Support nested entities when using AssignField (#450)

Addresses #402

Continuation of #401

This now allows us to log not just the value types but also deeply
nested entities on other entities.

E.g `threat.indicator.file.pe.company` now successfully assigns to
`doc.Threat.IndicatorFile.Pe.Company`

The only thing we don't support today is self referential (reused)
entities e.g `process.parent.*` since these require a tad more massaging
of the intermediary model.

src/Elastic.CommonSchema/AssignableInterfaces.Generated.cs

@@ -0,0 +1,301 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+/*
+IMPORTANT NOTE
+==============
+This file has been generated. 
+If you wish to submit a PR please modify the original csharp file and submit the PR with that change. Thanks!
+*/
+
+// ReSharper disable RedundantUsingDirective
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Linq;
+using System.Net;
+using System.Runtime.Serialization;
+using System.Text.Json.Serialization;
+
+#nullable enable
+namespace Elastic.CommonSchema
+{
+
+	///<summary> Interface for entities that can assign an IAs: Client, Destination, Server, Source</summary>
+	public interface IAs {
+		///<summary>as</summary>
+		public As? As { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IGeo: Client, Destination, Host, Observer, Server, Source</summary>
+	public interface IGeo {
+		///<summary>geo</summary>
+		public Geo? Geo { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IUser: Client, Destination, Process, Server, Source</summary>
+	public interface IUser {
+		///<summary>user</summary>
+		public User? User { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an ICloudOrigin: Cloud</summary>
+	public interface ICloudOrigin {
+		///<summary>origin</summary>
+		public CloudOrigin? Origin { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an ICloudTarget: Cloud</summary>
+	public interface ICloudTarget {
+		///<summary>target</summary>
+		public CloudTarget? Target { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IHash: Dll, File, Process</summary>
+	public interface IHash {
+		///<summary>hash</summary>
+		public Hash? Hash { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IPe: Dll, File, Process</summary>
+	public interface IPe {
+		///<summary>pe</summary>
+		public Pe? Pe { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an ICodeSignature: Dll, File, Process</summary>
+	public interface ICodeSignature {
+		///<summary>code_signature</summary>
+		public CodeSignature? CodeSignature { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IX509: File</summary>
+	public interface IX509 {
+		///<summary>x509</summary>
+		public X509? X509 { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IElf: File, Process</summary>
+	public interface IElf {
+		///<summary>elf</summary>
+		public Elf? Elf { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IMacho: File, Process</summary>
+	public interface IMacho {
+		///<summary>macho</summary>
+		public Macho? Macho { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IOs: Host, Observer, UserAgent</summary>
+	public interface IOs {
+		///<summary>os</summary>
+		public Os? Os { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IRisk: Host, User</summary>
+	public interface IRisk {
+		///<summary>risk</summary>
+		public Risk? Risk { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IVlan: Network</summary>
+	public interface IVlan {
+		///<summary>vlan</summary>
+		public Vlan? Vlan { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IGroup: Process, User</summary>
+	public interface IGroup {
+		///<summary>group</summary>
+		public Group? Group { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IRealGroup: Process</summary>
+	public interface IRealGroup {
+		///<summary>real_group</summary>
+		public Group? RealGroup { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an ISavedGroup: Process</summary>
+	public interface ISavedGroup {
+		///<summary>saved_group</summary>
+		public Group? SavedGroup { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an ISupplementalGroups: Process</summary>
+	public interface ISupplementalGroups {
+		///<summary>supplemental_groups</summary>
+		public Group[]? SupplementalGroups { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IAttestedGroups: Process</summary>
+	public interface IAttestedGroups {
+		///<summary>attested_groups</summary>
+		public Group[]? AttestedGroups { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IEntryMetaSource: Process</summary>
+	public interface IEntryMetaSource {
+		///<summary>entry_meta.source</summary>
+		public Source? EntryMetaSource { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an ISavedUser: Process</summary>
+	public interface ISavedUser {
+		///<summary>saved_user</summary>
+		public User? SavedUser { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IRealUser: Process</summary>
+	public interface IRealUser {
+		///<summary>real_user</summary>
+		public User? RealUser { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IAttestedUser: Process</summary>
+	public interface IAttestedUser {
+		///<summary>attested_user</summary>
