Merge pull request #34033 from terminux

* pr/34033:
  Auto-configure Spring Kafka ContainerCustomizer

Closes gh-34033

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/kafka/KafkaAnnotationDrivenConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * 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.
@@ -24,6 +24,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.kafka.annotation.EnableKafka;
 import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
+import org.springframework.kafka.config.ContainerCustomizer;
 import org.springframework.kafka.config.KafkaListenerConfigUtils;
 import org.springframework.kafka.core.ConsumerFactory;
 import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
@@ -31,6 +32,7 @@ import org.springframework.kafka.core.KafkaTemplate;
 import org.springframework.kafka.listener.AfterRollbackProcessor;
 import org.springframework.kafka.listener.BatchInterceptor;
 import org.springframework.kafka.listener.CommonErrorHandler;
+import org.springframework.kafka.listener.ConcurrentMessageListenerContainer;
 import org.springframework.kafka.listener.ConsumerAwareRebalanceListener;
 import org.springframework.kafka.listener.RecordInterceptor;
 import org.springframework.kafka.listener.adapter.RecordFilterStrategy;
@@ -121,10 +123,12 @@ class KafkaAnnotationDrivenConfiguration {
 	@ConditionalOnMissingBean(name = "kafkaListenerContainerFactory")
 	ConcurrentKafkaListenerContainerFactory<?, ?> kafkaListenerContainerFactory(
 			ConcurrentKafkaListenerContainerFactoryConfigurer configurer,
-			ObjectProvider<ConsumerFactory<Object, Object>> kafkaConsumerFactory) {
+			ObjectProvider<ConsumerFactory<Object, Object>> kafkaConsumerFactory,
+			ObjectProvider<ContainerCustomizer<Object, Object, ConcurrentMessageListenerContainer<Object, Object>>> kafkaContainerCustomizer) {
 		ConcurrentKafkaListenerContainerFactory<Object, Object> factory = new ConcurrentKafkaListenerContainerFactory<>();
 		configurer.configure(factory, kafkaConsumerFactory
 				.getIfAvailable(() -> new DefaultKafkaConsumerFactory<>(this.properties.buildConsumerProperties())));
+		kafkaContainerCustomizer.ifAvailable(factory::setContainerCustomizer);
 		return factory;
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/kafka/KafkaAutoConfigurationTests.java

@@ -53,6 +53,7 @@ import org.springframework.kafka.annotation.EnableKafkaStreams;
 import org.springframework.kafka.annotation.KafkaStreamsDefaultConfiguration;
 import org.springframework.kafka.config.AbstractKafkaListenerContainerFactory;
 import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
+import org.springframework.kafka.config.ContainerCustomizer;
 import org.springframework.kafka.config.KafkaListenerContainerFactory;
 import org.springframework.kafka.config.KafkaStreamsConfiguration;
 import org.springframework.kafka.config.StreamsBuilderFactoryBean;
@@ -65,6 +66,7 @@ import org.springframework.kafka.core.KafkaTemplate;
 import org.springframework.kafka.listener.AfterRollbackProcessor;
 import org.springframework.kafka.listener.BatchInterceptor;
 import org.springframework.kafka.listener.CommonErrorHandler;
+import org.springframework.kafka.listener.ConcurrentMessageListenerContainer;
 import org.springframework.kafka.listener.ConsumerAwareRebalanceListener;
 import org.springframework.kafka.listener.ContainerProperties;
 import org.springframework.kafka.listener.ContainerProperties.AckMode;
@@ -696,6 +698,17 @@ class KafkaAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	void testConcurrentKafkaListenerContainerFactoryWithCustomContainerCustomizer() {
+		this.contextRunner.withUserConfiguration(ObservationEnabledContainerCustomizerConfiguration.class)
+				.run((context) -> {
+					ConcurrentKafkaListenerContainerFactory<?, ?> factory = context
+							.getBean(ConcurrentKafkaListenerContainerFactory.class);
+					ConcurrentMessageListenerContainer<?, ?> container = factory.createContainer("someTopic");
+					assertThat(container.getContainerProperties().isObservationEnabled()).isEqualTo(true);
+				});
+	}
+
 	@Test
 	void specificSecurityProtocolOverridesCommonSecurityProtocol() {
 		this.contextRunner.withPropertyValues("spring.kafka.security.protocol=SSL",
@@ -765,6 +778,16 @@ class KafkaAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class ObservationEnabledContainerCustomizerConfiguration {
+
+		@Bean
+		ContainerCustomizer<Object, Object, ConcurrentMessageListenerContainer<Object, Object>> myContainerCustomizer() {
+			return (container) -> container.getContainerProperties().setObservationEnabled(true);
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class RecordInterceptorConfiguration {