Pattern databases are XML files that contain rules describing the message patterns. For sample pattern databases, see Downloading sample pattern databases.
The following scheme describes the V5 format of the pattern database. This format is backwards-compatible with the earlier formats.
For a sample database containing only a single pattern, see Example: A pattern database containing a single rule.
Use the pdbtool utility that is bundled with syslog-ng to test message patterns and convert existing databases to the latest format. For details, see The pdbtool manual page.
To automatically create an initial pattern database from an existing log file, use the pdbtool patternize command. For details, see The pdbtool manual page.
The following pattern database contains a single rule that matches a log message of the ssh application. A sample log message looks like:
Accepted password for sampleuser from 10.50.0.247 port 42156 ssh2
The following is a simple pattern database containing a matching rule.
<patterndb version='5' pub_date='2010-10-17'>
<ruleset name='ssh' id='123456678'>
<pattern>ssh</pattern>
<rules>
<rule provider='me' id='182437592347598' class='system'>
<patterns>
<pattern>Accepted @QSTRING:SSH.AUTH_METHOD: @ for@QSTRING:SSH_USERNAME: @from\ @QSTRING:SSH_CLIENT_ADDRESS: @port @NUMBER:SSH_PORT_NUMBER:@ ssh2</pattern>
</patterns>
</rule>
</rules>
</ruleset>
</patterndb>
Note that the rule uses macros that refer to parts of the message, for example, you can use the ${SSH_USERNAME} macro refer to the username used in the connection.
The following is the same example, but with a test message and test values for the parsers.
<patterndb version='4' pub_date='2010-10-17'>
<ruleset name='ssh' id='123456678'>
<pattern>ssh</pattern>
<rules>
<rule provider='me' id='182437592347598' class='system'>
<patterns>
<pattern>Accepted @QSTRING:SSH.AUTH_METHOD: @ for@QSTRING:SSH_USERNAME: @from\ @QSTRING:SSH_CLIENT_ADDRESS: @port @NUMBER:SSH_PORT_NUMBER:@ ssh2</pattern>
</patterns>
<examples>
<example>
<test_message>Accepted password for sampleuser from 10.50.0.247 port 42156 ssh2</test_message>
<test_values>
<test_value name="SSH.AUTH_METHOD">password</test_value>
<test_value name="SSH_USERNAME">sampleuser</test_value>
<test_value name="SSH_CLIENT_ADDRESS">10.50.0.247</test_value>
<test_value name="SSH_PORT_NUMBER">42156</test_value>
</test_values>
</example>
</examples>
</rule>
</rules>
</ruleset>
</patterndb>/patterndb
The container element of the pattern database.
version: The schema version of the pattern database. The current version is 4.
pubdate: The publication date of the XML file.
/patterndb/ruleset
A container element to group log patterns for an application or program. A <patterndb> element may contain any number of <ruleset> elements.
name: The name of the application. Note that the function of this attribute is to make the database more readable, syslog-ng uses the <pattern> element to identify the applications sending log messages.
id: A unique ID of the application, for example, the md5 sum of the name attribute.
description: OPTIONAL — A description of the ruleset or the application.
url: OPTIONAL — An URL referring to further information about the ruleset or the application.
rule_urls: OPTIONAL — To list multiple URLs referring to further information about the ruleset or the application, enclose the <url> elements into an <urls> element.
<ruleset name='su' id='480de478-d4a6-4a7f-bea4-0c0245d361e1'>
A container element. A <patterns> element may contain any number of <pattern> elements.
N/A
pattern: The name of the application — syslog-ng matches this value to the ${PROGRAM} header of the syslog message to find the rulesets applicable to the syslog message.
Specifying multiple patterns is useful if two or more applications have different names (that is, different ${PROGRAM} fields), but otherwise send identical log messages.
It is not necessary to use multiple patterns if only the end of the ${PROGRAM} fields is different, use only the beginning of the ${PROGRAM} field as the pattern. For example, the Postfix email server sends messages using different process names, but all of them begin with the postfix string.
You can also use parsers in the program pattern if needed, and use the parsed results later. For example: <pattern>postfix\@ESTRING:.postfix.component:[@</pattern>
If the <pattern> element of a ruleset is not specified, syslog-ng OSE will use this ruleset as a fallback ruleset: it will apply the ruleset to messages that have an empty PROGRAM header, or if none of the program patterns matched the PROGRAM header of the incoming message.
<patterns>
<pattern>firstapplication</pattern>
<pattern>otherapplication</pattern>
</patterns>
Using parsers in the program pattern:
<pattern>postfix\@ESTRING:.postfix.component:[@</pattern>
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