How I cut the time it takes to build an Erlang docker image in half. While adding support for a rebar3 option to only build dependencies and not project applications, rebar3 compile --deps_only, I realized it might already actually work for the Docker use case I had in mind.
So I gave it a try and, yup, turns out it does!
The idea is to cache a docker layer of the built dependencies to reuse if they haven’t changed. ...