShardCount;
 import org.elasticsearch.action.support.master.MasterNodeOperationRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 
 
@@ -52,6 +53,11 @@ public class RolloverRequestBuilder extends MasterNodeOperationRequestBuilder<Ro
         return this;
     }
 
+    public RolloverRequestBuilder addMaxIndexSizeCondition(ByteSizeValue size){
+        this.request.addMaxIndexSizeCondition(size);
+        return this;
+    }
+
     public RolloverRequestBuilder dryRun(boolean dryRun) {
         this.request.dryRun(dryRun);
         return this;

core/src/main/java/org/elasticsearch/action/admin/indices/rollover/TransportRolloverAction.java

@@ -43,6 +43,7 @@ import org.elasticsearch.cluster.metadata.MetaDataIndexAliasesService;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.index.shard.DocsStats;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
@@ -195,7 +196,8 @@ public class TransportRolloverAction extends TransportMasterNodeAction<RolloverR
     static Set<Condition.Result> evaluateConditions(final Set<Condition> conditions,
                                                     final DocsStats docsStats, final IndexMetaData metaData) {
         final long numDocs = docsStats == null ? 0 : docsStats.getCount();
-        final Condition.Stats stats = new Condition.Stats(numDocs, metaData.getCreationDate());
+        final long indexSize = docsStats == null ? 0 : docsStats.getTotalSizeInBytes();
+        final Condition.Stats stats = new Condition.Stats(numDocs, metaData.getCreationDate(), new ByteSizeValue(indexSize));
         return conditions.stream()
             .map(condition -> condition.evaluate(stats))
             .collect(Collectors.toSet());

core/src/main/java/org/elasticsearch/indices/IndicesModule.java

@@ -22,6 +22,7 @@ package org.elasticsearch.indices;
 import org.elasticsearch.action.admin.indices.rollover.Condition;
 import org.elasticsearch.action.admin.indices.rollover.MaxAgeCondition;
 import org.elasticsearch.action.admin.indices.rollover.MaxDocsCondition;
+import org.elasticsearch.action.admin.indices.rollover.MaxSizeCondition;
 import org.elasticsearch.action.resync.TransportResyncReplicationAction;
 import org.elasticsearch.index.shard.PrimaryReplicaSyncer;
 import org.elasticsearch.common.geo.ShapesAvailability;
@@ -79,6 +80,7 @@ public class IndicesModule extends AbstractModule {
     private void registerBuiltinWritables() {
         namedWritables.add(new Entry(Condition.class, MaxAgeCondition.NAME, MaxAgeCondition::new));
         namedWritables.add(new Entry(Condition.class, MaxDocsCondition.NAME, MaxDocsCondition::new));
+        namedWritables.add(new Entry(Condition.class, MaxSizeCondition.NAME, MaxSizeCondition::new));
     }
 
     public List<Entry> getNamedWriteables() {

core/src/test/java/org/elasticsearch/action/admin/indices/rollover/ConditionTests.java

@@ -19,6 +19,8 @@
 
 package org.elasticsearch.action.admin.indices.rollover;
 
+import org.elasticsearch.common.unit.ByteSizeUnit;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.test.ESTestCase;
 
@@ -30,12 +32,12 @@ public class ConditionTests extends ESTestCase {
         final MaxAgeCondition maxAgeCondition = new MaxAgeCondition(TimeValue.timeValueHours(1));
 
         long indexCreatedMatch = System.currentTimeMillis() - TimeValue.timeValueMinutes(61).getMillis();
-        Condition.Result evaluate = maxAgeCondition.evaluate(new Condition.Stats(0, indexCreatedMatch));
+        Condition.Result evaluate = maxAgeCondition.evaluate(new Condition.Stats(0, indexCreatedMatch, randomByteSize()));
         assertThat(evaluate.condition, equalTo(maxAgeCondition));
         assertThat(evaluate.matched, equalTo(true));
 
         long indexCreatedNotMatch = System.currentTimeMillis() - TimeValue.timeValueMinutes(59).getMillis();
-        evaluate = maxAgeCondition.evaluate(new Condition.Stats(0, indexCreatedNotMatch));
+        evaluate = maxAgeCondition.evaluate(new Condition.Stats(0, indexCreatedNotMatch, randomByteSize()));
         assertThat(evaluate.condition, equalTo(maxAgeCondition));
         assertThat(evaluate.matched, equalTo(false));
     }
@@ -44,13 +46,33 @@ public class ConditionTests extends ESTestCase {
         final MaxDocsCondition maxDocsCondition = new MaxDocsCondition(100L);
 
