Add possibility to define runtime fields in a search request.

src/main/asciidoc/reference/elasticsearch-misc.adoc

@@ -183,3 +183,81 @@ If the class to be retrieved has a `GeoPoint` property named _location_, the fol
 Sort.by(new GeoDistanceOrder("location", new GeoPoint(48.137154, 11.5761247)))
 ----
 ====
+
+[[elasticsearch.misc.runtime-fields]]
+== Runtime Fields
+
+From version 7.12 on Elasticsearch has added the feature of runtime fields (https://www.elastic.co/guide/en/elasticsearch/reference/7.12/runtime.html).
+Spring Data Elasticsearch supports this in two ways:
+
+=== Runtime field definitions in the index mappings
+
+The first way to define runtime fields is by adding the definitions to the index mappings (see https://www.elastic.co/guide/en/elasticsearch/reference/7.12/runtime-mapping-fields.html).
+To use this approach in Spring Data Elasticsearch the user must provide a JSON file that contains the corresponding definition, for example:
+
+.runtime-fields.json
+====
+[source,json]
+----
+{
+  "day_of_week": {
+    "type": "keyword",
+    "script": {
+      "source": "emit(doc['@timestamp'].value.dayOfWeekEnum.getDisplayName(TextStyle.FULL, Locale.ROOT))"
+    }
+  }
+}
+----
+====
+
+The path to this JSON file, which must be present on the classpath, must then be set in the `@Mapping` annotation of the entity:
+
+====
+[source,java]
+----
+@Document(indexName = "runtime-fields")
+@Mapping(runtimeFieldsPath = "/runtime-fields.json")
+public class RuntimeFieldEntity {
+	// properties, getter, setter,...
+}
+
+----
+====
+
+=== Runtime fields definitions set on a Query
+
+The second way to define runtime fields is by adding the definitions to a search query (see https://www.elastic.co/guide/en/elasticsearch/reference/7.12/runtime-search-request.html).
+The following code example shows how to do this with Spring Data Elasticsearch :
+
+The entity used is a simple object that has a `price` property:
+
+====
+[source,java]
+----
+@Document(indexName = "some_index_name")
+public class SomethingToBuy {
+
+	private @Id @Nullable String id;
+	@Nullable @Field(type = FieldType.Text) private String description;
+	@Nullable @Field(type = FieldType.Double) private Double price;
+
+	// getter and setter
+}
+
+----
+====
+
+The following query uses a runtime field that calculates a `priceWithTax` value by adding 19% to the price and uses this value in the search query to find all entities where `priceWithTax` is higher or equal than a given value:
+
+====
+[source,java]
+----
+RuntimeField runtimeField = new RuntimeField("priceWithTax", "double", "emit(doc['price'].value * 1.19)");
+Query query = new CriteriaQuery(new Criteria("priceWithTax").greaterThanEqual(16.5));
+query.addRuntimeField(runtimeField);
+
+SearchHits<SomethingToBuy> searchHits = operations.search(query, SomethingToBuy.class);
+----
+====
+
+This works with every implementation of the `Query` interface.

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

@@ -1020,7 +1020,17 @@ private SearchRequest prepareSearchRequest(Query query, @Nullable Class<?> clazz
 			request.requestCache(query.getRequestCache());
 		}
 
+		if (!query.getRuntimeFields().isEmpty()) {
+
+			Map<String, Object> runtimeMappings = new HashMap<>();
+			query.getRuntimeFields().forEach(runtimeField -> {
+				runtimeMappings.put(runtimeField.getName(), runtimeField.getMapping());
+			});
+			sourceBuilder.runtimeMappings(runtimeMappings);
+		}
+
 		request.source(sourceBuilder);
+
 		return request;
 	}
 
@@ -1112,6 +1122,15 @@ private SearchRequestBuilder prepareSearchRequestBuilder(Query query, Client cli
 			searchRequestBuilder.setRequestCache(query.getRequestCache());
 		}
 
+		if (!query.getRuntimeFields().isEmpty()) {
+
+			Map<String, Object> runtimeMappings = new HashMap<>();
+			query.getRuntimeFields().forEach(runtimeField -> {
+				runtimeMappings.put(runtimeField.getName(), runtimeField.getMapping());
+			});
+			searchRequestBuilder.setRuntimeMappings(runtimeMappings);
+		}
+
 		return searchRequestBuilder;
 	}
 

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

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2021 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
+ *
+ *      https://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.core;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.util.Assert;
+
+/**
+ * Defines a runtime field to be added to a Query
+ *
+ * @author Peter-Josef Meisch
+ * @since 4.3
+ */
+public class RuntimeField {
+
+	private final String name;
+	private final String type;
+	private final String script;
+
+	public RuntimeField(String name, String type, String script) {
+
+		Assert.notNull(name, "name must not be null");
+		Assert.notNull(type, "type must not be null");
+		Assert.notNull(script, "script must not be null");
+
+		this.name = name;
+		this.type = type;
+		this.script = script;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	/**
+	 * @return the mapping as a Map like it is needed for the Elasticsearch client
+	 */
+	public Map<String, Object> getMapping() {
+
+		Map<String, Object> map = new HashMap<>();
+		map.put("type", type);
+		map.put("script", script);
+		return map;
+	}
+}

src/main/java/org/springframework/data/elasticsearch/core/query/BaseQuery.java

@@ -28,6 +28,7 @@
 
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.elasticsearch.core.RuntimeField;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
@@ -67,6 +68,7 @@ public class BaseQuery implements Query {
 	protected List<RescorerQuery> rescorerQueries = new ArrayList<>();
 	@Nullable protected Boolean requestCache;
 	private List<IdWithRouting> idsWithRouting = Collections.emptyList();
+	private final List<RuntimeField> runtimeFields = new ArrayList<>();
 
