Record Events Produced by a Handler

Ina example application there is a command (a CQRS message) named ``CreateUser``.

That command is handled by the ``CreateUserHandler``. The command handler creates

Inan example application there is a command (a CQRS message) named ``CreateUser``.

That command is handled by the ``CreateUserHandler`` which creates

a ``User`` object, stores that object to a database and dispatches an ``UserCreatedEvent``.

That event is also a normal message but is handled by an *event* bus.

There are many subscribers to the ``UserCreatedEvent``, one subscriber may send

a welcome email to the new user. Since we are using the ``DoctrineTransactionMiddleware``

we wrap all database queries in one database transaction and rollback that transaction

if an exception is thrown. Thatwould mean that if an exception is thrown when sending

if an exception is thrown. Thatmeans that if an exception is thrown when sending

the welcome email, then the user will not be created.

The solution to this issue is to not dispatch the ``UserCreatedEvent`` in the

..code-block::yaml

..code-block::php