Elasticsearch: Add CreteCreateMessage which supports Elasticsearch op_type 'create'

[danelkotev]

op_type that can be used to force a create operation, allowing for "put-if-absent" behavior. When create is used, the index operation will fail if a document by that id already exists in the index.

Pull Request Checklist

• Have you read through the contributor guidelines and contributor advice?
• Have you signed the Lightbend CLA?
• Have you updated the documentation?
• Have you added tests for any changed functionality?

Fixes

Fixes #xxxx

Purpose

Add op_type 'create' which index only if not exists.

Background Context

Adding missing Elasticsearch supported option to create a document only if not exists.

References

https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-index_.html

[ennru]

Great addition. Just some other wording as "raising an error" sounds more like an exception being thrown.

[ennru]

LGTM.

[ennru]

Thank you for your contribution!

[tomerbendror]

Hi,

Just wanted to ask if you already known what the target release the next version

Thanks, Tomer

[ennru]

The release train has left the station: #1516
Expected arrival mid next week.

It includes a major make-over of Alpakka Elasticsearch.