nbconn

#!/bin/bash
#
# nbconn
#
# Connect to remote Jupyter server.
#
# Copyright (C) 2019 Matthew Stone <mrstone3@wisc.edu>
# Distributed under terms of the MIT license.

set -euo pipefail

usage() {
  cat <<EOF
usage: nbconn [-h] [-u USER] [-s HOST] [-p PORT] server

Connect to remote Jupyter server. 

Sets up port forwarding from a local port to the remote port where the server
is running (by default uses the same port both locally and remotely), then
opens the Jupyter server in the system default browser.

Includes shortcuts with default usernames/hostnames/ports for most frequently
used connections, but permits over-writing these.

Required arguments:
  server      Server name (used to look up default user/host/port)

Optional arguments:
  -u USER     Username
  -s HOST     Host adddress
  -p PORT     Port
  -h          Show this help message and exit.
EOF
}

USER=""
HOST=""
PORT=""
while getopts ":u:s:p:h" opt; do
  case ${opt} in
    u)
      USER=$OPTARG
      ;;
    s)
      HOST=$OPTARG
      ;;
    p)
      PORT=$OPTARG
      ;;
    h)
      usage
      exit 0
      ;;
    #TODO: add -k kill option
    *)
      echo "Invalid option" 1>&2
      usage
      exit 1
      ;;
  esac
done
shift $((OPTIND - 1))

if [[ $# -ne 1 ]]; then
  # TODO: don't require server default if all three of user,host,port specified
  echo -e "ERROR: Requires exactly one argument\n" 1>&2
  usage
  exit 1
fi

server=$1

case ${server} in
  roy1)
    DEFAULT_USER=mstone
    DEFAULT_HOST=roy-exec-1.discovery.wisc.edu
    DEFAULT_PORT=8892
    ;;
  roy4)
    DEFAULT_USER=mstone
    DEFAULT_HOST=roy-exec-4.discovery.wisc.edu
    DEFAULT_PORT=8892
    ;;
  mi2)
    # TODO: can we check VPN status?
    DEFAULT_USER=mrstone3
    DEFAULT_HOST=mi2.biostat.wisc.edu
    DEFAULT_PORT=8896
    ;;
  *)
    echo "ERROR: Invalid server shortcut: ${server}" 1>&2
    exit 1
    ;;
esac

# Set defaults if they weren't overridden at command line
if [[ -z "${USER}" ]]; then
  USER=${DEFAULT_USER}
fi

if [[ -z "${HOST}" ]]; then
  HOST=${DEFAULT_HOST}
fi

if [[ -z "${PORT}" ]]; then
  PORT=${DEFAULT_PORT}
fi

# Set up port forwarding
ssh -N -f -L localhost:${PORT}:localhost:${PORT} ${USER}@${HOST}

# Open in browser
open http://localhost:${PORT}