APM Server specification validation

ElasticApmAgent.sln

@@ -109,6 +109,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elastic.Apm.StackExchange.R
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "scripts", "build\scripts\scripts.fsproj", "{CB623206-F69E-4004-8527-D4B971AA981A}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elastic.Apm.Specification", "src\Elastic.Apm.Specification\Elastic.Apm.Specification.csproj", "{5D076C7F-1F8B-4B11-9910-48717D133963}"
+EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elastic.Apm.AspNetCore.Static.Tests", "test\Elastic.Apm.AspNetCore.Static.Tests\Elastic.Apm.AspNetCore.Static.Tests.csproj", "{2250D888-E4CC-4B2B-AF31-5C78D76EC73D}"
 EndProject
 Global
@@ -264,6 +266,10 @@ Global
 		{6D413E0A-1CB7-4A2D-8E99-DB4F58D3463E}.Release|Any CPU.Build.0 = Release|Any CPU
 		{CB623206-F69E-4004-8527-D4B971AA981A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{CB623206-F69E-4004-8527-D4B971AA981A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5D076C7F-1F8B-4B11-9910-48717D133963}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5D076C7F-1F8B-4B11-9910-48717D133963}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5D076C7F-1F8B-4B11-9910-48717D133963}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5D076C7F-1F8B-4B11-9910-48717D133963}.Release|Any CPU.Build.0 = Release|Any CPU
 		{2250D888-E4CC-4B2B-AF31-5C78D76EC73D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{2250D888-E4CC-4B2B-AF31-5C78D76EC73D}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{2250D888-E4CC-4B2B-AF31-5C78D76EC73D}.Release|Any CPU.ActiveCfg = Release|Any CPU
@@ -309,6 +315,7 @@ Global
 		{9FBC8D8C-E600-464D-AE4E-AC1FB59485F6} = {3C791D9C-6F19-4F46-B367-2EC0F818762D}
 		{6D413E0A-1CB7-4A2D-8E99-DB4F58D3463E} = {267A241E-571F-458F-B04C-B6C4DE79E735}
 		{CB623206-F69E-4004-8527-D4B971AA981A} = {B406113B-0917-4531-AFEE-66DDB952590F}
+		{5D076C7F-1F8B-4B11-9910-48717D133963} = {3734A52F-2222-454B-BF58-1BA5C1F29D77}
 		{2250D888-E4CC-4B2B-AF31-5C78D76EC73D} = {267A241E-571F-458F-B04C-B6C4DE79E735}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution

src/Elastic.Apm.Specification/Elastic.Apm.Specification.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFrameworks>netstandard2.0;net461</TargetFrameworks>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="NJsonSchema" Version="10.2.2" />
+      <PackageReference Include="SharpZipLib" Version="1.3.0" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\Elastic.Apm\Elastic.Apm.csproj" />
+    </ItemGroup>
+
+</Project>

src/Elastic.Apm.Specification/ImplementationProperty.cs

@@ -0,0 +1,42 @@
+// 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
+
+using System;
+
+namespace Elastic.Apm.Specification
+{
+	/// <summary>
+	/// A property defined on a type that implements the APM server specification
+	/// </summary>
+	public class ImplementationProperty
+	{
+		public ImplementationProperty(string name, Type propertyType, Type declaringType)
+		{
+			Name = name;
+			PropertyType = propertyType;
+			DeclaringType = declaringType;
+		}
+
+		/// <summary>
+		/// The name of the property
+		/// </summary>
+		public string Name { get; }
+
+		/// <summary>
+		/// The type of the property
+		/// </summary>
+		public Type PropertyType { get; }
+
+		/// <summary>
+		/// The type that declares the property
+		/// </summary>
+		public Type DeclaringType { get; }
+
+		/// <summary>
+		/// The max length that the property value can have
+		/// </summary>
+		public int? MaxLength { get; set;  }
+	}
+}

