If you are also using Ruby, you can use Kiba ETL (disclaimer: I'm Kiba ETL author) in conjunction with Sidekiq (quick example: https://gist.github.com/thbar/ec90bbd5877d1aae40510fadd43206...).

This allows to build ETL jobs which react to all sorts of external application triggers (such as an upload made by a user in that case, but it could be an API notification / webhook etc).