DATAES-504 - Add ReactiveElasticsearchOperations & ReactiveElasticsearchTemplate

ReactiveElasticsearchOperations is the gateway to executing high level commands against an Elasticsearch cluster using the ReactiveElasticsearchClient.

The ReactiveElasticsearchTemplate is the default implementation of ReactiveElasticsearchOperations and offers the following set of features.

* Read/Write mapping support for domain types.
* A rich query and criteria api.
* Resource management and Exception translation.

To get started the ReactiveElasticsearchTemplate needs to know about the actual client to work with.
The easiest way of setting up the ReactiveElasticsearchTemplate is via AbstractReactiveElasticsearchConfiguration providing
dedicated configuration method hooks for base package, the initial entity set etc.

@configuration
public class Config extends AbstractReactiveElasticsearchConfiguration {

    @bean
    @OverRide
    public ReactiveElasticsearchClient reactiveElasticsearchClient() {
        // ...
    }
}

NOTE: If applicable set default HttpHeaders via the ClientConfiguration of the ReactiveElasticsearchClient.

TIP: If needed the ReactiveElasticsearchTemplate can be configured with default RefreshPolicy and IndicesOptions that get applied to the related requests by overriding the defaults of refreshPolicy() and indicesOptions().

The ReactiveElasticsearchTemplate lets you save, find and delete your domain objects and map those objects to documents stored in Elasticsearch.

@document(indexName = "marvel", type = "characters")
public class Person {

    private @id String id;
    private String name;
    private int age;

    // Getter/Setter omitted...
}

template.save(new Person("Bruce Banner", 42)) // save a new document
    .doOnNext(System.out::println)
    .flatMap(person -> template.findById(person.id, Person.class)) // then go find it
    .doOnNext(System.out::println)
    .flatMap(person -> template.delete(person)) // just to remove remove it again
    .doOnNext(System.out::println)
    .flatMap(id -> template.count(Person.class)) // so we've got nothing at the end
    .doOnNext(System.out::println)
    .subscribe(); // yeah :)

The above outputs the following sequence on the console.

> Person(id=QjWCWWcBXiLAnp77ksfR, name=Bruce Banner, age=42)
> Person(id=QjWCWWcBXiLAnp77ksfR, name=Bruce Banner, age=42)
> QjWCWWcBXiLAnp77ksfR
> 0

Original Pull Request: spring-projects#229

Author: christophstrobl

src/main/asciidoc/index.adoc

@@ -30,6 +30,7 @@ include::{spring-data-commons-docs}/repositories.adoc[]
 :leveloffset: +1
 include::reference/elasticsearch-clients.adoc[]
 include::reference/data-elasticsearch.adoc[]
+include::reference/reactive-elasticsearch-operations.adoc[]
 include::reference/elasticsearch-misc.adoc[]
 :leveloffset: -1
 

