Add ElasticCompatibilityProcessor (#81)

* Add initial compatibility processor

* Misc formatting

* Add tests

* Update E2E test readme

examples/Example.MinimalApi/appsettings.json

@@ -2,11 +2,11 @@
   "Logging": {
     "LogLevel": {
       "Default": "Information",
-      "Microsoft.AspNetCore": "Warning"
+      "Microsoft.AspNetCore": "Warning",
+      "Elastic.OpenTelemetry": "Information"
     }
   },
   "AllowedHosts": "*",
-  "ServiceName": "elastic-minimal-api-example",
   "AspNetCoreInstrumentation": {
     "RecordException": "true"
   }

src/Elastic.OpenTelemetry/Diagnostics/LoggerMessages.cs

@@ -4,15 +4,27 @@
 
 using System.Diagnostics;
 using Elastic.OpenTelemetry.Diagnostics.Logging;
-using Elastic.OpenTelemetry.Processors;
 using Microsoft.Extensions.Logging;
 
 namespace Elastic.OpenTelemetry.Diagnostics;
 
 internal static partial class LoggerMessages
 {
-	[LoggerMessage(EventId = 100, Level = LogLevel.Trace, Message = $"{nameof(TransactionIdProcessor)} added 'transaction.id' tag to Activity.")]
-	internal static partial void TransactionIdProcessorTagAdded(this ILogger logger);
+#pragma warning disable SYSLIB1006 // Multiple logging methods cannot use the same event id within a class
+	// We explictly reuse the same event ID and this is the same log message, but with different types for the structured data
+
+	[LoggerMessage(EventId = 100, Level = LogLevel.Trace, Message = "{ProcessorName} found `{AttributeName}` attribute with value '{AttributeValue}' on the span.")]
+	internal static partial void FoundTag(this ILogger logger, string processorName, string attributeName, string attributeValue);
+
+	[LoggerMessage(EventId = 100, Level = LogLevel.Trace, Message = "{ProcessorName} found `{AttributeName}` attribute with value '{AttributeValue}' on the span.")]
+	internal static partial void FoundTag(this ILogger logger, string processorName, string attributeName, int attributeValue);
+
+	[LoggerMessage(EventId = 101, Level = LogLevel.Trace, Message = "{ProcessorName} set `{AttributeName}` attribute with value '{AttributeValue}' on the span.")]
+	internal static partial void SetTag(this ILogger logger, string processorName, string attributeName, string attributeValue);
+
+	[LoggerMessage(EventId = 101, Level = LogLevel.Trace, Message = "{ProcessorName} set `{AttributeName}` attribute with value '{AttributeValue}' on the span.")]
+	internal static partial void SetTag(this ILogger logger, string processorName, string attributeName, int attributeValue);
+#pragma warning restore SYSLIB1006 // Multiple logging methods cannot use the same event id within a class
 
 	[LoggerMessage(EventId = 20, Level = LogLevel.Trace, Message = "Added '{ProcessorTypeName}' processor to '{BuilderTypeName}'.")]
 	public static partial void LogProcessorAdded(this ILogger logger, string processorTypeName, string builderTypeName);

src/Elastic.OpenTelemetry/Diagnostics/Logging/CompositeLogger.cs

@@ -17,6 +17,7 @@ internal sealed class CompositeLogger(ILogger? additionalLogger) : IDisposable,
 {
 	public FileLogger FileLogger { get; } = new();
 
+	private ILogger? _additionalLogger = additionalLogger;
 	private bool _isDisposed;
 
 	public void Dispose()
@@ -39,22 +40,22 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
 		if (FileLogger.IsEnabled(logLevel))
 			FileLogger.Log(logLevel, eventId, state, exception, formatter);
 
-		if (additionalLogger == null)
+		if (_additionalLogger == null)
 			return;
 
