metrics.sh/metrics/disk_usage.sh

#!/bin/sh

init () {
  if [ -z $DISK_USAGE_MOUNTPOINT ]; then
    if is_osx; then
      DISK_USAGE_MOUNTPOINT="/dev/disk1"
    else
      DISK_USAGE_MOUNTPOINT="/dev/vda"
    fi
  fi
}

collect () {
  report $(df | awk -v disk_regexp="^$DISK_USAGE_MOUNTPOINT" \
                                '$0 ~ disk_regexp { printf "%.1f", $5 }')
}

docs () {
  echo "Disk usage percentage for a file system at a given mount point."
  echo "\$DISK_USAGE_MOUNTPOINT=$DISK_USAGE_MOUNTPOINT"
}