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12.5.1. Options of XML parsers

The XML parser has the following options.


Synopsis: drop-invalid()
Format: yes|no
Default: no
Mandatory: no

Description: If set, messages with an invalid XML will be dropped entirely.


Synopsis: exclude-tags()
Format: list of globs


If not set, no filtering is done.

Mandatory: no

Description: The XML parser matches tags against the listed globs. If there is a match, the given subtree of the XML will be omitted.

Example 12.12. Using exclude_tags
parser xml_parser {
       xml(template("$MSG") exclude_tags("tag1", "tag2", "inner*"));

From this XML input:


The following output is generated:



Synopsis: prefix()

Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:

  • To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.

  • To refer to a particular data that has a prefix, use the prefix in the name of the macro, for example, ${} .

  • If you forward the parsed messages using the IETF-syslog protocol, you can insert all the parsed data into the SDATA part of the message using the prefix( option.

Names starting with a dot (for example, .example) are reserved for use by syslog-ng PE. If you use such a macro name as the name of a parsed value, it will attempt to replace the original value of the macro (note that only soft macros can be overwritten, see Section 11.1.4, Hard vs. soft macros for details). To avoid such problems, use a prefix when naming the parsed values, for example, prefix(my-parsed-data.)

The prefix() option is optional and its default value is ".xml".


Synopsis: strip-whitespaces()
Format: yes|no
Default: no
Mandatory: no

Description: Strip the whitespaces from the XML text nodes before adding them to the message.

Example 12.13. Using strip-whitespaces
parser xml_parser {
       xml(template("$MSG") strip_whitespaces(yes));

From this XML input:

<tag1> Tag </tag1>

The following output is generated:



Synopsis: template("${<macroname>}")

Description: The macro that contains the part of the message that the parser will process. It can also be a macro created by a previous parser of the log path. By default, the parser processes the entire message (${MESSAGE}).