dovecot - Nov 2013 - Is it safe to manipulate Maildir files directly?

Dovecoters,

is it safe to manipulate files in Maildir/xxx directly or will Dovecot become
unstable if I don't make these changes by talking to Dovecot and having it
make the changes?  (I'm running 2.1.7 under Wheezy, IMAP only)

My specific application: I am running spamassassin and would like users to be
able to submit spam (and ham) directly by moving it into special folders.  A
cron job can then find it and take action: feed spam messages to the bayesian
trainer and then delete them; feed ham messages to the trainer and then move
them into ~/Maildir/cur/

Having the cron job find the messages and train spamassassin is no problem.  The
question is how to move the messages.  Is it safe to simply rename the files
from my cron job?

The dovecot wiki implies that dovecot will notice a change in mtime and deal
with it safely.  Am I reading this correctly?  Changing a message flags (i.e.
name) and/or directory will change mtime.

If I have to go through to Dovecot I am afraid I'd need the user's
credentials, which is not appropriate.

Thanks!
-d

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On Mon, 4 Nov 2013, David Henkel-Wallace wrote:
> is it safe to manipulate files in Maildir/xxx directly or will Dovecot
if "xxx" does not include the Dovecot-related index files etc., then
yes.
> become unstable if I don't make these changes by talking to Dovecot and
> having it make the changes?  (I'm running 2.1.7 under Wheezy, IMAP
only)
>
> My specific application: I am running spamassassin and would like users 
> to be able to submit spam (and ham) directly by moving it into special 
> folders.  A cron job can then find it and take action: feed spam 
> messages to the bayesian trainer and then delete them; feed ham messages 
> to the trainer and then move them into ~/Maildir/cur/
I did this before switching to antispam.
I use antispam with spool2dir now, that central directory has a inotify 
watcher that trains the messages instantly.
> Having the cron job find the messages and train spamassassin is no 
> problem.  The question is how to move the messages.  Is it safe to 
> simply rename the files from my cron job?
You mean "ham -> ~/Maildir/cur"? Yes, but there is a slight chance,
that
an user already copy'ed the message there. If the stem of the filename, 
the part before the colon ":", is already present in the Maildir/cur
or
~~/new, Dovecot might gets confused. I think all present versions generate 
an error in the sense "duplicate found, fixed by renaming into
something".

I did not moved the message files from "ham" into the INBOX. I named
the
folders: spam/yes and spam/no, all my users moved messages into spam/yes, 
but copied them into spam/no and moved them themselves into their correct 
mailbox. Maybe, you can avoid that step, too.

- -- 
Steffen Kaiser
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On Mon, 4 Nov 2013 21:49:59 -0800
David Henkel-Wallace <gumby at henkel-wallace.org> wrote:

> Having the cron job find the messages and train spamassassin is no
> problem.  The question is how to move the messages.  Is it safe to
> simply rename the files from my cron job?
> 
[...]
> If I have to go through to Dovecot I am afraid I'd need the user's
> credentials, which is not appropriate.
> 
you can do all this with doveadm scripts. 
http://wiki2.dovecot.org/Tools/Doveadm
Something like this should work:

doveadm search -A mailbox 'hamreport' 2>/dev/null | while read
user guid uid; do  doveadm fetch -u $user text mailbox-guid $guid uid
$uid | sa-learn --ham ; doveadm move -u $user INBOX mailbox-guid $guid
uid $uid ; done


this should fetch all mails in the 'hamreport' folder of every user,
pass it to sa-learn and then move it to the user's INBOX
you don't need the user credentials , but you have to make sure
doveadm can find all users (iterate_query setting with SQL auth db)

hth
Oli

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