         long maxDocsMatch = randomIntBetween(100, 1000);
-        Condition.Result evaluate = maxDocsCondition.evaluate(new Condition.Stats(maxDocsMatch, 0));
+        Condition.Result evaluate = maxDocsCondition.evaluate(new Condition.Stats(maxDocsMatch, 0, randomByteSize()));
         assertThat(evaluate.condition, equalTo(maxDocsCondition));
         assertThat(evaluate.matched, equalTo(true));
 
         long maxDocsNotMatch = randomIntBetween(0, 99);
-        evaluate = maxDocsCondition.evaluate(new Condition.Stats(0, maxDocsNotMatch));
+        evaluate = maxDocsCondition.evaluate(new Condition.Stats(0, maxDocsNotMatch, randomByteSize()));
         assertThat(evaluate.condition, equalTo(maxDocsCondition));
         assertThat(evaluate.matched, equalTo(false));
     }
+
+    public void testMaxSize() throws Exception {
+        MaxSizeCondition maxSizeCondition = new MaxSizeCondition(new ByteSizeValue(randomIntBetween(10, 20), ByteSizeUnit.MB));
+
+        Condition.Result result = maxSizeCondition.evaluate(new Condition.Stats(randomNonNegativeLong(), randomNonNegativeLong(),
+            new ByteSizeValue(0, ByteSizeUnit.MB)));
+        assertThat(result.matched, equalTo(false));
+
+        result = maxSizeCondition.evaluate(new Condition.Stats(randomNonNegativeLong(), randomNonNegativeLong(),
+            new ByteSizeValue(randomIntBetween(0, 9), ByteSizeUnit.MB)));
+        assertThat(result.matched, equalTo(false));
+
+        result = maxSizeCondition.evaluate(new Condition.Stats(randomNonNegativeLong(), randomNonNegativeLong(),
+            new ByteSizeValue(randomIntBetween(20, 1000), ByteSizeUnit.MB)));
+        assertThat(result.matched, equalTo(true));
+    }
+
+    private ByteSizeValue randomByteSize() {
+        return new ByteSizeValue(randomNonNegativeLong(), ByteSizeUnit.BYTES);
+    }
 }

core/src/test/java/org/elasticsearch/action/admin/indices/rollover/RolloverIT.java

@@ -19,13 +19,15 @@
 
 package org.elasticsearch.action.admin.indices.rollover;
 
+import org.elasticsearch.ResourceAlreadyExistsException;
 import org.elasticsearch.action.admin.indices.alias.Alias;
 import org.elasticsearch.action.admin.indices.settings.get.GetSettingsResponse;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeUnit;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.ResourceAlreadyExistsException;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.InternalSettingsPlugin;
@@ -36,9 +38,15 @@ import org.joda.time.format.DateTimeFormat;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
+import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.everyItem;
+import static org.hamcrest.Matchers.hasProperty;
+import static org.hamcrest.Matchers.is;
 
