telegraf-bcachefs-input/bcachefs.sh

#!/bin/bash

convert_to_bytes() {
    local val="$1"
    local num unit int frac mul result

    # trim whitespace
    val="${val#"${val%%[![:space:]]*}"}"
    val="${val%"${val##*[![:space:]]}"}"

    # empty input -> 0
    [[ -z "$val" ]] && echo 0 && return

    # check if numeric (optional decimal + unit)
    if [[ ! $val =~ ^[0-9]+([.][0-9]+)?[KMGTkmgT]?$ ]]; then
        echo 0
        return
    fi

    # separate number and unit
    num="${val%[KMGTkmgT]}"
    unit="${val#$num}"

    # handle decimals
    if [[ "$num" == *.* ]]; then
        int="${num%%.*}"
        frac="${num#*.}"
        frac="${frac}000"
        frac="${frac:0:3}"
    else
        int="$num"
        frac="0"
    fi

    # multiplier
    case "${unit^^}" in
        K) mul=1024 ;;
        M) mul=$((1024*1024)) ;;
        G) mul=$((1024*1024*1024)) ;;
        T) mul=$((1024*1024*1024*1024)) ;;
        *) mul=1 ;;
    esac

    # use base 10 for all arithmetic to avoid octal errors
    result=$((10#$int * mul + 10#$frac * mul / 1000))

    echo "$result"
}

function ensure_comma() {
    if [[ $FIRST -eq 1 ]]
    then
        FIRST=
    else
        echo -n ,
    fi
}

FSPATH="/mnt"

PARSER_STATE=0
while IFS= read -r line; do
    case $PARSER_STATE in
    0)
        if [[ $line =~ ^Filesystem:[[:space:]]+([^[:space:]]+)$ ]]
        then
            uuid="${BASH_REMATCH[1]}"
        elif [[ $line == Data\ type* ]]
        then
            PARSER_STATE=1
        elif [[ $line == "Compression:" ]]
        then
            #echo -n "bcachefs_compression,fspath=$FSPATH,uuid=$uuid "
            FIRST=1
            PARSER_STATE=2
        elif [[ $line == "Btree usage:" ]]
        then
            echo -n "bcachefs_btree_usage,fspath=$FSPATH,uuid=$uuid "
            FIRST=1
            PARSER_STATE=3
        elif [[ $line =~ ^Pending\ reconcile: ]]
        then
            echo -n "bcachefs_reconcile,fspath=$FSPATH,uuid=$uuid "
            FIRST=1
            PARSER_STATE=4
            REMAINING=(replicas checksum erasure_code compression target high_priority pending)
        elif [[ $line =~ ^([^ ]+)\ \(device\ ([0-9]+)\):[[:space:]]+([^[:space:]]+)[[:space:]]+([^[:space:]]+)[[:space:]]+([0-9]+)%$ ]]
        then
            echo -n "bcachefs_devices,fspath=$FSPATH,uuid=$uuid,label=${BASH_REMATCH[1]},devid=${BASH_REMATCH[2]},device=${BASH_REMATCH[3]} mode=\"${BASH_REMATCH[4]}\",usage=${BASH_REMATCH[5]}"
            PARSER_STATE=5
        #else
            #echo unknown?
        fi
        ;;
    1)
        if [[ "$line" == "" ]]
        then
            PARSER_STATE=0
        fi
        ;;
    2)
        if [[ "$line" == "" ]]
        then
            #echo
            PARSER_STATE=0
        elif [[ $line =~ ^([^[:space:]]+)[[:space:]]*(.*)$ ]]
        then
            field="${BASH_REMATCH[1]// /_}"
            rest="${BASH_REMATCH[2]}"

            read -r val1 val2 val3 <<<"$rest"
            val1="$(convert_to_bytes "$val1")"

            #ensure_comma

            #echo -n "${field}_compressed=$val1"
            if [[ ! -z "$val2" ]]
            then
                val2="$(convert_to_bytes "$val2")"
                #echo -n ",${field}_uncompressed=$val2"
            fi
            if [[ ! -z "$val3" ]]
            then
                val3="$(convert_to_bytes "$val3")"
                #echo -n ",${field}_avgextsize=$val3"
            fi
        #else
            #echo unknown?
        fi
        ;;
    3)
        if [[ "$line" == "" ]]
        then
            echo
            PARSER_STATE=0
        elif [[ $line =~ ^([^:]+)[:space:]+(.*)$ ]]
        then
            field="${BASH_REMATCH[1]// /_}"
            val="${BASH_REMATCH[2]}"
            val="$(convert_to_bytes "$val")"

            ensure_comma

            echo -n "$field=$val"
        #else
            #echo unknown?
        fi
        ;;
    4)
        if [[ "$line" == "" ]]
        then
            for field in "${REMAINING[@]}"
            do
                ensure_comma
                echo -n "${field}_data=0,${field}_metadata=0"
            done

            echo
            PARSER_STATE=0
        elif [[ $line =~ ^([^:]+):[[:space:]]*(.*)$ ]]
        then
            field="${BASH_REMATCH[1]// /_}"
            rest="${BASH_REMATCH[2]}"

            read -r val1 val2 <<<"$rest"
            val1="$(convert_to_bytes "$val1")"
            val2="$(convert_to_bytes "$val2")"

            ensure_comma

            echo -n "${field}_data=$val1,${field}_metadata=$val2"

            REMAINING=( "${REMAINING[@]/$field}" )
        #else
            #echo unknown?
        fi
        ;;
    5)
        if [[ "$line" == "" ]]
        then
            echo
            PARSER_STATE=0
        elif [[ $line =~ ^[[:space:]]*([^:]+):[[:space:]]*(.*)$ ]]
        then
            field="${BASH_REMATCH[1]// /_}"
            rest="${BASH_REMATCH[2]}"

            read -r val1 val2 val3 <<<"$rest"
            val1="$(convert_to_bytes "$val1")"

            echo -n ",${field}_data=$val1"
            if [[ ! -z "$val2" ]]
            then
                echo -n ",${field}_buckets=$val2"
            fi
            if [[ ! -z "$val3" ]]
            then
                val3="$(convert_to_bytes "$val3")"
                echo -n ",${field}_fragmented=$val3"
            fi
        #else
            #echo unknown?
        fi
        ;;
    esac

    #if [[ $PARSER_STATE -ne 1 ]]
    #then
    #    echo "Got line: $line"
    #fi
done < <(sudo bcachefs fs usage -a "$FSPATH")