Docker Compose not working: PDO driver mismatch

Ok so I'm trying to install Wallabag and use MySql as a DB. The provisioner has failed every time, so I exec into the container and run `php /var/www/wallabag/bin/console wallabag:install --env=prod -vvv` which gets me this:


In that list, `pdo_sqlite` is wrong, it should be MySql. I've verified it's set:

It then tells me that my DB appears to be there, would I like to reset it. I say yes and get:

Which is an exception thrown my the MySql driver, not sqlite.

Does anyone know what's going on? My `docker-compose` file is an _exact_ copy of the one in the example.