buildkit --mount=bind during build

[dln22]

Hello,

If I have a very large file that I only need during build time, and If I use the following commands:

docker buildx build Dockerfile .

and then a line somewhere in the Dockerfile:

RUN --mount=type=bind,target=/target_path,readonly,source=large_dir_or_file

would that very large file still got send to the docker daemon? I am wondering if the --mount command offers any advantage here for the large files?

Thank you,
Daniel

[tonistiigi]

I will still get sent to the daemon. It needs to be snapshotted so it can be safely accessed. It will not appear in your final image, though if you use --mount.