[Dovecot] Pigeonhole: extprograms - pipe

[Anes Mukhametov]

Hello!

I've tried to use extprograms pipe feature but stuck with "Broken pipe"
errors in mail log:

May 17 15:18:57 backend1 dovecot: lmtp(20338, user at domain.tld): Debug:
3VMVFWFKllFyTwAArRg8UA: sieve: action pipe: running program: learn
May 17 15:18:57 backend1 dovecot: script: Error: write(response) failed:
Broken pipe
May 17 15:18:57 backend1 dovecot: lmtp(20338, user at domain.tld):
3VMVFWFKllFyTwAArRg8UA: sieve: execution of script
/data/mail/storage/domain/user at domain.tld/.dovecot.sieve;name=main script
failed, but implicit keep was successful (user logfile
/data/mail/storage/domain/buser at domain.tld/.dovecot.sieve.log should reveal
additional details)

/data/mail/storage/domain/buser at domain.tld/.dovecot.sieve.log:
error: msgid=<c7cd36f19be8164addf091a646b8b284 at domain.tld>: pipe action:
failed to pipe message to program `learn': refer to server log for more
information. [2013-05-17 15:18:57] ham user at domain.tld 50796.


Sieve script contents:
require ["fileinto","copy","mailbox","vnd.dovecot.pipe"];

if anyof (header :is "Subject" "ham")
{
pipe :try "learn" ["ham"];
        fileinto "INBOX/ham";
        stop;
}

Sieve plugin config uncommented conents:
sieve_plugins = sieve_extprograms
*sieve_pipe_socket_dir = sieve-pipe*

  # Define the executed script as parameter to the sieve service
  executable = script /etc/dovecot/scripts/spam.sh

  # Use some unprivileged user for executing the program
  user = nobody

  # The unix socket located in the sieve_pipe_socket_dir (as defined in the
  # plugin {} section above)
  unix_listener sieve-pipe/learn {
    # LDA/LMTP must have access
     user = nobody
     mode = 0777
  }
}


spam.sh is message processing script which interacts with spamassassin.
I've tested pipe with spam.sh that redirects stdin to /dev/null and returns
0 but errors were logged anyway.
Note that spam.sh runs, getting the message from sieve and processing it to
spamassassin without a problem, but "broken pipe" is being logged.