Extract RabbitTemplate auto-configuration in a configurer

This commit movers the auto-configuration of RabbitTemplate to a
dedicated class that can be reused to create additional template with
similar settings.

CLoses gh-19440

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

@@ -152,36 +152,25 @@ public class RabbitAutoConfiguration {
 	protected static class RabbitTemplateConfiguration {
 
 		@Bean
-		@ConditionalOnSingleCandidate(ConnectionFactory.class)
-		@ConditionalOnMissingBean(RabbitOperations.class)
-		public RabbitTemplate rabbitTemplate(RabbitProperties properties,
+		@ConditionalOnMissingBean
+		public RabbitTemplateConfigurer rabbitTemplateConfigurer(RabbitProperties properties,
 				ObjectProvider<MessageConverter> messageConverter,
-				ObjectProvider<RabbitRetryTemplateCustomizer> retryTemplateCustomizers,
-				ConnectionFactory connectionFactory) {
-			PropertyMapper map = PropertyMapper.get();
-			RabbitTemplate template = new RabbitTemplate(connectionFactory);
-			messageConverter.ifUnique(template::setMessageConverter);
-			template.setMandatory(determineMandatoryFlag(properties));
-			RabbitProperties.Template templateProperties = properties.getTemplate();
-			if (templateProperties.getRetry().isEnabled()) {
-				template.setRetryTemplate(
-						new RetryTemplateFactory(retryTemplateCustomizers.orderedStream().collect(Collectors.toList()))
-								.createRetryTemplate(templateProperties.getRetry(),
-										RabbitRetryTemplateCustomizer.Target.SENDER));
-			}
-			map.from(templateProperties::getReceiveTimeout).whenNonNull().as(Duration::toMillis)
-					.to(template::setReceiveTimeout);
-			map.from(templateProperties::getReplyTimeout).whenNonNull().as(Duration::toMillis)
-					.to(template::setReplyTimeout);
-			map.from(templateProperties::getExchange).to(template::setExchange);
-			map.from(templateProperties::getRoutingKey).to(template::setRoutingKey);
-			map.from(templateProperties::getDefaultReceiveQueue).whenNonNull().to(template::setDefaultReceiveQueue);
-			return template;
+				ObjectProvider<RabbitRetryTemplateCustomizer> retryTemplateCustomizers) {
+			RabbitTemplateConfigurer configurer = new RabbitTemplateConfigurer();
+			configurer.setMessageConverter(messageConverter.getIfUnique());
+			configurer
+					.setRetryTemplateCustomizers(retryTemplateCustomizers.orderedStream().collect(Collectors.toList()));
+			configurer.setRabbitProperties(properties);
+			return configurer;
 		}
 
-		private boolean determineMandatoryFlag(RabbitProperties properties) {
-			Boolean mandatory = properties.getTemplate().getMandatory();
-			return (mandatory != null) ? mandatory : properties.isPublisherReturns();
+		@Bean
+		@ConditionalOnSingleCandidate(ConnectionFactory.class)
+		@ConditionalOnMissingBean(RabbitOperations.class)
+		public RabbitTemplate rabbitTemplate(RabbitTemplateConfigurer configurer, ConnectionFactory connectionFactory) {
+			RabbitTemplate template = new RabbitTemplate();
+			configurer.configure(template, connectionFactory);
+			return template;
 		}
 
