command.rb

class Command
  def initialize(command, target, script, uses_bash)
    @command, @target, @script, @uses_bash = command, target, script, uses_bash
  end

  def result
    command == :exec ? exec_command : run_command
  end

  def exec_command
    "docker exec -it `docker-compose ps -q #{target}` #{script}"
  end

  def run_command
    "docker run -it #{volumes} #{links} #{environment} #{image} #{script}"
  end

  private

  attr_reader :target, :uses_bash, :command

  def script
    uses_bash ? "bash -l -c \"#{script_with_working_dir.gsub('"', '\"')}\"" : @script
  end

  def script_with_working_dir
    working_dir ? "cd #{working_dir} && #{@script}" : @script
  end

  def image
    service["image"]
  end

  def working_dir
    service["working_dir"]
  end

  def volumes
    service['volumes'].map do |volume|
      "-v " + volume \
        .gsub('./', Dir.pwd + "/") \
        .gsub(named_volumes_regexp, 'fulcrumdocker_\1')
    end.join(' ')
  end

  def links
    service['depends_on'].map { |l| "--link #{l}" }.join(' ')
  end

  def environment
    service['environment'].map { |key, value| "-e #{key}='#{value}'" }.join(' ')
  end

  def named_volumes_regexp
    /(#{docker_compose_config['volumes'].keys.join('|')})/
  end

  def service
    docker_compose_config['services'][target.to_s]
  end

  def docker_compose_config
    @docker_compose_config ||= YAML.load(File.read 'docker-compose.yml')
  end
end