rename-keys.md

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rename_keys

The rename_keys processor renames keys in an event.

Configuration

You can configure the rename_keys processor with the following options.

Option	Required	Description
entries	Yes	A list of event entries to rename.
from_key	Yes	The key of the entry to be renamed.
to_key	Yes	The new key of the entry.
overwrite_if_to_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:
    file:
      path: "/full/path/to/logs_json.log"
      record_type: "event"
      format: "json"
  processor:
    - rename_keys:
        entries:
        - from_key: "message"
          to_key: "newMessage"
          overwrite_if_to_key_exists: true
  sink:
    - stdout:

{% 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 rename_keys processor, if the logs_json.log file contains the following event record:

{"message": "hello"}

When you run the rename_keys processor, it parses the message into the following "newMessage" output:

{"newMessage": "hello"}

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

Special considerations

Renaming operations occur in the order that the key-value pair entries are listed in the pipeline.yaml file. This means that chaining (where key-value pairs are renamed in sequence) is implicit in the rename_keys processor. See the following example pipeline.yaml file:

pipeline:
  source:
    file:
      path: "/full/path/to/logs_json.log"
      record_type: "event"
      format: "json"
  processor:
    - rename_keys:
        entries:
        - from_key: "message"
          to_key: "message2"
        - from_key: "message2"
          to_key: "message3"
  sink:
    - stdout:

Add the following contents to the logs_json.log file:

{"message": "hello"}

{% include copy.html %}

After the rename_keys processor runs, the following output appears:

{"message3": "hello"}