opensearch-docs-cn/_data-prepper/pipelines/configuration/processors/copy-values.md

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copy_values

The copy_values processor copies values within an event and is a mutate event processor.

Configuration

You can configure the copy_values processor with the following options.

Option	Required	Description
entries	Yes	A list of entries to be copied in an event.
from_key	Yes	The key of the entry to be copied.
to_key	Yes	The key of the new entry to be added.
overwrite_if_key_exists	No	When set to true, the existing value is overwritten if key already exists in the event. The default value is false.

Usage

To get started, create the following pipeline.yaml file:

pipeline:
  source:
    ...
  ....  
  processor:
    - copy_values:
        entries:
        - from_key: "message"
          to_key: "newMessage"
          overwrite_if_to_key_exists: true
  sink:

{% include copy.html %}

Next, create a log file named logs_json.log and replace the path in the file source of your pipeline.yaml file with that filepath. For more information, see Configuring Data Prepper.

For example, before you run the copy_values processor, if the logs_json.log file contains the following event record:

{"message": "hello"}

When you run this processor, it parses the message into the following output:

{"message": "hello", "newMessage": "hello"}

If newMessage already exists, its existing value is overwritten with value.