Configure NettyStreamFactoryFactory by default if available

Closes gh-11526
Closes gh-10961

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

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -16,11 +16,13 @@
 
 package org.springframework.boot.autoconfigure.mongo;
 
+import java.nio.channels.SocketChannel;
 import java.util.List;
 
 import javax.annotation.PreDestroy;
 
 import com.mongodb.async.client.MongoClientSettings;
+import com.mongodb.connection.netty.NettyStreamFactoryFactory;
 import com.mongodb.reactivestreams.client.MongoClient;
 
 import org.springframework.beans.factory.ObjectProvider;
@@ -30,6 +32,8 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
 import org.springframework.core.env.Environment;
 
 /**
@@ -46,16 +50,10 @@ public class MongoReactiveAutoConfiguration {
 
 	private final MongoClientSettings settings;
 
-	private final ReactiveMongoClientFactory factory;
-
 	private MongoClient mongo;
 
-	public MongoReactiveAutoConfiguration(MongoProperties properties,
-			ObjectProvider<MongoClientSettings> settings, Environment environment,
-			ObjectProvider<List<MongoClientSettingsBuilderCustomizer>> builderCustomizers) {
+	public MongoReactiveAutoConfiguration(ObjectProvider<MongoClientSettings> settings) {
 		this.settings = settings.getIfAvailable();
-		this.factory = new ReactiveMongoClientFactory(properties, environment,
-				builderCustomizers.getIfAvailable());
 	}
 
 	@PreDestroy
@@ -67,9 +65,35 @@ public class MongoReactiveAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
-	public MongoClient reactiveStreamsMongoClient() {
-		this.mongo = this.factory.createMongoClient(this.settings);
+	public MongoClient reactiveStreamsMongoClient(MongoProperties properties,
+			Environment environment,
+			ObjectProvider<List<MongoClientSettingsBuilderCustomizer>> builderCustomizers) {
+		ReactiveMongoClientFactory factory = new ReactiveMongoClientFactory(properties,
+				environment, builderCustomizers.getIfAvailable());
+		this.mongo = factory.createMongoClient(this.settings);
 		return this.mongo;
 	}
 
+	@Configuration
+	@ConditionalOnClass(SocketChannel.class)
+	static class NettyDriverConfiguration {
+
+		@Bean
+		@Order(Ordered.HIGHEST_PRECEDENCE)
+		public MongoClientSettingsBuilderCustomizer nettyDriverCustomizer(
+				ObjectProvider<MongoClientSettings> settings) {
+			return (builder) -> {
+				if (!isStreamFactoryFactoryDefined(settings.getIfAvailable())) {
+					builder.streamFactoryFactory(
+							NettyStreamFactoryFactory.builder().build());
+				}
+			};
+		}
+
+		private boolean isStreamFactoryFactoryDefined(MongoClientSettings settings) {
+			return settings != null && settings.getStreamFactoryFactory() != null;
+		}
+
+	}
+
 }

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

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -20,9 +20,11 @@ import java.util.concurrent.TimeUnit;
 
 import com.mongodb.ReadPreference;
 import com.mongodb.async.client.MongoClientSettings;
+import com.mongodb.connection.AsynchronousSocketChannelStreamFactoryFactory;
 import com.mongodb.connection.SocketSettings;
 import com.mongodb.connection.StreamFactory;
 import com.mongodb.connection.StreamFactoryFactory;
+import com.mongodb.connection.netty.NettyStreamFactoryFactory;
 import com.mongodb.reactivestreams.client.MongoClient;
 import org.junit.Test;
 
@@ -86,6 +88,16 @@ public class MongoReactiveAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	public void nettyStreamFactoryFactoryIsConfiguredAutomatically() {
+		this.contextRunner.run((context) -> {
+			assertThat(context).hasSingleBean(MongoClient.class);
+			assertThat(context.getBean(MongoClient.class).getSettings()
+					.getStreamFactoryFactory())
+					.isInstanceOf(NettyStreamFactoryFactory.class);
+		});
+	}
+
 	@Test
 	public void customizerOverridesAutoConfig() {
 		this.contextRunner
@@ -95,6 +107,8 @@ public class MongoReactiveAutoConfigurationTests {
 			MongoClient client = context.getBean(MongoClient.class);
 			assertThat(client.getSettings().getApplicationName())
 					.isEqualTo("overridden-name");
+			assertThat(client.getSettings().getStreamFactoryFactory())
+					.isEqualTo(SimpleCustomizerConfig.streamFactoryFactory);
 		});
 	}
 
@@ -133,10 +147,14 @@ public class MongoReactiveAutoConfigurationTests {
 	@Configuration
 	static class SimpleCustomizerConfig {
 
+		private static final StreamFactoryFactory streamFactoryFactory =
+				new AsynchronousSocketChannelStreamFactoryFactory();
+
 		@Bean
 		public MongoClientSettingsBuilderCustomizer customizer() {
 			return (clientSettingsBuilder) -> clientSettingsBuilder
-					.applicationName("overridden-name");
+					.applicationName("overridden-name")
+					.streamFactoryFactory(streamFactoryFactory);
 		}
 
 	}

spring-boot-project/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -3660,7 +3660,9 @@ instead of using `MongoDbFactory`. If you want to take complete control of estab
 the MongoDB connection, you can also declare your own `MongoDbFactory` or `MongoClient`
 bean.
 
-
+NOTE: If you are using the reactive driver, Netty is required for SSL. The
+auto-configuration configures this factory automatically if Netty is available and the
+factory to use hasn't been customized already.
 
 [[boot-features-mongo-template]]
 ==== MongoTemplate