Xvfb startup init script for headless selenium started via Jenkins

xvfb_daemon.sh

#!/bin/bash
# /etc/init.d/xvfb_daemon
# Debian-compatible Xvfb startup script.
# Tom Meier <tom@venombytes.com>
# Jeffery Fernandez <jeffery@fernandez.net.au>
#
### BEGIN INIT INFO
# Provides:          xvfb_daemon
# Required-Start:    $remote_fs $syslog $network
# Required-Stop:     $remote_fs $syslog $network
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start Xvfb as a Daemon
# Description:       Controls the Xvfb daemon which starts/stops the X-Server Virtual Frame Buffer
# Example Use:
#     - Set an ENV variable to "DISPLAY=:99"
#     - In Jenkins/CI server set command to run before specs : "/etc/init.d/xvfb_daemon start"
### END INIT INFO

DESC="X-Server Virtual Frame Buffer Daemon"
NAME=xvfb_daemon
SCRIPTNAME=/etc/init.d/$NAME
CURRENT_USER=`whoami`

PROG="Xvfb"
PROG_PATH=/usr/bin/$PROG
DISPLAY_NUMBER=99

PROG_OPTIONS=":$DISPLAY_NUMBER -screen 0 800x600x16 -ac -pn -noreset"
PROG_OUTPUT=/var/log/xvfb-daemon.log
PIDFILE=/var/run/xvfb-daemon.pid

DAEMON=/usr/bin/daemon
DAEMON_ARGS="--name=$NAME --inherit --output=$PROG_OUTPUT --pidfile=$PIDFILE"

[ "${NETWORKING}" = "no" ] && exit 0

# Verify that all xvfb processes have been shutdown
# and if not, then do killall for them
get_running()
{
    return `ps --no-headers -f | egrep -e $1 | grep -c . `
}

force_stop()
{
    stop_program=$1
    if [ -x /usr/bin/killall ]; then
        get_running $1
        if [ $? -ne 0 ]; then
            echo "Stopping $stop_program"
            killall -u $CURRENT_USER $stop_program || return 3
        fi
    else
        echo "Error: Could not find /bin/killall. Cannot stop $stop_program."
    fi
}

# Get the status of the daemon process
get_daemon_status()
{
    $DAEMON $DAEMON_ARGS --running || return 1
}


#
# Function that starts the daemon/service
#
do_start()
{
  # Return
  #   0 if daemon has been started
  #   1 if daemon was already running
  #   2 if daemon could not be started
  $DAEMON $DAEMON_ARGS --running && return 1

  # --user in daemon doesn't prepare environment variables like HOME, USER, LOGNAME or USERNAME,
  # so we let su do so for us now
  $DAEMON $DAEMON_ARGS -- $PROG_PATH $PROG_OPTIONS || return 2
}


#
# Function that stops the daemon/service
#
do_stop()
{
  # Return
  #   0 if daemon has been stopped
  #   1 if daemon was already stopped
  #   2 if daemon could not be stopped
  #   other if a failure occurred
  get_daemon_status
  case "$?" in
      0)
        $DAEMON $DAEMON_ARGS --stop || return 2
        # wait for the process to really terminate
        for n in 1 2 3 4 5; do
            sleep 1
            $DAEMON $DAEMON_ARGS --running || break
        done
        if get_daemon_status; then
            force_stop $PROG || return 3
        fi
        ;;
      *)
        force_stop $PROG || return 3
        ;;
  esac

  # Many daemons don't delete their pidfiles when they exit.
  rm -f $PIDFILE
  return 0
}




case "$1" in
    start)
      echo -n "Starting : $DESC on display $DISPLAY_NUMBER"
      do_start
      ;;
    stop)
      echo -n "Shutting down : $DESC"
      do_stop
      ;;
    restart|reload)
      $0 stop
      $0 start
      ;;
    status)
      get_daemon_status
      case "$?" in
         0) echo "$PROG is running with the pid `cat $PIDFILE`";;
         *)
              get_running $PROG
              procs=$?
              if [ $procs -eq 0 ]; then
                  echo -n "$PROG is not running"
                  if [ -f $PIDFILE ]; then
                      echo ", but the pidfile ($PIDFILE) still exists"
                  else
                      echo
                  fi

              else
                  echo "$procs instances of $PROG are running at the moment"
                  echo "but the pidfile $PIDFILE is missing"
              fi
              ;;
      esac
      ;;
    *)
     echo $"Usage: $0 (start|stop|restart|reload|status)"
     exit 1
     ;;
esac
echo
exit $RETVAL