Implement support for reindex API.

Original Pull Request #2070 
Closes #1529

src/main/java/org/springframework/data/elasticsearch/client/reactive/DefaultReactiveElasticsearchClient.java

@@ -83,11 +83,13 @@
 import org.elasticsearch.client.GetAliasesResponse;
 import org.elasticsearch.client.Request;
 import org.elasticsearch.client.indices.*;
+import org.elasticsearch.client.tasks.TaskSubmissionResponse;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.index.get.GetResult;
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.DeleteByQueryRequest;
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
+import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.script.mustache.SearchTemplateRequest;
@@ -143,6 +145,7 @@
  * @author Brian Clozel
  * @author Farid Faoudi
  * @author George Popides
+ * @author Sijia Liu
  * @since 3.2
  * @see ClientConfiguration
  * @see ReactiveRestClients
@@ -509,6 +512,19 @@ public Mono<BulkResponse> bulk(HttpHeaders headers, BulkRequest bulkRequest) {
 				.next();
 	}
 
+	@Override
+	public Mono<BulkByScrollResponse> reindex(HttpHeaders headers, ReindexRequest reindexRequest) {
+		return sendRequest(reindexRequest, requestCreator.reindex(), BulkByScrollResponse.class, headers)
+				.next();
+	}
+
+	@Override
+	public Mono<String> submitReindex(HttpHeaders headers, ReindexRequest reindexRequest) {
+		return sendRequest(reindexRequest, requestCreator.submitReindex(), TaskSubmissionResponse.class, headers)
+				.next()
+				.map(TaskSubmissionResponse::getTask);
+	}
+
 	@Override
 	public <T> Mono<T> execute(ReactiveElasticsearchClientCallback<T> callback) {
 

src/main/java/org/springframework/data/elasticsearch/client/reactive/ReactiveElasticsearchClient.java

@@ -54,6 +54,7 @@
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.DeleteByQueryRequest;
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
+import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.script.mustache.SearchTemplateRequest;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.aggregations.Aggregation;
@@ -76,6 +77,7 @@
  * @author Henrique Amaral
  * @author Thomas Geese
  * @author Farid Faoudi
+ * @author Sijia Liu
  * @since 3.2
  * @see ClientConfiguration
  * @see ReactiveRestClients
@@ -713,6 +715,75 @@ default Mono<BulkResponse> bulk(BulkRequest bulkRequest) {
 	 */
 	Mono<BulkResponse> bulk(HttpHeaders headers, BulkRequest bulkRequest);
 
+	/**
+	 * Execute the given {@link ReindexRequest} against the {@literal reindex} API.
+	 *
+	 * @param consumer must not be {@literal null}
+	 * @return the {@link Mono} emitting the response
+	 * @since 4.4
+	 */
+	default Mono<BulkByScrollResponse> reindex(Consumer<ReindexRequest> consumer){
+
+		ReindexRequest reindexRequest = new ReindexRequest();
+		consumer.accept(reindexRequest);
+		return reindex(reindexRequest);
+	}
+
+	/**
+	 * Execute the given {@link ReindexRequest} against the {@literal reindex} API.
+	 *
+	 * @param reindexRequest must not be {@literal null}
+	 * @return the {@link Mono} emitting the response
+	 * @since 4.4
+	 */
+	default Mono<BulkByScrollResponse> reindex(ReindexRequest reindexRequest){
+		return reindex(HttpHeaders.EMPTY, reindexRequest);
+	}
+
+	/**
+	 * Execute the given {@link ReindexRequest} against the {@literal reindex} API.
+	 *
+	 * @param headers Use {@link HttpHeaders} to provide eg. authentication data. Must not be {@literal null}.
+	 * @param reindexRequest must not be {@literal null}
+	 * @return the {@link Mono} emitting the response
+	 * @since 4.4
+	 */
+	Mono<BulkByScrollResponse> reindex(HttpHeaders headers, ReindexRequest reindexRequest);
+
+	/**
+	 * Execute the given {@link ReindexRequest} against the {@literal reindex} API.
+	 *
+	 * @param consumer must not be {@literal null}
+	 * @return the {@link Mono} emitting the task id
+	 * @since 4.4
+	 */
+	default Mono<String> submitReindex(Consumer<ReindexRequest> consumer){
+
+		ReindexRequest reindexRequest = new ReindexRequest();
+		consumer.accept(reindexRequest);
+		return submitReindex(reindexRequest);
+	}
+
+	/**
+	 * Execute the given {@link ReindexRequest} against the {@literal reindex} API.
+	 *
+	 * @param reindexRequest must not be {@literal null}
+	 * @return the {@link Mono} emitting the task id
+	 * @since 4.4
+	 */
+	default Mono<String> submitReindex(ReindexRequest reindexRequest){
+		return submitReindex(HttpHeaders.EMPTY, reindexRequest);
+	}
+
+	/**
+	 * Execute the given {@link ReindexRequest} against the {@literal reindex} API.
+	 *
+	 * @param headers Use {@link HttpHeaders} to provide eg. authentication data. Must not be {@literal null}.
+	 * @param reindexRequest must not be {@literal null}
+	 * @return the {@link Mono} emitting the task id
+	 * @since 4.4
+	 */
+	Mono<String> submitReindex(HttpHeaders headers, ReindexRequest reindexRequest);
 	/**
 	 * Compose the actual command/s to run against Elasticsearch using the underlying {@link WebClient connection}.
 	 * {@link #execute(ReactiveElasticsearchClientCallback) Execute} selects an active server from the available ones and

