Introduce annotations on Agent types (#990)

This commit introduces annotations to agent types
that detail the APM server spec constraints.

- Rename to TruncateJsonConverter
- Use MaxLengthAttribute to specify maxLength constraint
- Rename SanitizationAttribute to SanitizeAttribute
- Move Truncate to StringExtensions
- Add RequiredAttribute
- Move SpanCount into Api namespace and add
as a property on ITransaction.

src/Elastic.Apm/Api/CapturedException.cs

@@ -3,15 +3,15 @@
 // See the LICENSE file in the project root for more information
 
 using System.Collections.Generic;
+using Elastic.Apm.Api.Constraints;
 using Elastic.Apm.Helpers;
-using Elastic.Apm.Report.Serialization;
 using Newtonsoft.Json;
 
 namespace Elastic.Apm.Api
 {
 	public class CapturedException
 	{
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Code { get; set; }
 
 		public bool Handled { get; set; }
@@ -21,7 +21,7 @@ public class CapturedException
 		[JsonProperty("stacktrace")]
 		public List<CapturedStackFrame> StackTrace { get; set; }
 
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Type { get; set; }
 
 		public override string ToString() => new ToStringBuilder(nameof(CapturedException))

src/Elastic.Apm/Api/Constraints/MaxLengthAttribute.cs

@@ -0,0 +1,34 @@
+// 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.Api.Constraints
+{
+	/// <summary>
+	/// Specifies the maximum length of string data allowed in a property, based on the APM server specification.
+	/// </summary>
+	[AttributeUsage(AttributeTargets.Property)]
+	public sealed class MaxLengthAttribute : Attribute
+	{
+		/// <summary>
+		/// The maximum length.
+		/// </summary>
+		public int Length { get; }
+
+		/// <summary>
+		/// Initializes a new instance of <see cref="MaxLengthAttribute"/>
+		/// with a maximum length of <see cref="Consts.PropertyMaxLength"/>
+		/// </summary>
+		public MaxLengthAttribute() : this(Consts.PropertyMaxLength)
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of <see cref="MaxLengthAttribute"/> with a given maximum length
+		/// </summary>
+		public MaxLengthAttribute(int length) => Length = length;
+	}
+}

src/Elastic.Apm/Api/Constraints/RequiredAttribute.cs

@@ -0,0 +1,15 @@
+// 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.Api.Constraints
+{
+	/// <summary>
+	/// Specifies that a data field value is required.
+	/// </summary>
+	[AttributeUsage(AttributeTargets.Property)]
+	public sealed class RequiredAttribute : Attribute { }
+}

src/Elastic.Apm/Report/Serialization/SanitizationAttribute.cs → src/Elastic.Apm/Api/Constraints/SanitizeAttribute.cs

@@ -1,14 +1,15 @@
-// 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.Report.Serialization
-{
-	/// <summary>
-	/// An attribute to mark fields for sanitization. This attribute is known to <see cref="ElasticApmContractResolver"/> and it applies a Converter
-	/// to sanitize field(s) accordingly.
-	/// </summary>
-	internal class SanitizationAttribute : Attribute { }
-}
+// 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 Elastic.Apm.Report.Serialization;
+
+namespace Elastic.Apm.Api.Constraints
+{
+	/// <summary>
+	/// An attribute to mark fields for sanitization. This attribute is known to <see cref="ElasticApmContractResolver"/> and it applies a Converter
+	/// to sanitize field(s) accordingly.
+	/// </summary>
+	internal sealed class SanitizeAttribute : Attribute { }
+}

src/Elastic.Apm/Api/Container.cs

@@ -2,14 +2,14 @@
 // 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 Elastic.Apm.Report.Serialization;
-using Newtonsoft.Json;
+using Elastic.Apm.Api.Constraints;
 
 namespace Elastic.Apm.Api
 {
 	public class Container
 	{
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[Required]
+		[MaxLength]
 		public string Id { get; set; }
 	}
 }

src/Elastic.Apm/Api/Database.cs

@@ -2,8 +2,7 @@
 // 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 Elastic.Apm.Report.Serialization;
-using Newtonsoft.Json;
+using Elastic.Apm.Api.Constraints;
 
 namespace Elastic.Apm.Api
 {
@@ -18,7 +17,7 @@ public class Database
 
 		public string Instance { get; set; }
 
-		[JsonConverter(typeof(TrimmedStringJsonConverter), 10_000)]
+		[MaxLength(10_000)]
 		public string Statement { get; set; }
 
 		public string Type { get; set; }

src/Elastic.Apm/Api/Destination.cs

@@ -2,8 +2,7 @@
 // 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 Elastic.Apm.Report.Serialization;
-using Newtonsoft.Json;
+using Elastic.Apm.Api.Constraints;
 
 namespace Elastic.Apm.Api
 {
@@ -24,7 +23,7 @@ public class Destination
 		/// (for example <see cref="SpanContext.Http" /> or <see cref="SpanContext.Db" />).
 		/// Explicitly setting this property to <c>null</c> will prohibit this automatic deduction.
 		/// </summary>
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Address
 		{
 			get => _address.Value;
@@ -72,20 +71,20 @@ public class DestinationService
 			/// <summary>
 			/// Identifier for the destination service (e.g. 'http://elastic.co', 'elasticsearch', 'rabbitmq')"
 			/// </summary>
-			[JsonConverter(typeof(TrimmedStringJsonConverter))]
+			[MaxLength]
 			public string Name { get; set; }
 
