[incision]

I'm not sure how to interpret that quote.

In the context of Docker it's inconvenient, but entirely straightforward to create images that don't include those elements.

It's a matter of creating an unwieldy chain of build steps to avoid committing intermediate containers.

If/when something like this [1] gets merged things will be greatly simplified.

1: https://github.com/docker/docker/pull/8021

[vidarh]

I don't know what you consider an unwieldy chain of build steps, but for Ruby it's simply a matter of building the container, and run it with your app directory (or a suitable build location) mounted as a volume, install dev-dependencies then executing "bundler install --standalone --path vendor", and subsequently using that as the basis for building the final container image.

You can make that cleaner by making the build steps into one Docker image, the final app into a second, and have them share a base image that contains all the basic dependencies.

For Ruby at least the intermediate build step would typically only need to be re-run whenever your Gemfile/Gemfile.lock changes.