Fix issue where application fails to start with multiple TransactionManager beans

Prior to this commit, if an application had multiple PlatformTransactionManager beans it would fail to start even when configuring a proper TransactionOperations qualified bean.
This commit introduces the @SpringSessionTransactionManager bean qualifier to specify which bean should be injected into Spring Session JDBC configuration, if no bean specified, it tries to resolve a unique PlatformTransactionManager bean from the application context to maintain backward compatibility.

Closes gh-2801

spring-session-jdbc/src/main/java/org/springframework/session/jdbc/config/annotation/SpringSessionTransactionManager.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2014-2024 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.session.jdbc.config.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.session.jdbc.JdbcIndexedSessionRepository;
+
+/**
+ * Qualifier annotation for a
+ * {@link org.springframework.transaction.PlatformTransactionManager} to be injected in
+ * {@link JdbcIndexedSessionRepository}.
+ *
+ * @author Marcus da Coregio
+ * @since 3.1.5
+ */
+@Target({ ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE, ElementType.ANNOTATION_TYPE })
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Qualifier
+public @interface SpringSessionTransactionManager {
+
+}

spring-session-jdbc/src/main/java/org/springframework/session/jdbc/config/annotation/web/http/JdbcHttpSessionConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2022 the original author or authors.
+ * Copyright 2014-2024 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.
@@ -24,10 +24,14 @@ import java.util.stream.Collectors;
 
 import javax.sql.DataSource;
 
+import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.EmbeddedValueResolverAware;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -54,6 +58,7 @@ import org.springframework.session.config.SessionRepositoryCustomizer;
 import org.springframework.session.config.annotation.web.http.SpringHttpSessionConfiguration;
 import org.springframework.session.jdbc.JdbcIndexedSessionRepository;
 import org.springframework.session.jdbc.config.annotation.SpringSessionDataSource;
+import org.springframework.session.jdbc.config.annotation.SpringSessionTransactionManager;
 import org.springframework.session.web.http.SessionRepositoryFilter;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.TransactionDefinition;
@@ -77,7 +82,8 @@ import org.springframework.util.StringValueResolver;
  */
 @Configuration(proxyBeanMethods = false)
 @Import(SpringHttpSessionConfiguration.class)
-public class JdbcHttpSessionConfiguration implements BeanClassLoaderAware, EmbeddedValueResolverAware, ImportAware {
+public class JdbcHttpSessionConfiguration implements BeanClassLoaderAware, EmbeddedValueResolverAware, ImportAware,
+		ApplicationContextAware, InitializingBean {
 
 	private Duration maxInactiveInterval = MapSession.DEFAULT_MAX_INACTIVE_INTERVAL;
 
@@ -109,6 +115,21 @@ public class JdbcHttpSessionConfiguration implements BeanClassLoaderAware, Embed
 
 	private StringValueResolver embeddedValueResolver;
 
+	private ApplicationContext applicationContext;
+
+	@Override
+	public void afterPropertiesSet() throws Exception {
+		if (this.transactionOperations == null && this.transactionManager == null) {
+			this.transactionManager = getUniqueTransactionManager();
+			if (this.transactionManager == null) {
+				throw new IllegalStateException(
+						"""
+								Could not resolve an unique PlatformTransactionManager bean from the application context.
+								Please provide either a TransactionOperations bean named springSessionTransactionOperations or a PlatformTransactionManager bean qualified with @SpringSessionTransactionManager""");
+			}
+		}
+	}
+
 	@Bean
 	public JdbcIndexedSessionRepository sessionRepository() {
 		JdbcTemplate jdbcTemplate = createJdbcTemplate(this.dataSource);
@@ -195,7 +216,8 @@ public class JdbcHttpSessionConfiguration implements BeanClassLoaderAware, Embed
 		this.dataSource = dataSourceToUse;
 	}
 
-	@Autowired
+	@Autowired(required = false)
+	@SpringSessionTransactionManager
 	public void setTransactionManager(PlatformTransactionManager transactionManager) {
 		this.transactionManager = transactionManager;
 	}
@@ -266,6 +288,15 @@ public class JdbcHttpSessionConfiguration implements BeanClassLoaderAware, Embed
 		this.saveMode = attributes.getEnum("saveMode");
 	}
 
+	@Override
+	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+		this.applicationContext = applicationContext;
+	}
+
+	private PlatformTransactionManager getUniqueTransactionManager() {
+		return this.applicationContext.getBeanProvider(PlatformTransactionManager.class).getIfUnique();
+	}
+
 	private static JdbcTemplate createJdbcTemplate(DataSource dataSource) {
 		JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
 		jdbcTemplate.setExceptionTranslator(new SQLErrorCodeSQLExceptionTranslator(dataSource));
@@ -273,7 +304,7 @@ public class JdbcHttpSessionConfiguration implements BeanClassLoaderAware, Embed
 		return jdbcTemplate;
 	}
 