-		if (additionalLogger.IsEnabled(logLevel))
-			additionalLogger.Log(logLevel, eventId, state, exception, formatter);
+		if (_additionalLogger.IsEnabled(logLevel))
+			_additionalLogger.Log(logLevel, eventId, state, exception, formatter);
 	}
 
 	public bool LogFileEnabled => FileLogger.FileLoggingEnabled;
 	public string LogFilePath => FileLogger.LogFilePath ?? string.Empty;
 
-	public void SetAdditionalLogger(ILogger? logger) => additionalLogger ??= logger;
+	public void SetAdditionalLogger(ILogger? logger) => _additionalLogger ??= logger;
 
-	public bool IsEnabled(LogLevel logLevel) => FileLogger.IsEnabled(logLevel) || (additionalLogger?.IsEnabled(logLevel) ?? false);
+	public bool IsEnabled(LogLevel logLevel) => FileLogger.IsEnabled(logLevel) || (_additionalLogger?.IsEnabled(logLevel) ?? false);
 
 	public IDisposable BeginScope<TState>(TState state) where TState : notnull =>
-		new CompositeDisposable(FileLogger.BeginScope(state), additionalLogger?.BeginScope(state));
+		new CompositeDisposable(FileLogger.BeginScope(state), _additionalLogger?.BeginScope(state));
 
 	private class CompositeDisposable(params IDisposable?[] disposables) : IDisposable
 	{

src/Elastic.OpenTelemetry/Diagnostics/Logging/LogState.cs

@@ -10,6 +10,7 @@ namespace Elastic.OpenTelemetry.Diagnostics.Logging;
 internal class LogState : IReadOnlyList<KeyValuePair<string, object?>>
 {
 	private readonly Activity? _activity;
+
 	public Activity? Activity
 	{
 		get => _activity;
@@ -44,7 +45,7 @@ public string? SpanId
 		init => _spanId = value;
 	}
 
-	private readonly List<KeyValuePair<string, object?>> _values = new();
+	private readonly List<KeyValuePair<string, object?>> _values = [];
 
 	public IEnumerator<KeyValuePair<string, object?>> GetEnumerator() => _values.GetEnumerator();
 

src/Elastic.OpenTelemetry/ElasticOpenTelemetryBuilder.cs

@@ -86,6 +86,7 @@ public ElasticOpenTelemetryBuilder(ElasticOpenTelemetryOptions options)
 			logging.IncludeScopes = true;
 			//TODO add processor that adds service.id
 		});
+
 		openTelemetry
 			.WithLogging(logging =>
 			{

src/Elastic.OpenTelemetry/Extensions/TracerProviderBuilderExtensions.cs

@@ -20,8 +20,14 @@ public static class TracerProviderBuilderExtensions
 	/// <summary>
 	/// Include Elastic trace processors to ensure data is enriched and extended.
 	/// </summary>
-	public static TracerProviderBuilder AddElasticProcessors(this TracerProviderBuilder builder, ILogger? logger = null) =>
-		builder.LogAndAddProcessor(new TransactionIdProcessor(logger ?? NullLogger.Instance), logger ?? NullLogger.Instance);
+	public static TracerProviderBuilder AddElasticProcessors(this TracerProviderBuilder builder, ILogger? logger = null)
+	{
+		logger ??= NullLogger.Instance;
+
+		return builder
+			.LogAndAddProcessor(new TransactionIdProcessor(logger), logger)
+			.LogAndAddProcessor(new ElasticCompatibilityProcessor(logger), logger);
+	}
 
 	private static TracerProviderBuilder LogAndAddProcessor(this TracerProviderBuilder builder, BaseProcessor<Activity> processor, ILogger logger)
 	{

