Processors - Lowercase - 《Elasticsearch v7.9 Reference》

Lowercase processor

Converts a string to its lowercase equivalent. If the field is an array of strings, all members of the array will be converted.

Table 27. Lowercase Options

Name	Required	Default	Description
`field`	yes	-	The field to make lowercase
`target_field`	no	`field`	The field to assign the converted value to, by default `field` is updated in-place
`ignore_missing`	no	`false`	If `true` and `field` does not exist or is `null`, the processor quietly exits without modifying the document
`if`	no	-	Conditionally execute this processor.
`on_failure`	no	-	Handle failures for this processor. See Handling Failures in Pipelines.
`ignore_failure`	no	`false`	Ignore failures for this processor. See Handling Failures in Pipelines.
`tag`	no	-	An identifier for this processor. Useful for debugging and metrics.

{
  "lowercase": {
    "field": "foo"
  }
}