 @ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST)
 public class RolloverIT extends ESIntegTestCase {
@@ -128,15 +136,23 @@ public class RolloverIT extends ESIntegTestCase {
         index("test_index-0", "type1", "1", "field", "value");
         flush("test_index-0");
         final RolloverResponse response = client().admin().indices().prepareRolloverIndex("test_alias")
+            .addMaxIndexSizeCondition(new ByteSizeValue(10, ByteSizeUnit.MB))
             .addMaxIndexAgeCondition(TimeValue.timeValueHours(4)).get();
         assertThat(response.getOldIndex(), equalTo("test_index-0"));
         assertThat(response.getNewIndex(), equalTo("test_index-000001"));
         assertThat(response.isDryRun(), equalTo(false));
         assertThat(response.isRolledOver(), equalTo(false));
-        assertThat(response.getConditionStatus().size(), equalTo(1));
-        final Map.Entry<String, Boolean> conditionEntry = response.getConditionStatus().iterator().next();
-        assertThat(conditionEntry.getKey(), equalTo(new MaxAgeCondition(TimeValue.timeValueHours(4)).toString()));
-        assertThat(conditionEntry.getValue(), equalTo(false));
+        assertThat(response.getConditionStatus().size(), equalTo(2));
+
+
+        assertThat(response.getConditionStatus(), everyItem(hasProperty("value", is(false))));
+        Set<String> conditions = response.getConditionStatus().stream()
+            .map(Map.Entry::getKey)
+            .collect(Collectors.toSet());
+        assertThat(conditions, containsInAnyOrder(
+            new MaxSizeCondition(new ByteSizeValue(10, ByteSizeUnit.MB)).toString(),
+            new MaxAgeCondition(TimeValue.timeValueHours(4)).toString()));
+
         final ClusterState state = client().admin().cluster().prepareState().get().getState();
         final IndexMetaData oldIndex = state.metaData().index("test_index-0");
         assertTrue(oldIndex.getAliases().containsKey("test_alias"));
@@ -218,4 +234,47 @@ public class RolloverIT extends ESIntegTestCase {
         assertThat(response.isRolledOver(), equalTo(true));
         assertThat(response.getConditionStatus().size(), equalTo(0));
     }
+
+    public void testRolloverMaxSize() throws Exception {
+        assertAcked(prepareCreate("test-1").addAlias(new Alias("test_alias")).get());
+        int numDocs = randomIntBetween(10, 20);
+        for (int i = 0; i < numDocs; i++) {
+            index("test-1", "doc", Integer.toString(i), "field", "foo-" + i);
+        }
+        flush("test-1");
+        refresh("test_alias");
+
+        // A large max_size
+        {
+            final RolloverResponse response = client().admin().indices()
+                .prepareRolloverIndex("test_alias")
+                .addMaxIndexSizeCondition(new ByteSizeValue(randomIntBetween(100, 50 * 1024), ByteSizeUnit.MB))
+                .get();
+            assertThat(response.getOldIndex(), equalTo("test-1"));
+            assertThat(response.getNewIndex(), equalTo("test-000002"));
+            assertThat("No rollover with a large max_size condition", response.isRolledOver(), equalTo(false));
+        }
+
+        // A small max_size
+        {
+            final RolloverResponse response = client().admin().indices()
+                .prepareRolloverIndex("test_alias")
+                .addMaxIndexSizeCondition(new ByteSizeValue(randomIntBetween(1, 20), ByteSizeUnit.BYTES))
+                .get();
+            assertThat(response.getOldIndex(), equalTo("test-1"));
+            assertThat(response.getNewIndex(), equalTo("test-000002"));
+            assertThat("Should rollover with a small max_size condition", response.isRolledOver(), equalTo(true));
+        }
+
+        // An empty index
+        {
+            final RolloverResponse response = client().admin().indices()
+                .prepareRolloverIndex("test_alias")
+                .addMaxIndexSizeCondition(new ByteSizeValue(randomNonNegativeLong(), ByteSizeUnit.BYTES))
+                .get();
+            assertThat(response.getOldIndex(), equalTo("test-000002"));
+            assertThat(response.getNewIndex(), equalTo("test-000003"));
+            assertThat("No rollover with an empty index", response.isRolledOver(), equalTo(false));
+        }
+    }
 }

core/src/test/java/org/elasticsearch/action/admin/indices/rollover/RolloverRequestTests.java

@@ -19,17 +19,38 @@
 
 package org.elasticsearch.action.admin.indices.rollover;
 
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.NamedWriteableAwareStreamInput;
+import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.unit.ByteSizeUnit;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.indices.IndicesModule;
 import org.elasticsearch.test.ESTestCase;
+import org.junit.Before;
 
+import java.util.Collections;
+import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.hamcrest.Matchers.equalTo;
 
