82 lines
2.4 KiB
Plaintext
82 lines
2.4 KiB
Plaintext
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[[painless-bucket-selector-agg-context]]
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=== Bucket selector aggregation context
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Use a Painless script in an
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{ref}/search-aggregations-pipeline-bucket-selector-aggregation.html[`bucket_selector` aggregation]
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to determine if a bucket should be retained or filtered out.
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==== Variables
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`params` (`Map`, read-only)::
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User-defined parameters passed in as part of the query. The parameters
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include values defined as part of the `buckets_path`.
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==== Return
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boolean::
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True if the bucket should be retained, false if the bucket should be filtered out.
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==== API
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To run this example, first follow the steps in <<painless-context-examples, context examples>>.
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The painless context in a `bucket_selector` aggregation provides a `params` map. This map contains both
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user-specified custom values, as well as the values from other aggregations specified in the `buckets_path`
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property.
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Unlike some other aggregation contexts, the `bucket_selector` context must return a boolean `true` or `false`.
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This example finds the max of each bucket, adds a user-specified base_cost, and retains all of the
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buckets that are greater than `10`.
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[source,Painless]
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--------------------------------------------------
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params.max + params.base_cost > 10
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--------------------------------------------------
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Note that the values are extracted from the `params` map. The script is in the form of an expression
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that returns `true` or `false`. In context, the aggregation looks like this:
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[source,console]
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--------------------------------------------------
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GET /seats/_search
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{
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"size": 0,
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"aggs": {
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"theatres": {
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"terms": {
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"field": "theatre",
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"size": 10
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},
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"aggs": {
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"max_cost": {
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"max": {
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"field": "cost"
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}
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},
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"filtering_agg": {
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"bucket_selector": {
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"buckets_path": { <1>
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"max": "max_cost"
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},
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"script": {
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"params": {
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"base_cost": 5 <2>
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},
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"source": "params.max + params.base_cost > 10"
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}
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}
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}
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}
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}
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}
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}
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--------------------------------------------------
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// TEST[setup:seats]
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<1> The `buckets_path` points to the max aggregations (`max_cost`) and adds `max` variables
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to the `params` map
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<2> The user-specified `base_cost` is also added to the `params` map
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