Get dynamically assigned ports in Docker

.bashrc

function port {
  if [[ $2 ]]; then
    FORMAT='{{(index (index .NetworkSettings.Ports "'$2'/tcp") 0).HostPort}}'
  elif [[ $1 ]]; then
    FORMAT='{{range $p, $conf := .NetworkSettings.Ports}} {{$p}} -> {{(index $conf 0).HostPort}} {{end}}'
  else
    echo "error: missing container-id"
    echo "usage: port <container-id> [port]"
    return 1
  fi

  docker inspect --format="${FORMAT}" $1
}

OR just use

docker port <container-id>

Doh! 😲 Thanks for the tweet, Jessie!