# Store SpamAssassin bayes in SQL

Attention

Check out the lightweight on-premises email archiving software developed by iRedMail team: Spider Email Archiver.

Warning

The bayesian classifier can only score new messages after it already learn 200 known spams and 200 known hams.

## Summary

This article will guide you to configure related components to store SpamAssassin Bayes data in SQL server, and allow webmail users to report spam with one click.

Tested with:

- iRedMail-0.8.0 and later releases
- CentOS 6.2 (x86_64)
- SpamAssassin-3.3.1
- Amavisd-new-2.6.6
- MySQL-5.1.61
- Roundcubemail-0.7.2

Notes:

- This article should work with all iRedMail releases. We take iRedMail-0.8.0 for example.
- This article should work with all backends: OpenLDAP, MySQL, MariaDB, PostgreSQL. We take MySQL backend for example.
- This article should work with Amavisd-new-2.6.0 and later versions.

IMPORTANT NOTES:

- The bayesian classifier can only score new messages after it already learn known spams and 200 known hams.
- If Spamassassin fails to identify a spam, teach it so it can do better next time. e.g. Mark it as spam in roundcube webmail.
- Read `References` section at the end of this article before asking questions.

## Create required SQL database used to store bayes data

We need to create a SQL database and necessary tables to store SpamAssassin bayes data. The RPM package installed on CentOS 6 doesn't ship SQL template for bayes database, so we have to download it from Apache web site. We're running SpamAssassin-3.3.1, so what we need is this SQL template file: http://svn.apache.org/repos/asf/spamassassin/tags/spamassassin_release_3_3_1/sql/bayes_mysql.sql If you're running different version, please find the proper SQL file here: http://svn.apache.org/repos/asf/spamassassin/tags/.

    # cd /root/
    # wget http://svn.apache.org/repos/asf/spamassassin/tags/spamassassin_release_3_3_1/sql/bayes_mysql.sql

Create MySQL database and import SQL template file:

    # mysql -uroot -p
    mysql> CREATE DATABASE sa_bayes;
    mysql> USE sa_bayes;
    mysql> SOURCE /root/bayes_mysql.sql;

Create a new MySQL user (with password `sa_user_password`) and grant permissions. IMPORTANT NOTE: Please replace password `sa_user_password` by your own password.

    mysql> GRANT SELECT, INSERT, UPDATE, DELETE ON sa_bayes.* TO sa_user@localhost IDENTIFIED BY 'sa_user_password';
    mysql> FLUSH PRIVILEGES;

## Enable Bayes modules in SpamAssassin

Edit `/etc/mail/spamassassin/local.cf`, add (or modify below settings):

    use_bayes          1
    bayes_auto_learn   1
    bayes_auto_expire  1

    # Store bayesian data in MySQL
    bayes_store_module Mail::SpamAssassin::BayesStore::MySQL
    bayes_sql_dsn      DBI:mysql:sa_bayes:127.0.0.1:3306

    # Store bayesian data in PostgreSQL
    #bayes_store_module Mail::SpamAssassin::BayesStore::PgSQL
    #bayes_sql_dsn      DBI:Pg:sa_bayes:127.0.0.1:5432

    bayes_sql_username sa_user
    bayes_sql_password sa_user_password

    # Override the username used for storing data in the database.
    # This could be used to group users together to share bayesian filter data.
    # You can also use this config option to trick sa-learn to learn data as a
    # specific user.
    #
    # In iRedMail, SpamAssassin is called by Amavisd, so we must set it to be
    # same as Amavisd daemon user:
    #   - on Linux, it's user `amavis`.
    #   - on FreeBSD, it's user `vscan`.
    #   - on OpenBSD, it's user `_vscan`.
    bayes_sql_override_username amavis

Make sure SpamAssassin will load bayes modules:

    # /etc/init.d/amavisd stop
    # amavisd -c /etc/amavisd/amavisd.conf debug 2>&1 | grep -i 'bayes'
    May 16 09:59:33 ... SpamAssassin loaded plugins: ..., Bayes, ...
    May 16 10:27:38 ... extra modules loaded after daemonizing/chrooting:
        Mail/SpamAssassin/BayesStore/MySQL.pm, Mail/SpamAssassin/BayesStore/SQL.pm, ...

Looks fine, now press `Ctrl-C` to terminate above command, and start Amavisd service again normally:

    # /etc/init.d/amavisd restart

It is required to initialize the database by learning a message. We use the sample spam email shipped in the RPM package provided by CentOS 6:

    # rpm -ql spamassassin | grep 'sample-spam'
    /usr/share/doc/spamassassin-3.3.1/sample-spam.txt

    # sa-learn --spam --username=amavis /usr/share/doc/spamassassin-3.3.1/sample-spam.txt
    Learned tokens from 1 message(s) (1 message(s) examined)

## Check number of learned spams/hams

Run SQL commands below to check how many spams/hams have been learnt (note: the numbers will be different on your server):

    mysql> USE sa_bayes;
    mysql> SELECT username,spam_count,ham_count FROM bayes_vars;
    +----------+------------+-----------+
    | username | spam_count | ham_count |
    +----------+------------+-----------+
    | amavis   |          3 |        38 |
    +----------+------------+-----------+

## Auto learn spam/ham with Dovecot imap_sieve plugin

- Auto learn spam/ham with Dovecot imap_sieve plugin

## Backup your `sa_bayes` database

Don't forget to update `/var/vmail/backup/backup_mysql.sh` (or `backup_pgsql.sh` if you're running PostgreSQL backend) to backup this newly created `sa_bayes` database. For example:

    # Part of file `/var/vmail/backup/backup_mysql.sh`
    DATABASES='... sa_bayes'

## References

- Bayes Introduction. Please do read section `Things to remember`.
- SpamAssassin Bayes Frequently Asked Questions