Symfony 3 - EntityManager dependency injection with multiple db connections

You can extend Doctrine's EntityManagerDecorator, which implements EntityManagerInterface and accepts an instance of EntityManager in its constructor.

First extend the EntityManagerDecorator class once for each of your connections.

namespace MyBundle\Service\Database;use Doctrine\ORM\Decorator\EntityManagerDecorator;class PrismEntityManager extends EntityManagerDecorator {}class BaanEntityManager extends EntityManagerDecorator {}

Then in your service configuration, you need to manually wire these two services.

MyBundle\Service\Database\PrismEntityManager:    arguments:        $wrapped: '@doctrine.orm.prism_entity_manager'MyBundle\Service\Database\BaanEntityManager:    arguments:        $wrapped: '@doctrine.orm.baan_entity_manager'

Now you just have to type-hint for one of these services.

public function __construct(FormFactoryInterface $formFactory, PrismEntityManager $em, RouterInterface $router){    $this->formFactory = $formFactory;    $this->em = $em;    $this->router = $router;}

I don't know if i understood your question correctly or not but you can set different configurations for different database connection as below:

dbal:    default_connection: default    connections:        default:            driver:   pdo_mysql            host:     "%database_host%"            port:     "%database_port%"            dbname:   "%database_name%"            user:     "%database_user%"            password: "%database_password%"            charset:  UTF8            mapping_types:            enum: smallint        custom:            driver:   pdo_mysql            host:     '%database_host2%'            port:     '%database_port2%'            dbname:   '%database_name2%'            user:     '%database_user2%'            password: '%database_password2%'            charset:  UTF8            mapping_types:            enum: smallint    orm:        default_entity_manager: default        auto_generate_proxy_classes: "%kernel.debug%"        entity_managers:            auto_mapping: true            default:                naming_strategy: doctrine.orm.naming_strategy.underscore                connection: default                mappings:                    EntityBundle:                        type: annotation                        alias: DBAlias            custom:                naming_strategy: doctrine.orm.naming_strategy.underscore                connection: custom                mappings:                    EntityBundle:                        type: annotation                        alias: DBAlias

Now you can passed your custom EntityManager using doctrine.orm.custom_entity_manager.

I think, I had the same issue with DBAL Connections as you have with EntityManager. I have solved this issue with some proxy class - described in this answer:https://stackoverflow.com/a/46265170/6357312

Any question let me know.