screenshot-service/Docker/ephemeral-x.sh

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#!/bin/sh -x
# Source: https://github.com/jordansissel/xdotool/blob/master/t/ephemeral-x.sh
# Start an ephemeral X server.
#
# This is useful for when you want to launch an X server for a specific
# process. When that process exits, the X server will be killed.
#
XSERVER="Xvfb -dpi 600 -screen 0 2880x1620x24" # 1080p * 1.5 for tesseract readability. Assuming x1.5 scale set up in Firefox
WINMGR=fluxbox
prog=$0
usage() {
echo "Usage: $prog [-x XSERVER] [-w WINDOWMANAGER] [-q] [-h] <command>"
echo "-h this help"
echo "-q quiet"
echo "-w window manager process to start once Xserver is up"
echo " (default: '$WINMGR')"
echo "-x Xserver (and args) to run"
echo " (default: '$XSERVER')"
echo
echo "This tool will pick an unused DISPLAY value (:0, :1, etc) and"
echo "start an Xserver on that display, then run your command."
echo
echo "Examples:"
echo " $prog -x 'Xephyr -screen 1280x720' xterm"
echo " $prog -x 'Xvnc -httpd /usr/share/vnc/classes -geometry 1024x768 -depth 24' -w "gnome-session" firefox"
}
quiet() {
return 0 # forcing quiet behavior
[ "0$QUIET" -eq 1 ]
}
test_x_available() {
xsocket=$1
! test -S $xsocket
}
test_x_healthy() {
xpid=$1
xsocket=$2
displaynum=$3
# Try xterm to see if X is up.
if which xterm > /dev/null 2>&1 ; then
DISPLAY=:$displaynum xterm -e 'true'
return $?
fi
# Try xdotool if available, if xterm is not.
if which xdotool > /dev/null 2>&1 ; then
DISPLAY=:$displaynum xdotool getmouselocation > /dev/null 2>&1
return $?
fi
# Try lsof if no X clients (above) are available
if which lsof > /dev/null 2>&1 ; then
lsof -p $xpid | grep -qF $xsocket
return $?
fi
echo "Unable to determine if X is healthy (no tools available)"
return false
}
cleanup() {
if [ ! -z "$winmgrpid" ] ; then
kill -TERM "$winmgrpid" || true
fi
kill -TERM "$xpid" || true
pkill -KILL -P $$ || true
}
POSIXLY_CORRECT=1 getopt -s sh +x:w:qh "$@" > /dev/null
if [ $? -ne 0 ] ; then
echo "Invalid arguments..."
exit 1
fi
eval "set -- $(POSIXLY_CORRECT=1 getopt -s sh +x:w:qh "$@")"
while [ "0$#" -gt 0 ] ; do
case $1 in
-x) XSERVER="$2"; shift ;;
-w) WINMGR="$2"; shift ;;
-q) QUIET=1 ;;
-h) usage; exit ;;
--) shift; break ;;
esac
shift
done
if [ "$1" = "FAIL" ] ; then
usage
exit 1
fi
num=-1
XSERVERNAME=${XSERVER%% *}
if ! which "$XSERVERNAME" > /dev/null 2>&1 ; then
echo "Unable to find $XSERVERNAME. Aborting."
cleanup
exit 1
fi
while true; do
num=$(expr $num + 1)
xsocket=/tmp/.X11-unix/X$num
quiet || echo "Trying :$num"
test_x_available $xsocket || continue
(
if quiet ; then
exec > /dev/null
exec 2> /dev/null
fi
echo set -- $XSERVER
set -- $XSERVER
cmd=$1
shift
exec $cmd :$num "$@" > /dev/null 2>&1
) &
xpid=$!
healthy=0
for i in 1 2 3 4 5 6 7 8 9 ; do
# Break early if the xserver died
#ps -p $xpid > /dev/null 2>&1 || break
kill -0 $xpid > /dev/null 2>&1 || break
# See if the xserver got a hold of the display socket.
# If so, the server is up and healthy.
sleep 1
if test_x_healthy $xpid $xsocket $num ; then
quiet || echo "$XSERVERNAME looks healthy. Moving on."
healthy=1
break
fi
sleep 0.2 || sleep 1 # In case your sleep doesn't take subsecond values
done
if [ "0$healthy" -eq 1 ] ; then
break
fi
done
sleep 3; # didn't work without it on the server for some reason
export DISPLAY=:$num
quiet || echo "Using display: $DISPLAY"
if [ ! -z "$WINMGR" -a "$WINMGR" != "none" ] ; then
if ! which $WINMGR > /dev/null 2>&1 ; then
echo "Cannot find $WINMGR. Aborting."
cleanup
exit 1
fi
WINMGRNAME=${WINMGR%% *}
$WINMGR > /dev/null 2> /dev/null &
winmgrpid=$!
# Wait for the window manager to startup
quiet || echo "Waiting for window manager '$WINMGRNAME' to be healthy."
# Wait for the window manager to start.
for i in 1 2 3 4 5 6 7 8 9 10 ABORT ; do
# A good signal that the WM has started is that the WM_STATE property is
# set or that any NETWM/ICCCM property is set.
if xprop -root | egrep -q 'WM_STATE|^_NET' ; then
quiet || echo "$WINMGRNAME looks healthy. Moving on."
break;
fi
sleep 1
if [ "$i" = "ABORT" ] ; then
quiet || echo "Window manager ($WINMGRNAME) seems to have failed starting up."
cleanup
exit 1
fi
done
fi