In the Node build stage we build our bundled assets into an
/app/public directory, but the above line is being used in the Python build stage which copies those files to
/public.
This lets us take the final assets and make them a part of the Python image without having to install Node, Webpack and 500mb+ worth of packages. We only end up with a few CSS, JS and image files. Then we can volume mount out those files so nginx can read them.
This is really nice and comes full circle with the override file pattern. Now in production we don’t need to run Webpack because our fully built assets are built into the Python image.