Re: error writing to filter (bogofilter)

* Christian Ebert on Thursday, June 13, 2013 at 14:04:24 +0100
> * Sam Varshavchik on Thursday, June 13, 2013 at 08:06:13 -0400
>> Christian Ebert writes:
>>> After an upgrade to Mac OS 10.8.4 (64bit) from 10.5.8 (32bit) I
>>> get the following error for _some_ messages:
>>> 
>>> temporary failure.
>>> Command output: maildrop: error writing to filter.
>>> /usr/local/bin/maildrop: Unable to filter message.
>>> 
>>> The offending rule is rather bog standard:
>>> xfilter "/usr/local/bin/bogofilter -u -e -p"
>>> 
>>> Trying the bogofilter suspect on an offending message however
>>> seems to cause no problems:
>>> 
>>> $ bogofilter -u -e -p < testbogomsg 1>/dev/null
>>> $ echo $?
>>> 0
>>> 
>>> Of course I recompiled all involved programs, like maildrop,
>>> bogofilter, tokyocabinet.
>>> 
>>> What could be the problem?
>> 
>> bogofilter does not read the entire contents of the message from its
>> standard input. It terminates before it is read in its entirety.
>> xfilter pipes the message to the external filter program that it runs.
>> If xfilter detects that the pipe is broken, before it's finished
>> writing the entire message to the pipe, it concludes that the external
>> filter has crashed.
>> 
>> Given the buffering involved with pipes, you get non-predictable
>> behavior that, sometimes, maildrop succesfully finishes writing the
>> end of the message, which gets buffered in the pipe before the
>> external command terminates without reading in its entirety. There's
>> no way to detect that, so, depending on random factors, sometimes an
>> error gets detected, sometimes not; and this depends in part on the
>> underlying operating system platform and implementation. It's not
>> surprising that different behavior is observed after upgrading.
> 
> Thanks for the explanation. However, it's not completely random,
> it is replicable with certain messages.
> 
> What shall I do? Take it to the bogofilter list? Switch back to
> procmail - it has no trouble with exactly the same message(s)?

Sorry for having sounded a bit harsh, but I'm a sorta desperate
here - I had taken my entire postfix config apart before I nailed
it down to this rather trivial cause.

Are you suggesting that the only way around this in practice is:
1. inspect the postfix queue
2. in case there is this problem, disable bogofilter by
   temporarily changing the mailfilter
3. sendmail -q
4. reinstate bogofilter in the mailfilter

At least for me this is not even a workaround.

Would it help if I sent you one of the "offending" messages
via pm for inspection?

-- 
Die Wolke Wolfgang
Eine Kindergeschichte mit Bildern. Von Michael Weber.
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