Spring Data MongoDB #Transactional failure - spring-data-mongodb

Question

Could someone please tell me why this spring transaction is not rolling back appropriately?
The error I get is this:
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.transaction.PlatformTransactionManager' available
This is my repository with a save transaction that will intentionally fail:
#Repository
public class TransactionalRepository {
private final PlayerRepository playerRepository;
#Autowired
public TransactionalRepository(PlayerRepository playerRepository) {
this.playerRepository = playerRepository;
}
public Player saveSuccess(Player player) {
return playerRepository.save(player);
}
#Transactional
public Player saveFail(Player player) {
player.setName("FAIL"); // should not be saved in DB if transaction rollback is successful
player = playerRepository.save(player);
throw new IllegalStateException("intentionally fail transaction");
}
}
And here is the test:
#RunWith(SpringRunner.class)
#SpringBootTest
public class MongoTransactionApplicationTests {
#Autowired
public TransactionalRepository playerRepository;
#Test
public void contextLoads() {
Player player = new Player();
player.setId(UUID.randomUUID().toString());
final String PLAYER_NAME = "new-"+player.getId().subSequence(0,8);
player.setName(PLAYER_NAME);
player = playerRepository.saveSuccess(player);
try {
player = playerRepository.saveFail(player);
} catch (IllegalStateException e) {
// this is supposed to fail
}
Assert.assertEquals(PLAYER_NAME, player.getName());
}
}
Download all the code here if you want to see it run

Answer 1

Unlike other implementations the Spring Data MongoDB module does not by default register a PlatformTransactionManager if none is present. This is up to the users configuration, to avoid errors with non MongoDB 4.x servers as well as projects already using #Transactional along with a non MongoDB specific transaction manager implementation. Please refer to the reference documentation for details.
Just add a MongoTransactionManager to your configuration.
#Bean
MongoTransactionManager txManager(MongoDbFactory dbFactory) {
return new MongoTransactionManager(dbFactory);
}
You might also want to check out the Spring Data Examples and have a look at the one for MongoDB transactions.