tunnelDs9

#!/usr/bin/env bash
#
# Allow remoteHost to talk to a local ds9 by talking to access point localhost:$xpa_port, e.g.
#   xpaset -p localhost:10198 "frame 0; raise"
#
# You need to start ds9 locally with
#    env XPA_PORT="DS9:ds9 $xpa_port $[$xpa_port + 1]" ds9 &
#
# Note that the LSST ds9 code understands XPA_PORT, so there's no need to play with XPANS
#
remoteHost=lsst8.ncsa.uiuc.edu
ds9Port=22345
kill=0
list=0

while [ ! -z $1 ]; do
    case $1 in
      -h|--help)
         echo "Usage: ds9-tunnel [--kill|--list] [remote-machine [port]]" >&2
         exit 0;;
      -k|--kill)
         kill=1;;
      -l|--list)
         list=1;;
      -*)
         echo "Unknown option $1" >&2
         exit 1;;
      *)
         break;;
    esac
    shift
done

if [ $list = 1 ]; then
    if [ $kill = 1 ]; then
        echo "Ignoring request to kill the tunnel" >&2
    fi
    if [ ! -z $1 ]; then
        echo "Ignoring arguments: $@" >&2
    fi
    
    ls $HOME/.ds9* 2> /dev/null | perl -ne 'if(/-([^-]+)-(\d+)$/) { printf "%-30s %d\n", $1, $2 }'

    exit 0
fi

if [ ! -z $1 ]; then
   remoteHost=$1; shift
fi
if [ ! -z $1 ]; then
    ds9Port=$1; shift
fi

pidFile=$HOME/.ds9-$remoteHost-$ds9Port

if [ $kill = 1 ]; then
    if [ ! -f $pidFile ]; then
        echo "I can't find the PID as $pidFile doesn't exist" >&2
        exit 1
    fi

    pid=$(cat $pidFile)
    echo "Killing $pid" >&2

    if kill -0 $pid > /dev/null 2>&1; then
        kill $pid && rm -f $pidFile
    else
        echo "Process $pid doesn't seem to exist" >&2
        rm -f $pidFile
    fi


    exit 0
elif [ -f $pidFile ]; then
    pid=$(cat $pidFile)

    if kill -0 $pid > /dev/null 2>&1; then
        echo "The ds9 tunnels already seem to exist, process $pid.  Please use ds9-remote --kill to remove them, then try again" >&2
        exit 1
    fi
    rm -f $pidFile
fi

ssh -N -f $remoteHost \
    -R $ds9Port:localhost:$ds9Port -R $[$ds9Port+1]:localhost:$[$ds9Port+1] > /dev/null 2>&1
pid=$[$$+2]                             # it must use the double-fork trick

echo $pid > $pidFile &

value="DS9:ds9 $ds9Port $[$ds9Port + 1]"
echo "You'll need to set XPA_PORT to '$value' both locally (before starting ds9) and remotely (before starting the client)" >&2

case $SHELL in
  */csh)
   echo "setenv XPA_PORT '$value'";;
  *)
   echo "export XPA_PORT='$value'";;
esac