yum_updates_check.sh

#!/bin/bash
#
# Description: Custom plugin returns number of pending updates on a 
# yum-based system.
# Author: Andrew Regner
# License: MIT
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

yum check-update | awk '
$2 ~ /^[0-9]/ {
  count[$3] += 1;
  total += 1;
}

END {
  if(total > 0)
    printf("status pending updates: %d\n", total);
  else
    printf("status no updates\n");

  printf("metric total_updates uint32 %d\n", total);
  for(repo in count)
    printf("metric pending_%s uint32 %d\n", repo, count[repo]);
}'