Regular expression

The regular expression (regex) mapping serves as a dynamic replacement tool, similar to a lookup table, but leverages the flexibility of regular expressions to define complex matching and replacement rules. The attributes that need to be set in a regex mapping are:

Configuration Attributes for Regex Mapping

Attribute	Required (Y/N)	Description
from	Y	Specifies the field name from which data is mapped.
to	Y	Specifies the field name to which data is mapped.
precedence	N	Determines the order in which mappings are applied.
Function type	Y	Must be set to "String functions" to use regex capabilities.
function	Y	Set to "regular expression" to enable regex-based mapping.
Regex	Y	Defines the regular expression used for matching patterns within the field. Mode modifiers: Optional modifiers that adjust the behavior of the regex, such as (?s) to make the dot match newline characters.
Replacement string	N	Defines the replacement string or format based on capture groups; defaults to the first capture group if unspecified.

Advanced Options

• Value Map: A regex mapping can include a nested value map, utilizing the capture groups ($n$) defined in the Regex attribute for detailed replacements in the "Replacement string".
• Capture Groups in to and from Fields: If capture groups are used in the from and to fields, the "Replacement string" can be adjusted to reference these using $n# to avoid confusion with capture groups from the regex pattern itself.

Example Application

Consider the scenario where the Zabbix API outputs a field with value vfs.fs.size[/,free] that you need to parse for monitoring disk space. Using regex mapping, this value can be split into two different fields:

• /metric/type: Extracted to represent the metric type, such as "disk_free".
• /ci/element: Used to capture specific filesystem elements, such as "/".