src/main/asciidoc/reference/reactive-elasticsearch-operations.adoc

@@ -0,0 +1,132 @@
+[[elasticsearch.reactive.operations]]
+= Reactive Elasticsearch Operations
+
+`ReactiveElasticsearchOperations` is the gateway to executing high level commands against an Elasticsearch cluster using the `ReactiveElasticsearchClient`.
+
+The `ReactiveElasticsearchTemplate` is the default implementation of `ReactiveElasticsearchOperations` and offers the following set of features.
+
+* Read/Write mapping support for domain types.
+* A rich query and criteria api.
+* Resource management and Exception translation.
+
+[[elasticsearch.reactive.template]]
+== Reactive Elasticsearch Template
+
+To get started the `ReactiveElasticsearchTemplate` needs to know about the actual client to work with.
+Please see <<elasticsearch.clients.reactive>> for details on the client.
+
+[[elasticsearch.reactive.template.configuration]]
+=== Reactive Template Configuration
+
+The easiest way of setting up the `ReactiveElasticsearchTemplate` is via `AbstractReactiveElasticsearchConfiguration` providing
+dedicated configuration method hooks for `base package`, the `initial entity set` etc.
+
+.The AbstractReactiveElasticsearchConfiguration
+====
+[source,java]
+----
+@Configuration
+public class Config extends AbstractReactiveElasticsearchConfiguration {
+
+    @Bean <1>
+    @Override
+    public ReactiveElasticsearchClient reactiveElasticsearchClient() {
+        // ...
+    }
+}
+----
+<1> Configure the client to use. This can be done by `ReactiveRestClients` or directly via `DefaultReactiveElasticsearchClient`.
+====
+
+NOTE: If applicable set default `HttpHeaders` via the `ClientConfiguration` of the `ReactiveElasticsearchClient`.
+
+TIP: If needed the `ReactiveElasticsearchTemplate` can be configured with default `RefreshPolicy` and `IndicesOptions` that get applied to the related requests by overriding the defaults of `refreshPolicy()` and `indicesOptions()`.
+
+However one might want to be more in control over the actual components and use a more verbose approach.
+
+.Configure the ReactiveElasticsearchTemplate
+====
+[source,java]
+----
+@Configuration
+public class Config {
+
+    @Bean <1>
+    public ReactiveElasticsearchClient reactiveElasticsearchClient() {
+        // ...
+    }
+
+    @Bean <2>
+    public ElasticsearchConverter elasticsearchConverter() {
+        return new MappingElasticsearchConverter(elasticsearchMappingContext());
+    }
+
+    @Bean <3>
+    public SimpleElasticsearchMappingContext elasticsearchMappingContext() {
+        return new SimpleElasticsearchMappingContext();
+    }
+
+    @Bean <4>
+    public ReactiveElasticsearchOperations reactiveElasticsearchOperations() {
+        return new ReactiveElasticsearchTemplate(reactiveElasticsearchClient(), elasticsearchConverter());
+    }
+}
+----
+<1> Configure the client to use. This can be done by `ReactiveRestClients` or directly via `DefaultReactiveElasticsearchClient`.
+<2> Set up the `ElasticsearchConverter` used for domain type mapping utilizing metadata provided by the mapping context.
+<3> The Elasticsearch specific mapping context for domain type metadata.
+<4> The actual template based on the client and conversion infrastructure.
+====
+
+[[elasticsearch.reactive.template.usage]]
+=== Reactive Template Usage
+
+`ReactiveElasticsearchTemplate` lets you save, find and delete your domain objects and map those objects to documents stored in Elasticsearch.
+
+Consider the following:
+
+.Use the ReactiveElasticsearchTemplate
+====
+[source,java]
+----
+@Document(indexName = "marvel", type = "characters")
+public class Person {
+
+    private @Id String id;
+    private String name;
+    private int age;
+
+    // Getter/Setter omitted...
+}
+----
+
+[source,java]
+----
+template.save(new Person("Bruce Banner", 42)) <1>
+    .doOnNext(System.out::println)
+    .flatMap(person -> template.findById(person.id, Person.class)) <2>
+    .doOnNext(System.out::println)
+    .flatMap(person -> template.delete(person)) <3>
+    .doOnNext(System.out::println)
+    .flatMap(id -> template.count(Person.class)) <4>
+    .doOnNext(System.out::println)
+    .subscribe(); <5>
+----
+
+The above outputs the following sequence on the console.
+
+[source,text]
+----
+> Person(id=QjWCWWcBXiLAnp77ksfR, name=Bruce Banner, age=42)
+> Person(id=QjWCWWcBXiLAnp77ksfR, name=Bruce Banner, age=42)
+> QjWCWWcBXiLAnp77ksfR
+> 0
+----
+<1> Insert a new `Person` document into the _marvel_ index under type _characters_. The `id` is generated on server side and set into the instance returned.
+<2> Lookup the `Person` with matching `id` in the _marvel_ index under type _characters_.
+<3> Delete the `Person` with matching `id`, extracted from the given instance, in the _marvel_ index under type _characters_.
+<4> Count the total number of documents in the _marvel_ index under type _characters_.
+<5> Don't forget to _subscribe()_.
+====
+
+