 		@Bean

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

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2012-2019 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.time.Duration;
+import java.util.List;
+
+import org.springframework.amqp.rabbit.connection.ConnectionFactory;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.amqp.support.converter.MessageConverter;
+import org.springframework.boot.context.properties.PropertyMapper;
+
+/**
+ * Configure {@link RabbitTemplate} with sensible defaults.
+ *
+ * @author Stephane Nicoll
+ * @since 2.3.0
+ */
+public class RabbitTemplateConfigurer {
+
+	private MessageConverter messageConverter;
+
+	private List<RabbitRetryTemplateCustomizer> retryTemplateCustomizers;
+
+	private RabbitProperties rabbitProperties;
+
+	/**
+	 * Set the {@link MessageConverter} to use or {@code null} if the out-of-the-box
+	 * converter should be used.
+	 * @param messageConverter the {@link MessageConverter}
+	 */
+	protected void setMessageConverter(MessageConverter messageConverter) {
+		this.messageConverter = messageConverter;
+	}
+
+	/**
+	 * Set the {@link RabbitRetryTemplateCustomizer} instances to use.
+	 * @param retryTemplateCustomizers the retry template customizers
+	 */
+	protected void setRetryTemplateCustomizers(List<RabbitRetryTemplateCustomizer> retryTemplateCustomizers) {
+		this.retryTemplateCustomizers = retryTemplateCustomizers;
+	}
+
+	/**
+	 * Set the {@link RabbitProperties} to use.
+	 * @param rabbitProperties the {@link RabbitProperties}
+	 */
+	protected void setRabbitProperties(RabbitProperties rabbitProperties) {
+		this.rabbitProperties = rabbitProperties;
+	}
+
+	protected final RabbitProperties getRabbitProperties() {
+		return this.rabbitProperties;
+	}
+
+	/**
+	 * Configure the specified {@link RabbitTemplate}. The template can be further tuned
+	 * and default settings can be overridden.
+	 * @param template the {@link RabbitTemplate} instance to configure
+	 * @param connectionFactory the {@link ConnectionFactory} to use
+	 */
+	public void configure(RabbitTemplate template, ConnectionFactory connectionFactory) {
+		PropertyMapper map = PropertyMapper.get();
+		template.setConnectionFactory(connectionFactory);
+		if (this.messageConverter != null) {
+			template.setMessageConverter(this.messageConverter);
+		}
+		template.setMandatory(determineMandatoryFlag());
+		RabbitProperties.Template templateProperties = this.rabbitProperties.getTemplate();
+		if (templateProperties.getRetry().isEnabled()) {
+			template.setRetryTemplate(new RetryTemplateFactory(this.retryTemplateCustomizers)
+					.createRetryTemplate(templateProperties.getRetry(), RabbitRetryTemplateCustomizer.Target.SENDER));
+		}
+		map.from(templateProperties::getReceiveTimeout).whenNonNull().as(Duration::toMillis)
+				.to(template::setReceiveTimeout);
+		map.from(templateProperties::getReplyTimeout).whenNonNull().as(Duration::toMillis)
+				.to(template::setReplyTimeout);
+		map.from(templateProperties::getExchange).to(template::setExchange);
+		map.from(templateProperties::getRoutingKey).to(template::setRoutingKey);
+		map.from(templateProperties::getDefaultReceiveQueue).whenNonNull().to(template::setDefaultReceiveQueue);
+	}
+
+	private boolean determineMandatoryFlag() {
+		Boolean mandatory = this.rabbitProperties.getTemplate().getMandatory();
+		return (mandatory != null) ? mandatory : this.rabbitProperties.isPublisherReturns();
+	}
+
+}

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

@@ -333,6 +333,30 @@ class RabbitAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	void testRabbitTemplateConfigurersIsAvailable() {
+		this.contextRunner.withUserConfiguration(TestConfiguration.class)
+				.run((context) -> assertThat(context).hasSingleBean(RabbitTemplateConfigurer.class));
+	}
+
+	@Test
+	void testRabbitTemplateConfigurerUsesConfig() {
+		this.contextRunner.withUserConfiguration(MessageConvertersConfiguration.class)
+				.withPropertyValues("spring.rabbitmq.template.exchange:my-exchange",
+						"spring.rabbitmq.template.routing-key:my-routing-key",
+						"spring.rabbitmq.template.default-receive-queue:default-queue")
+				.run((context) -> {
+					RabbitTemplateConfigurer configurer = context.getBean(RabbitTemplateConfigurer.class);
+					RabbitTemplate template = mock(RabbitTemplate.class);
+					ConnectionFactory connectionFactory = mock(ConnectionFactory.class);
+					configurer.configure(template, connectionFactory);
+					verify(template).setMessageConverter(context.getBean("myMessageConverter", MessageConverter.class));
+					verify(template).setExchange("my-exchange");
+					verify(template).setRoutingKey("my-routing-key");
+					verify(template).setDefaultReceiveQueue("default-queue");
+				});
+	}
+
 	@Test
 	void testConnectionFactoryBackOff() {
 		this.contextRunner.withUserConfiguration(TestConfiguration2.class).run((context) -> {

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

@@ -5131,6 +5131,8 @@ To retry operations, you can enable retries on the `AmqpTemplate` (for example,
 Retries are disabled by default.
 You can also customize the `RetryTemplate` programmatically by declaring a `RabbitRetryTemplateCustomizer` bean.
 
+If you need to create more `RabbitTemplate` instances or if you want to override the default, Spring Boot provides a `RabbitTemplateConfigurer` bean that you can use to initialize a `RabbitTemplate` with the same settings as the factories used by the auto-configuration.
+
 
 
 [[boot-features-using-amqp-receiving]]