Append

Mutate Elastic Compatible

Synopsis

Appends one or more values to an array field.

Schema

- append:
    description: <text>
    field: <ident>
    value: <any>
    allow_duplicates: <boolean>
    if: <script>
    ignore_failure: <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		Field to append the value to
value	Y		The value to be appended
allow_duplicates	N	true	If false, only distinct values are appended
description	N	-	Explanatory notes
if	N	-	Condition to run
ignore_failure	N	false	See Handling Failures
on_failure	N	-	See Handling Failures
on_success	N	-	See Handling Success
tag	N	-	Identifier

Details

If the field exists and is an array, the operation is carried out. If the field exists and is a scalar, the field is converted to an array before the operation. If the field doesn't exist, an array is created containing the provided values.

note

The append processor can be combined with foreach to append values from another array field.

Examples

Basic Usage

When appending to a non-existent field...	{ "name": "document1" } - append: field: tags value: important
a new array is created:	{ "name": "document1", "tags": ["important"] }

Multiple Values

Multiple values can be appended at once...	{ "categories": ["books"] } - append: field: categories value: - magazines - newspapers
which extends the existing array:	{ "categories": ["books", "magazines", "newspapers"] }

Handling Duplicates

With allow_duplicates: false...	{ "tags": ["urgent", "important"] } - append: field: tags value: important allow_duplicates: false
duplicate values are skipped:	{ "tags": ["urgent", "important"] }

Converting Scalar to Array

When appending to a scalar field...	{ "status": "active" } - append: field: status value: pending
it's automatically converted to an array:	{ "status": ["active", "pending"] }

Using Templates

Template values can be used with mustache syntax...	{ "user_id": "12345", "roles": ["user"] } - append: field: roles value: "role_{{{user_id}}}"
which get evaluated during processing:	{ "user_id": "12345", "roles": ["user", "role_12345"] }