change how telegraf script determine if there is already and instance of the script already running

salt/telegraf/scripts/redis.sh

@@ -15,14 +15,14 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-THEGREP=$(ps -ef | grep $0 | grep -v $$ | grep -v grep)
-
-if [ ! "$THEGREP" ]; then
+# if this script isn't already running
+if [[ ! "`pidof -x $(basename $0) -o %PPID`" ]]; then
 
     UNPARSED=$(redis-cli llen logstash:unparsed | awk '{print $1}')
     PARSED=$(redis-cli llen logstash:parsed | awk '{print $1}')
 
     echo "redisqueue unparsed=$UNPARSED,parsed=$PARSED"
-else
-   exit 0
+
 fi
+
+exit 0