 public class RolloverRequestTests extends ESTestCase {
 
+    private NamedWriteableRegistry writeableRegistry;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        super.setUp();
+        writeableRegistry = new NamedWriteableRegistry(new IndicesModule(Collections.emptyList()).getNamedWriteables());
+    }
+
     public void testConditionsParsing() throws Exception {
         final RolloverRequest request = new RolloverRequest(randomAlphaOfLength(10), randomAlphaOfLength(10));
         final XContentBuilder builder = XContentFactory.jsonBuilder()
@@ -37,11 +58,12 @@ public class RolloverRequestTests extends ESTestCase {
                 .startObject("conditions")
                     .field("max_age", "10d")
                     .field("max_docs", 100)
+                    .field("max_size", "45gb")
                 .endObject()
             .endObject();
         RolloverRequest.PARSER.parse(createParser(builder), request, null);
         Set<Condition> conditions = request.getConditions();
-        assertThat(conditions.size(), equalTo(2));
+        assertThat(conditions.size(), equalTo(3));
         for (Condition condition : conditions) {
             if (condition instanceof MaxAgeCondition) {
                 MaxAgeCondition maxAgeCondition = (MaxAgeCondition) condition;
@@ -49,6 +71,9 @@ public class RolloverRequestTests extends ESTestCase {
             } else if (condition instanceof MaxDocsCondition) {
                 MaxDocsCondition maxDocsCondition = (MaxDocsCondition) condition;
                 assertThat(maxDocsCondition.value, equalTo(100L));
+            } else if (condition instanceof MaxSizeCondition) {
+                MaxSizeCondition maxSizeCondition = (MaxSizeCondition) condition;
+                assertThat(maxSizeCondition.value.getBytes(), equalTo(ByteSizeUnit.GB.toBytes(45)));
             } else {
                 fail("unexpected condition " + condition);
             }
@@ -87,4 +112,33 @@ public class RolloverRequestTests extends ESTestCase {
         assertThat(request.getCreateIndexRequest().aliases().size(), equalTo(1));
         assertThat(request.getCreateIndexRequest().settings().getAsInt("number_of_shards", 0), equalTo(10));
     }
+
+    public void testSerialize() throws Exception {
+        RolloverRequest originalRequest = new RolloverRequest("alias-index", "new-index-name");
+        originalRequest.addMaxIndexDocsCondition(randomNonNegativeLong());
+        originalRequest.addMaxIndexAgeCondition(TimeValue.timeValueNanos(randomNonNegativeLong()));
+        originalRequest.addMaxIndexSizeCondition(new ByteSizeValue(randomNonNegativeLong()));
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            originalRequest.writeTo(out);
+            BytesReference bytes = out.bytes();
+            try (StreamInput in = new NamedWriteableAwareStreamInput(bytes.streamInput(), writeableRegistry)) {
+                RolloverRequest cloneRequest = new RolloverRequest();
+                cloneRequest.readFrom(in);
+                assertThat(cloneRequest.getNewIndexName(), equalTo(originalRequest.getNewIndexName()));
+                assertThat(cloneRequest.getAlias(), equalTo(originalRequest.getAlias()));
+
+                List<String> originalConditions = originalRequest.getConditions().stream()
+                    .map(Condition::toString)
+                    .sorted()
+                    .collect(Collectors.toList());
+
+                List<String> cloneConditions = cloneRequest.getConditions().stream()
+                    .map(Condition::toString)
+                    .sorted()
+                    .collect(Collectors.toList());
+
+                assertThat(originalConditions, equalTo(cloneConditions));
+            }
+        }
+    }
 }

core/src/test/java/org/elasticsearch/action/admin/indices/rollover/TransportRolloverActionTests.java

@@ -32,23 +32,24 @@ import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeUnit;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.index.shard.DocsStats;
 import org.elasticsearch.test.ESTestCase;
+import org.mockito.ArgumentCaptor;
 
-import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 
-import org.mockito.ArgumentCaptor;
 import static org.elasticsearch.action.admin.indices.rollover.TransportRolloverAction.evaluateConditions;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasSize;
 import static org.mockito.Matchers.any;
-import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 
@@ -59,7 +60,7 @@ public class TransportRolloverActionTests extends ESTestCase {
         long docsInShards = 200;
 
         final Condition condition = createTestCondition();
-        evaluateConditions(Sets.newHashSet(condition), createMetaData(), createIndecesStatResponse(docsInShards, docsInPrimaryShards));
+        evaluateConditions(Sets.newHashSet(condition), createMetaData(), createIndicesStatResponse(docsInShards, docsInPrimaryShards));
         final ArgumentCaptor<Condition.Stats> argument = ArgumentCaptor.forClass(Condition.Stats.class);
         verify(condition).evaluate(argument.capture());
 
