#!/bin/bash
# /nightlies/cron_wrapper.sh

# check for no argument case and stop
if [ -z $1 ]; then
  echo "need argument"
  exit 1
fi

# set permanent $LOG file var
LOG="/var/log/crontab-nightlies-log/crontab.log"
# set $LOG_LOCKED_ERR in case locking failed
LOG_LOCK_ERR="/var/log/crontab-nightlies-log/crontab_lock_problem.$$"

# temp files to store stdout and stderr
# named with the PID of this script in their name so they'll be unique
STDERR="/var/tmp/stderr.$$"
STDOUT="/var/tmp/stdout.$$"

# $STDOUT and $STDERR are removed when the script exits for any reason
trap  "rm -f $STDOUT $STDERR" 0

# run a command from this script's argument
# redirect stdout to $STDOUT file and redirect stderr to $STDERR file

DATE=$(date)
echo -n "$DATE: "  >> $STDOUT
echo "Running command: $@" >> $STDOUT
"$@" > $STDOUT 2> $STDERR

# get return code from the command run
code=$?

if [ $code != 0 ] ; then
        # echoing to stdout/stderr makes cron send email
        echo "stdout:"
        cat $STDOUT
        echo "stderr:"
        cat $STDERR
else
        # normal exit: just log stdout

	# lock $LOG with file descriptor 200
	exec 200>>$LOG
	# if $LOG is locked by other process - wait for 20 sec
	flock -w 20 200 || LOG=$LOG_LOCK_ERR
	echo "stdout:" >> $LOG
	cat $STDOUT >> $LOG
	echo "stderr:" >> $LOG
	cat $STDERR >> $LOG
	# unlock
	flock -u 200
fi