src/Elastic.OpenTelemetry/Processors/ElasticCompatibilityProcessor.cs

@@ -0,0 +1,137 @@
+// 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.Diagnostics;
+using Elastic.OpenTelemetry.Diagnostics;
+using Microsoft.Extensions.Logging;
+using OpenTelemetry;
+using static Elastic.OpenTelemetry.SemanticConventions.TraceSemanticConventions;
+
+namespace Elastic.OpenTelemetry.Processors;
+
+/// <summary>
+/// This processor ensures that the data is compatible with Elastic backends.
+/// <para>
+/// It checks for the presence of the older semantic conventions and if they are not present, it will
+/// add them. This is only necessary for compatibility with older versions of the intake OTel endpoints
+/// on Elastic APM. These issues will be fixed centrally in future versions of the intake code.
+/// </para>
+/// </summary>
+/// <param name="logger"></param>
+public class ElasticCompatibilityProcessor(ILogger logger) : BaseProcessor<Activity>
+{
+	private readonly ILogger _logger = logger;
+
+	/// <inheritdoc />
+	public override void OnEnd(Activity activity)
+	{
+		if (activity.Kind == ActivityKind.Server)
+		{
+			// For inbound HTTP requests (server), ASP.NET Core sets the newer semantic conventions in
+			// the latest versions. For now, we need to ensure the older semantic conventions are also
+			// included on the spans sent to the Elastic backend as the intake system is currently
+			// unaware of the newer semantic conventions. We send the older attributes to ensure that
+			// the UI functions as expected. The http and net host conventions are required to build
+			// up the URL displayed in the trace sample UI within Kibana. This will be fixed in future
+			// version of apm-data.
+
+			string? httpScheme = null;
+			string? httpTarget = null;
+			string? urlScheme = null;
+			string? urlPath = null;
+			string? urlQuery = null;
+			string? netHostName = null;
+			int? netHostPort = null;
+			string? serverAddress = null;
+			int? serverPort = null;
+
+			// We loop once, collecting all the attributes we need for the older and newer
+			// semantic conventions. This is a bit more verbose but ensures we don't iterate
+			// the tags multiple times.
+			foreach (var tag in activity.TagObjects)
+			{
+				if (tag.Key == HttpScheme)
+					httpScheme = ProcessStringAttribute(tag);
+
+				if (tag.Key == HttpTarget)
+					httpTarget = ProcessStringAttribute(tag);
+
+				if (tag.Key == UrlScheme)
+					urlScheme = ProcessStringAttribute(tag);
+
+				if (tag.Key == UrlPath)
+					urlPath = ProcessStringAttribute(tag);
+
+				if (tag.Key == UrlQuery)
+					urlQuery = ProcessStringAttribute(tag);
+
+				if (tag.Key == NetHostName)
+					netHostName = ProcessStringAttribute(tag);
+
+				if (tag.Key == ServerAddress)
+					serverAddress = ProcessStringAttribute(tag);
+
+				if (tag.Key == NetHostPort)
+					netHostPort = ProcessIntAttribute(tag);
+
+				if (tag.Key == ServerPort)
+					serverPort = ProcessIntAttribute(tag);
+			}
+
+			// Set the older semantic convention attributes
+			if (httpScheme is null && urlScheme is not null)
+				SetStringAttribute(HttpScheme, urlScheme);
+
+			if (httpTarget is null && urlPath is not null)
+			{
+				var target = urlPath;
+
+				if (urlQuery is not null)
+					target += $"?{urlQuery}";
+
+				SetStringAttribute(HttpTarget, target);
+			}
+
+			if (netHostName is null && serverAddress is not null)
+				SetStringAttribute(NetHostName, serverAddress);
+
+			if (netHostPort is null && serverPort is not null)
+				SetIntAttribute(NetHostPort, serverPort.Value);
+		}
+
+		string? ProcessStringAttribute(KeyValuePair<string, object?> tag)
+		{
+			if (tag.Value is string value)
+			{
+				_logger.FoundTag(nameof(ElasticCompatibilityProcessor), tag.Key, value);
+				return value;
+			}
+
+			return null;
+		}
+
+		int? ProcessIntAttribute(KeyValuePair<string, object?> tag)
+		{
+			if (tag.Value is int value)
+			{
+				_logger.FoundTag(nameof(ElasticCompatibilityProcessor), tag.Key, value);
+				return value;
+			}
+
+			return null;
+		}
+
+		void SetStringAttribute(string attributeName, string value)
+		{
+			_logger.SetTag(nameof(ElasticCompatibilityProcessor), attributeName, value);
+			activity.SetTag(attributeName, value);
+		}
+
+		void SetIntAttribute(string attributeName, int value)
+		{
+			_logger.SetTag(nameof(ElasticCompatibilityProcessor), attributeName, value);
+			activity.SetTag(attributeName, value);
+		}
+	}
+}