@@ -69,8 +70,11 @@ public class TransportRolloverActionTests extends ESTestCase {
     public void testEvaluateConditions() throws Exception {
         MaxDocsCondition maxDocsCondition = new MaxDocsCondition(100L);
         MaxAgeCondition maxAgeCondition = new MaxAgeCondition(TimeValue.timeValueHours(2));
+        MaxSizeCondition maxSizeCondition = new MaxSizeCondition(new ByteSizeValue(randomIntBetween(10, 100), ByteSizeUnit.MB));
+
         long matchMaxDocs = randomIntBetween(100, 1000);
         long notMatchMaxDocs = randomIntBetween(0, 99);
+        ByteSizeValue notMatchMaxSize = new ByteSizeValue(randomIntBetween(0, 9), ByteSizeUnit.MB);
         final Settings settings = Settings.builder()
             .put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT)
             .put(IndexMetaData.SETTING_INDEX_UUID, UUIDs.randomBase64UUID())
@@ -81,30 +85,56 @@ public class TransportRolloverActionTests extends ESTestCase {
             .creationDate(System.currentTimeMillis() - TimeValue.timeValueHours(3).getMillis())
             .settings(settings)
             .build();
-        final HashSet<Condition> conditions = Sets.newHashSet(maxDocsCondition, maxAgeCondition);
-        Set<Condition.Result> results = evaluateConditions(conditions, new DocsStats(matchMaxDocs, 0L, between(1, 10000)), metaData);
-        assertThat(results.size(), equalTo(2));
+        final Set<Condition> conditions = Sets.newHashSet(maxDocsCondition, maxAgeCondition, maxSizeCondition);
+        Set<Condition.Result> results = evaluateConditions(conditions,
+            new DocsStats(matchMaxDocs, 0L, ByteSizeUnit.MB.toBytes(120)), metaData);
+        assertThat(results.size(), equalTo(3));
         for (Condition.Result result : results) {
             assertThat(result.matched, equalTo(true));
         }
-        results = evaluateConditions(conditions, new DocsStats(notMatchMaxDocs, 0, between(1, 10000)), metaData);
-        assertThat(results.size(), equalTo(2));
+
+        results = evaluateConditions(conditions, new DocsStats(notMatchMaxDocs, 0, notMatchMaxSize.getBytes()), metaData);
+        assertThat(results.size(), equalTo(3));
         for (Condition.Result result : results) {
             if (result.condition instanceof MaxAgeCondition) {
                 assertThat(result.matched, equalTo(true));
             } else if (result.condition instanceof MaxDocsCondition) {
                 assertThat(result.matched, equalTo(false));
+            } else if (result.condition instanceof MaxSizeCondition) {
+                assertThat(result.matched, equalTo(false));
             } else {
                 fail("unknown condition result found " + result.condition);
             }
         }
-        results = evaluateConditions(conditions, null, metaData);
-        assertThat(results.size(), equalTo(2));
+    }
+
+    public void testEvaluateWithoutDocStats() throws Exception {
+        MaxDocsCondition maxDocsCondition = new MaxDocsCondition(randomNonNegativeLong());
+        MaxAgeCondition maxAgeCondition = new MaxAgeCondition(TimeValue.timeValueHours(randomIntBetween(1, 3)));
+        MaxSizeCondition maxSizeCondition = new MaxSizeCondition(new ByteSizeValue(randomNonNegativeLong()));
+
+        Set<Condition> conditions = Sets.newHashSet(maxDocsCondition, maxAgeCondition, maxSizeCondition);
+        final Settings settings = Settings.builder()
+            .put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(IndexMetaData.SETTING_INDEX_UUID, UUIDs.randomBase64UUID())
+            .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, randomIntBetween(1, 1000))
+            .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, randomInt(10))
+            .build();
+
+        final IndexMetaData metaData = IndexMetaData.builder(randomAlphaOfLength(10))
+            .creationDate(System.currentTimeMillis() - TimeValue.timeValueHours(randomIntBetween(5, 10)).getMillis())
+            .settings(settings)
+            .build();
+        Set<Condition.Result> results = evaluateConditions(conditions, null, metaData);
+        assertThat(results.size(), equalTo(3));
+
         for (Condition.Result result : results) {
             if (result.condition instanceof MaxAgeCondition) {
                 assertThat(result.matched, equalTo(true));
             } else if (result.condition instanceof MaxDocsCondition) {
                 assertThat(result.matched, equalTo(false));
+            } else if (result.condition instanceof MaxSizeCondition) {
+                assertThat(result.matched, equalTo(false));
             } else {
                 fail("unknown condition result found " + result.condition);
             }
@@ -211,7 +241,7 @@ public class TransportRolloverActionTests extends ESTestCase {
         assertThat(createIndexRequest.cause(), equalTo("rollover_index"));
     }
 