 			/// <summary>
 			/// Identifier for the destination service resource being operated on (e.g. 'http://elastic.co:80', 'elasticsearch',
 			/// 'rabbitmq/queue_name')
 			/// </summary>
-			[JsonConverter(typeof(TrimmedStringJsonConverter))]
+			[MaxLength]
 			public string Resource { get; set; }
 
 			/// <summary>
 			/// Type of the destination service (e.g. 'db', 'elasticsearch'). Should typically be the same as span.type.
 			/// </summary>
-			[JsonConverter(typeof(TrimmedStringJsonConverter))]
+			[MaxLength]
 			public string Type { get; set; }
 		}
 

src/Elastic.Apm/Api/Http.cs

@@ -4,6 +4,7 @@
 
 using System;
 using System.Net.Http;
+using Elastic.Apm.Api.Constraints;
 using Elastic.Apm.Report.Serialization;
 using Newtonsoft.Json;
 
@@ -18,7 +19,7 @@ public class Http
 		private Uri _originalUrl;
 		private string _url;
 
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Method { get; set; }
 
 		/// <summary>

src/Elastic.Apm/Api/IExecutionSegment.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Threading.Tasks;
+using Elastic.Apm.Api.Constraints;
 
 namespace Elastic.Apm.Api
 {
@@ -21,11 +22,13 @@ public interface IExecutionSegment
 		/// is automatically calculated when <see cref="End" /> is called.
 		/// </summary>
 		/// <value>The duration.</value>
+		[Required]
 		double? Duration { get; set; }
 
 		/// <summary>
 		/// The id of the item.
 		/// </summary>
+		[Required]
 		string Id { get; }
 
 		/// <summary>
@@ -65,6 +68,7 @@ public interface IExecutionSegment
 		/// <summary>
 		/// Hex encoded 128 random bits ID of the correlated trace.
 		/// </summary>
+		[Required]
 		string TraceId { get; }
 
 		/// <summary>

src/Elastic.Apm/Api/IMetricSet.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information
 
 using System.Collections.Generic;
+using Elastic.Apm.Api.Constraints;
 
 namespace Elastic.Apm.Api
 {
@@ -14,6 +15,7 @@ public interface IMetricSet
 		/// <summary>
 		/// List of captured metrics as key - value pairs
 		/// </summary>
+		[Required]
 		IEnumerable<MetricSample> Samples { get; set; }
 
 		// TODO: Rename to Timestamp for consistency?

src/Elastic.Apm/Api/ITransaction.cs

@@ -3,6 +3,8 @@
 // See the LICENSE file in the project root for more information
 
 using System.Collections.Generic;
+using Elastic.Apm.Api.Constraints;
+using Elastic.Apm.Model;
 
 namespace Elastic.Apm.Api
 {
@@ -35,8 +37,15 @@ public interface ITransaction : IExecutionSegment
 		/// The type of the transaction.
 		/// Example: 'request'
 		/// </summary>
+		[Required]
 		string Type { get; set; }
 
+		/// <summary>
+		/// The total number of correlated spans, including started and dropped
+		/// </summary>
+		[Required]
+		SpanCount SpanCount { get; }
+
 		/// <summary>
 		/// If the transaction does not have a ParentId yet, calling this method generates a new ID, sets it as the ParentId of
 		/// this transaction,

src/Elastic.Apm/Api/Kubernetes/KubernetesMetadata.cs

@@ -2,15 +2,14 @@
 // 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 Elastic.Apm.Api.Constraints;
 using Elastic.Apm.Helpers;
-using Elastic.Apm.Report.Serialization;
-using Newtonsoft.Json;
 
 namespace Elastic.Apm.Api.Kubernetes
 {
 	public class KubernetesMetadata
 	{
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Namespace { get; set; }
 
 		public Node Node { get; set; }

src/Elastic.Apm/Api/Kubernetes/Node.cs

@@ -2,15 +2,14 @@
 // 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 Elastic.Apm.Api.Constraints;
 using Elastic.Apm.Helpers;
-using Elastic.Apm.Report.Serialization;
-using Newtonsoft.Json;
 
 namespace Elastic.Apm.Api.Kubernetes
 {
 	public class Node
 	{
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Name { get; set; }
 
 		public override string ToString() => new ToStringBuilder(nameof(Node)) { { nameof(Name), Name } }.ToString();

src/Elastic.Apm/Api/Kubernetes/Pod.cs

@@ -2,18 +2,17 @@
 // 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 Elastic.Apm.Api.Constraints;
 using Elastic.Apm.Helpers;
-using Elastic.Apm.Report.Serialization;
-using Newtonsoft.Json;
 
 namespace Elastic.Apm.Api.Kubernetes
 {
 	public class Pod
 	{
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Name { get; set; }
 
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string Uid { get; set; }
 
 		public override string ToString() => new ToStringBuilder(nameof(Pod)) { { nameof(Name), Name }, { nameof(Uid), Uid } }.ToString();

src/Elastic.Apm/Api/Node.cs

@@ -2,16 +2,16 @@
 // 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 Elastic.Apm.Api.Constraints;
 using Elastic.Apm.Helpers;
-using Elastic.Apm.Report.Serialization;
 using Newtonsoft.Json;
 
 namespace Elastic.Apm.Api
 {
 	public class Node
 	{
 		[JsonProperty("configured_name")]
-		[JsonConverter(typeof(TrimmedStringJsonConverter))]
+		[MaxLength]
 		public string ConfiguredName { get; set; }
 
 		public override string ToString() => new ToStringBuilder(nameof(Node)) { { nameof(ConfiguredName), ConfiguredName } }.ToString();