elasticsearch/docs/reference/enrich-processor/append-processor.md

navigation_title	mapped_pages
Append	https://www.elastic.co/guide/en/elasticsearch/reference/current/append-processor.html

Append processor [append-processor]

Appends one or more values to an existing array if the field already exists and it is an array. Converts a scalar to an array and appends one or more values to it if the field exists and it is a scalar. Creates an array containing the provided values if the field doesn’t exist. Accepts a single value or an array of values.

$append-options

Name	Required	Default	Description
field	yes	-	The field to be appended to. Supports template snippets.
value	yes	-	The value to be appended. Supports template snippets.
allow_duplicates	no	true	If false, the processor does not appendvalues already present in the field.
media_type	no	application/json	The media type for encoding value. Applies only when value is atemplate snippet. Must be one of application/json, text/plain, orapplication/x-www-form-urlencoded.
description	no	-	Description of the processor. Useful for describing the purpose of the processor or its configuration.
if	no	-	Conditionally execute the processor. See Conditionally run a processor.
ignore_failure	no	false	Ignore failures for the processor. See Handling pipeline failures.
on_failure	no	-	Handle failures for the processor. See Handling pipeline failures.
tag	no	-	Identifier for the processor. Useful for debugging and metrics.

{
  "append": {
    "field": "tags",
    "value": ["production", "{{{app}}}", "{{{owner}}}"]
  }
}