On 05/10/2025 11:34, Hadmut Danisch via dovecot wrote:

On Sun, Oct 05, 2025 at 07:34:14AM +0300, Sulev-Madis Silber via dovecot wrote:

...

at that point, why not run scripts already?

Because I wanted to do it just straigthforward, keep things together in one place, not open a new djungle of error sources and complications, and not run a new process for every single mail that comes in.

And because I'd consider this as the MDA's task and wouldn't love to attach external scripts just to help it do it's job.

And because if I had to do everything with a self written script, I wouldn't bother to use dovecot's sieve at all and just use my script.

:-) Does your old server speak IMAP? If so, would imapsync be suitable?

On October 10, 2025 9:18:35 AM GMT+03:00, "Kamil Jońca via dovecot" <dovecot@dovecot.org> wrote:

Hadmut Danisch via dovecot <dovecot@dovecot.org> writes:

...

Hi,

can dovecot sieve query any external database ( berkeley database file, rest api, whatever) to determine the target folder by sender address?

dovecot alone cannot do this.

But I believe that you can do in your sieve file:

--8<---------------cut here---------------start------------->8--- require [ "vnd.dovecot.execute", "vnd.dovecot.pipe" ,"vnd.dovecot.filter", "fileinto" ] // I do not know if all vnd.* are really needed execute :pipe :output "calculated_mailbox" "fancy_script.sh" [ "parameter1" , "parameter2" , ... ] ; fileinto "${calculated_mailbox}"; --8<---------------cut here---------------end--------------->8---

and your "fancy_script" can do anything you want. Be aware, that dovecot enforces timeout for script.

KJ

i heard he doesn't want it. but sieve can't possibly include everything and also a kitchen sink directly inside it

i use it in mail monitoring so i know that mail enters via smtp and it also goes thru sieve

require [ "variables", "regex", "fileinto", "mailbox", "imap4flags", "vnd.dovecot.execute" ];

and in the end, just before

fileinto :create "yyy/${aaa}";

i have this

if string :is "${bbb}" "xxx" { execute :pipe "zzz.sh"; discard; stop; }

while script does this

#!/bin/sh -Cefu

set -Cefu

file=/ddd/fff.eee

temp_file="$file.tmp"

umask 022

rm -f "$temp_file"

( cat; printf 'ts=%d\r\n' "date +%s" ) > "$temp_file"

mv -f "$temp_file" "$file"

for completeness, other end is

#!/bin/sh -Cefu

set -Cefu

cd /000 || exit 1

to=111

dst_file=222

status_file=tmp/status

debug=

_fail() { echo "$0: fail: $1" | wall }

if [ ! -t 0 ] then sleep "jot -r 1 0 10" fi

rm -f "$status_file"

str="env LANG=C tr -cd '[:alnum:]' < /dev/urandom | head -c 128"

ts_start="date +%s"

echo "$str" | mail "$to"

timeout -k 40 30 tail -0 -F "$dst_file" | tr -u -d '\r'
| egrep --line-buffered "^$str$" | while read line do ts_end_remote="grep -m 1 ^ts= \"$dst_file\" | cut -d = -f 2 \ | tr -d '\r'"

if echo "$ts_end_remote" | egrep -q '^[0-9]+$'
then
	echo ok > "$status_file"
	
	
	if [ "$debug" ]
	then
		echo "ok in ~$((ts_end_remote - ts_start))s"
	fi
else
	echo fail > "$status_file"
	
	
	_fail "invalid ts_end_remote"
fi


pkill -P "$$" timeout

done

if [ ! -f "$status_file" ] then _fail timeout fi

rm -f "$status_file"

note, can contain fbsd specifics

i don't think external programs are bad, but you need to verify they are secure and they don't consume too many resources

querying a database is expensive enough

just don't self-ddos it with every-mail-script that performs 10s long unoptimized sql queries

or, worse

yolo-pipe bobby-tables content from the internet into your non-input-checked utility

both issues can be mitigated by proper techniques!