src/main/java/org/springframework/data/elasticsearch/client/reactive/RequestCreator.java

@@ -49,6 +49,7 @@
 import org.elasticsearch.client.indices.PutIndexTemplateRequest;
 import org.elasticsearch.client.indices.PutMappingRequest;
 import org.elasticsearch.index.reindex.DeleteByQueryRequest;
+import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
 import org.elasticsearch.script.mustache.SearchTemplateRequest;
 import org.springframework.data.elasticsearch.UncategorizedElasticsearchException;
@@ -289,4 +290,14 @@ default Function<GetIndexRequest, Request> getIndex() {
 	default Function<ClusterHealthRequest, Request> clusterHealth() {
 		return RequestConverters::clusterHealth;
 	}
+
+	/**
+	 * @since 4.4
+	 */
+	default Function<ReindexRequest, Request> reindex() { return RequestConverters::reindex; }
+
+	/**
+	 * @since 4.4
+	 */
+	default Function<ReindexRequest, Request> submitReindex() { return RequestConverters::submitReindex; }
 }

src/main/java/org/springframework/data/elasticsearch/client/util/RequestConverters.java

@@ -532,11 +532,11 @@ public static Request rankEval(RankEvalRequest rankEvalRequest) {
 		return request;
 	}
 
-	public static Request reindex(ReindexRequest reindexRequest) throws IOException {
+	public static Request reindex(ReindexRequest reindexRequest) {
 		return prepareReindexRequest(reindexRequest, true);
 	}
 
-	static Request submitReindex(ReindexRequest reindexRequest) throws IOException {
+	public static Request submitReindex(ReindexRequest reindexRequest) {
 		return prepareReindexRequest(reindexRequest, false);
 	}
 
@@ -547,9 +547,16 @@ private static Request prepareReindexRequest(ReindexRequest reindexRequest, bool
 				.withTimeout(reindexRequest.getTimeout()).withWaitForActiveShards(reindexRequest.getWaitForActiveShards())
 				.withRequestsPerSecond(reindexRequest.getRequestsPerSecond());
 
+		if(reindexRequest.getDestination().isRequireAlias()){
+			params.putParam("require_alias", Boolean.TRUE.toString());
+		}
 		if (reindexRequest.getScrollTime() != null) {
 			params.putParam("scroll", reindexRequest.getScrollTime());
 		}
+		params.putParam("slices", Integer.toString(reindexRequest.getSlices()));
+		if(reindexRequest.getMaxDocs() > -1){
+			params.putParam("max_docs", Integer.toString(reindexRequest.getMaxDocs()));
+		}
 		request.setEntity(createEntity(reindexRequest, REQUEST_BODY_CONTENT_TYPE));
 		return request;
 	}

src/main/java/org/springframework/data/elasticsearch/core/DocumentOperations.java

