Bug#929798: exim4-base: /etc/cron.daily/exim4-base will not rotate paniclog if it is 100% noise.

[Andreas Metzler]

On 2019-05-31 Kyrian <kyrian at ore.org> wrote:
> Quoting Andreas Metzler <ametzler at bebt.de>:
[...]
> > So if paniclog is non-empty, but only contains ignored lines then the
> > log is not-rotated but warning mails are not sent out. So "warning
> > emails keep coming" will not happen.

> Yes, I agree that is the logic that the script follows.

> Anyway, having worked through it all again in my head and worked out the
> bits that are deliberate on the developer's part, and the red herrings, I
> think this is the issue I meant...

> If you have a paniclog full of rubbish you want to ignore (say 4138/4143
> lines are junk in the log, and the error is not in the last
> $E4BCD_PANICLOG_LINES lines), the step that does 'tail -n' on the paniclog
> and sends it out without filtering in the same way with
> $E4BCD_PANICLOG_NOISE, then all the email gives you are the lines of noise
> (which looks remarkably similar day-to-day if it's all exactly the same
> error with just different timestamps, and perhaps that lead me to think
> 'once' was being ignored), not the actual non-ignored lines that triggered
> the email.

Hello,

that part (sending out the unfiltered lines) does not make a lot of
sense. Thanks for explaining the issue in detail.

> I think that's what got me thinking that the log rotation should happen if
> the paniclog has *something* in it even if it's junk that you ignore,
> because you can get a loooot of junk in those logs. That might end up being
> counter-intuitive for some use cases though I guess. Another thing to do
> might be to change the "tail -n" line to:

> grep -v "$E4BCD_PANICLOG_NOISE" /var/log/exim4/paniclog | tail -n
> "${E4BCD_PANICLOG_LINES}"

Sounds like a good idea.

[...]
> This is sounding more like a feature request than a bug I suppose.

I can see reasons both for rotating paniclog consisting entirely of
noise (space) and for not rotating it (an important one being "we have
always done that").

I will definitely change the mail, but tend to keep the rotation logic
unchanged.

cu Andreas

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