middlewares.xml

<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="doctrine.dbal.connection_expiries" class="ArrayObject" />
        <service id="doctrine.dbal.logging_middleware" class="Doctrine\DBAL\Logging\Middleware" abstract="true">
            <argument type="service" id="logger" />
            <tag name="monolog.logger" channel="doctrine" />
        </service>
        <service id="doctrine.debug_data_holder" class="Doctrine\Bundle\DoctrineBundle\Middleware\BacktraceDebugDataHolder">
            <argument type="collection" />
            <tag name="kernel.reset" method="reset" />
        </service>
        <service id="doctrine.dbal.debug_middleware" class="Doctrine\Bundle\DoctrineBundle\Middleware\DebugMiddleware" abstract="true">
            <argument type="service" id="doctrine.debug_data_holder" />
            <argument type="service" id="debug.stopwatch" on-invalid="null" />
        </service>
        <service id="doctrine.dbal.idle_connection_middleware" class="Doctrine\Bundle\DoctrineBundle\Middleware\IdleConnectionMiddleware" abstract="true">
            <argument type="service" id="doctrine.dbal.connection_expiries" />
            <argument /> <!-- check timing -->
        </service>
    </services>
</container>