src/Elastic.Apm.Specification/JsonSchemaExtensions.cs

@@ -0,0 +1,33 @@
+// 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
+
+using System.IO;
+using NJsonSchema;
+
+namespace Elastic.Apm.Specification
+{
+	public static class JsonSchemaExtensions
+	{
+		/// <summary>
+		/// Gets the schema $id if it exists, the name of the property if the schema represents a property,
+		/// or the file name of the schema document path.
+		/// </summary>
+		/// <param name="schema"></param>
+		/// <returns></returns>
+		public static string GetNameOrSpecificationId(this JsonSchema schema)
+		{
+			if (schema.ExtensionData != null && schema.ExtensionData.TryGetValue("$id", out var id))
+				return id.ToString();
+
+			if (schema is JsonSchemaProperty schemaProperty && !string.IsNullOrEmpty(schemaProperty.Name))
+				return schemaProperty.Name;
+
+			if (!string.IsNullOrEmpty(schema.DocumentPath))
+				return Path.GetFileNameWithoutExtension(schema.DocumentPath);
+
+			return null;
+		}
+	}
+}

src/Elastic.Apm.Specification/TypeValidationError.cs

@@ -0,0 +1,51 @@
+// 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
+
+using System;
+using System.IO;
+
+namespace Elastic.Apm.Specification
+{
+	public class TypeValidationIgnore
+	{
+		public string Schema { get; }
+		public string PropertyName { get; }
+		public string Message { get; }
+
+		public TypeValidationIgnore(string schema, string propertyName, string message)
+		{
+			Schema = schema;
+			PropertyName = propertyName;
+			Message = message;
+		}
+
+		public override string ToString() => $"ignored property name: {PropertyName}, schema: {Schema}. {Message}.";
+	}
+
+	public class TypeValidationError
+	{
+		public string Schema { get; }
+		public string PropertyName { get; }
+		public string Message { get; }
+
+		public Type SpecType { get; }
+
+		public TypeValidationError(Type specType, string schema, string propertyName, string message)
+		{
+			SpecType = specType;
+			Schema = schema;
+			PropertyName = propertyName;
+			Message = message;
+		}
+
+		public static TypeValidationError NotFound(Type specType, string id, string name) =>
+			new TypeValidationError(specType, id, name, "not found");
+
+		public static TypeValidationError ExpectedType(Type specType, Type propertyType, string expectedType, string id, string name) =>
+			new TypeValidationError(specType, id, name, $"expected type '{expectedType}' but found '{propertyType.FullName}'");
+
+		public override string ToString() => $"{SpecType}, property name: {PropertyName}, schema: {Schema}. {Message}.";
+	}
+}

src/Elastic.Apm.Specification/TypeValidationResult.cs

@@ -0,0 +1,52 @@
+// 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
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Elastic.Apm.Specification
+{
+	public class TypeValidationResult
+	{
+		private readonly List<TypeValidationError> _errors = new List<TypeValidationError>();
+		private readonly List<TypeValidationIgnore> _ignores = new List<TypeValidationIgnore>();
+		public Type Type { get; }
+		public string SpecificationId { get; }
+		public Validation Validation { get; }
+		public IEnumerable<TypeValidationError> Errors => _errors;
+
+		public IEnumerable<TypeValidationIgnore> Ignores => _ignores;
+
+		public bool Success => !Errors.Any();
+
+		internal void AddError(TypeValidationError error) => _errors.Add(error);
+
+		internal void AddIgnore(TypeValidationIgnore error) => _ignores.Add(error);
+
+		public TypeValidationResult(Type type, string specificationId, Validation validation)
+		{
+			Type = type;
+			SpecificationId = specificationId;
+			Validation = validation;
+		}
+
+		public override string ToString()
+		{
+			var builder = new StringBuilder(Type.FullName)
+				.Append(": ")
+				.AppendLine(Success ? "success" : "failure");
+
+			foreach (var error in Errors)
+				builder.AppendLine(error.ToString());
+
+			foreach (var ignore in Ignores)
+				builder.AppendLine(ignore.ToString());
+
+			return builder.ToString();
+		}
+	}
+}

src/Elastic.Apm.Specification/Validation.cs

@@ -0,0 +1,27 @@
+// 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
+
+namespace Elastic.Apm.Specification
+{
+	/// <summary>
+	/// Determines how validation is performed
+	/// </summary>
+	public enum Validation
+	{
+		/// <summary>
+		/// Validates the type against the specification. A type must be a valid implementation of the specification, but
+		/// it may be only a subset of the properties i.e. schema properties of type "null" may not be implemented.
+		/// </summary>
+		TypeToSpec,
+		/// <summary>
+		/// Validates the specification against the type. A type must match the specification exactly in order to be valid
+		/// </summary>
+		/// <remarks>
+		/// It's expected that the type is the implementation of the entire specification and not a subset
+		/// of properties.
+		/// </remarks>
+		SpecToType
+	}
+}