[docker build process][1]

I read that `docker build` is using some templates written in `go` but I'm trying to achieve this for a `yarn add` or `start` from a python script. Their outputs are too verbose and I don't want to see the whole thing. PS, I'm very familiar with Jinja.

  [1]: https://i.sstatic.net/jp0fc.gif

I'm MacOS Big Sur 14.1
& Docker version 20.10.7, build f0df350