omlibdbi: Generic Database Output Module

Module Name: omlibdbi

Author: Rainer Gerhards <rgerhards@adiscon.com>

Description:

This modules supports a large number of database systems via libdbi. Libdbi abstracts the database layer and provides drivers for many systems. Drivers are available via the libdbi-drivers project. As of this writing, the following drivers are available:

The following drivers are in various stages of completion:

These drivers seem to be quite usable, at least from an rsyslog point of view.

Libdbi provides a slim layer between rsyslog and the actual database engine. We have not yet done any performance testing (e.g. omlibdbi vs. ommysql) but honestly believe that the performance impact should be irrelevant, if at all measurable. Part of that assumption is that rsyslog just does the “insert” and most of the time is spent either in the database engine or rsyslog itself. It’s hard to think of any considerable time spent in the libdbi abstraction layer.

Setup

In order for this plugin to work, you need to have libdbi, the libdbi driver for your database backend and the client software for your database backend installed. There are libdbi packages for many distributions. Please note that rsyslogd requires a quite recent version (0.8.3) of libdbi. It may work with older versions, but these need some special ./configure options to support being called from a dlopen()ed plugin (as omlibdbi is). So in short, you probably save you a lot of headache if you make sure you have at least libdbi version 0.8.3 on your system.

Configuration Directives:

  • $ActionLibdbiDriverDirectory /path/to/dbd/drivers

    This is a global setting. It points libdbi to its driver directory. Usually, you do not need to set it. If you installed libdbi-driver’s at a non-standard location, you may need to specify the directory here. If you are unsure, do not use this configuration directive. Usually, everything works just fine.

  • $ActionLibdbiDriver drivername

    Name of the dbidriver to use, see libdbi-drivers documentation. As a quick excerpt, at least those were available at the time of this writiting “mysql” (suggest to use ommysql instead), “firebird” (Firbird and InterBase), “ingres”, “msql”, “Oracle”, “sqlite”, “sqlite3”, “freetds” (for Microsoft SQL and Sybase) and “pgsql” (suggest to use ompgsql instead).

  • $ActionLibdbiHost hostname

    The host to connect to.

  • $ActionLibdbiUserName user

    The user used to connect to the database.

  • $ActionlibdbiPassword

    That user’s password.

  • $ActionlibdbiDBName db

    The database that shall be written to.

  • selector line: :omlibdbi:;template

    executes the recently configured omlibdbi action. The ;template part is optional. If no template is provided, a default template is used (which is currently optimized for MySQL - sorry, folks...)

Caveats/Known Bugs:

You must make sure that any templates used for omlibdbi properly escape strings. This is usually done by supplying the SQL (or STDSQL) option to the template. Omlibdbi rejects templates without this option for security reasons. However, omlibdbi does not detect if you used the right option for your backend. Future versions of rsyslog (with full expression  support) will provide advanced ways of handling this situation. So far, you must be careful. The default template provided by rsyslog is suitable for MySQL, but not necessarily for your database backend. Be careful!

If you receive the rsyslog error message “libdbi or libdbi drivers not present on this system” you may either not have libdbi and its drivers installed or (very probably) the version is earlier than 0.8.3. In this case, you need to make sure you have at least 0.8.3 and the libdbi driver for your database backend present on your system.

I do not have most of the database supported by omlibdbi in my lab. So it received limited cross-platform tests. If you run into troubles, be sure the let us know at http://www.rsyslog.com.

Sample:

The following sample writes all syslog messages to the database “syslog_db” on mysqlserver.example.com. The server is MySQL and being accessed under the account of “user” with password “pwd” (if you have empty passwords, just remove the $ActionLibdbiPassword line).

$ModLoad omlibdbi $ActionLibdbiDriver mysql $ActionLibdbiHost
mysqlserver.example.com $ActionLibdbiUserName user $ActionLibdbiPassword
pwd $ActionLibdbiDBName syslog\_db \*.\* :omlibdbi:

This documentation is part of the rsyslog project.

Copyright © 2008-2014 by Rainer Gerhards and Adiscon. Released under the GNU GPL version 3 or higher.

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