Add new doctrine processors

your implementation is not enough to support object managers properly. In case an exception happens, the object manager gets closed, and becomes unusable. With your implementation, the next messages needing Doctrine won't be processable until you restart the process.

The solution is to inject the ManagerRegistry instead, to be able to reset the manager in case it was closed, which will delete the instance from the Symfony container (in case of the Symfony implementation), leading to the creation of a new manager instance the next time you need it (assuming you inject the registry in your services, not the object manager itself, as this would not be compatible with the resetting).
 The resetting is quite important for long running processes