Don't apply multiple session configurations

Add additional @ConditionalOnMissingBean guards to session
configurations to ensure that the first wins. Also reorder imports
to prefer Redis over JDBC.

See gh-5158

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/HashMapSessionConfiguration.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.autoconfigure.session;
 
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
@@ -33,6 +34,7 @@ import org.springframework.session.config.annotation.web.http.EnableSpringHttpSe
 @Configuration
 @EnableSpringHttpSession
 @Conditional(SessionCondition.class)
+@ConditionalOnMissingBean(SessionRepository.class)
 class HashMapSessionConfiguration {
 
 	@Bean

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/HazelcastSessionConfiguration.java

@@ -20,8 +20,10 @@ import com.hazelcast.core.HazelcastInstance;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.session.SessionRepository;
 import org.springframework.session.hazelcast.config.annotation.web.http.HazelcastHttpSessionConfiguration;
 
 /**
@@ -32,6 +34,7 @@ import org.springframework.session.hazelcast.config.annotation.web.http.Hazelcas
  * @author Stephane Nicoll
  */
 @Configuration
+@ConditionalOnMissingBean(SessionRepository.class)
 @ConditionalOnBean(HazelcastInstance.class)
 @Conditional(SessionCondition.class)
 class HazelcastSessionConfiguration {

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/JdbcSessionConfiguration.java

@@ -20,8 +20,10 @@ import javax.sql.DataSource;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.session.SessionRepository;
 import org.springframework.session.jdbc.config.annotation.web.http.JdbcHttpSessionConfiguration;
 
 /**
@@ -31,6 +33,7 @@ import org.springframework.session.jdbc.config.annotation.web.http.JdbcHttpSessi
  * @author Stephane Nicoll
  */
 @Configuration
+@ConditionalOnMissingBean(SessionRepository.class)
 @ConditionalOnBean(DataSource.class)
 @Conditional(SessionCondition.class)
 class JdbcSessionConfiguration {

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/MongoSessionConfiguration.java

@@ -18,9 +18,11 @@ package org.springframework.boot.autoconfigure.session;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.mongodb.core.MongoOperations;
+import org.springframework.session.SessionRepository;
 import org.springframework.session.data.mongo.config.annotation.web.http.MongoHttpSessionConfiguration;
 
 /**
@@ -30,6 +32,7 @@ import org.springframework.session.data.mongo.config.annotation.web.http.MongoHt
  * @author Stephane Nicoll
  */
 @Configuration
+@ConditionalOnMissingBean(SessionRepository.class)
 @ConditionalOnBean(MongoOperations.class)
 @Conditional(SessionCondition.class)
 class MongoSessionConfiguration {

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/RedisSessionConfiguration.java

@@ -18,10 +18,12 @@ package org.springframework.boot.autoconfigure.session;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.redis.connection.RedisConnectionFactory;
 import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.session.SessionRepository;
 import org.springframework.session.data.redis.config.annotation.web.http.RedisHttpSessionConfiguration;
 
 /**
@@ -33,6 +35,7 @@ import org.springframework.session.data.redis.config.annotation.web.http.RedisHt
  * @author Stephane Nicoll
  */
 @Configuration
+@ConditionalOnMissingBean(SessionRepository.class)
 @ConditionalOnBean({ RedisTemplate.class, RedisConnectionFactory.class })
 @Conditional(SessionCondition.class)
 class RedisSessionConfiguration {

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/SessionAutoConfiguration.java

@@ -44,9 +44,9 @@ import org.springframework.session.SessionRepository;
  * @since 1.4.0
  */
 @Configuration
+@ConditionalOnMissingBean(SessionRepository.class)
 @ConditionalOnClass(Session.class)
 @ConditionalOnWebApplication
-@ConditionalOnMissingBean(SessionRepository.class)
 @EnableConfigurationProperties(SessionProperties.class)
 @AutoConfigureAfter({ DataSourceAutoConfiguration.class, HazelcastAutoConfiguration.class,
 		MongoAutoConfiguration.class, RedisAutoConfiguration.class })

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/StoreType.java

@@ -26,24 +26,24 @@ package org.springframework.boot.autoconfigure.session;
 public enum StoreType {
 
 	/**
-	 * JDBC backed sessions.
+	 * Redis backed sessions.
 	 */
-	JDBC,
+	REDIS,
 
 	/**
-	 * Mongo backed sessions.
+	 * Hazelcast backed sessions.
 	 */
-	MONGO,
+	HAZELCAST,
 
 	/**
-	 * Redis backed sessions.
+	 * Mongo backed sessions.
 	 */
-	REDIS,
+	MONGO,
 
 	/**
-	 * Hazelcast backed sessions.
+	 * JDBC backed sessions.
 	 */
-	HAZELCAST,
+	JDBC,
 
 	/**
 	 * Simple in-memory map of sessions.

spring-boot-samples/spring-boot-sample-session-redis/src/test/java/sample/session/redis/SampleSessionRedisApplicationTests.java

@@ -56,6 +56,7 @@ public class SampleSessionRedisApplicationTests {
 			if (!redisServerRunning(ex)) {
 				return;
 			}
+			throw ex;
 		}
 
 		URI uri = URI.create("http://localhost:" + port + "/");