#!/bin/bash

: <<EOF

=head1 NAME

df_abs - Plugin to monitor absolute disk usage

=head1 CONFIGURATION

The following configuration parameters are used by this plugin

 [df_abs]
  env.exclude     - space separated list of file system types to exclude
  env.exclude_re  - space separated regex list of devices or mount points to exclude
  env.warning     - Warning percentage
  env.critical    - Critical percentage
  env.total       - Enable/Disable graph total [on|off]
  env.dfopts      - Override commandline options for calling "df"

This plugin will monitor local filesystems by default.  To monitor
network filesystems, set "env.dfopts", and omit the "-l" option.

=head2 DEFAULT CONFIGURATION

 [df_abs]
  env.exclude     iso9660
  env.exclude_re  ^/dev/sdc
  env.warning     92
  env.critical    98
  env.total       on
  env.dfopts      -P -l

=head2 EXAMPLE CONFIGURATION

To monitor remote filesystems, omit the "-l" option from the
"env.dfopts" defaults.

  [df_abs]
    env.dfopts -P

=head1 LICENSE

GPLv2

=head1 MAGIC MARKERS

 #%# family=manual
 #%# capabilities=autoconf

=cut

EOF

. "$MUNIN_LIBDIR/plugins/plugin.sh"

if [ "$1" = "autoconf" ]; then
    echo yes
    exit 0
fi

# Append $mnt in case $dev is not a real block device
get_fieldname() {
    local dev="$1"
    local mnt="$2"
    case "$dev" in
        /* )
            clean_fieldname "$dev"
            ;;
        * )
            clean_fieldname "$dev $mnt"
            ;;
    esac
}

# Test whether the given text (first parameter) matches one of the given regular expressions
# (second parameter; space separated list). Returns success (0) in case of a match.
check_for_regex_match() {
    local text="$1"
    local list_of_regex="$2"
    local re
    for re in $list_of_regex; do
        if [[ "$text" =~ $re ]]; then
            return 0
        fi
    done
    # no expression matched the text
    return 1
}

total=${total:-on}

dfopts=${dfopts:-"-P -l"}
exclude_re=${exclude_re:-}
exclude=${exclude:-iso9660}
exclude=$(echo "$exclude" | sed -r -e 's/ +/ -x /g' -e 's/^/-x /')

if [ "$1" = "config" ]; then
    echo 'graph_title Filesystem usage (in bytes)'
    echo 'graph_args --base 1024 --lower-limit 0'
    echo 'graph_vlabel bytes'
    echo 'graph_category disk'
    if [ "$total" = "on" ]; then
        echo 'graph_total Total'
    fi
    # shellcheck disable=SC2086
    df $dfopts $exclude | sed 1d | grep -v "//" |
            while read -r dev size used avail cap mnt; do
        check_for_regex_match "$dev" "$exclude_re" && continue
        check_for_regex_match "$mnt" "$exclude_re" && continue
        name="$(get_fieldname "$dev" "$mnt")"
        echo "$name.label $mnt"
        echo "$name.cdef $name,1024,*"
        warn=$(get_warning "$name")
        crit=$(get_critical "$name")
        if [ -n "$warn" ]; then
            echo "$name.warning $((size * warn / 100))"
        fi
        if [ -n "$crit" ]; then
            echo "$name.critical $((size * crit / 100))"
        fi
    done
    exit 0
fi

# shellcheck disable=SC2034,SC2086
df $dfopts $exclude | sed 1d | grep -v "//" |
        while read -r dev size used avail cap mnt; do
    check_for_regex_match "$dev" "$exclude_re" && continue
    check_for_regex_match "$mnt" "$exclude_re" && continue
    echo "$(get_fieldname "$dev" "$mnt").value $used"
done