Add ConnectionDetail support to Rabbit auto-configuration

Update Rabbit auto-configuration so that `RabbitConnectionDetails`
beans may be optionally used to provide connection details.

See gh-34657

Co-Authored-By: Mortitz Halbritter <mkammerer@vmware.com>
Co-Authored-By: Phillip Webb <pwebb@vmware.com>

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

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.autoconfigure.amqp;
 
+import java.util.stream.Collectors;
+
 import org.springframework.amqp.rabbit.connection.AbstractConnectionFactory;
 import org.springframework.amqp.rabbit.connection.ConnectionNameStrategy;
 import org.springframework.boot.context.properties.PropertyMapper;
@@ -27,6 +29,9 @@ import org.springframework.util.Assert;
  *
  * @param <T> the connection factory type.
  * @author Chris Bono
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
  * @since 2.6.0
  */
 public abstract class AbstractConnectionFactoryConfigurer<T extends AbstractConnectionFactory> {
@@ -35,9 +40,31 @@ public abstract class AbstractConnectionFactoryConfigurer<T extends AbstractConn
 
 	private ConnectionNameStrategy connectionNameStrategy;
 
+	private final RabbitConnectionDetails connectionDetails;
+
+	/**
+	 * Creates a new configurer that will configure the connection factory using the given
+	 * {@code properties}.
+	 * @param properties the properties to use to configure the connection factory
+	 */
 	protected AbstractConnectionFactoryConfigurer(RabbitProperties properties) {
-		Assert.notNull(properties, "RabbitProperties must not be null");
+		this(properties, new PropertiesRabbitConnectionDetails(properties));
+	}
+
+	/**
+	 * Creates a new configurer that will configure the connection factory using the given
+	 * {@code properties} and {@code connectionDetails}, with the latter taking priority.
+	 * @param properties the properties to use to configure the connection factory
+	 * @param connectionDetails the connection details to use to configure the connection
+	 * factory
+	 * @since 3.1.0
+	 */
+	protected AbstractConnectionFactoryConfigurer(RabbitProperties properties,
+			RabbitConnectionDetails connectionDetails) {
+		Assert.notNull(properties, "Properties must not be null");
+		Assert.notNull(connectionDetails, "ConnectionDetails must not be null");
 		this.rabbitProperties = properties;
+		this.connectionDetails = connectionDetails;
 	}
 
 	protected final ConnectionNameStrategy getConnectionNameStrategy() {
@@ -55,7 +82,11 @@ public abstract class AbstractConnectionFactoryConfigurer<T extends AbstractConn
 	public final void configure(T connectionFactory) {
 		Assert.notNull(connectionFactory, "ConnectionFactory must not be null");
 		PropertyMapper map = PropertyMapper.get();
-		map.from(this.rabbitProperties::determineAddresses).to(connectionFactory::setAddresses);
+		String addresses = this.connectionDetails.getAddresses()
+			.stream()
+			.map((address) -> address.host() + ":" + address.port())
+			.collect(Collectors.joining(","));
+		map.from(addresses).to(connectionFactory::setAddresses);
 		map.from(this.rabbitProperties::getAddressShuffleMode)
 			.whenNonNull()
 			.to(connectionFactory::setAddressShuffleMode);

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

@@ -25,12 +25,32 @@ import org.springframework.boot.context.properties.PropertyMapper;
  * Configures Rabbit {@link CachingConnectionFactory} with sensible defaults.
  *
  * @author Chris Bono
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
  * @since 2.6.0
  */
 public class CachingConnectionFactoryConfigurer extends AbstractConnectionFactoryConfigurer<CachingConnectionFactory> {
 
+	/**
+	 * Creates a new configurer that will configure the connection factory using the given
+	 * {@code properties}.
+	 * @param properties the properties to use to configure the connection factory
+	 */
 	public CachingConnectionFactoryConfigurer(RabbitProperties properties) {
-		super(properties);
+		this(properties, new PropertiesRabbitConnectionDetails(properties));
+	}
+
+	/**
+	 * Creates a new configurer that will configure the connection factory using the given
+	 * {@code properties} and {@code connectionDetails}, with the latter taking priority.
+	 * @param properties the properties to use to configure the connection factory
+	 * @param connectionDetails the connection details to use to configure the connection
+	 * factory
+	 * @since 3.1.0
+	 */
+	public CachingConnectionFactoryConfigurer(RabbitProperties properties, RabbitConnectionDetails connectionDetails) {
+		super(properties, connectionDetails);
 	}
 
