Add inference processor

src/Nest/Ingest/ProcessorFormatter.cs

@@ -42,6 +42,7 @@ internal class ProcessorFormatter : IJsonFormatter<IProcessor>
 			{ "circle", 30 },
 			{ "enrich", 31 },
 			{ "csv", 32 },
+			{ "inference", 33 },
 		};
 
 		public IProcessor Deserialize(ref JsonReader reader, IJsonFormatterResolver formatterResolver)
@@ -161,6 +162,9 @@ public IProcessor Deserialize(ref JsonReader reader, IJsonFormatterResolver form
 					case 32:
 						processor = Deserialize<CsvProcessor>(ref reader, formatterResolver);
 						break;
+					case 33:
+						processor = Deserialize<InferenceProcessor>(ref reader, formatterResolver);
+						break;
 				}
 			}
 			else
@@ -230,6 +234,9 @@ public void Serialize(ref JsonWriter writer, IProcessor value, IJsonFormatterRes
 				case "gsub":
 					Serialize<IGsubProcessor>(ref writer, value, formatterResolver);
 					break;
+				case "inference":
+					Serialize<IInferenceProcessor>(ref writer, value, formatterResolver);
+					break;
 				case "join":
 					Serialize<IJoinProcessor>(ref writer, value, formatterResolver);
 					break;

