Query rules retriever

[kderusso]

Example script to demonstrate:

PUT my-index/_doc/id1
{
  "text": "ID1 - pinned doc for foo"
}

PUT my-index/_doc/id2
{
  "text": "ID2 - exclude doc for bar"
}

PUT my-index/_doc/id3
{
  "text": "ID3 - baz, no rule attached"
}

PUT /_query_rules/my-ruleset
{
  "rules": [
    {
      "rule_id": "rule1",
      "type": "pinned",
      "criteria": [
        {
          "type": "exact",
          "metadata": "foo",
          "values": [ "foo" ]
        }
      ],
      "actions": {
        "ids": [
          "id1"
        ]
      }
    },
    {
      "rule_id": "rule2",
      "type": "exclude",
      "criteria": [
        {
          "type": "exact",
          "metadata": "bar",
          "values": [ "bar" ]
        }
      ],
      "actions": {
        "ids": [
          "id2"
        ]
      }
    }
  ]
}

GET my-index/_search
{
  "retriever": {
    "rule": {
      "match_criteria": {
        "foo": "foo",
        "bar": "bar"
      },
      "ruleset_ids": [
        "my-ruleset"
      ],
      "retriever": {
        "standard": {
          "query": {
            "query_string": {
              "query": "bar"
            }
          }
        }
      }
    }
  },
  "explain": true
}

GET my-index/_search
{
  "retriever": {
    "rule": {
      "match_criteria": {
        "foo": "foo",
        "bar": "bar"
      },
      "ruleset_ids": [
        "my-ruleset"
      ],
      "retriever": {
        "rrf": {
          "retrievers": [
            {
              "standard": {
                "query": {
                  "query_string": {
                    "query": "bar"
                  }
                }
              }
            },
            {
              "standard": {
                "query": {
                  "query_string": {
                    "query": "baz"
                  }
                }
              }
            }
          ]
        }
      }
    }
  }
}

[kderusso]

@elasticmachine merge upstream

[kderusso]

@elasticmachine update branch

[pmpailis]

Thanks @kderusso ! Some minor comments only, but this looks good!

[jimczi]

Thanks @kderusso
I left more comments.
We also need a test that extends AbstractXContentTestCase<QueryRuleRetrieverBuilder> to validate the rest parsing.

[pmpailis]

LGTM!

[jimczi]

LGTM

[elasticsearchmachine]

💔 Backport failed

Status	Branch	Result
❌	8.x	Commit could not be cherrypicked due to conflicts

You can use sqren/backport to manually backport by running backport --upstream elastic/elasticsearch --pr 114855