@@ -18,6 +18,8 @@
 import java.util.Collection;
 import java.util.List;
 
+import org.springframework.data.elasticsearch.core.reindex.ReindexRequest;
+import org.springframework.data.elasticsearch.core.reindex.ReindexResponse;
 import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
 import org.springframework.data.elasticsearch.core.query.BulkOptions;
 import org.springframework.data.elasticsearch.core.query.ByQueryResponse;
@@ -34,6 +36,7 @@
  *
  * @author Peter-Josef Meisch
  * @author Farid Faoudi
+ * @author Sijia Liu
  * @since 4.0
  */
 public interface DocumentOperations {
@@ -322,4 +325,26 @@ default void bulkUpdate(List<UpdateQuery> queries, IndexCoordinates index) {
 	 * @since 4.2
 	 */
 	ByQueryResponse updateByQuery(UpdateQuery updateQuery, IndexCoordinates index);
+
+	/**
+	 * Copies documents from a source to a destination.
+	 * The source can be any existing index, alias, or data stream. The destination must differ from the source.
+	 * For example, you cannot reindex a data stream into itself.
+	 * (@see https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html)
+	 *
+	 * @param reindexRequest reindex request parameters
+	 * @return the reindex response
+	 * @since 4.4
+	 */
+	ReindexResponse reindex(ReindexRequest reindexRequest);
+
+	/**
+	 * Submits a reindex task.
+	 * (@see https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html)
+	 *
+	 * @param reindexRequest reindex request parameters
+	 * @return the task id
+	 * @since 4.4
+	 */
+	String submitReindex(ReindexRequest reindexRequest);
 }

src/main/java/org/springframework/data/elasticsearch/core/ElasticsearchRestTemplate.java

@@ -61,7 +61,9 @@
 import org.springframework.data.elasticsearch.core.cluster.ElasticsearchClusterOperations;
 import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;
 import org.springframework.data.elasticsearch.core.document.DocumentAdapters;
+import org.springframework.data.elasticsearch.core.reindex.ReindexRequest;
 import org.springframework.data.elasticsearch.core.document.SearchDocumentResponse;
+import org.springframework.data.elasticsearch.core.reindex.ReindexResponse;
 import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
 import org.springframework.data.elasticsearch.core.query.BulkOptions;
 import org.springframework.data.elasticsearch.core.query.ByQueryResponse;
@@ -106,6 +108,7 @@
  * @author Gyula Attila Csorogi
  * @author Massimiliano Poggi
  * @author Farid Faoudi
+ * @author Sijia Liu
  * @since 4.4
  */
 public class ElasticsearchRestTemplate extends AbstractElasticsearchTemplate {
@@ -277,6 +280,26 @@ public ByQueryResponse updateByQuery(UpdateQuery query, IndexCoordinates index)
 		return ResponseConverter.byQueryResponseOf(bulkByScrollResponse);
 	}
 
+	@Override
+	public ReindexResponse reindex(ReindexRequest postReindexRequest) {
+
+		Assert.notNull(postReindexRequest, "postReindexRequest must not be null");
+
+		final org.elasticsearch.index.reindex.ReindexRequest reindexRequest = requestFactory.reindexRequest(postReindexRequest);
+		final BulkByScrollResponse bulkByScrollResponse = execute(
+				client -> client.reindex(reindexRequest, RequestOptions.DEFAULT));
+		return ResponseConverter.reindexResponseOf(bulkByScrollResponse);
+	}
+
+	@Override
+	public String submitReindex(ReindexRequest postReindexRequest) {
+		Assert.notNull(postReindexRequest, "postReindexRequest must not be null");
+
+		final org.elasticsearch.index.reindex.ReindexRequest reindexRequest = requestFactory.reindexRequest(postReindexRequest);
+		return execute(
+				client -> client.submitReindexTask(reindexRequest, RequestOptions.DEFAULT).getTask());
+	}
+
 	public List<IndexedObjectInformation> doBulkOperation(List<?> queries, BulkOptions bulkOptions,
 			IndexCoordinates index) {
 		BulkRequest bulkRequest = prepareWriteRequest(requestFactory.bulkRequest(queries, bulkOptions, index));

src/main/java/org/springframework/data/elasticsearch/core/ReactiveDocumentOperations.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.elasticsearch.core;
 
