Add Kafka transaction support property

Add `spring.kafka.producer.transaction-id-prefix` property that will be
passed to `DefaultKafkaProducerFactory.setTransactionIdPrefix(...)`

See gh-11076

Author: nklmish

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

@@ -38,13 +38,15 @@
 import org.springframework.kafka.support.LoggingProducerListener;
 import org.springframework.kafka.support.ProducerListener;
 import org.springframework.kafka.support.converter.RecordMessageConverter;
+import org.springframework.kafka.transaction.KafkaTransactionManager;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for Apache Kafka.
  *
  * @author Gary Russell
  * @author Stephane Nicoll
  * @author Eddú Meléndez
+ * @author Nakul Mishra
  * @since 1.5.0
  */
 @Configuration
@@ -94,8 +96,20 @@ public ProducerListener<Object, Object> kafkaProducerListener() {
 	@Bean
 	@ConditionalOnMissingBean(ProducerFactory.class)
 	public ProducerFactory<?, ?> kafkaProducerFactory() {
-		return new DefaultKafkaProducerFactory<>(
+		DefaultKafkaProducerFactory<Object, Object> factory = new DefaultKafkaProducerFactory<>(
 				this.properties.buildProducerProperties());
+		KafkaProperties.Producer producer = this.properties.getProducer();
+		if (producer.getTransactionIdPrefix() != null) {
+			factory.setTransactionIdPrefix(producer.getTransactionIdPrefix());
+		}
+		return factory;
+	}
+
+	@Bean
+	@ConditionalOnProperty(name = "spring.kafka.producer.transaction-id-prefix")
+	@ConditionalOnMissingBean
+	public KafkaTransactionManager<?, ?> kafkaTransactionManager(ProducerFactory<?, ?> producerFactory) {
+		return new KafkaTransactionManager<>(producerFactory);
 	}
 
 	@Bean

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

@@ -45,6 +45,7 @@
  * @author Gary Russell
  * @author Stephane Nicoll
  * @author Artem Bilan
+ * @author Nakul Mishra
  * @since 1.5.0
  */
 @ConfigurationProperties(prefix = "spring.kafka")
@@ -519,6 +520,11 @@ public static class Producer {
 		 */
 		private Integer retries;
 
+		/**
+		 * When non empty, enables transactional support for producer.
+		 */
+		private String transactionIdPrefix;
+
 		/**
 		 * Additional producer-specific properties used to configure the client.
 		 */
@@ -600,6 +606,14 @@ public void setRetries(Integer retries) {
 			this.retries = retries;
 		}
 
+		public String getTransactionIdPrefix() {
+			return this.transactionIdPrefix;
+		}
+
+		public void setTransactionIdPrefix(String transactionIdPrefix) {
+			this.transactionIdPrefix = transactionIdPrefix;
+		}
+
 		public Map<String, String> getProperties() {
 			return this.properties;
 		}

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

@@ -48,6 +48,7 @@
 import org.springframework.kafka.support.converter.MessagingMessageConverter;
 import org.springframework.kafka.support.converter.RecordMessageConverter;
 import org.springframework.kafka.test.utils.KafkaTestUtils;
+import org.springframework.kafka.transaction.KafkaTransactionManager;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.entry;
@@ -59,6 +60,7 @@
  * @author Gary Russell
  * @author Stephane Nicoll
  * @author Eddú Meléndez
+ * @author Nakul Mishra
  */
 public class KafkaAutoConfigurationTests {
 
@@ -198,6 +200,9 @@ public void producerProperties() {
 					assertThat(
 							context.getBeansOfType(KafkaJaasLoginModuleInitializer.class))
 									.isEmpty();
+					assertThat(
+							context.getBeansOfType(KafkaTransactionManager.class))
+									.isEmpty();
 					assertThat(configs.get("foo.bar.baz")).isEqualTo("qux.fiz.buz");
 					assertThat(configs.get("fiz.buz")).isEqualTo("fix.fox");
 				});
@@ -256,6 +261,7 @@ public void listenerProperties() {
 						"spring.kafka.listener.poll-timeout=2000",
 						"spring.kafka.listener.type=batch",
 						"spring.kafka.jaas.enabled=true",
+						"spring.kafka.producer.transaction-id-prefix=foo",
 						"spring.kafka.jaas.login-module=foo",
 						"spring.kafka.jaas.control-flag=REQUISITE",
 						"spring.kafka.jaas.options.useKeyTab=true")
@@ -297,6 +303,9 @@ public void listenerProperties() {
 					assertThat(dfa.getPropertyValue("loginModule")).isEqualTo("foo");
 					assertThat(dfa.getPropertyValue("controlFlag")).isEqualTo(
 							AppConfigurationEntry.LoginModuleControlFlag.REQUISITE);
+					assertThat(
+							context.getBeansOfType(KafkaTransactionManager.class))
+							.hasSize(1);
 					assertThat(((Map<String, String>) dfa.getPropertyValue("options")))
 							.containsExactly(entry("useKeyTab", "true"));
 				});