-	private static TransactionTemplate createTransactionTemplate(PlatformTransactionManager transactionManager) {
+	private TransactionTemplate createTransactionTemplate(PlatformTransactionManager transactionManager) {
 		TransactionTemplate transactionTemplate = new TransactionTemplate(transactionManager);
 		transactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRES_NEW);
 		transactionTemplate.afterPropertiesSet();

spring-session-jdbc/src/test/java/org/springframework/session/jdbc/config/annotation/web/http/JdbcHttpSessionConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2022 the original author or authors.
+ * Copyright 2014-2024 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.
@@ -46,13 +46,19 @@ import org.springframework.session.Session;
 import org.springframework.session.config.SessionRepositoryCustomizer;
 import org.springframework.session.jdbc.JdbcIndexedSessionRepository;
 import org.springframework.session.jdbc.config.annotation.SpringSessionDataSource;
+import org.springframework.session.jdbc.config.annotation.SpringSessionTransactionManager;
 import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.TransactionDefinition;
+import org.springframework.transaction.TransactionException;
+import org.springframework.transaction.TransactionManager;
+import org.springframework.transaction.TransactionStatus;
 import org.springframework.transaction.support.TransactionOperations;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatException;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatNoException;
 import static org.mockito.Mockito.mock;
 
 /**
@@ -319,6 +325,34 @@ class JdbcHttpSessionConfigurationTests {
 		assertThat(sessionRepository).extracting("defaultMaxInactiveInterval").isEqualTo(Duration.ZERO);
 	}
 
+	// gh-2801
+	@Test
+	void configureWhenMultipleTransactionManagersAndQualifiedTransactionOperationsThenApplicationShouldStart() {
+		assertThatNoException().isThrownBy(() -> registerAndRefresh(MultipleTransactionManagerConfig.class,
+				CustomTransactionOperationsConfiguration.class));
+	}
+
+	// gh-2801
+	@Test
+	void configureWhenMultipleTransactionManagersAndQualifiedTransactionManagerThenApplicationShouldStartAndUseQualified() {
+		assertThatNoException().isThrownBy(() -> registerAndRefresh(MultipleTransactionManagerConfig.class,
+				QualifiedTransactionManagerConfig.class, DefaultConfiguration.class));
+		JdbcHttpSessionConfiguration configuration = this.context.getBean(JdbcHttpSessionConfiguration.class);
+		Object transactionManager = ReflectionTestUtils.getField(configuration, "transactionManager");
+		assertThat(transactionManager).isInstanceOf(MyTransactionManager.class);
+	}
+
+	// gh-2801
+	@Test
+	void configureWhenMultipleTransactionManagersAndNoQualifiedBeanThenApplicationShouldFailToStart() {
+		assertThatException()
+			.isThrownBy(() -> registerAndRefresh(MultipleTransactionManagerConfig.class, DefaultConfiguration.class))
+			.havingRootCause()
+			.isInstanceOf(IllegalStateException.class)
+			.withMessage("Could not resolve an unique PlatformTransactionManager bean from the application context.\n"
+					+ "Please provide either a TransactionOperations bean named springSessionTransactionOperations or a PlatformTransactionManager bean qualified with @SpringSessionTransactionManager");
+	}
+
 	private void registerAndRefresh(Class<?>... annotatedClasses) {
 		this.context.register(annotatedClasses);
 		this.context.refresh();
@@ -576,4 +610,59 @@ class JdbcHttpSessionConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class MultipleTransactionManagerConfig {
+
+		@Bean
+		DataSource dataSource() {
+			return mock(DataSource.class);
+		}
+
+		@Bean
+		TransactionManager transactionManager1() {
+			return new MyTransactionManager();
+		}
+
+		@Bean
+		TransactionManager transactionManager2() {
+			return mock(PlatformTransactionManager.class);
+		}
+
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class QualifiedTransactionManagerConfig {
+
+		@Bean
+		DataSource dataSource() {
+			return mock(DataSource.class);
+		}
+
+		@Bean
+		@SpringSessionTransactionManager
+		TransactionManager myTransactionManager() {
+			return new MyTransactionManager();
+		}
+
+	}
+
+	static class MyTransactionManager implements PlatformTransactionManager {
+
+		@Override
+		public TransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException {
+			return null;
+		}
+
+		@Override
+		public void commit(TransactionStatus status) throws TransactionException {
+
+		}
+
+		@Override
+		public void rollback(TransactionStatus status) throws TransactionException {
+
+		}
+
+	}
+
 }