Fix #3320 Add Painless script execute API (#3370)

* Generate ExcecutePainlessScript methods/descriptors etc

* Implement ExecutePainlessScript API with tests

Omitting `context` for now since that only takes a single option now
which is also the default. Waiting for the API to crystalize here.

* make Result generic in preparation for 6.4

Author: Mpdreamz

src/CodeGeneration/ApiGenerator/ApiGenerator.cs

@@ -57,7 +57,32 @@ public static void Generate(string downloadBranch, params string[] folders)
 			"xpack.ml.delete_filter.json",
 			"xpack.ml.get_filters.json",
 			"xpack.ml.put_filter.json",
-			"rank_eval.json"
+			"rank_eval.json",
+			// these API's are new and need to be mapped
+			"xpack.license.get_basic_status.json",
+			"xpack.license.post_start_basic.json",
+			"xpack.ml.delete_calendar.json",
+			"xpack.ml.delete_calendar_event.json",
+			"xpack.ml.delete_calendar_job.json",
+			"xpack.ml.get_calendar_events.json",
+			"xpack.ml.get_calendars.json",
+			"xpack.ml.info.json",
+			"xpack.ml.post_calendar_events.json",
+			"xpack.ml.put_calendar.json",
+			"xpack.ml.put_calendar_job.json",
+			"xpack.ml.get_calendar_job.json",
+
+			"xpack.rollup.delete_job.json",
+			"xpack.rollup.get_jobs.json",
+			"xpack.rollup.get_rollup_caps.json",
+			"xpack.rollup.put_job.json",
+			"xpack.rollup.rollup_search.json",
+			"xpack.rollup.start_job.json",
+			"xpack.rollup.stop_job.json",
+			"xpack.sql.clear_cursor.json",
+			"xpack.sql.query.json",
+			"xpack.sql.translate.json",
+			"xpack.ssl.certificates.json",
 		};
 
 		private static RestApiSpec CreateRestApiSpecModel(string downloadBranch, string[] folders)

src/Elasticsearch.Net/Domain/RequestParameters/RequestParameters.Generated.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Threading.Tasks;
+using Elasticsearch.Net;
+using System.Threading;
+
+namespace Nest
+{
+	public partial interface IElasticClient
+	{
+		/// <summary>
+		/// Executes an arbitrary Painless script and returns a result.
+		/// Useful for testing the syntactical correctness of Painless scripts
+		/// </summary>
+		IExecutePainlessScriptResponse<TResult> ExecutePainlessScript<TResult>(Func<ExecutePainlessScriptDescriptor, IExecutePainlessScriptRequest> selector);
+
+		/// <inheritdoc cref="ExecutePainlessScript{TResult}(System.Func{Nest.ExecutePainlessScriptDescriptor,Nest.IExecutePainlessScriptRequest})"/>
+		IExecutePainlessScriptResponse<TResult> ExecutePainlessScript<TResult>(IExecutePainlessScriptRequest request);
+
+		/// <inheritdoc cref="ExecutePainlessScript{TResult}(System.Func{Nest.ExecutePainlessScriptDescriptor,Nest.IExecutePainlessScriptRequest})"/>
+		Task<IExecutePainlessScriptResponse<TResult>> ExecutePainlessScriptAsync<TResult>(Func<ExecutePainlessScriptDescriptor, IExecutePainlessScriptRequest> selector,
+			CancellationToken cancellationToken = default(CancellationToken));
+
+		/// <inheritdoc cref="ExecutePainlessScript{TResult}(System.Func{Nest.ExecutePainlessScriptDescriptor,Nest.IExecutePainlessScriptRequest})"/>
+		Task<IExecutePainlessScriptResponse<TResult>> ExecutePainlessScriptAsync<TResult>(IExecutePainlessScriptRequest request, CancellationToken cancellationToken = default(CancellationToken));
+
+	}
+
+	public partial class ElasticClient
+	{
+		/// <inheritdoc />
+		public IExecutePainlessScriptResponse<TResult> ExecutePainlessScript<TResult>(Func<ExecutePainlessScriptDescriptor, IExecutePainlessScriptRequest> selector) =>
+			this.ExecutePainlessScript<TResult>(selector?.Invoke(new ExecutePainlessScriptDescriptor()));
+
+		/// <inheritdoc />
+		public IExecutePainlessScriptResponse<TResult> ExecutePainlessScript<TResult>(IExecutePainlessScriptRequest request) =>
+			this.Dispatcher.Dispatch<IExecutePainlessScriptRequest, ExecutePainlessScriptRequestParameters, ExecutePainlessScriptResponse<TResult>>(
+				request,
+				this.LowLevelDispatch.ScriptsPainlessExecuteDispatch<ExecutePainlessScriptResponse<TResult>>
+			);
+
+		/// <inheritdoc />
+		public Task<IExecutePainlessScriptResponse<TResult>> ExecutePainlessScriptAsync<TResult>(Func<ExecutePainlessScriptDescriptor, IExecutePainlessScriptRequest> selector,
+			CancellationToken cancellationToken = default(CancellationToken)) =>
+			this.ExecutePainlessScriptAsync<TResult>(selector?.Invoke(new ExecutePainlessScriptDescriptor()), cancellationToken);
+
+		/// <inheritdoc />
+		public Task<IExecutePainlessScriptResponse<TResult>> ExecutePainlessScriptAsync<TResult>(IExecutePainlessScriptRequest request, CancellationToken cancellationToken = default(CancellationToken)) =>
+			this.Dispatcher.DispatchAsync<IExecutePainlessScriptRequest, ExecutePainlessScriptRequestParameters, ExecutePainlessScriptResponse<TResult>, IExecutePainlessScriptResponse<TResult>>(
+				request,
+				cancellationToken,
+				this.LowLevelDispatch.ScriptsPainlessExecuteDispatchAsync<ExecutePainlessScriptResponse<TResult>>
+			);
+	}
+}

src/Elasticsearch.Net/ElasticLowLevelClient.Generated.cs

@@ -0,0 +1,25 @@
+using System;
+using Newtonsoft.Json;
+
+namespace Nest
+{
+	public partial interface IExecutePainlessScriptRequest
+	{
+		[JsonProperty("script")]
+		IInlineScript Script { get; set; }
+	}
+
+	public partial class ExecutePainlessScriptRequest
+	{
+		public IInlineScript Script { get; set; }
+	}
+
+	[DescriptorFor("ScriptsPainlessExecute")]
+	public partial class ExecutePainlessScriptDescriptor
+	{
+		IInlineScript IExecutePainlessScriptRequest.Script { get; set; }
+
+		public ExecutePainlessScriptDescriptor Script(Func<InlineScriptDescriptor, IInlineScript> selector) =>
+			Assign(a => a.Script = selector?.Invoke(new InlineScriptDescriptor()));
+	}
+}

src/Elasticsearch.Net/IElasticLowLevelClient.Generated.cs

@@ -0,0 +1,15 @@
+using Newtonsoft.Json;
+
+namespace Nest
+{
+	public interface IExecutePainlessScriptResponse<TResult> : IResponse
+	{
+		[JsonProperty("result")]
+		TResult Result { get; }
+	}
+
+	public class ExecutePainlessScriptResponse<TResult> : ResponseBase, IExecutePainlessScriptResponse<TResult>
+	{
+		public TResult Result { get; set; }
+	}
+}