src/Nest/Ingest/Processors/InferenceProcessor.cs

@@ -0,0 +1,219 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+using System.Runtime.Serialization;
+using Elasticsearch.Net;
+using Elasticsearch.Net.Utf8Json;
+using Nest;
+
+namespace Nest
+{
+	/// <summary>
+	/// Uses a pre-trained data frame analytics model to infer against the data that is being ingested in the pipeline.
+	/// <para />
+	/// Available in Elasticsearch 7.6.0+ with at least basic license.
+	/// </summary>
+	[InterfaceDataContract]
+	public interface IInferenceProcessor : IProcessor
+	{
+		/// <summary>
+		/// The ID of the model to load and infer against.
+		/// </summary>
+		[DataMember(Name = "model_id")]
+		string ModelId { get; set; }
+
+		/// <summary>
+		/// Field added to incoming documents to contain results objects.
+		/// </summary>
+		[DataMember(Name ="target_field")]
+		Field TargetField { get; set; }
+
+		/// <summary>
+		/// Maps the document field names to the known field names of the model.
+		/// </summary>
+		[DataMember(Name = "field_mappings")]
+		IDictionary<Field, Field> FieldMappings { get; set; }
+
+		/// <summary>
+		/// Contains the inference type and its options.
+		/// </summary>
+		[DataMember(Name = "inference_config")]
+		IInferenceConfig InferenceConfig { get; set; }
+	}
+
+	/// <inheritdoc cref="IInferenceProcessor" />
+	public class InferenceProcessor : ProcessorBase, IInferenceProcessor
+	{
+		/// <inheritdoc />
+		public string ModelId { get; set; }
+
+		/// <inheritdoc />
+		public Field TargetField { get; set; }
+
+		/// <inheritdoc />
+		public IDictionary<Field, Field> FieldMappings { get; set; }
+
+		/// <inheritdoc />
+		public IInferenceConfig InferenceConfig { get; set; }
+
+		protected override string Name => "inference";
+	}
+
+	/// <inheritdoc cref="IInferenceProcessor" />
+	public class InferenceProcessorDescriptor<T>
+		: ProcessorDescriptorBase<InferenceProcessorDescriptor<T>, IInferenceProcessor>, IInferenceProcessor
+		where T : class
+	{
+		protected override string Name => "inference";
+
+		Field IInferenceProcessor.TargetField { get; set; }
+		string IInferenceProcessor.ModelId { get; set; }
+		IInferenceConfig IInferenceProcessor.InferenceConfig { get; set; }
+		IDictionary<Field, Field> IInferenceProcessor.FieldMappings { get; set; }
+
+		/// <inheritdoc cref="IInferenceProcessor.TargetField" />
+		public InferenceProcessorDescriptor<T> TargetField(Field field) => Assign(field, (a, v) => a.TargetField = v);
+
+		/// <inheritdoc cref="IInferenceProcessor.TargetField" />
+		public InferenceProcessorDescriptor<T> TargetField<TValue>(Expression<Func<T, TValue>> objectPath) =>
+			Assign(objectPath, (a, v) => a.TargetField = v);
+
+		/// <inheritdoc cref="IInferenceProcessor.ModelId" />
+		public InferenceProcessorDescriptor<T> ModelId(string modelId) =>
+			Assign(modelId, (a, v) => a.ModelId = v);
+
+		/// <inheritdoc cref="IInferenceProcessor.ModelId" />
+		public InferenceProcessorDescriptor<T> InferenceConfig(Func<InferenceConfigDescriptor<T>, IInferenceConfig> selector) =>
+			Assign(selector, (a, v) => a.InferenceConfig = v.InvokeOrDefault(new InferenceConfigDescriptor<T>()));
+
+		/// <inheritdoc cref="IInferenceProcessor.FieldMappings" />
+		public InferenceProcessorDescriptor<T> FieldMappings(Func<FluentDictionary<Field, Field>, FluentDictionary<Field, Field>> selector = null) =>
+			Assign(selector, (a, v) => a.FieldMappings = v.InvokeOrDefault(new FluentDictionary<Field, Field>()));
+	}
+
+	[ReadAs(typeof(InferenceConfig))]
+	public interface IInferenceConfig
+	{
+
+		[DataMember(Name = "regression")]
+		IRegressionInferenceConfig Regression { get; set; }
+
+		[DataMember(Name = "classification")]
+		IClassificationInferenceConfig Classification { get; set; }
+	}
+
+	public class InferenceConfig
+		: IInferenceConfig
+	{
+		public IRegressionInferenceConfig Regression { get; set; }
+
+		public IClassificationInferenceConfig Classification { get; set; }
+	}
+
+	public class InferenceConfigDescriptor<T> : DescriptorBase<InferenceConfigDescriptor<T>, IInferenceConfig>, IInferenceConfig
+	{
+		IRegressionInferenceConfig IInferenceConfig.Regression { get; set; }
+		IClassificationInferenceConfig IInferenceConfig.Classification { get; set; }
+
+		public InferenceConfigDescriptor<T> Regression(Func<RegressionInferenceConfigDescriptor<T>, IRegressionInferenceConfig> selector) =>
+			Assign(selector, (a, v) => a.Regression = v.InvokeOrDefault(new RegressionInferenceConfigDescriptor<T>()));
+
+		public InferenceConfigDescriptor<T> Classification(Func<ClassificationInferenceConfigDescriptor<T>, IClassificationInferenceConfig> selector) =>
+			Assign(selector, (a, v) => a.Classification = v.InvokeOrDefault(new ClassificationInferenceConfigDescriptor<T>()));
+	}
+
+	[ReadAs(typeof(RegressionInferenceConfig))]
+	public interface IRegressionInferenceConfig
+	{
+		/// <summary>
+		/// Specifies the field to which the inference prediction is written. Defaults to <c>predicted_value</c>.
+		/// </summary>
+		[DataMember(Name = "results_field")]
+		Field ResultsField { get; set; }
+	}
+
+	public class RegressionInferenceConfig : IRegressionInferenceConfig
+	{
+		/// <summary>
+		/// Specifies the field to which the inference prediction is written. Defaults to <c>predicted_value</c>.
+		/// </summary>
+		public Field ResultsField { get; set; }
+	}
+
+	public class RegressionInferenceConfigDescriptor<T>
+		: DescriptorBase<RegressionInferenceConfigDescriptor<T>, IRegressionInferenceConfig>, IRegressionInferenceConfig
+	{
+		Field IRegressionInferenceConfig.ResultsField { get; set; }
+
+		/// <inheritdoc cref="IRegressionInferenceConfig.ResultsField" />
+		public RegressionInferenceConfigDescriptor<T> ResultsField(Field field) => Assign(field, (a, v) => a.ResultsField = v);
+
+		/// <inheritdoc cref="IRegressionInferenceConfig.ResultsField" />
+		public RegressionInferenceConfigDescriptor<T> ResultsField<TValue>(Expression<Func<T, TValue>> objectPath) =>
+			Assign(objectPath, (a, v) => a.ResultsField = v);
+	}
+
+	[ReadAs(typeof(ClassificationInferenceConfig))]
+	public interface IClassificationInferenceConfig
+	{
+		/// <summary>
+		/// Specifies the field to which the inference prediction is written. Defaults to <c>predicted_value</c>.
+		/// </summary>
+		[DataMember(Name = "results_field")]
+		Field ResultsField { get; set; }
+
+		/// <summary>
+		/// Specifies the number of top class predictions to return. Defaults to <c>0</c>.
+		/// </summary>
+		[DataMember(Name = "num_top_classes")]
+		int? NumTopClasses { get; set; }
+
+		/// <summary>
+		/// Specifies the field to which the top classes are written. Defaults to <c>top_classes</c>.
+		/// </summary>
+		[DataMember(Name = "top_classes_results_field")]
+		Field TopClassesResultsField { get; set; }
+	}
+
+	public class ClassificationInferenceConfig : IClassificationInferenceConfig
+	{
+		/// <summary>
+		/// Specifies the field to which the inference prediction is written. Defaults to <c>predicted_value</c>.
+		/// </summary>
+		public Field ResultsField { get; set; }
+
+		/// <summary>
+		/// Specifies the number of top class predictions to return. Defaults to <c>0</c>.
+		/// </summary>
+		public int? NumTopClasses { get; set; }
+
+		/// <summary>
+		/// Specifies the field to which the top classes are written. Defaults to <c>top_classes</c>.
+		/// </summary>
+		public Field TopClassesResultsField { get; set; }
+	}
+
+	public class ClassificationInferenceConfigDescriptor<T> : DescriptorBase<ClassificationInferenceConfigDescriptor<T>, IClassificationInferenceConfig>, IClassificationInferenceConfig
+	{
+		Field IClassificationInferenceConfig.ResultsField { get; set; }
+		int? IClassificationInferenceConfig.NumTopClasses { get; set; }
+		Field IClassificationInferenceConfig.TopClassesResultsField { get; set; }
+
+		/// <inheritdoc cref="IClassificationInferenceConfig.ResultsField" />
+		public ClassificationInferenceConfigDescriptor<T> ResultsField(Field field) => Assign(field, (a, v) => a.ResultsField = v);
+
+		/// <inheritdoc cref="IClassificationInferenceConfig.ResultsField" />
+		public ClassificationInferenceConfigDescriptor<T> ResultsField<TValue>(Expression<Func<T, TValue>> objectPath) =>
+			Assign(objectPath, (a, v) => a.ResultsField = v);
+
+		/// <inheritdoc cref="IClassificationInferenceConfig.NumTopClasses" />
+		public ClassificationInferenceConfigDescriptor<T> NumTopClasses(int? numTopClasses) => Assign(numTopClasses, (a, v) => a.NumTopClasses = v);
+
+		/// <inheritdoc cref="IClassificationInferenceConfig.TopClassesResultsField" />
+		public ClassificationInferenceConfigDescriptor<T> TopClassesResultsField(Field field) => Assign(field, (a, v) => a.TopClassesResultsField = v);
+
+		/// <inheritdoc cref="IClassificationInferenceConfig.TopClassesResultsField" />
+		public ClassificationInferenceConfigDescriptor<T> TopClassesResultsField<TValue>(Expression<Func<T, TValue>> objectPath) =>
+			Assign(objectPath, (a, v) => a.TopClassesResultsField = v);
+	}
+}