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

@@ -56,11 +56,13 @@
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.get.GetResult;
+import org.elasticsearch.index.reindex.BulkByScrollResponse;
+import org.elasticsearch.index.reindex.DeleteByQueryRequest;
 import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.search.SearchHit;
 import org.reactivestreams.Publisher;
-import org.springframework.dao.DataAccessResourceFailureException;
+import org.springframework.data.elasticsearch.ElasticsearchException;
 import org.springframework.data.elasticsearch.client.ClientConfiguration;
 import org.springframework.data.elasticsearch.client.ElasticsearchHost;
 import org.springframework.data.elasticsearch.client.NoReachableHostException;
@@ -249,7 +251,9 @@ public Mono<UpdateResponse> update(HttpHeaders headers, UpdateRequest updateRequ
 	 */
 	@Override
 	public Mono<DeleteResponse> delete(HttpHeaders headers, DeleteRequest deleteRequest) {
-		return sendRequest(deleteRequest, RequestCreator.delete(), DeleteResponse.class, headers).publishNext();
+
+		return sendRequest(deleteRequest, RequestCreator.delete(), DeleteResponse.class, headers) //
+				.publishNext();
 	}
 
 	/*
@@ -264,6 +268,16 @@ public Flux<SearchHit> search(HttpHeaders headers, SearchRequest searchRequest)
 				.flatMap(Flux::fromIterable);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient#ping(org.springframework.http.HttpHeaders, org.elasticsearch.index.reindex.DeleteByQueryRequest)
+	 */
+	public Mono<BulkByScrollResponse> deleteBy(HttpHeaders headers, DeleteByQueryRequest deleteRequest) {
+
+		return sendRequest(deleteRequest, RequestCreator.deleteByQuery(), BulkByScrollResponse.class, headers) //
+				.publishNext();
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient#ping(org.springframework.data.elasticsearch.client.reactive.ReactiveElasticsearchClient.ReactiveElasticsearchClientCallback)
@@ -364,27 +378,22 @@ private static <T> Mono<T> doDecode(ClientResponse response, Class<T> responseTy
 
 		try {
 
-			XContentParser contentParser = createParser(mediaType, content);
+			Method fromXContent = ReflectionUtils.findMethod(responseType, "fromXContent", XContentParser.class);
+
+			return Mono.justOrEmpty(responseType
+					.cast(ReflectionUtils.invokeMethod(fromXContent, responseType, createParser(mediaType, content))));
+
+		} catch (Exception errorParseFailure) {
 
 			try {
+				return Mono.error(BytesRestResponse.errorFromXContent(createParser(mediaType, content)));
+			} catch (Exception e) {
 
-				Method fromXContent = ReflectionUtils.findMethod(responseType, "fromXContent", XContentParser.class);
 				return Mono
-						.justOrEmpty(responseType.cast(ReflectionUtils.invokeMethod(fromXContent, responseType, contentParser)));
-
-			} catch (Exception errorParseFailure) {
-				try {
-					return Mono.error(BytesRestResponse.errorFromXContent(contentParser));
-				} catch (Exception e) {
-					// return Mono.error to avoid ElasticsearchStatusException to be caught by outer catch.
-					return Mono.error(new ElasticsearchStatusException("Unable to parse response body",
-							RestStatus.fromCode(response.statusCode().value())));
-				}
+						.error(new ElasticsearchStatusException(content, RestStatus.fromCode(response.statusCode().value())));
 			}
-
-		} catch (IOException e) {
-			return Mono.error(new DataAccessResourceFailureException("Error parsing XContent.", e));
 		}
+
 	}
 
 	private static XContentParser createParser(String mediaType, String content) throws IOException {
@@ -437,6 +446,18 @@ static Function<UpdateRequest, Request> update() {
 		static Function<DeleteRequest, Request> delete() {
 			return RequestConverters::delete;
 		}
+
+		static Function<DeleteByQueryRequest, Request> deleteByQuery() {
+
+			return request -> {
+
+				try {
+					return RequestConverters.deleteByQuery(request);
+				} catch (IOException e) {
+					throw new ElasticsearchException("Could not parse request", e);
+				}
+			};
+		}
 	}
 
