Saving JPA entity not working in JavaDelegate

Camunda 7 Topics Discussion & Questions
1

We have a problem saving an JPA entity within the execute method of a Camunda JavaDelegate. The entity is not persisted to the database.
When calling the same code from a normal Spring @RestController, it works fine.

Short excerpt from our code:

@Component
@Transactional  // do we need this...?
public class CreateUser implements JavaDelegate {

   @Autowired private UserRepository userRepository;

   @Override public void execute(DelegateExecution camunda) {     
      User user = new User(...);
      userRepository.save(user); // The user is _not_ saved in the database
   }
}

We compared the detailled log files when calling from JavaDelegate and from the Spring @RestController. They were identical, except the following lines just directly after userRepository.save which are missing when calling from JavaDelegate:

2019-04-30 12:17:55.759 DEBUG 9092 --- [nio-8080-exec-1] o.h.e.t.internal.TransactionImpl         : On TransactionImpl creation, JpaCompliance#isJpaTransactionComplianceEnabled == false
2019-04-30 12:17:55.759 DEBUG 9092 --- [nio-8080-exec-1] o.h.e.t.internal.TransactionImpl         : begin
2019-04-30 12:17:56.019 TRACE 9092 --- [nio-8080-exec-1] j.i.AbstractLogicalConnectionImplementor : Preparing to begin transaction via JDBC Connection.setAutoCommit(false)
2019-04-30 12:17:56.040 TRACE 9092 --- [nio-8080-exec-1] j.i.AbstractLogicalConnectionImplementor : Transaction begun via JDBC Connection.setAutoCommit(false)
2019-04-30 12:17:56.040 TRACE 9092 --- [nio-8080-exec-1] cResourceLocalTransactionCoordinatorImpl : ResourceLocalTransactionCoordinatorImpl#afterBeginCallback

It seems as if no transaction is opened when calling from JavaDelegate.
Any idea?

2

We could solve the problem very easily.

We had two configurations for the datasource, an application.yaml and also a @Config Spring class (including a transaction manager), see the code below. As soon as we deleted the @Config, everything was working.

Here is the @Config we now deleted (shortened):

@Configuration
public class Config {

  @Bean public PlatformTransactionManager transactionManager() {
    return new DataSourceTransactionManager(dataSource());
  }

  @Bean public DataSource dataSource() {
    // ... return a new SimpleDriverDataSource
  }

}

And here is the application.yaml that we kept (shortened):

camunda.bpm:
  database:
    type: mysql

spring.jpa:
  properties.hibernate.dialect: org.hibernate.dialect.MySQL5Dialect
  hibernate.ddl-auto: update 

spring.datasource:
  url: jdbc:mysql://xxx/xxx
  username: xxx
  password: xxx
  driver-class-name: com.mysql.jdbc.Driver
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