+import org.springframework.data.elasticsearch.core.reindex.ReindexRequest;
+import org.springframework.data.elasticsearch.core.reindex.ReindexResponse;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -38,6 +40,7 @@
  * @author Aleksei Arsenev
  * @author Roman Puchkovskiy
  * @author Farid Faoudi
+ * @author Sijia Liu
  * @since 4.0
  */
 public interface ReactiveDocumentOperations {
@@ -302,4 +305,26 @@ default Mono<Void> bulkUpdate(List<UpdateQuery> queries, IndexCoordinates index)
 	 * @since 4.2
 	 */
 	Mono<ByQueryResponse> updateByQuery(UpdateQuery updateQuery, IndexCoordinates index);
+
+	/**
+	 * Copies documents from a source to a destination.
+	 * The source can be any existing index, alias, or data stream. The destination must differ from the source.
+	 * For example, you cannot reindex a data stream into itself.
+	 * (@see https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html)
+	 *
+	 * @param reindexRequest reindex request parameters
+	 * @return a {@link Mono} emitting the reindex response
+	 * @since 4.4
+	 */
+	Mono<ReindexResponse> reindex(ReindexRequest reindexRequest);
+
+	/**
+	 * Submits a reindex task.
+	 * (@see https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html)
+	 *
+	 * @param reindexRequest reindex request parameters
+	 * @return a {@link Mono} emitting the {@literal task} id.
+	 * @since 4.4
+	 */
+	Mono<String> submitReindex(ReindexRequest reindexRequest);
 }

src/main/java/org/springframework/data/elasticsearch/core/ReactiveElasticsearchTemplate.java

@@ -70,6 +70,8 @@
 import org.springframework.data.elasticsearch.core.event.ReactiveAfterLoadCallback;
 import org.springframework.data.elasticsearch.core.event.ReactiveAfterSaveCallback;
 import org.springframework.data.elasticsearch.core.event.ReactiveBeforeConvertCallback;
+import org.springframework.data.elasticsearch.core.reindex.ReindexRequest;
+import org.springframework.data.elasticsearch.core.reindex.ReindexResponse;
 import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentEntity;
 import org.springframework.data.elasticsearch.core.mapping.ElasticsearchPersistentProperty;
 import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
@@ -105,6 +107,7 @@
  * @author Russell Parry
  * @author Thomas Geese
  * @author Farid Faoudi
+ * @author Sijia Liu
  * @since 3.2
  */
 public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOperations, ApplicationContextAware {
@@ -609,6 +612,28 @@ public Mono<ByQueryResponse> updateByQuery(UpdateQuery updateQuery, IndexCoordin
 		});
 	}
 
+	@Override
+	public Mono<ReindexResponse> reindex(ReindexRequest postReindexRequest) {
+
+		Assert.notNull(postReindexRequest, "postReindexRequest must not be null");
+
+		return Mono.defer(() -> {
+			final org.elasticsearch.index.reindex.ReindexRequest reindexRequest = requestFactory.reindexRequest(postReindexRequest);
+			return Mono.from(execute(client -> client.reindex(reindexRequest))).map(ResponseConverter::reindexResponseOf);
+		});
+	}
+
+	@Override
+	public Mono<String> submitReindex(ReindexRequest postReindexRequest) {
+
+		Assert.notNull(postReindexRequest, "postReindexRequest must not be null");
+
+		return Mono.defer(() -> {
+			final org.elasticsearch.index.reindex.ReindexRequest reindexRequest = requestFactory.reindexRequest(postReindexRequest);
+			return Mono.from(execute(client -> client.submitReindex(reindexRequest)));
+		});
+	}
+
 	@Override
 	public Mono<ByQueryResponse> delete(Query query, Class<?> entityType) {
 		return delete(query, entityType, getIndexCoordinatesFor(entityType));