#!/bin/bash
# Nagios plugin to check iowait on Linux

if ! command -v iostat &>/dev/null; then
  echo "iostat not found! Please install sysstat:"
  echo "sudo apt install sysstat"
  exit 1
fi

# Define usage function
function usage {
  echo "Usage: $0 [-w <warning threshold>] [-c <critical threshold>]"
  echo "  -w: Warning threshold for iowait percentage (default: 50)"
  echo "  -c: Critical threshold for iowait percentage (default: 75)"
  exit 3
}

# Parse command line arguments
while getopts "w:c:" opt; do
  case $opt in
  w) WARNING_THRESHOLD=$OPTARG ;;
  c) CRITICAL_THRESHOLD=$OPTARG ;;
  \?)
    echo "Invalid option: -$OPTARG" >&2
    usage
    ;;
  :)
    echo "Option -$OPTARG requires an argument." >&2
    usage
    ;;
  esac
done

# Set default warning and critical thresholds if not provided
WARNING_THRESHOLD=${WARNING_THRESHOLD:-50}
CRITICAL_THRESHOLD=${CRITICAL_THRESHOLD:-75}

IOWAIT=$(iostat -c | awk '/^ /{print $4}')

if (($(echo "$IOWAIT > $CRITICAL_THRESHOLD" | bc -l))); then
  echo "CRITICAL - iowait percentage is $IOWAIT% | iowait=$IOWAIT%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"
  exit 2
fi

if (($(echo "$IOWAIT > $WARNING_THRESHOLD" | bc -l))); then
  echo "WARNING - iowait percentage is $IOWAIT% | iowait=$IOWAIT%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"
  exit 1
fi

echo "OK - iowait percentage is $IOWAIT% | iowait=$IOWAIT%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"
exit 0