old_contents: import sh
  from sh import docker
  
  
  def get_ip():
      """Return a string of the IP of the hosts eth0 interface."""
      intf = sh.ifconfig.eth0()
      return sh.perl(intf, "-ne", 's/dr:(\S+)/print $1/e')
  
  
  def cleanup_inside(name):
      """
      Clean the inside of a container by deleting the containers and images within it.
      """
      docker("exec", "-t", name, "bash", "-c",
             "docker rm -f $(docker ps -qa) ; docker rmi $(docker images -qa)",
             _ok_code=[0, 1, 255])  # 255 is; "bash": executable file not found in $PATH
  
  
  def delete_container(name):
      """
      Cleanly delete a container.
      """
      # We *must* remove all inner containers and images before removing the outer
      # container. Otherwise the inner images will stick around and fill disk.
      # https://github.com/jpetazzo/dind#important-warning-about-disk-usage
      cleanup_inside(name)
      sh.docker.rm("-f", name, _ok_code=[0, 1])
  
new_contents: import sh
  from sh import docker
  import socket
  
  
  def get_ip():
      """Return a string of the IP of the hosts eth0 interface."""
      s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
      s.connect(("8.8.8.8", 80))
      ip = s.getsockname()[0]
      s.close()
      return ip
  
  
  def cleanup_inside(name):
      """
      Clean the inside of a container by deleting the containers and images within it.
      """
      docker("exec", "-t", name, "bash", "-c",
             "docker rm -f $(docker ps -qa) ; docker rmi $(docker images -qa)",
             _ok_code=[0, 1, 255])  # 255 is; "bash": executable file not found in $PATH
  
  
  def delete_container(name):
      """
      Cleanly delete a container.
      """
      # We *must* remove all inner containers and images before removing the outer
      # container. Otherwise the inner images will stick around and fill disk.
      # https://github.com/jpetazzo/dind#important-warning-about-disk-usage
      cleanup_inside(name)
      sh.docker.rm("-f", name, _ok_code=[0, 1])
  
subject: Use socket connection to get own IP.