Allow the auto-configured RabbitMQ ConnectionFactory to be customized

Closes gh-6719

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/amqp/ConnectionFactoryCustomizer.java

+/*
+ * Copyright 2012-2021 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.boot.autoconfigure.amqp;
+
+import com.rabbitmq.client.ConnectionFactory;
+
+/**
+ * Callback interface that can be implemented by beans wishing to customize the
+ * auto-configured RabbitMQ {@link ConnectionFactory}.
+ *
+ * @author Andy Wilkinson
+ * @since 2.5.0
+ */
+@FunctionalInterface
+public interface ConnectionFactoryCustomizer {
+
+	/**
+	 * Customize the {@link ConnectionFactory}.
+	 * @param factory the factory to customize
+	 */
+	void customize(ConnectionFactory factory);
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/amqp/RabbitAutoConfiguration.java

 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -100,9 +100,13 @@ public class RabbitAutoConfiguration {
 		public CachingConnectionFactory rabbitConnectionFactory(RabbitProperties properties,
 				ResourceLoader resourceLoader, ObjectProvider<CredentialsProvider> credentialsProvider,
 				ObjectProvider<CredentialsRefreshService> credentialsRefreshService,
-				ObjectProvider<ConnectionNameStrategy> connectionNameStrategy) throws Exception {
-			CachingConnectionFactory factory = new CachingConnectionFactory(getRabbitConnectionFactoryBean(properties,
-					resourceLoader, credentialsProvider, credentialsRefreshService).getObject());
+				ObjectProvider<ConnectionNameStrategy> connectionNameStrategy,
+				ObjectProvider<ConnectionFactoryCustomizer> connectionFactoryCustomizers) throws Exception {
+			com.rabbitmq.client.ConnectionFactory connectionFactory = getRabbitConnectionFactoryBean(properties,
+					resourceLoader, credentialsProvider, credentialsRefreshService).getObject();
+			connectionFactoryCustomizers.orderedStream()
+					.forEach((customizer) -> customizer.customize(connectionFactory));
+			CachingConnectionFactory factory = new CachingConnectionFactory(connectionFactory);
 			PropertyMapper map = PropertyMapper.get();
 			map.from(properties::determineAddresses).to(factory::setAddresses);
 			map.from(properties::getAddressShuffleMode).whenNonNull().to(factory::setAddressShuffleMode);

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/amqp/RabbitAutoConfigurationTests.java

 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -26,6 +26,7 @@ import javax.net.ssl.TrustManager;
 
 import com.rabbitmq.client.Address;
 import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.JDKSaslConfig;
 import com.rabbitmq.client.SslContextFactory;
 import com.rabbitmq.client.TrustEverythingTrustManager;
 import com.rabbitmq.client.impl.CredentialsProvider;
@@ -33,6 +34,7 @@ import com.rabbitmq.client.impl.CredentialsRefreshService;
 import com.rabbitmq.client.impl.DefaultCredentialsProvider;
 import org.aopalliance.aop.Advice;
 import org.junit.jupiter.api.Test;
+import org.mockito.InOrder;
 
 import org.springframework.amqp.core.AcknowledgeMode;
 import org.springframework.amqp.core.AmqpAdmin;
@@ -60,6 +62,8 @@ import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
 import org.springframework.retry.RetryPolicy;
 import org.springframework.retry.backoff.BackOffPolicy;
 import org.springframework.retry.backoff.ExponentialBackOffPolicy;
@@ -75,6 +79,7 @@ import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.isNull;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 
@@ -822,6 +827,29 @@ class RabbitAutoConfigurationTests {
 						.isNull());
 	}
 
+	@Test
+	void whenAConnectionFactoryCustomizerIsDefinedThenItCustomizesTheConnectionFactory() {
+		this.contextRunner.withUserConfiguration(SaslConfigCustomizerConfiguration.class)
+				.run((context) -> assertThat(getTargetConnectionFactory(context).getSaslConfig())
+						.isInstanceOf(JDKSaslConfig.class));
+	}
+
+	@Test
+	void whenMultipleConnectionFactoryCustomizersAreDefinedThenTheyAreCalledInOrder() {
+		this.contextRunner.withUserConfiguration(MultipleConnectionFactoryCustomizersConfiguration.class)
+				.run((context) -> {
+					ConnectionFactoryCustomizer firstCustomizer = context.getBean("firstCustomizer",
+							ConnectionFactoryCustomizer.class);
+					ConnectionFactoryCustomizer secondCustomizer = context.getBean("secondCustomizer",
+							ConnectionFactoryCustomizer.class);
+					InOrder inOrder = inOrder(firstCustomizer, secondCustomizer);
+					com.rabbitmq.client.ConnectionFactory targetConnectionFactory = getTargetConnectionFactory(context);
+					inOrder.verify(firstCustomizer).customize(targetConnectionFactory);
+					inOrder.verify(secondCustomizer).customize(targetConnectionFactory);
+					inOrder.verifyNoMoreInteractions();
+				});
+	}
+
 	private TrustManager getTrustManager(com.rabbitmq.client.ConnectionFactory rabbitConnectionFactory) {
 		SslContextFactory sslContextFactory = (SslContextFactory) ReflectionTestUtils.getField(rabbitConnectionFactory,
 				"sslContextFactory");
@@ -1071,4 +1099,31 @@ class RabbitAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class SaslConfigCustomizerConfiguration {
+
+		@Bean
+		ConnectionFactoryCustomizer connectionFactoryCustomizer() {
+			return (connectionFactory) -> connectionFactory.setSaslConfig(new JDKSaslConfig(connectionFactory));
+		}
+
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class MultipleConnectionFactoryCustomizersConfiguration {
+
+		@Bean
+		@Order(Ordered.LOWEST_PRECEDENCE)
+		ConnectionFactoryCustomizer secondCustomizer() {
+			return mock(ConnectionFactoryCustomizer.class);
+		}
+
+		@Bean
+		@Order(0)
+		ConnectionFactoryCustomizer firstCustomizer() {
+			return mock(ConnectionFactoryCustomizer.class);
+		}
+
+	}
+
 }

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

@@ -5428,8 +5428,10 @@ Alternatively, you could configure the same connection using the `addresses` att
 NOTE: When specifying addresses that way, the `host` and `port` properties are ignored.
 If the address uses the `amqps` protocol, SSL support is enabled automatically.
 
-If a `ConnectionNameStrategy` bean exists in the context, it will be automatically used to name connections created by the auto-configured `ConnectionFactory`.
-See {spring-boot-autoconfigure-module-code}/amqp/RabbitProperties.java[`RabbitProperties`] for more of the supported options.
+See {spring-boot-autoconfigure-module-code}/amqp/RabbitProperties.java[`RabbitProperties`] for more of the supported property-based configuration options.
+To configure lower-level details of the RabbitMQ `ConnectionFactory` that is used by Spring AMQP, define a `ConnectionFactoryCustomizer` bean.
+
+If a `ConnectionNameStrategy` bean exists in the context, it will be automatically used to name connections created by the auto-configured `CachingConnectionFactory`.
 
 TIP: See https://spring.io/blog/2010/06/14/understanding-amqp-the-protocol-used-by-rabbitmq/[Understanding AMQP, the protocol used by RabbitMQ] for more details.