What are the required stanza attributes when configuring the transforms.

REGEX = < regular expression >

* Enter a regular expression to operate on your data.

FORMAT = < string >

* NOTE: This option is valid for both index-time and search-time field extraction. Index-time field extraction configuration require the FORMAT settings. The FORMAT settings is optional for search-time field extraction configurations.

* This setting specifies the format of the event, including any field names or values you want to add.

DEST_KEY = < key >

* NOTE: This setting is only valid for index-time field extractions.

* Specifies where SPLUNK software stores the expanded FORMAT results in accordance with the REGEX match.