| `entries` | Yes | A list of entries to add to an event. |
| `key` | Yes | The key of the new entry to be added. Some examples of keys include `my_key`, `myKey`, and `object/sub_Key`. |
| `value` | Yes | The value of the new entry to be added. You can use the following data types: strings, Booleans, numbers, null, nested objects, and arrays. |
| `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`. |
To get started, create the following `pipeline.yaml` file:
```yaml
pipeline:
source:
file:
path: "/full/path/to/logs_json.log"
record_type: "event"
format: "json"
processor:
- add_entries:
entries:
- key: "newMessage"
value: 3
overwrite_if_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]({{site.url}}{{site.baseurl}}/data-prepper/getting-started/#2-configuring-data-prepper).
For example, before you run the `add_entries` processor, if the `logs_json.log` file contains the following event record:
```json
{"message": "hello"}
```
Then when you run the `add_entries` processor using the previous configuration, it adds a new entry `{"newMessage": 3}` to the existing event `{"message": "hello"}` so that the new event contains two entries in the final output:
```json
{"message": "hello", "newMessage": 3}
```
> If `newMessage` already exists, its existing value is overwritten with a value of `3`.
