Allow auto-configured Rabbit Stream Environment to be customized

Closes gh-32580

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

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2022 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.stream.Environment;
+import com.rabbitmq.stream.EnvironmentBuilder;
+
+/**
+ * Callback interface that can be implemented by beans wishing to customize the
+ * auto-configured {@link Environment} that is created by an {@link EnvironmentBuilder}.
+ *
+ * @author Andy Wilkinson
+ * @since 3.0.0
+ */
+@FunctionalInterface
+public interface EnvironmentBuilderCustomizer {
+
+	/**
+	 * Customize the {@code EnvironmentBuilder}.
+	 * @param builder the builder to customize
+	 */
+	void customize(EnvironmentBuilder builder);
+
+}

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

@@ -65,8 +65,11 @@ class RabbitStreamConfiguration {
 
 	@Bean(name = "rabbitStreamEnvironment")
 	@ConditionalOnMissingBean(name = "rabbitStreamEnvironment")
-	Environment rabbitStreamEnvironment(RabbitProperties properties) {
-		return configure(Environment.builder(), properties).build();
+	Environment rabbitStreamEnvironment(RabbitProperties properties,
+			ObjectProvider<EnvironmentBuilderCustomizer> customizers) {
+		EnvironmentBuilder builder = configure(Environment.builder(), properties);
+		customizers.orderedStream().forEach((customizer) -> customizer.customize(builder));
+		return builder.build();
 	}
 
 	@Bean

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

@@ -16,6 +16,10 @@
 
 package org.springframework.boot.autoconfigure.amqp;
 
+import java.time.Duration;
+
+import com.rabbitmq.stream.BackOffDelayPolicy;
+import com.rabbitmq.stream.Codec;
 import com.rabbitmq.stream.Environment;
 import com.rabbitmq.stream.EnvironmentBuilder;
 import org.assertj.core.api.InstanceOfAssertFactories;
@@ -32,6 +36,7 @@ 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.annotation.Order;
 import org.springframework.rabbit.stream.config.StreamRabbitListenerContainerFactory;
 import org.springframework.rabbit.stream.listener.ConsumerCustomizer;
 import org.springframework.rabbit.stream.listener.StreamListenerContainer;
@@ -209,6 +214,17 @@ class RabbitStreamConfigurationTests {
 				});
 	}
 
+	@Test
+	void environmentCreatedByBuilderCanBeCustomized() {
+		this.contextRunner.withUserConfiguration(EnvironmentBuilderCustomizers.class).run((context) -> {
+			Environment environment = context.getBean(Environment.class);
+			assertThat(environment).extracting("codec")
+					.isEqualTo(context.getBean(EnvironmentBuilderCustomizers.class).codec);
+			assertThat(environment).extracting("recoveryBackOffDelayPolicy")
+					.isEqualTo(context.getBean(EnvironmentBuilderCustomizers.class).recoveryBackOffDelayPolicy);
+		});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class TestConfiguration {
 
@@ -272,4 +288,26 @@ class RabbitStreamConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class EnvironmentBuilderCustomizers {
+
+		private final Codec codec = mock(Codec.class);
+
+		private final BackOffDelayPolicy recoveryBackOffDelayPolicy = BackOffDelayPolicy.fixed(Duration.ofSeconds(5));
+
+		@Bean
+		@Order(1)
+		EnvironmentBuilderCustomizer customizerA() {
+			return (builder) -> builder.codec(this.codec);
+		}
+
+		@Bean
+		@Order(0)
+		EnvironmentBuilderCustomizer customizerB() {
+			return (builder) -> builder.codec(mock(Codec.class))
+					.recoveryBackOffDelayPolicy(this.recoveryBackOffDelayPolicy);
+		}
+
+	}
+
 }