Dictionary quota
================
The /dictionary/ quota backend supports both *storage* and *messages* quota
limits. The current quota is kept in a dictionary. The available dictionaries
are:
* MySQL
* PostgreSQL
* Flat file
The quota root format is:
---%<-------------------------------------------------------------------------
quota = dict:<quota root name>:<username>[:<option>[...]]:<dictionary URI>
---%<-------------------------------------------------------------------------
If /username/ is left empty, the logged in username is used (this is typically
what you want). Another useful username is '%d' for supporting domain-wide
quotas.
The supported options are:
* noenforcing: Don't enforce quota limits, only track them.
* ignoreunlimited: If user has unlimited quota, don't track it.
* ns=<prefix>: This quota root is tracked only for the given namespace.
Examples
--------
---%<-------------------------------------------------------------------------
plugin {
# SQL backend:
quota = dict:User quota::proxy::quota
# file backend:
quota = dict:User quota::file:%h/Maildir/dovecot-quota
quota_rule = *:storage=10M:messages=1000
}
dict {
quota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
}
---%<-------------------------------------------------------------------------
The above SQL example uses dictionary proxy process (see below), because SQL
libraries aren't linked to all Dovecot binaries. The file example accesses the
file directly.
Example 'dovecot-dict-sql.conf.ext':
---%<-------------------------------------------------------------------------
connect = host=localhost dbname=mails user=sqluser password=sqlpass
map {
pattern = priv/quota/storage
table = quota
username_field = username
value_field = bytes
}
map {
pattern = priv/quota/messages
table = quota
username_field = username
value_field = messages
}
---%<-------------------------------------------------------------------------
Create the table like this:
---%<-------------------------------------------------------------------------
CREATE TABLE quota (
username varchar(100) not null,
bytes bigint not null default 0,
messages integer not null default 0,
primary key (username)
);
---%<-------------------------------------------------------------------------
MySQL uses the following queries to update the quota. You need suitable
privileges.
---%<-------------------------------------------------------------------------
INSERT INTO table (bytes,username) VALUES ('112497180','foo@spam.dom') ON
DUPLICATE KEY UPDATE bytes='112497180';
INSERT INTO table (messages,username) VALUES ('1743','foo@spam.dom') ON
DUPLICATE KEY UPDATE messages='1743';
UPDATE table SET bytes=bytes-14433,messages=messages-2 WHERE username =
'foo@spam.dom';
---%<-------------------------------------------------------------------------
If you're using PostgreSQL, you'll need a trigger:
---%<-------------------------------------------------------------------------
CREATE OR REPLACE FUNCTION merge_quota() RETURNS TRIGGER AS $$
BEGIN
IF NEW.messages < 0 OR NEW.messages IS NULL THEN
-- ugly kludge: we came here from this function, really do try to insert
IF NEW.messages IS NULL THEN
NEW.messages = 0;
ELSE
NEW.messages = -NEW.messages;
END IF;
return NEW;
END IF;
LOOP
UPDATE quota SET bytes = bytes + NEW.bytes,
messages = messages + NEW.messages
WHERE username = NEW.username;
IF found THEN
RETURN NULL;
END IF;
BEGIN
IF NEW.messages = 0 THEN
INSERT INTO quota (bytes, messages, username)
VALUES (NEW.bytes, NULL, NEW.username);
ELSE
INSERT INTO quota (bytes, messages, username)
VALUES (NEW.bytes, -NEW.messages, NEW.username);
END IF;
return NULL;
EXCEPTION WHEN unique_violation THEN
-- someone just inserted the record, update it
END;
END LOOP;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER mergequota BEFORE INSERT ON quota
FOR EACH ROW EXECUTE PROCEDURE merge_quota();
---%<-------------------------------------------------------------------------
Dictionary proxy server
-----------------------
To avoid each process making a new SQL connection, you can make all dictionary
communications go through a dictionary server process which keeps the
connections permanently open.
The dictionary server is referenced with URI 'proxy:<dictionary server socket
path>:<dictionary name>'. The socket path may be left empty if you haven't
changed 'base_dir' setting in 'dovecot.conf'. Otherwise set it to
'<base_dir>/dict-server'. The dictionary names are configured in
'dovecot.conf'. For example:
---%<-------------------------------------------------------------------------
dict {
quota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
expire = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
}
---%<-------------------------------------------------------------------------
See <Dict.txt> for more information, especially about permission issues.
(This file was created from the wiki on 2011-01-13 04:52)
y~or5J ={Eeu磝Qk ᯘG{?+]ן?wM3X^歌>{7پK>on\jy R g/=fOroNVv~Y+ NGuÝHWyw[eQʨSb> >}Gmx[o[<{Ϯ_qF vM IENDB`
