Pipeline specified in a search request (ad hoc execution).

[macohen]

As a user of search pipelines I want to define a search pipeline on the fly in QueryDSL search request

[msfroh]

Copy/pasting the relevant snippet from the RFC:

// Specify an ad hoc search pipeline as part of a search request.
POST /my-index/_search

{
  "query" : {
    "match" : {
      "text_field" : "some search text"
    }
  },
  "pipeline" : {
    "request_processors" : [
      {
        "external_synonyms" : {
          "service_url" : "https://my-synonym-service/"
        }
      },
      {
        "ml_ranker_bracket" : {
          "result_oversampling" : 2, // Request 2 * size results
          "model_id" : "doc-features-20230109",
          "id" : "ml_ranker_identifier"
        }
      }
    ],
    "response_processors" : [
      {
        "result_blocker" : {
          "service_url" : "https://result-blocklist-service/"
        },
        "ml_ranker_bracket" : {
          // Placed here to indicate that it should run after result_blocker.
          // If not part of response_processors, it will run before result_blocker.
          "id" : "ml_ranker_identifier" 
        }
      }
    ]
  }
}