Apply gridFsDatabase to auto-configured ReactiveGridFsTemplate

Closes gh-18284

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/mongo/MongoReactiveDataAutoConfiguration.java

@@ -16,7 +16,15 @@
 
 package org.springframework.boot.autoconfigure.data.mongo;
 
+import java.util.Optional;
+
+import com.mongodb.ClientSessionOptions;
+import com.mongodb.reactivestreams.client.ClientSession;
 import com.mongodb.reactivestreams.client.MongoClient;
+import com.mongodb.reactivestreams.client.MongoDatabase;
+import org.bson.codecs.Codec;
+import org.bson.codecs.configuration.CodecRegistry;
+import reactor.core.publisher.Mono;
 
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@@ -31,6 +39,8 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.dao.DataAccessException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.mongodb.ReactiveMongoDatabaseFactory;
 import org.springframework.data.mongodb.core.ReactiveMongoOperations;
 import org.springframework.data.mongodb.core.ReactiveMongoTemplate;
@@ -42,6 +52,7 @@ import org.springframework.data.mongodb.core.convert.NoOpDbRefResolver;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.gridfs.ReactiveGridFsOperations;
 import org.springframework.data.mongodb.gridfs.ReactiveGridFsTemplate;
+import org.springframework.util.StringUtils;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for Spring Data's reactive mongo
@@ -98,8 +109,77 @@ public class MongoReactiveDataAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean(ReactiveGridFsOperations.class)
 	public ReactiveGridFsTemplate reactiveGridFsTemplate(ReactiveMongoDatabaseFactory reactiveMongoDatabaseFactory,
-			MappingMongoConverter mappingMongoConverter, DataBufferFactory dataBufferFactory) {
+			MappingMongoConverter mappingMongoConverter, DataBufferFactory dataBufferFactory,
-		return new ReactiveGridFsTemplate(dataBufferFactory, reactiveMongoDatabaseFactory, mappingMongoConverter, null);
+			MongoProperties properties) {
+		return new ReactiveGridFsTemplate(dataBufferFactory,
+				new GridFsReactiveMongoDatabaseFactory(reactiveMongoDatabaseFactory, properties), mappingMongoConverter,
+				null);
+	}
+
+	/**
+	 * {@link ReactiveMongoDatabaseFactory} decorator to use
+	 * {@link MongoProperties#getGridFsDatabase()} when set.
+	 */
+	static class GridFsReactiveMongoDatabaseFactory implements ReactiveMongoDatabaseFactory {
+
+		private final ReactiveMongoDatabaseFactory delegate;
+
+		private final MongoProperties properties;
+
+		GridFsReactiveMongoDatabaseFactory(ReactiveMongoDatabaseFactory delegate, MongoProperties properties) {
+			this.delegate = delegate;
+			this.properties = properties;
+		}
+
+		@Override
+		public boolean hasCodecFor(Class<?> type) {
+			return this.delegate.hasCodecFor(type);
+		}
+
+		@Override
+		public Mono<MongoDatabase> getMongoDatabase() throws DataAccessException {
+			String gridFsDatabase = this.properties.getGridFsDatabase();
+			if (StringUtils.hasText(gridFsDatabase)) {
+				return this.delegate.getMongoDatabase(gridFsDatabase);
+			}
+			return this.delegate.getMongoDatabase();
+		}
+
+		@Override
+		public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException {
+			return this.delegate.getMongoDatabase(dbName);
+		}
+
+		@Override
+		public <T> Optional<Codec<T>> getCodecFor(Class<T> type) {
+			return this.delegate.getCodecFor(type);
+		}
+
+		@Override
+		public PersistenceExceptionTranslator getExceptionTranslator() {
+			return this.delegate.getExceptionTranslator();
+		}
+
+		@Override
+		public CodecRegistry getCodecRegistry() {
+			return this.delegate.getCodecRegistry();
+		}
+
+		@Override
+		public Mono<ClientSession> getSession(ClientSessionOptions options) {
+			return this.delegate.getSession(options);
+		}
+
+		@Override
+		public ReactiveMongoDatabaseFactory withSession(ClientSession session) {
+			return this.delegate.withSession(session);
+		}
+
+		@Override
+		public boolean isTransactionActive() {
+			return this.delegate.isTransactionActive();
+		}
+
 	}
 
 }

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/data/mongo/MongoReactiveDataAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -21,9 +21,12 @@ import org.junit.jupiter.api.Test;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
 import org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration;
+import org.springframework.boot.test.context.assertj.AssertableApplicationContext;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.data.mongodb.ReactiveMongoDatabaseFactory;
 import org.springframework.data.mongodb.core.ReactiveMongoTemplate;
 import org.springframework.data.mongodb.gridfs.ReactiveGridFsTemplate;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -45,8 +48,17 @@ class MongoReactiveDataAutoConfigurationTests {
 	}
 
 	@Test
-	void gridFsTemplateExists() {
+	void whenNoGridFsDatabaseIsConfiguredTheGridFsTemplateUsesTheMainDatabase() {
-		this.contextRunner.run((context) -> assertThat(context).hasSingleBean(ReactiveGridFsTemplate.class));
+		this.contextRunner.run((context) -> {
+			assertThat(grisFsTemplateDatabaseName(context)).isEqualTo("test");
+		});
+	}
+
+	@Test
+	void whenGridFsDatabaseIsConfiguredThenGridFsTemplateUsesIt() {
+		this.contextRunner.withPropertyValues("spring.data.mongodb.gridFsDatabase:grid").run((context) -> {
+			assertThat(grisFsTemplateDatabaseName(context)).isEqualTo("grid");
+		});
 	}
 
 	@Test
@@ -56,4 +68,12 @@ class MongoReactiveDataAutoConfigurationTests {
 		runner.run((context) -> assertThat(context).doesNotHaveBean(MongoReactiveDataAutoConfiguration.class));
 	}
 
+	private String grisFsTemplateDatabaseName(AssertableApplicationContext context) {
+		assertThat(context).hasSingleBean(ReactiveGridFsTemplate.class);
+		ReactiveGridFsTemplate template = context.getBean(ReactiveGridFsTemplate.class);
+		ReactiveMongoDatabaseFactory factory = (ReactiveMongoDatabaseFactory) ReflectionTestUtils.getField(template,
+				"dbFactory");
+		return factory.getMongoDatabase().block().getName();
+	}
+
 }