convert a bosh job into a Dockerfile that builds a container with all the job's packages installed

bosh2docker.rb

require 'yaml'
require 'fileutils'

job = ARGV[0]

job_spec = YAML.load_file(File.join('jobs', job, 'spec'))
packages = job_spec['packages']

work_dir = 'docker'
FileUtils.mkdir_p(work_dir)
docker_file = open(File.join(work_dir, 'Dockerfile'), 'w')

docker_file << "FROM ubuntu\n"
docker_file << "ADD pre_packaging /build\n"
docker_file << "RUN mkdir -p /var/vcap/packages\n"
docker_file << "\n"

pre_packaging_dir = FileUtils.mkdir_p(File.join(work_dir, 'pre_packaging'))

def package_deps(package)
  spec = YAML.load_file(File.join('packages', package, 'spec'))
  deps = (spec.fetch('dependencies', [])).map { |p| package_deps(p) }.flatten
  deps << package
end

build_order = packages.inject([]) { |order, p| order + package_deps(p) }.uniq

build_order.each do |package|
  package_dir = File.join('packages', package)
  pre_packaging_script = File.join(package_dir, 'pre_packaging')
  FileUtils.mkdir_p(File.join(pre_packaging_dir, package))

  packaging_script = File.join(package_dir, 'packaging')
  open(packaging_script) do |f|
    docker_file << "# #{package}\n"
    docker_file << "ENV BOSH_INSTALL_TARGET /var/vcap/packages/#{package}\n"
    docker_file << "RUN cd /build/#{package}\n\n"
    f.each_line do |line|
      docker_file << "RUN #{line}"
    end
    docker_file << "\n"
  end

  # create temp dir
  # puts package files in temp dir
  #
  # if pre_packaging script
  #   set BUILD_DIR to temp dir
  #   cd temp dir
  #   run prepackaging script
  #
  # tar up temp dir and put in docker/pre_packaging/package
end