 	@Override

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

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2012-2023 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 java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Adapts {@link RabbitProperties} to {@link RabbitConnectionDetails}.
+ *
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
+ * @since 3.1.0
+ */
+public class PropertiesRabbitConnectionDetails implements RabbitConnectionDetails {
+
+	private final RabbitProperties properties;
+
+	public PropertiesRabbitConnectionDetails(RabbitProperties properties) {
+		this.properties = properties;
+	}
+
+	@Override
+	public String getUsername() {
+		return this.properties.determineUsername();
+	}
+
+	@Override
+	public String getPassword() {
+		return this.properties.determinePassword();
+	}
+
+	@Override
+	public String getVirtualHost() {
+		return this.properties.determineVirtualHost();
+	}
+
+	@Override
+	public List<Address> getAddresses() {
+		List<Address> addresses = new ArrayList<>();
+		for (String address : this.properties.determineAddresses().split(",")) {
+			String[] components = address.split(":");
+			addresses.add(new Address(components[0], Integer.parseInt(components[1])));
+		}
+		return addresses;
+	}
+
+}

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

@@ -59,21 +59,6 @@ import org.springframework.core.io.ResourceLoader;
  * <li>{@link org.springframework.amqp.core.AmqpAdmin } instance as long as
  * {@literal spring.rabbitmq.dynamic=true}.</li>
  * </ul>
- * <p>
- * The {@link org.springframework.amqp.rabbit.connection.CachingConnectionFactory} honors
- * the following properties:
- * <ul>
- * <li>{@literal spring.rabbitmq.port} is used to specify the port to which the client
- * should connect, and defaults to 5672.</li>
- * <li>{@literal spring.rabbitmq.username} is used to specify the (optional) username.
- * </li>
- * <li>{@literal spring.rabbitmq.password} is used to specify the (optional) password.
- * </li>
- * <li>{@literal spring.rabbitmq.host} is used to specify the host, and defaults to
- * {@literal localhost}.</li>
- * <li>{@literal spring.rabbitmq.virtualHost} is used to specify the (optional) virtual
- * host to which the client should connect.</li>
- * </ul>
  *
  * @author Greg Turnquist
  * @author Josh Long
@@ -82,6 +67,8 @@ import org.springframework.core.io.ResourceLoader;
  * @author Phillip Webb
  * @author Artsiom Yudovin
  * @author Chris Bono
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
  * @since 1.0.0
  */
 @AutoConfiguration
@@ -93,13 +80,24 @@ public class RabbitAutoConfiguration {
 	@Configuration(proxyBeanMethods = false)
 	protected static class RabbitConnectionFactoryCreator {
 
+		private final RabbitProperties properties;
+
+		private final RabbitConnectionDetails connectionDetails;
+
+		protected RabbitConnectionFactoryCreator(RabbitProperties properties,
+				ObjectProvider<RabbitConnectionDetails> connectionDetails) {
+			this.properties = properties;
+			this.connectionDetails = connectionDetails
+				.getIfAvailable(() -> new PropertiesRabbitConnectionDetails(properties));
+		}
+
 		@Bean
 		@ConditionalOnMissingBean
-		RabbitConnectionFactoryBeanConfigurer rabbitConnectionFactoryBeanConfigurer(RabbitProperties properties,
-				ResourceLoader resourceLoader, ObjectProvider<CredentialsProvider> credentialsProvider,
+		RabbitConnectionFactoryBeanConfigurer rabbitConnectionFactoryBeanConfigurer(ResourceLoader resourceLoader,
+				ObjectProvider<CredentialsProvider> credentialsProvider,
 				ObjectProvider<CredentialsRefreshService> credentialsRefreshService) {
 			RabbitConnectionFactoryBeanConfigurer configurer = new RabbitConnectionFactoryBeanConfigurer(resourceLoader,
-					properties);
+					this.properties, this.connectionDetails);
 			configurer.setCredentialsProvider(credentialsProvider.getIfUnique());
 			configurer.setCredentialsRefreshService(credentialsRefreshService.getIfUnique());
 			return configurer;
@@ -107,9 +105,10 @@ public class RabbitAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean
-		CachingConnectionFactoryConfigurer rabbitConnectionFactoryConfigurer(RabbitProperties rabbitProperties,
+		CachingConnectionFactoryConfigurer rabbitConnectionFactoryConfigurer(
 				ObjectProvider<ConnectionNameStrategy> connectionNameStrategy) {
-			CachingConnectionFactoryConfigurer configurer = new CachingConnectionFactoryConfigurer(rabbitProperties);
+			CachingConnectionFactoryConfigurer configurer = new CachingConnectionFactoryConfigurer(this.properties,
+					this.connectionDetails);
 			configurer.setConnectionNameStrategy(connectionNameStrategy.getIfUnique());
 			return configurer;
 		}