 	@Override
 	@Nullable
@@ -374,4 +376,16 @@ public Boolean getRequestCache() {
 		return this.requestCache;
 	}
 
+	@Override
+	public void addRuntimeField(RuntimeField runtimeField) {
+
+		Assert.notNull(runtimeField, "runtimeField must not be null");
+
+		this.runtimeFields.add(runtimeField);
+	}
+
+	@Override
+	public List<RuntimeField> getRuntimeFields() {
+		return runtimeFields;
+	}
 }

src/main/java/org/springframework/data/elasticsearch/core/query/Query.java

@@ -24,6 +24,7 @@
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.elasticsearch.core.RuntimeField;
 import org.springframework.data.elasticsearch.core.SearchHit;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -392,6 +393,20 @@ default List<RescorerQuery> getRescorerQueries() {
 	@Nullable
 	Boolean getRequestCache();
 
+	/**
+	 * Adds a runtime field to the query.
+	 *
+	 * @param runtimeField the runtime field definition, must not be {@literal null}
+	 * @since 4.3
+	 */
+	void addRuntimeField(RuntimeField runtimeField);
+
+	/**
+	 * @return the runtime fields for this query. May be empty but not null
+	 * @since 4.3
+	 */
+	List<RuntimeField> getRuntimeFields();
+
 	/**
 	 * @since 4.3
 	 */

src/test/java/org/springframework/data/elasticsearch/core/RuntimeFieldsIntegrationTests.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2021 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
+ *
+ *      https://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.core;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Order;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.elasticsearch.annotations.Document;
+import org.springframework.data.elasticsearch.annotations.Field;
+import org.springframework.data.elasticsearch.annotations.FieldType;
+import org.springframework.data.elasticsearch.core.mapping.IndexCoordinates;
+import org.springframework.data.elasticsearch.core.query.Criteria;
+import org.springframework.data.elasticsearch.core.query.CriteriaQuery;
+import org.springframework.data.elasticsearch.core.query.Query;
+import org.springframework.data.elasticsearch.junit.jupiter.SpringIntegrationTest;
+import org.springframework.data.elasticsearch.utils.IndexNameProvider;
+import org.springframework.lang.Nullable;
+
+/**
+ * @author Peter-Josef Meisch
+ */
+@SpringIntegrationTest
+public abstract class RuntimeFieldsIntegrationTests {
+
+	@Autowired private ElasticsearchOperations operations;
+	@Autowired protected IndexNameProvider indexNameProvider;
+	private IndexOperations indexOperations;
+
+	@BeforeEach
+	void setUp() {
+
+		indexNameProvider.increment();
+		indexOperations = operations.indexOps(SomethingToBuy.class);
+		indexOperations.createWithMapping();
+	}
+
+	@Test
+	@Order(java.lang.Integer.MAX_VALUE)
+	void cleanup() {
+		operations.indexOps(IndexCoordinates.of("*")).delete();
+	}
+
+	@Test // #1971
+	@DisplayName("should use runtime-field from query in search")
+	void shouldUseRuntimeFieldFromQueryInSearch() {
+
+		insert("1", "item 1", 13.5);
+		insert("2", "item 2", 15);
+		Query query = new CriteriaQuery(new Criteria("priceWithTax").greaterThanEqual(16.5));
+		RuntimeField runtimeField = new RuntimeField("priceWithTax", "double", "emit(doc['price'].value * 1.19)");
+		query.addRuntimeField(runtimeField);
+
+		SearchHits<SomethingToBuy> searchHits = operations.search(query, SomethingToBuy.class);
+
+		assertThat(searchHits.getTotalHits()).isEqualTo(1);
+		assertThat(searchHits.getSearchHit(0).getId()).isEqualTo("2");
+	}
+
+	private void insert(String id, String description, double price) {
+		SomethingToBuy entity = new SomethingToBuy();
+		entity.setId(id);
+		entity.setDescription(description);
+		entity.setPrice(price);
+		operations.save(entity);
+	}
+
+	@Document(indexName = "#{@indexNameProvider.indexName()}")
+	private static class SomethingToBuy {
+		private @Id @Nullable String id;
+
+		@Nullable @Field(type = FieldType.Text) private String description;
+
+		@Nullable @Field(type = FieldType.Double) private Double price;
+
+		@Nullable
+		public String getId() {
+			return id;
+		}
+
+		public void setId(@Nullable String id) {
+			this.id = id;
+		}
+
+		@Nullable
+		public String getDescription() {
+			return description;
+		}
+
+		public void setDescription(@Nullable String description) {
+			this.description = description;
+		}
+
+		@Nullable
+		public Double getPrice() {
+			return price;
+		}
+
+		public void setPrice(@Nullable Double price) {
+			this.price = price;
+		}
+	}
+}

src/test/java/org/springframework/data/elasticsearch/core/RuntimeFieldsRestTemplateIntegrationTests.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2021 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
+ *
+ *      https://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.core;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.data.elasticsearch.junit.jupiter.ElasticsearchRestTemplateConfiguration;
+import org.springframework.data.elasticsearch.utils.IndexNameProvider;
+import org.springframework.test.context.ContextConfiguration;
+
+/**
+ * @author Peter-Josef Meisch
+ */
+@ContextConfiguration(classes = { RuntimeFieldsRestTemplateIntegrationTests.Config.class })
+public class RuntimeFieldsRestTemplateIntegrationTests extends RuntimeFieldsIntegrationTests {
+
+	@Configuration
+	@Import({ ElasticsearchRestTemplateConfiguration.class })
+	static class Config {
+		@Bean
+		IndexNameProvider indexNameProvider() {
+			return new IndexNameProvider("runtime-fields-rest-template");
+		}
+	}
+}