src/Nest/Ingest/ProcessorsDescriptor.cs

@@ -79,6 +79,10 @@ public ProcessorsDescriptor Grok<T>(Func<GrokProcessorDescriptor<T>, IGrokProces
 		public ProcessorsDescriptor Gsub<T>(Func<GsubProcessorDescriptor<T>, IGsubProcessor> selector) where T : class =>
 			Assign(selector, (a, v) => a.AddIfNotNull(v?.Invoke(new GsubProcessorDescriptor<T>())));
 
+		/// <inheritdoc cref="IInferenceProcessor"/>
+		public ProcessorsDescriptor Inference<T>(Func<InferenceProcessorDescriptor<T>, IInferenceProcessor> selector) where T : class =>
+			Assign(selector, (a, v) => a.AddIfNotNull(v?.Invoke(new InferenceProcessorDescriptor<T>())));
+
 		/// <inheritdoc cref="IJoinProcessor"/>
 		public ProcessorsDescriptor Join<T>(Func<JoinProcessorDescriptor<T>, IJoinProcessor> selector) where T : class =>
 			Assign(selector, (a, v) => a.AddIfNotNull(v?.Invoke(new JoinProcessorDescriptor<T>())));

tests/Tests/Ingest/ProcessorAssertions.cs

@@ -27,7 +27,6 @@ public abstract class ProcessorAssertion : IProcessorAssertion
 		public abstract string Key { get; }
 	}
 
-
 	public static class ProcessorAssertions
 	{
 		public static IEnumerable<IProcessorAssertion> All =>
@@ -279,6 +278,58 @@ public class Gsub : ProcessorAssertion
 			public override string Key => "gsub";
 		}
 
+		[SkipVersion("<7.6.0", "Introduced in Elasticsearch 7.6.0+")]
+		public class Inference : ProcessorAssertion
+		{
+			public override Func<ProcessorsDescriptor, IPromise<IList<IProcessor>>> Fluent => d => d
+				.Inference<Project>(c => c
+					.TargetField(p => p.Name)
+					.ModelId("model_id")
+					.FieldMappings()
+					.InferenceConfig(i => i
+						.Classification(cc => cc
+							.ResultsField("results")
+							.NumTopClasses(10)
+							.TopClassesResultsField("topClasses")
+						)
+					)
+				);
+
+			public override IProcessor Initializer => new InferenceProcessor
+			{
+				TargetField = "name",
+				ModelId = "model_id",
+				FieldMappings = new Dictionary<Field, Field>(),
+				InferenceConfig = new InferenceConfig
+				{
+					Classification = new ClassificationInferenceConfig
+					{
+						ResultsField = "results",
+						NumTopClasses = 10,
+						TopClassesResultsField = "topClasses"
+					}
+				}
+			};
+
+			public override object Json => new
+			{
+				target_field = "name",
+				model_id = "model_id",
+				field_mappings = new {},
+				inference_config = new
+				{
+					classification = new
+					{
+						results_field = "results",
+						num_top_classes = 10,
+						top_classes_results_field = "topClasses"
+					}
+				}
+			};
+
+			public override string Key => "inference";
+		}
+
 		public class Join : ProcessorAssertion
 		{
 			public override Func<ProcessorsDescriptor, IPromise<IList<IProcessor>>> Fluent =>