Opensearch adding new value to the old one

OpenSearch
1

Versions (relevant - OpenSearch/Dashboard/Server OS/Browser):
opensearch 2.8.0

Describe the issue:
I have an opensearch and logstash stack; logstash sending logs from the base and i need to not just replace old values(that’s already works with method update in logstash and templates in opensearch), but adding new to them(something like concatenation).
Is it possible?

Configuration:

Relevant Logs or Screenshots:

2

You can use the update API of OpenSearch to append a value to an existing array field, like this:

POST test/_update/1
{
  "script": {
    "source": "ctx._source.tags.add(params.tag)",
    "lang": "painless",
    "params": {
      "tag": "blue"
    }
  }
}