+		public User? AttestedUser { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessParent: Process</summary>
+	public interface IProcessParent {
+		///<summary>parent</summary>
+		public ProcessParent? Parent { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessEntryLeader: Process</summary>
+	public interface IProcessEntryLeader {
+		///<summary>entry_leader</summary>
+		public ProcessEntryLeader? EntryLeader { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessSessionLeader: Process</summary>
+	public interface IProcessSessionLeader {
+		///<summary>session_leader</summary>
+		public ProcessSessionLeader? SessionLeader { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessGroupLeader: Process</summary>
+	public interface IProcessGroupLeader {
+		///<summary>group_leader</summary>
+		public ProcessGroupLeader? GroupLeader { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessPrevious: Process</summary>
+	public interface IProcessPrevious {
+		///<summary>previous</summary>
+		public ProcessPrevious[]? Previous { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IServiceOrigin: Service</summary>
+	public interface IServiceOrigin {
+		///<summary>origin</summary>
+		public ServiceOrigin? Origin { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IServiceTarget: Service</summary>
+	public interface IServiceTarget {
+		///<summary>target</summary>
+		public ServiceTarget? Target { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IIndicatorX509: Threat</summary>
+	public interface IIndicatorX509 {
+		///<summary>indicator.x509</summary>
+		public X509? IndicatorX509 { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IIndicatorAs: Threat</summary>
+	public interface IIndicatorAs {
+		///<summary>indicator.as</summary>
+		public As? IndicatorAs { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IIndicatorFile: Threat</summary>
+	public interface IIndicatorFile {
+		///<summary>indicator.file</summary>
+		public File? IndicatorFile { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IIndicatorGeo: Threat</summary>
+	public interface IIndicatorGeo {
+		///<summary>indicator.geo</summary>
+		public Geo? IndicatorGeo { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IIndicatorRegistry: Threat</summary>
+	public interface IIndicatorRegistry {
+		///<summary>indicator.registry</summary>
+		public Registry? IndicatorRegistry { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IIndicatorUrl: Threat</summary>
+	public interface IIndicatorUrl {
+		///<summary>indicator.url</summary>
+		public Url? IndicatorUrl { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IClientX509: Tls</summary>
+	public interface IClientX509 {
+		///<summary>client.x509</summary>
+		public X509? ClientX509 { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IServerX509: Tls</summary>
+	public interface IServerX509 {
+		///<summary>server.x509</summary>
+		public X509? ServerX509 { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IUserTarget: User</summary>
+	public interface IUserTarget {
+		///<summary>target</summary>
+		public UserTarget? Target { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IUserEffective: User</summary>
+	public interface IUserEffective {
+		///<summary>effective</summary>
+		public UserEffective? Effective { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IUserChanges: User</summary>
+	public interface IUserChanges {
+		///<summary>changes</summary>
+		public UserChanges? Changes { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessParentGroupLeader: ProcessParent</summary>
+	public interface IProcessParentGroupLeader {
+		///<summary>group_leader</summary>
+		public ProcessParentGroupLeader? GroupLeader { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessEntryLeaderParent: ProcessEntryLeader</summary>
+	public interface IProcessEntryLeaderParent {
+		///<summary>parent</summary>
+		public ProcessEntryLeaderParent? Parent { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessSessionLeaderParent: ProcessSessionLeader</summary>
+	public interface IProcessSessionLeaderParent {
+		///<summary>parent</summary>
+		public ProcessSessionLeaderParent? Parent { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessEntryLeaderParentSessionLeader: ProcessEntryLeaderParent</summary>
+	public interface IProcessEntryLeaderParentSessionLeader {
+		///<summary>session_leader</summary>
+		public ProcessEntryLeaderParentSessionLeader? SessionLeader { get; set; }
+	}
+
+	///<summary> Interface for entities that can assign an IProcessSessionLeaderParentSessionLeader: ProcessSessionLeaderParent</summary>
+	public interface IProcessSessionLeaderParentSessionLeader {
+		///<summary>session_leader</summary>
+		public ProcessSessionLeaderParentSessionLeader? SessionLeader { get; set; }
+	}
+}

src/Elastic.CommonSchema/EcsDocument.Generated.cs

@@ -24,7 +24,7 @@ If you wish to submit a PR please modify the original csharp file and submit the
 namespace Elastic.CommonSchema
 {
 	///<inheritdoc cref="BaseFieldSet"/>
-	public partial class EcsDocument : BaseFieldSet 
+	public partial class EcsDocument : BaseFieldSet , IAs, ICodeSignature, IElf, IGeo, IGroup, IHash, IMacho, IOs, IPe, IRisk, IUser, IVlan, IX509
 	{
 
 		/// <summary>