Limiting a script from sending alerts

Question

I've got a bash script which detects a failed system component running on a unix box. The script sends out an email on failure. The script runs via run every minute (via cron). What's the easiest way to throttle sending the alerts to something like every 15 minutes?

Could I create/update a file when I send an alert and only send the file if the date of said file is so many minutes old?

Answer 1

You could implement a go-between for the script sending alerts. Instead of sending an email 'directly' (via sendmail, another mail app) you could send it to another script which would actually make the call. This script could then track (using another file) the last time at which a mail was sent. This way, you could check how often you're sending them out. :)

Answer 2

Something like this might work:

stamp=/tmp/mystamp
# create stamp file, if we haven't yet
[ ! -f $stmp ] && touch $stamp
tmp=$(tempfile)

# see if 15 minutes has passed...
diff=$(echo $(date -d "15 minutes ago"  +%y%d%m%H%M) - $(date -d "$(stat $tmp |grep Change |cut -d: -f2-)" +%y%d%m%H%M)  |bc)
rm $tmp

# if we last touched the stamp file less than 15 minutes ago
# then quit
[ $diff -le 0 ] && exit 0

# update the stamp file
touch $stamp

# do your thing...
echo 'Warning! Warning!' |mail -s "FOOBAR" [email protected]

Answer 3

If you encounter the error condition, touch a temp file (say /tmp/alert.email). Next in the script, check to see if the file exists and if it does and the # of minutes is 0,15,30,45, then send an email. I'm not sure if this does exactly what you want. Basically it:

• Sends an email no more often than once every 15 minutes.
• Sends an email for all error conditions, but not necessarily immediately.
• May send an error message immediately or up to 14 minutes later.

So have something later like:

#!/bin/bash 

MIN=`date '+%M'`

if [ *ERROR_COND* ] ; then
   touch /tmp/alert.email
fi

if [[ -f /tmp/alert.email &&  ( $MIN = "15" || $MIN = "30" || $MIN = "45" || $MIN = "00" ) ]] ; then
   # email here
   rm -f /tmp/alert.email
fi