Check disk space usage on all mounted partitions and email when over the thresholds.

check_free_disk_space.sh

#!/bin/bash

#
# Check disk space usage on all mounted partitions
# and email when over the thresholds.
#
# @author Dumitru Uzun ([email protected])
# @version 1.0.0
# @src https://gist.github.com/duzun/bb9378b38f6b18b1b725ae4260ca726b
#
# Usage:
#   check_free_disk_space.sh
#       Display disk usage for all partitions
#
#   check_free_disk_space.sh [email protected]
#       If usage over threshold, send a report to [email protected]
#

# The thresholds
THRESHOLD_USE=${THRESHOLD_USE:-85}
THRESHOLD_INODES=${THRESHOLD_INODES:-80}


# For internal usage:
declare -A MOUNT
declare -A FREE_SPACE
declare -A SPACE_USE
declare -A INODES
declare -a over_threashold=()


main() {
    local email="${1}"
    local key

    init_df

    for key in "${!MOUNT[@]}"; do
        if [ "${SPACE_USE[$key]}" -gt "$THRESHOLD_USE" ] || \
           { [ "${INODES[$key]}" != "-" ] && [ "${INODES[$key]}" -gt "$THRESHOLD_INODES" ]; };
        then
            over_threashold+=("$key")
        fi
    done

    show_info "${!MOUNT[@]}"

    [ "${#over_threashold[@]}" -eq 0 ] && return;

    echo "Over threshold: "
    for key in "${over_threashold[@]}"; do
        echo -e "\t${MOUNT[$key]} ($key)";
    done | sort
    echo

    if [ -n "$email" ]; then
        send_email "$email" "${over_threashold[@]}"
    else
        return 1
    fi
}

show_info() {
    local exiding
    local key
    if [ "$1" = "-e" ]; then
        exiding=1
        shift
    fi

    for key in "$@"; do
        echo
        echo -e "${MOUNT[$key]} \t($key):"
        echo -e "\tSpace:  ${SPACE_USE[$key]}% used, ${FREE_SPACE[$key]} free"
        [ "${INODES[$key]}" = "-" ] || \
        echo -e "\tInodes: ${INODES[$key]}% used"

        if [ -n "$exiding" ]; then
            if [ "${SPACE_USE[$key]}" -gt "$THRESHOLD_USE" ]; then
                echo
                echo "Disk Usage is:"
                sizes_l1 "${MOUNT[$key]}" 2> /dev/null
                echo
            fi

           if [ "${INODES[$key]}" != "-" ] && [ "${INODES[$key]}" -gt "$THRESHOLD_INODES" ]; then
                echo
                echo "Inodes usage is:"
                nr_files_l1 "${MOUNT[$key]}" 2> /dev/null
                echo
           fi
        fi
    done
    echo
}

init_df() {
    local line

    while read -r line; do
        set -- $line
        [ -z "${MOUNT[$1]}" ] && MOUNT[$1]=$6
        FREE_SPACE[$1]=$4
        SPACE_USE[$1]=${5//%/}
    done < <(_df -h)

    while read -r line; do
        set -- $line
        INODES[$1]=${5//%/}
    done < <(_df -hi)
}

dev_ip() {
    ip route show | grep -v br- | grep -v docker | grep src | \
        tr " " '\n' | grep -v '^$' | tail -1
}

_df() {
    df -x tmpfs -x devtmpfs -x overlay -x efivarfs \
        "$@" | tail -n +2 | sort
}

nr_files_l1() {
    local dir="${1:?}"
    dir="$(realpath "$dir")/"
    # dir="${dir//\/\//\/}"
    local len="${#dir}"
    find "$dir" -xdev -type f | \
        cut -c "$len-" | cut -d "/" -f 2 | \
        sort | uniq -c | sort -nr
}

sizes_l1() {
    local dir="${1:?}"
    [ "$dir" = "/" ] || dir="$dir/"
    du -xsh "$dir"*
}

send_email() {
    local from ip
    local email="${1:?}"
    shift

    from="$(id -nu)@$(hostname)"
    ip=$(dev_ip)

    sendmail -f "$from" "$email" << EOF
Subject: Disk Space Alert - $from $ENV

Your disk free space is critically low!

IP address of device: $ip
Hostname: $(hostname)

$(show_info -e "$@")

EOF
}

main "$@"