[Derived Fields] Add aggregation support for derived fields (opensear…

…ch-project#14618)

* Add aggregation support for derived fields

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* add unit test for a terms agg with derived fields

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* Fix license header and add changelog entry

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* move matrix_stats tests to aggs-matrix-stats module

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* Move matrix tests back and add dependency to painless module

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* add tests for all aggregations types and support ip_range

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* Add tests for agg script returned from DerivedFieldType

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* remove children aggs test as its not yet supported

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* Add more tests

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

* fix changelog

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

---------

Signed-off-by: Marc Handalian <marc.handalian@gmail.com>

CHANGELOG.md

@@ -33,6 +33,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Optimize Cluster Stats Indices to precomute node level stats ([#14426](https://github.com/opensearch-project/OpenSearch/pull/14426))
 - Add logic to create index templates (v2) using context field ([#14811](https://github.com/opensearch-project/OpenSearch/pull/14811))
 - Fix for hasInitiatedFetching to fix allocation explain and manual reroute APIs (([#14972](https://github.com/opensearch-project/OpenSearch/pull/14972))
+- Add basic aggregation support for derived fields ([#14618](https://github.com/opensearch-project/OpenSearch/pull/14618))
 - [Range Queries] Add new approximateable query framework to short-circuit range queries ([#13788](https://github.com/opensearch-project/OpenSearch/pull/13788))
 
 ### Dependencies

modules/lang-painless/build.gradle

@@ -46,6 +46,7 @@ ext {
 
 testClusters.all {
   module ':modules:mapper-extras'
+  module ':modules:aggs-matrix-stats'
   systemProperty 'opensearch.scripting.update.ctx_in_params', 'false'
   // TODO: remove this once cname is prepended to transport.publish_address by default in 8.0
   systemProperty 'opensearch.transport.cname_in_publish_address', 'true'