Add fields

The add_fields processor adds additional fields to the event. Fields can be scalar values, arrays, dictionaries, or any nested combination of these. The add_fields processor will overwrite the target field if it already exists. By default the fields that you specify will be grouped under the fields sub-dictionary in the event. To group the fields under a different sub-dictionary, use the target setting. To store the fields as top-level fields, set target: ''.

target: (Optional) Sub-dictionary to put all fields into. Defaults to fields. Setting this to @metadata will add values to the event metadata instead of fields.
fields: Fields to be added.

For example, this configuration:

 processors: - add_fields: target: project fields: name: myproject id: '574734885120952459'  

Adds these fields to any event:

{ "project": { "name": "myproject", "id": "574734885120952459" } }

This configuration will alter the event metadata:

processors: - add_fields: target: '@metadata' fields: op_type: "index"

When the event is ingested (e.g. by Elastisearch) the document will have op_type: "index" set as a metadata field.