# Structured data (SDATA) parser

Available in AxoSyslog 4.1 and later.

The `sdata-parser()` allows you to parse an RFC5424-style structured data string. You can use it to parse this relatively complex format separately, for example, to process malformatted messages. You can use the optional `prefix` option to add a specific string before the names of the parsed name-value pairs.

See also the related [`get_sdata()`](../../docs/axosyslog-core/4.26/filterx/function-reference/index.md#get_sdata) FilterX function, which extracts the SDATA of the current message into a dict. Unlike `sdata-parser()`, it cannot parse an arbitrary string, and has no `prefix` option.

## Declaration

Terminal window
```
       parser parser_name {
            sdata-parser(
                template("<string-or-template-to-parse>")
                prefix("<prefix-for-parsed-name-value-pairs>")
            );
        };
```

## internal()

|   
---|---  
Accepted values: | `yes`, `no`  
Default: | `no`  
  
_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()

|   
---|---  
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, `${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](../../docs/axosyslog-core/4.26/chapter-manipulating-messages/customizing-message-format/macros-hard-vs-soft/index.md) for details). To avoid such problems, use a prefix when naming the parsed values, for example, `prefix(my-parsed-data.)`

## template()

|   
---|---  
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}`).

Last modified August 6, 2026: [Adds missing internal option to some parsers (de08f2e7)](<https://github.com/axoflow/axosyslog-core-docs/commit/de08f2e7ef3bc5e7b7e7a01140535a380ad43a82>)