Generic SNMP monitor using snmpget

The following provides the equivalent to the original submission in this post. While the structure of that code is very nice, and it will work, the script stops before cleanup is completed leaving a dangling pid file that could kill non-related process.

Using the template and adding the SNMP portion of the code from above results in:

!/bin/bash
 
 Save as /usr/bin/monitors/custom_monitor.bash
 Make executable using chmod 700 custom_monitor.bash
 
 Use a custom shell command to perform a health check of the pool member IP address and port
 
 Log debug to local0.debug (/var/log/ltm)?
 Check if a variable named DEBUG exists from the monitor definition
 This can be set using a monitor variable DEBUG=0 or 1
if [ -n "$DEBUG" ]
then
   if [ $DEBUG -eq 1 ]; then echo "EAV `basename $0`: \$DEBUG: $DEBUG" | logger -p local0.debug; fi
else
    If the monitor config didn't specify debug, enable/disable it here
   DEBUG=0
   echo "EAV `basename $0`: \$DEBUG: $DEBUG" | logger -p local0.debug
fi
 
 Remove IPv6/IPv4 compatibility prefix (LTM passes addresses in IPv6 format)
IP=`echo $1 | sed 's/::ffff://'`
 
 Save the port for use in the shell command
PORT=$2;
 commented below as they are now sent as variables from the monitor rather than arguments
community=$3; community 
oid=$4; oid
expected_val=$5; expected value (for setting monitor UP)

 
 Check if there is a prior instance of the monitor running
pidfile="/var/run/`basename $0`.$IP.$PORT.pid"
if [ -f $pidfile ]
then
   kill -9 `cat $pidfile` > /dev/null 2>&1
   echo "EAV `basename $0`: exceeded monitor interval, needed to kill ${IP}:${PORT} with PID `cat $pidfile`" | logger -p local0.error
fi
 
 Add the current PID to the pidfile
echo "$$" > $pidfile
 
 Debug
if [ $DEBUG -eq 1 ]
then
     Customize the log statement here if you want to log the command run or the output 
   echo "EAV `basename $0`: Running for ${IP}:${PORT} using custom command" | logger -p local0.debug
fi
 
  Customize the shell command to run here. 
 Use $IP and $PORT to specify which host/port to perform the check against
 Modify this portion of the line:
 nc $IP $PORT | grep "my receive string" 
 And leave this portion as is:
 '2>&1 > /dev/null'
 The above code redirects stderr and stdout to nothing to ensure we don't errantly mark the pool member up
 
 Send the request request and check the response
snmpget -On -c $community $IP $oid | grep "$expected_val" 2>&1 > /dev/null
 
 Check if the command ran successfully
 Note that any standard output will result in the script execution being stopped
 So do any cleanup before echoing to STDOUT
if [ $? -eq 0 ]
then
   rm -f $pidfile
   if [ $DEBUG -eq 1 ]; then echo "EAV `basename $0`: Succeeded for ${IP}:${PORT}" | logger -p local0.debug; fi
   echo "UP"
else
   rm -f $pidfile
   if [ $DEBUG -eq 1 ]; then echo "EAV `basename $0`: Failed for ${IP}:${PORT}" | logger -p local0.debug; fi
fi