Lowercase

Mutate Elastic Compatible

Synopsis

Converts string values to lowercase.

Schema

- lowercase:
    field: <ident>
    target_field: <ident>
    fields: <string[]>
    exclude: <string[]>
    description: <text>
    if: <script>
    ignore_failure: <boolean>
    ignore_missing: <boolean>
    on_failure: <processor[]>
    on_success: <processor[]>
    tag: <string>

Configuration

The following fields are used to define the processor:

Field	Required	Default	Description
field	Y	-	Source field containing strings to convert
target_field	N	Same as field	Target field to store lowercase result
fields	N	-	Array of fields to convert to lowercase
exclude	N	-	Array of fields to exclude from conversion
description	N	-	Explanatory note
if	N	-	Condition to run
ignore_failure	N	false	Continue processing if conversion fails
ignore_missing	N	false	Skip processing if referenced field doesn't exist
on_failure	N	-	See Handling Failures
on_success	N	-	See Handling Success
tag	N	-	Identifier

Details

The processor can handle both single strings and arrays of strings, applying the transformation to all elements.

The processor is useful for standardizing text fields and tags or categories, prepare fields such as emails addresses for case-insensitive comparisons

note

The processor maintains the original field structure: single strings remain single strings, and arrays remain arrays.

warning

Non-string values in the input field will cause processing errors unless ignore_failure is set to true.

Examples

Basic

Converting a single string...	{ "username": "JohnDoe" } - lowercase: field: username
transforms the element:	{ "username": "johndoe" }

Arrays

Converting an array of strings...	{ "tags": ["User", "Admin", "MANAGER"] } - lowercase: field: tags
transforms all elements:	{ "tags": ["user", "admin", "manager"] }

Keep Original

Storing the result in a new field...	{ "original": "HELLO WORLD" } - lowercase: field: original target_field: lowercase_text
preserves the original:	{ "original": "HELLO WORLD", "lowercase_text": "hello world" }

Conditionals

Using selection criteria...	{ "level": "DEBUG", "should_convert": true } - lowercase: field: level if: "ctx.should_convert == true"
converts only values that meet the condition:	{ "level": "debug", "should_convert": true }

Error Handling

Handling non-string values gracefully...	{ "id": 12345, "name": "USER" } - lowercase: field: id ignore_failure: true on_failure: - set: field: error value: "Non-string field encountered"
continues the execution:	{ "id": 12345, "name": "USER", "error": "Non-string field encountered" }