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

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2012-2023 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 java.util.List;
+
+import org.springframework.boot.autoconfigure.service.connection.ConnectionDetails;
+import org.springframework.util.Assert;
+
+/**
+ * Details required to establish a connection to a RabbitMQ service.
+ *
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
+ * @since 3.1.0
+ */
+public interface RabbitConnectionDetails extends ConnectionDetails {
+
+	/**
+	 * Login user to authenticate to the broker.
+	 * @return the login user to authenticate to the broker or {@code null}
+	 */
+	default String getUsername() {
+		return null;
+	}
+
+	/**
+	 * Login to authenticate against the broker.
+	 * @return the login to authenticate against the broker or {@code null}
+	 */
+	default String getPassword() {
+		return null;
+	}
+
+	/**
+	 * Virtual host to use when connecting to the broker.
+	 * @return the virtual host to use when connecting to the broker or {@code null}
+	 */
+	default String getVirtualHost() {
+		return null;
+	}
+
+	/**
+	 * List of addresses to which the client should connect. Must return at least one
+	 * address.
+	 * @return the list of addresses to which the client should connect
+	 */
+	List<Address> getAddresses();
+
+	/**
+	 * Returns the first address.
+	 * @return the first address
+	 * @throws IllegalStateException if the address list is empty
+	 */
+	default Address getFirstAddress() {
+		List<Address> addresses = getAddresses();
+		Assert.state(!addresses.isEmpty(), "Address list is empty");
+		return addresses.get(0);
+	}
+
+	/**
+	 * A RabbitMQ address.
+	 *
+	 * @param host the host
+	 * @param port the port
+	 */
+	record Address(String host, int port) {
+	}
+
+}

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

@@ -22,6 +22,7 @@ import com.rabbitmq.client.impl.CredentialsProvider;
 import com.rabbitmq.client.impl.CredentialsRefreshService;
 
 import org.springframework.amqp.rabbit.connection.RabbitConnectionFactoryBean;
+import org.springframework.boot.autoconfigure.amqp.RabbitConnectionDetails.Address;
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.util.Assert;
@@ -30,6 +31,9 @@ import org.springframework.util.Assert;
  * Configures {@link RabbitConnectionFactoryBean} with sensible defaults.
  *
  * @author Chris Bono
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
  * @since 2.6.0
  */
 public class RabbitConnectionFactoryBeanConfigurer {
@@ -38,13 +42,39 @@ public class RabbitConnectionFactoryBeanConfigurer {
 
 	private final ResourceLoader resourceLoader;
 
+	private final RabbitConnectionDetails connectionDetails;
+
 	private CredentialsProvider credentialsProvider;
 
 	private CredentialsRefreshService credentialsRefreshService;
 
+	/**
+	 * Creates a new configurer that will use the given {@code resourceLoader} and
+	 * {@code properties}.
+	 * @param resourceLoader the resource loader
+	 * @param properties the properties
+	 */
 	public RabbitConnectionFactoryBeanConfigurer(ResourceLoader resourceLoader, RabbitProperties properties) {
+		this(resourceLoader, properties, new PropertiesRabbitConnectionDetails(properties));
+	}
+
+	/**
+	 * Creates a new configurer that will use the given {@code resourceLoader},
+	 * {@code properties}, and {@code connectionDetails}. The connection details have
+	 * priority over the properties.
+	 * @param resourceLoader the resource loader
+	 * @param properties the properties
+	 * @param connectionDetails the connection details.
+	 * @since 3.1.0
+	 */
+	public RabbitConnectionFactoryBeanConfigurer(ResourceLoader resourceLoader, RabbitProperties properties,
+			RabbitConnectionDetails connectionDetails) {
+		Assert.notNull(resourceLoader, "ResourceLoader must not be null");
+		Assert.notNull(properties, "Properties must not be null");
+		Assert.notNull(connectionDetails, "ConnectionDetails must not be null");
 		this.resourceLoader = resourceLoader;
 		this.rabbitProperties = properties;
+		this.connectionDetails = connectionDetails;
 	}
 
