Incorrect behavior for remove_ignored_files

[sumdog]

I had an issue trying to build a project called pixelfed:

require 'git'
require 'docker'
git = Git.clone('https://github.com/pixelfed/pixelfed', '.', :path => '/tmp/pxf')
git.checkout('v0.7.6')
Docker::Image.build_from_dir('/tmp/pxf')

This gave me the following:

Docker::Error::ServerError (Cannot locate specified Dockerfile: Dockerfile)

However doing this manually on the command line works fine:

git clone https://github.com/pixelfed/pixelfed
git checkout v0.7.6
docker build . -t pixelfed

At first I thought it was due to Dockerfile being a symbolic link, but after some debugging, it turns out in pixelfed, they keep their Dockerfiles in .dockerignore for some reason. This is probably not correct on their part, but I find it interesting the CLI tool still transmits everything in .dockerignore to the daemon itself (and the daemon then ignores those files in building/copying).

I found the issue where this support was added: #313

I can see the advantage of doing this before sending the data to the Docker daemon, but this behavior doesn't match the docker CLI and should probably have a configuration setting to enable it or disable it.

I'm not sure what the best/correct solution is, but if anyone else encounters this, here's a quick and dirty monkey patch:

require ' docker'

module Docker::Util
  def self.remove_ignored_files!(directory, files)
    # Remove this function as it breaks compatiablity
    # with the docker CLI; discovered with Pixelfed
  end
end