[mrtg] Reuse .old logfiles after rateup error

[Morty Abzug]

On Tue, Feb 23, 2010 at 06:28:26AM -0800, alfo wrote:

> Right now, when rateup fails it stops updating the .log file and only the
> .old logfile remains in the system.  When the error is solved I am not able
> to reuse that logfile anymore (the .old one), because the timestamps are not
> udpated (basically, mrtg doesn't update them if the last one is older than X
> hours), so I'm losing the historical information in case of error.
> 
> I was wondering if there is any script to update a .old logfile after an
> error occurs.

Which error are you getting?

I use the following bash functions to help find and fix MRTG logfile
problems:

function mrtg-logfile-check(){
        for file in "$@"; do
                echo file: $file
                        echo '    Sort diff (you can ignore problems with line1 and 2):'
                        sort -rn $file | diff - $file
                        echo '    Lines with wrong size:'
                        awk 'NR>1 && NF!=5{printf "line %-5d: ", NR; print}' $file
                        echo
                echo
        done
}

function mrtg-fix-time-problem (){
    perl -nae 'BEGIN{$now=time}
                if ($F[0]>$now && ($.==1 or $F[0]==$then)) {
                        s{^\d+}{$now}; $then=$F[0]
                } elsif ($F[0]>$now) {
                        next
                };
        print' "$@"
}

- Morty