 	public void setCredentialsProvider(CredentialsProvider credentialsProvider) {
@@ -65,12 +95,13 @@ public class RabbitConnectionFactoryBeanConfigurer {
 	public void configure(RabbitConnectionFactoryBean factory) {
 		Assert.notNull(factory, "RabbitConnectionFactoryBean must not be null");
 		factory.setResourceLoader(this.resourceLoader);
+		Address address = this.connectionDetails.getFirstAddress();
 		PropertyMapper map = PropertyMapper.get();
-		map.from(this.rabbitProperties::determineHost).whenNonNull().to(factory::setHost);
-		map.from(this.rabbitProperties::determinePort).to(factory::setPort);
-		map.from(this.rabbitProperties::determineUsername).whenNonNull().to(factory::setUsername);
-		map.from(this.rabbitProperties::determinePassword).whenNonNull().to(factory::setPassword);
-		map.from(this.rabbitProperties::determineVirtualHost).whenNonNull().to(factory::setVirtualHost);
+		map.from(address::host).whenNonNull().to(factory::setHost);
+		map.from(address::port).to(factory::setPort);
+		map.from(this.connectionDetails::getUsername).whenNonNull().to(factory::setUsername);
+		map.from(this.connectionDetails::getPassword).whenNonNull().to(factory::setPassword);
+		map.from(this.connectionDetails::getVirtualHost).whenNonNull().to(factory::setVirtualHost);
 		map.from(this.rabbitProperties::getRequestedHeartbeat)
 			.whenNonNull()
 			.asInt(Duration::getSeconds)

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

@@ -96,6 +96,9 @@ import static org.mockito.Mockito.mock;
  * @author Gary Russell
  * @author HaiTao Zhang
  * @author Franjo Zilic
+ * @author Moritz Halbritter
+ * @author Andy Wilkinson
+ * @author Phillip Webb
  */
 @ExtendWith(OutputCaptureExtension.class)
 class RabbitAutoConfigurationTests {
@@ -169,6 +172,26 @@ class RabbitAutoConfigurationTests {
 			});
 	}
 
+	@Test
+	@SuppressWarnings("unchecked")
+	void testConnectionFactoryWithOverridesWhenUsingConnectionDetails() {
+		this.contextRunner.withUserConfiguration(TestConfiguration.class, ConnectionDetailsConfiguration.class)
+			.withPropertyValues("spring.rabbitmq.host:remote-server", "spring.rabbitmq.port:9000",
+					"spring.rabbitmq.username:alice", "spring.rabbitmq.password:secret",
+					"spring.rabbitmq.virtual_host:/vhost")
+			.run((context) -> {
+				CachingConnectionFactory connectionFactory = context.getBean(CachingConnectionFactory.class);
+				assertThat(connectionFactory.getHost()).isEqualTo("rabbit.example.com");
+				assertThat(connectionFactory.getPort()).isEqualTo(12345);
+				assertThat(connectionFactory.getVirtualHost()).isEqualTo("/vhost-1");
+				assertThat(connectionFactory.getUsername()).isEqualTo("user-1");
+				assertThat(connectionFactory.getRabbitConnectionFactory().getPassword()).isEqualTo("password-1");
+				List<Address> addresses = (List<Address>) ReflectionTestUtils.getField(connectionFactory, "addresses");
+				assertThat(addresses).containsExactly(new Address("rabbit.example.com", 12345),
+						new Address("rabbit2.example.com", 23456));
+			});
+	}
+
 	@Test
 	@SuppressWarnings("unchecked")
 	void testConnectionFactoryWithCustomConnectionNameStrategy() {
@@ -1218,6 +1241,38 @@ class RabbitAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class ConnectionDetailsConfiguration {
+
+		@Bean
+		RabbitConnectionDetails rabbitConnectionDetails() {
+			return new RabbitConnectionDetails() {
+
+				@Override
+				public String getUsername() {
+					return "user-1";
+				}
+
+				@Override
+				public String getPassword() {
+					return "password-1";
+				}
+
+				@Override
+				public String getVirtualHost() {
+					return "/vhost-1";
+				}
+
+				@Override
+				public List<Address> getAddresses() {
+					return List.of(new Address("rabbit.example.com", 12345), new Address("rabbit2.example.com", 23456));
+				}
+
+			};
+		}
+
+	}
+
 	static class TestListener {
 
 		@RabbitListener(queues = "test", autoStartup = "false")