src/Elastic.OpenTelemetry/Processors/TransactionIdProcessor.cs

@@ -1,6 +1,7 @@
 // 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.Diagnostics;
 using Elastic.OpenTelemetry.Diagnostics;
 using Microsoft.Extensions.Logging;
@@ -30,6 +31,6 @@ public override void OnStart(Activity activity)
 			return;
 
 		activity.SetTag(TransactionIdTagName, _currentTransactionId.Value.Value.ToString());
-		logger.TransactionIdProcessorTagAdded();
+		logger.SetTag(nameof(TransactionIdProcessor), TransactionIdTagName, _currentTransactionId.Value.Value.ToString());
 	}
 }

src/Elastic.OpenTelemetry/SemanticConventions/TraceSemanticConventions.cs

@@ -0,0 +1,25 @@
+// 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.OpenTelemetry.SemanticConventions;
+
+internal static class TraceSemanticConventions
+{
+	// HTTP
+	public const string HttpScheme = "http.scheme";
+	public const string HttpTarget = "http.target";
+
+	// NET
+	public const string NetHostName = "net.host.name";
+	public const string NetHostPort = "net.host.port";
+
+	// SERVER
+	public const string ServerAddress = "server.address";
+	public const string ServerPort = "server.port";
+
+	// URL
+	public const string UrlPath = "url.path";
+	public const string UrlQuery = "url.query";
+	public const string UrlScheme = "url.scheme";
+}

tests/Elastic.OpenTelemetry.EndToEndTests/README.md

@@ -8,8 +8,8 @@ Requires an already running serverless observability project on cloud.
 The configuration can be provided either as asp.net secrets or environment variables.
 
 ```bash
-dotnet user-secrets set "E2E:Endpoint" "<url>" --project tests/Elastic.OpenTelemetry.IntegrationTests
-dotnet user-secrets set "E2E:Authorization" "<header>" --project tests/Elastic.OpenTelemetry.IntegrationTests
+dotnet user-secrets set "E2E:Endpoint" "<url>" --project tests/Elastic.OpenTelemetry.EndToEndTests
+dotnet user-secrets set "E2E:Authorization" "<header>" --project tests/Elastic.OpenTelemetry.EndToEndTests
 ```
 
 The equivalent environment variables are `E2E__ENDPOINT` and `E2E__AUTHORIZATION`. For local development setting 
@@ -38,8 +38,8 @@ Once invited and accepted the invited email can be used to login during the auto
 These can be provided again as user secrets:
 
 ```bash
-dotnet user-secrets set "E2E:BrowserEmail" "<email>" --project tests/Elastic.OpenTelemetry.IntegrationTests
-dotnet user-secrets set "E2E:BrowserPassword" "<password>" --project tests/Elastic.OpenTelemetry.IntegrationTests
+dotnet user-secrets set "E2E:BrowserEmail" "<email>" --project tests/Elastic.OpenTelemetry.EndToEndTests
+dotnet user-secrets set "E2E:BrowserPassword" "<password>" --project tests/Elastic.OpenTelemetry.EndToEndTests
 ```
 
 or environment variables (`E2E__BROWSEREMAIL` and `E2E__BROWSERPASSWORD`).