Bucket selector aggregation context

To run this example, first follow the steps in context examples.

The painless context in a bucket_selector aggregation provides a params map. This map contains both user-specified custom values, as well as the values from other aggregations specified in the buckets_path property.

Unlike some other aggregation contexts, the bucket_selector context must return a boolean true or false.

This example finds the max of each bucket, adds a user-specified base_cost, and retains all of the buckets that are greater than 10.

params.max + params.base_cost > 10

Note that the values are extracted from the params map. The script is in the form of an expression that returns true or false. In context, the aggregation looks like this:

GET /seats/_search
{
  "size": 0,
  "aggs": {
    "theatres": {
      "terms": {
        "field": "theatre",
        "size": 10
      },
      "aggs": {
        "max_cost": {
          "max": {
            "field": "cost"
          }
        },
        "filtering_agg": {
          "bucket_selector": {
            "buckets_path": { 
              "max": "max_cost"
            },
            "script": {
              "params": {
                "base_cost": 5 
              },
              "source": "params.max + params.base_cost > 10"
            }
          }
        }
      }
    }
  }
}