Options of the XML parsers

The XML parser has the following options.

create-lists()

Available in AxoSyslog version 3.20 and later.

Description: If an XML element appears multiple times on the same level, the parser stores the repeated values as a list-typed name-value pair. If you set create-lists(no), the parser concatenates the repeated values into a single string instead, which was the behavior before version 3.20.

For example, from the following XML input:

   <tag><item>first</item><item>second</item></tag>

The parser creates the ${.xml.tag.item} name-value pair with the list value first,second. With create-lists(no), the value of ${.xml.tag.item} is the string firstsecond.

drop-invalid()

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

exclude-tags()

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: Using exclude_tags

   parser xml_parser {
        xml(
            template("$MSG")
            exclude-tags("tag1", "tag2", "inner*")
        );
    };

From this XML input:

   <tag1>Text1</tag1><tag2>Text2</tag2><tag3>Text3<innertag>TextInner</innertag></tag3>

The following output is generated:

   {"_xml":{"tag3":"Text3"}}

internal()

Description: Marks this pipeline element as internal. Elements marked as internal() are treated as an implementation detail, so for example statistics of the given pipe are available only on higher stats level. This option is mainly useful for developers or when writing SCL blocks and integrations.

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, ${my-parsed-data.name}.
• 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(.SDATA.my-parsed-data.) option.

Names starting with a dot (for example, .example) are reserved for use by AxoSyslog. 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 Hard versus 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".

strip-whitespaces()

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

Example: Using strip-whitespaces

   parser xml_parser {
        xml(
            template("$MSG")
            strip-whitespaces(yes)
        );
    };

From this XML input:

   <tag1> Tag </tag1>

The following output is generated:

   {"_xml":{"tag1":"Tag"}}

template()

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}).