-    private IndicesStatsResponse createIndecesStatResponse(long totalDocs, long primaryDocs) {
+    private IndicesStatsResponse createIndicesStatResponse(long totalDocs, long primaryDocs) {
         final CommonStats primaryStats = mock(CommonStats.class);
         when(primaryStats.getDocs()).thenReturn(new DocsStats(primaryDocs, 0, between(1, 10000)));
 

docs/reference/indices/rollover-index.asciidoc

@@ -25,7 +25,8 @@ POST /logs_write/_rollover <2>
 {
   "conditions": {
     "max_age":   "7d",
-    "max_docs":  1000
+    "max_docs":  1000,
+    "max_size":  "5gb"
   }
 }
 --------------------------------------------------
@@ -34,7 +35,7 @@ POST /logs_write/_rollover <2>
 // TEST[s/# Add > 1000 documents to logs-000001/POST _reindex?refresh\n{"source":{"index":"twitter"},"dest":{"index":"logs-000001"}}/]
 <1> Creates an index called `logs-0000001` with the alias `logs_write`.
 <2> If the index pointed to by `logs_write` was created 7 or more days ago, or
-    contains 1,000 or more documents, then the `logs-000002` index is created
+    contains 1,000 or more documents, or has an index size at least around 5GB, then the `logs-000002` index is created
     and the `logs_write` alias is updated to point to `logs-000002`.
 
 The above request might return the following response:
@@ -50,7 +51,8 @@ The above request might return the following response:
   "dry_run": false, <2>
   "conditions": { <3>
     "[max_age: 7d]": false,
-    "[max_docs: 1000]": true
+    "[max_docs: 1000]": true,
+    "[max_size: 5gb]": false,
   }
 }
 --------------------------------------------------
@@ -76,7 +78,8 @@ POST /my_alias/_rollover/my_new_index_name
 {
   "conditions": {
     "max_age":   "7d",
-    "max_docs":  1000
+    "max_docs":  1000,
+    "max_size": "5gb"
   }
 }
 --------------------------------------------------
@@ -186,7 +189,8 @@ POST /logs_write/_rollover
 {
   "conditions" : {
     "max_age": "7d",
-    "max_docs": 1000
+    "max_docs": 1000,
+    "max_size": "5gb"
   },
   "settings": {
     "index.number_of_shards": 2
@@ -214,7 +218,8 @@ POST /logs_write/_rollover?dry_run
 {
   "conditions" : {
     "max_age": "7d",
-    "max_docs": 1000
+    "max_docs": 1000,
+    "max_size": "5gb"
   }
 }
 --------------------------------------------------

rest-api-spec/src/main/resources/rest-api-spec/test/indices.rollover/30_max_size_condition.yml

@@ -0,0 +1,60 @@
+---
+"Rollover with max_size condition":
+
+  - skip:
+      version: " - 6.99.99"
+      reason: max_size condition is introduced in v7
+
+  # create index with alias and replica
+  - do:
+      indices.create:
+        index: logs-1
+        wait_for_active_shards: 1
+        body:
+          aliases:
+            logs_search: {}
+
+  # index a document
+  - do:
+      index:
+        index: logs-1
+        type:  doc
+        id:    "1"
+        body:  { "foo": "hello world" }
+        refresh: true
+
+  # perform alias rollover with a large max_size, no action.
+  - do:
+      indices.rollover:
+        alias: "logs_search"
+        wait_for_active_shards: 1
+        body:
+          conditions:
+            max_size: 100mb
+
+  - match: { conditions: { "[max_size: 100mb]": false } }
+  - match: { rolled_over: false }
+
+  # perform alias rollover with a small max_size, got action.
+  - do:
+      indices.rollover:
+        alias: "logs_search"
+        wait_for_active_shards: 1
+        body:
+          conditions:
+            max_size: 10b
+
+  - match: { conditions: { "[max_size: 10b]": true } }
+  - match: { rolled_over: true }
+
+  # perform alias rollover on an empty index, no action.
+  - do:
+      indices.rollover:
+        alias: "logs_search"
+        wait_for_active_shards: 1
+        body:
+          conditions:
+            max_size: 1b
+
+  - match: { conditions: { "[max_size: 1b]": false } }
+  - match: { rolled_over: false }