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//usr/share/doc/rsyslog-5.8.10/rsconf1_rulesetparser.html

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<title>RulesetParser - rsyslog.conf file</title>
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<a href="rsyslog_conf_global.html">rsyslog.conf configuration directive</a>

<h2>$RulesetParser</h2>
Type: ruleset-specific configuration directive
Parameter Values: string
Available since: 5.3.4+
Default: rsyslog.rfc5424 followed by rsyslog.rfc5425
Description:

This directive permits to specify which
<a href="messageparser.html">message parsers</a> should be used for the ruleset
in question. It no ruleset is explicitely specified, the default ruleset is used. Message
parsers are contained in (loadable) parser modules with the most common cases
(RFC3164 and RFC5424) being build-in into rsyslogd.
When this directive is specified the first time for a ruleset, it will not only add the
parser to the ruleset's parser chain, it will also wipe out the default parser chain.
So if you need to have
them in addition to the custom parser, you need to specify those as well.
Order of directives is important. Parsers are tried one after another, in the order
they are specified inside the config. As soon as a parser is able to parse the message,
it will do so and no other parsers will be executed. If no matching parser can be found,
the message will be discarded and a warning message be issued (but only for the first
1,000 instances of this problem, to prevent message generation loops).
Note that the rfc3164 parser will always be able to parse a message - it may
just not be the format that you like. This has two important implications: 1) always place
that parser at the END of the parser list, or the other parsers after it will never
be tried and 2) if you would like to make sure no message is lost, placing the rfc3164
parser at the end of the parser list ensures that.
Multiple parser modules are very useful if you have various devices that emit 
messages that are malformed in various ways. The route to take then is
<ul>
<li>make sure you find a custom parser for that device; if there is no one, you
may consider writing one yourself (it is not that hard) or getting one written
as part of
<a href="http://www.rsyslog.com/professional-services">Adiscon's professional services
for rsyslog</a>.
<li>load your custom parsers via $ModLoad
<li>create a ruleset for each malformed format; assign the custom parser to it
<li>create a specific listening port for all devices that emit the same
malformed format
<li>bind the listener to the ruleset with the required parser
</ul>
Note that it may be cumbersome to add all rules to all rulesets. To avoid this,
you can either use $Include or <a href="omruleset.html">omruleset</a>
(what probably provides the best solution).
More information about rulesets in general can be found in
<a href="multi_ruleset.html">multi-ruleset support in rsyslog</a>.
Caveats:
currently none known

Example:
This example assumes there are two devices emiting malformed messages via UDP.
We have two custom parsers for them, named &quot;device1.parser&quot; and
&quot;device2.parser&quot;. In addition to that, we have a number of other
devices sending wellformed messages, also via UDP.
The solution is to listen for data from the two devices on two special
ports (10514 and 10515 in this example), create a ruleset for each and
assign the custom parsers to them. The rest of the messages are received via
port 514 using the regular parsers. Processing shall be equal for all messages.
So we simply forward the malformed messages to the regular queue once they are parsed (keep
in mind that a message is never again parsed once any parser properly processed it).

<textarea rows="40" cols="80">$ModLoad imudp
$ModLoad pmdevice1 # load parser "device1.parser" for device 1
$ModLoad pmdevice2 # load parser "device2.parser" for device 2

# define ruleset for the first device sending malformed data
$Ruleset maldev1
$RulesetCreateMainQueue on # create ruleset-specific queue
$RulesetParser "device1.parser" # note: this deactivates the default parsers
# forward all messages to default ruleset:
$ActionOmrulesetRulesetName RSYSLOG_DefaultRuleset 
*.* :omruleset:

# define ruleset for the second device sending malformed data
$Ruleset maldev2
$RulesetCreateMainQueue on # create ruleset-specific queue
$RulesetParser "device2.parser" # note: this deactivates the default parsers
# forward all messages to default ruleset:
$ActionOmrulesetRulesetName RSYSLOG_DefaultRuleset 
*.* :omruleset:

# switch back to default ruleset
$Ruleset RSYSLOG_DefaultRuleset
*.*           /path/to/file
auth.info     @authlogger.example.net
# whatever else you usually do...

# now define the inputs and bind them to the rulesets
# first the default listener (utilizing the default ruleset)
$UDPServerRun 514

# now the one with the parser for device type 1:
$InputUDPServerBindRuleset maldev1
$UDPServerRun 10514

# and finally the one for device type 2:
$InputUDPServerBindRuleset maldev2
$UDPServerRun 10515
</textarea>

For an example of how multiple parser can be chained (and an actual use case), please see
the example section on the <a href="pmlastmsg.html">pmlastmsg</a> parser
module.
Note the positions of the directives. With the current config language,
sequence of statements is very important. This is ugly, but unfortunately
the way it currently works.

[<a href="rsyslog_conf.html">rsyslog.conf overview</a>] [<a href="manual.html">manual 
index</a>] [<a href="http://www.rsyslog.com/">rsyslog site</a>]
This documentation is part of the
<a href="http://www.rsyslog.com/">rsyslog</a> project. 
Copyright &copy; 2009 by <a href="http://www.gerhards.net/rainer">Rainer Gerhards</a> and
<a href="http://www.adiscon.com/">Adiscon</a>. Released under the GNU GPL version 2 or higher.
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