How to avoid transferring everything as build context

All files you want to add to your docker image must be inside the “context”. Otherwise docker will throw an error.
What you can do is to explicitly add … well COPY … only the needed files. This can be specified inside the Dockerfile.
Assuming your Dockerfile resides in /mydir Something like:

FROM ubuntu:latest
COPY bin/heavy1.zip /tmp
ENTRYPOINT [‘myStartScript.sh’]

Now this will copy only the /mydir/bin/heavy1.zip file to /tmp of the image.
(Still assuming you’re in /mydir) Build it with:

docker build -t test .

Bare in mind that this will only copy - not unpack - the .zip File to the docker-image /tmp dir.