Add geotile_grid transform group by (#4917) (#4938)

Relates: elastic/elasticsearch#56514

Co-authored-by: Russ Cam <russ.cam@elastic.co>

src/Nest/XPack/Transform/Pivot/GeoTileGridGroupSource.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Runtime.Serialization;
+using Elasticsearch.Net.Utf8Json;
+
+namespace Nest
+{
+	/// <summary>
+	/// The geotile grid value source works on geo_point fields and groups points into buckets that represent
+	/// cells in a grid. The resulting grid can be sparse and only contains cells that have matching data.
+	/// <para />
+	/// Available in Elasticsearch 7.9.0+
+	/// </summary>
+	[InterfaceDataContract]
+	public interface IGeoTileGridGroupSource : ISingleGroupSource
+	{
+		/// <summary>
+		/// The highest-precision geotile of length 29 produces cells that cover less than 10cm by 10cm of land.
+		/// This precision is uniquely suited for composite aggregations as each tile does not have to be
+		/// generated and loaded in memory.
+		/// </summary>
+		[DataMember(Name = "precision")]
+		GeoTilePrecision? Precision { get; set; }
+
+		/// <summary>
+		/// Constrained to a specific geo bounding box, which reduces the range of tiles used.
+		/// These bounds are useful when only a specific part of a geographical area needs high precision tiling.
+		/// <para />
+		/// Available in Elasticsearch 7.6.0+.
+		/// </summary>
+		[DataMember(Name = "bounds")]
+		IBoundingBox Bounds { get; set; }
+	}
+
+	/// <inheritdoc cref="IGeoTileGridGroupSource" />
+	public class GeoTileGridGroupSource : SingleGroupSourceBase, IGeoTileGridGroupSource
+	{
+		/// <inheritdoc />
+		public GeoTilePrecision? Precision { get; set; }
+		/// <inheritdoc />
+		public IBoundingBox Bounds { get; set; }
+	}
+
+	/// <inheritdoc cref="IGeoTileGridGroupSource" />
+	public class GeoTileGridGroupSourceDescriptor<T>
+		: SingleGroupSourceDescriptorBase<GeoTileGridGroupSourceDescriptor<T>, IGeoTileGridGroupSource, T>,
+			IGeoTileGridGroupSource
+	{
+		GeoTilePrecision? IGeoTileGridGroupSource.Precision { get; set; }
+		IBoundingBox IGeoTileGridGroupSource.Bounds { get; set; }
+
+		/// <inheritdoc cref="IGeoTileGridGroupSource.Precision"/>
+		public GeoTileGridGroupSourceDescriptor<T> Precision(GeoTilePrecision? precision) =>
+			Assign(precision, (a, v) => a.Precision = v);
+
+		/// <inheritdoc cref="IGeoTileGridGroupSource.Bounds"/>
+		public GeoTileGridGroupSourceDescriptor<T> Bounds(Func<BoundingBoxDescriptor, IBoundingBox> selector) =>
+			Assign(selector, (a, v) => a.Bounds = v?.Invoke(new BoundingBoxDescriptor()));
+	}
+}

src/Nest/XPack/Transform/Pivot/SingleGroupSource.cs

@@ -86,6 +86,12 @@ public SingleGroupSourcesDescriptor<T> DateHistogram(string name,
 			Func<DateHistogramGroupSourceDescriptor<T>, IDateHistogramGroupSource> selector
 		) =>
 			Assign(new Tuple<string, IDateHistogramGroupSource>(name, selector?.Invoke(new DateHistogramGroupSourceDescriptor<T>())), (a, v) => a.Add(v.Item1, v.Item2));
+
+		/// <inheritdoc cref="IGeoTileGridGroupSource" />
+		public SingleGroupSourcesDescriptor<T> GeoTileGrid(string name,
+			Func<GeoTileGridGroupSourceDescriptor<T>, IGeoTileGridGroupSource> selector
+		) =>
+			Assign(new Tuple<string, IGeoTileGridGroupSource>(name, selector?.Invoke(new GeoTileGridGroupSourceDescriptor<T>())), (a, v) => a.Add(v.Item1, v.Item2));
 	}
 
 	internal class SingleGroupSourceFormatter : IJsonFormatter<ISingleGroupSource>
@@ -95,6 +101,7 @@ internal class SingleGroupSourceFormatter : IJsonFormatter<ISingleGroupSource>
 			{ "terms", 0 },
 			{ "date_histogram", 1 },
 			{ "histogram", 2 },
+			{ "geotile_grid", 3 },
 		};
 
 		public void Serialize(ref JsonWriter writer, ISingleGroupSource value, IJsonFormatterResolver formatterResolver)
@@ -121,6 +128,10 @@ public void Serialize(ref JsonWriter writer, ISingleGroupSource value, IJsonForm
 					writer.WritePropertyName("histogram");
 					Serialize(ref writer, histogramGroupSource, formatterResolver);
 					break;
+				case IGeoTileGridGroupSource geoTileGridGroupSource:
+					writer.WritePropertyName("geotile_grid");
+					Serialize(ref writer, geoTileGridGroupSource, formatterResolver);
+					break;
 				default:
 					throw new JsonParsingException($"Unknown {nameof(ISingleGroupSource)}: {value.GetType().Name}");
 			}
@@ -164,6 +175,10 @@ public ISingleGroupSource Deserialize(ref JsonReader reader, IJsonFormatterResol
 						groupSource = formatterResolver.GetFormatter<HistogramGroupSource>()
 							.Deserialize(ref reader, formatterResolver);
 						break;
+					case 3:
+						groupSource = formatterResolver.GetFormatter<GeoTileGridGroupSource>()
+							.Deserialize(ref reader, formatterResolver);
+						break;
 				}
 			}
 			else

tests/Tests/XPack/Transform/TransformApiTests.cs

@@ -13,7 +13,7 @@
 
 namespace Tests.XPack.Transform
 {
-	[SkipVersion("<7.7.0", "Introduced in 7.7.0")]
+	[SkipVersion("<7.9.0", "Geotile grid group by introduced in 7.9.0")]
 	public class TransformApiTests : CoordinatedIntegrationTestBase<WritableCluster>
 	{
 		private const string PutTransformStep = nameof(PutTransformStep);
@@ -61,6 +61,18 @@ public TransformApiTests(WritableCluster cluster, EndpointUsage usage) : base(ne
 											Field = Field<Project>(f => f.StartedOn),
 											CalendarInterval = DateInterval.Week
 										}
+									},
+									{
+										"geotile", new GeoTileGridGroupSource
+										{
+											Field = Field<Project>(f => f.LocationPoint),
+											Precision = GeoTilePrecision.Precision6,
+											Bounds = new BoundingBox
+											{
+												TopLeft = new GeoLocation(-90, 180),
+												BottomRight = new GeoLocation(90, -180)
+											}
+										}
 									}
 								}
 							}
@@ -92,6 +104,14 @@ public TransformApiTests(WritableCluster cluster, EndpointUsage usage) : base(ne
 										.Field(f => f.StartedOn)
 										.CalendarInterval(DateInterval.Week)
 									)
+									.GeoTileGrid("geotile", gtg => gtg
+										.Field(f => f.LocationPoint)
+										.Precision(GeoTilePrecision.Precision6)
+										.Bounds(b => b
+											.TopLeft(-90, 180)
+											.BottomRight(90, -180)
+										)
+									)
 								)
 							),
 						(v, c, f) => c.Transform.Put(v, f),