[FEATURE] java-client should support FunctionScore with MatchTermQuery

[m-hofmann]

We are trying to use java-client 2.6.0 to build a function score query boosting specific hits on fields. Our query JSON looks like this:

{
  "from": 0,
  "size": 20,
  "query": {
    "function_score": {
      "query": {
        "bool": {
          "should": [
            {
              "match": {
                "some_field": "1234"
              }
            }
          ],
          "minimum_should_match": 1
        }
      },
      "boost_mode": "multiply",
      "score_mode": "sum",
      "functions": [
        {
          "filter": {
            "match": {
              "some_field": "1234"
            }
          },
          "weight": 2
        }
      ]
    }
  }
}

unfortunately the java-client seems to support only specific function "kinds" for the functions block, like random_score or script_score. When we try to instantiate a query using the Java DSL that looks like the above snippet:

FunctionScore functionScore = new FunctionScore.Builder()
   .new ContainerBuilder()
   .filter(query)
   .weight(10.0)
   .build();

an exception org.opensearch.client.util.MissingRequiredPropertyException: Missing required property 'Builder.<variant kind> will be thrown.

What solution would you like?

Being able to build a function object combining a (match)query with a weight.

What alternatives have you considered?

We tried to disable API warnings using ApiTypeHelper.DANGEROUS_disableRequiredPropertiesCheck(true) but then serialization of the request in the search client fails.

Therefore we're switching back to the REST highlevel client for now.

[jmontgomery-wbd]

any updates on this? this is a pretty big miss....

[dblock]

@jmontgomery-wbd AFAIK nobody is working on this, care to help?

[jmontgomery-wbd]

@dblock it seems like there is a lot of red tape around contributing. I just pulled and made an update and it seems to have fixed it:

how can we properly test and merge that?

[dblock]

@jmontgomery-wbd No tape. Just make a pull request with a passing test that wasn't passing before.

[brianyee-fanatics]

Also looking for this feature.

[VachaShah]

This feature was added in PR #880 and will be released in the upcoming version. Currently the change is available to consume in 2.10.0-SNAPSHOT.