Hi @otijhuis, I took your idea and made some updates to my dockerfile. Now it works pretty well.
A fresh build takes about 2 minutes, because I have some expensive dependencies. A repeated build with a single line of code changed takes around 5 seconds, which is the same as yours as I follow the same strategy with you.
I split it into smaller stages because I want to make it easy to fit into another project without any assets. Eventually I will update my library dockerize later.
Currently, the building workflow goes like this:
This picture shows what stage will be rebuilt based on the location of the change (green texts on the top left).