 	/**

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

@@ -33,6 +33,8 @@
 import org.elasticsearch.action.update.UpdateRequest;
 import org.elasticsearch.action.update.UpdateResponse;
 import org.elasticsearch.index.get.GetResult;
+import org.elasticsearch.index.reindex.BulkByScrollResponse;
+import org.elasticsearch.index.reindex.DeleteByQueryRequest;
 import org.elasticsearch.search.SearchHit;
 import org.springframework.data.elasticsearch.client.ClientConfiguration;
 import org.springframework.data.elasticsearch.client.ElasticsearchHost;
@@ -348,6 +350,44 @@ default Flux<SearchHit> search(SearchRequest searchRequest) {
 	 */
 	Flux<SearchHit> search(HttpHeaders headers, SearchRequest searchRequest);
 
+	/**
+	 * Execute a {@link DeleteByQueryRequest} against the {@literal delete by query} API.
+	 *
+	 * @param consumer never {@literal null}.
+	 * @see <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete-by-query.html">Delete By
+	 *      Query API on elastic.co</a>
+	 * @return a {@link Mono} emitting the emitting operation response.
+	 */
+	default Mono<BulkByScrollResponse> deleteBy(Consumer<DeleteByQueryRequest> consumer) {
+
+		DeleteByQueryRequest request = new DeleteByQueryRequest();
+		consumer.accept(request);
+		return deleteBy(request);
+	}
+
+	/**
+	 * Execute a {@link DeleteByQueryRequest} against the {@literal delete by query} API.
+	 *
+	 * @param deleteRequest must not be {@literal null}.
+	 * @see <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete-by-query.html">Delete By
+	 *      Query API on elastic.co</a>
+	 * @return a {@link Mono} emitting the emitting operation response.
+	 */
+	default Mono<BulkByScrollResponse> deleteBy(DeleteByQueryRequest deleteRequest) {
+		return deleteBy(HttpHeaders.EMPTY, deleteRequest);
+	}
+
+	/**
+	 * Execute a {@link DeleteByQueryRequest} against the {@literal delete by query} API.
+	 *
+	 * @param headers Use {@link HttpHeaders} to provide eg. authentication data. Must not be {@literal null}.
+	 * @param deleteRequest must not be {@literal null}.
+	 * @see <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-delete-by-query.html">Delete By
+	 *      Query API on elastic.co</a>
+	 * @return a {@link Mono} emitting operation response.
+	 */
+	Mono<BulkByScrollResponse> deleteBy(HttpHeaders headers, DeleteByQueryRequest deleteRequest);
+
 	/**
 	 * 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/config/AbstractElasticsearchConfiguration.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed 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.springframework.data.elasticsearch.config;
+
+import org.elasticsearch.client.RestHighLevelClient;
+import org.springframework.context.annotation.Bean;
+import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
+import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
+
+/**
+ * @author Christoph Strobl
+ * @since 4.0
+ * @see ElasticsearchConfigurationSupport
+ */
+public abstract class AbstractElasticsearchConfiguration extends ElasticsearchConfigurationSupport {
+
+	/**
+	 * Return the {@link RestHighLevelClient} instance used to connect to the cluster. <br />
+	 * Annotate with {@link Bean} in case you want to expose a {@link RestHighLevelClient} instance to the
+	 * {@link org.springframework.context.ApplicationContext}.
+	 *
+	 * @return never {@literal null}.
+	 */
+	public abstract RestHighLevelClient elasticsearchClient();
+
+	/**
+	 * Creates {@link ElasticsearchOperations}.
+	 *
+	 * @return never {@literal null}.
+	 */
+	@Bean
+	public ElasticsearchOperations elasticsearchOperations() {
+		return new ElasticsearchRestTemplate(elasticsearchClient(), elasticsearchConverter());
+	}
+}