two things to check here. first, "could not find driver" means the mysql extension for php isn't installed in your build, if you're using a custom dockerfile it needs pdo_mysql added.

second, and probably the main issue: host, port, and database are all showing blank in the error, which means laravel isn't getting any connection info at all. you need DB_HOST, DB_PORT, DB_DATABASE, DB_USERNAME, and DB_PASSWORD set as variables on your service, pointing to your mysql service (DB_HOST should be something like mysql.railway.internal, DB_PORT is usually 3306). set those and it should pick up the connection.