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The add_entries processor adds entries to an event.


You can configure the add_entries processor with the following options.

Option Required Description
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.
metadata_key Yes The key for the new metadata attribute. The argument must be a literal string key and not a JSON Pointer. Either one string key or metadata_key is required.
format No A format string to use as the value of the new entry, for example, ${key1}-${key2}, where key1 and key2 are existing keys in the event. Required if neither value nor value_expression is specified.
value_expression No An expression string to use as the value of the new entry. For example, /key is an existing key in the event with a type of either a number, a string, or a Boolean. Expressions can also contain functions returning number/string/integer. For example, length(/key) will return the length of the key in the event when the key is a string. For more information about keys, see Expression syntax.
add_when No A conditional expression, such as /some-key == "test"', that will be evaluated to determine whether the processor will be run on the event.
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:

    - add_entries:
        - key: "newMessage"
          value: 3
          overwrite_if_key_exists: true
        - metadata_key: myMetadataKey
          value_expression: 'length("newMessage")'
          add_when: '/some_key == "test"'

For example, when your source contains the following event record:

{"message": "hello"}

And then you run the add_entries processor using the example pipeline, 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:

{"message": "hello", "newMessage": 3}

If newMessage already exists, its existing value is overwritten with a value of 3.

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