Build docker images with secrets. Use it just like the docker build command.

pip install git+git://github.com/defunctzombie/docker-build.git

Put some files into $HOME/.docker/private. They will be available during the build process.

Use docket like you would use docker build

docket -t foobar <path/to/build/root>

Any files in $HOME/.docker/private will be available during the build process. The folder structure under this directory will mirror the folder structure under / in the container.

These private files will not appear in any layer of the final image.