Optimistic Concurrency Control Support

[HDDTHR]

Is your feature request related to a problem? Please describe.
Although the Bulk API supports the if_seq_no and if_primary_term options for each document in the request below, the OpenSearch output plugin doesn't provide an option to set those values for the request.

POST _bulk
{"index":{"_index":"some-index","_id":"1", "if_seq_no": 100 "if_primary_term": 20 }}
{"amount": 500 }

Describe the solution you'd like
Adding two new options to support Optimistic Concurrency Control for the output plugin. It could look like this.

        opensearch {
            id => "os-output"
            hosts => "..."
            user => "..."
            password => "..."
            index => "some-index"
            document_id => "..."
            sequence_number => "[@metadata][_seq_no]"
            primary_term => "[@metadata][_seq_no]"
        }

Describe alternatives you've considered
I had to figure out a workaround, where I fetch the _version field alongside the document from OpenSearch, manually increment it by 1, and configure my output plugin as shown below.

        opensearch {
            id => "os-output"
            hosts => "..."
            user => "..."
            password => "..."
            index => "some-index"
            document_id => "..."
            version => "%{[@metadata][_version]}"
            version_type => "external"
        }

While this does work, I would rather not have to manage my version externally (and introduce unnecessary points of failure), as the only logic I need is to update the document in OpenSearch if there hasn't been any updates while the pipeline is running.

[krisfreedain]

Catch All Triage - 1 2