Enable metrics collection via provider (#43)

* Remove code handling ELASTIC_ environment variables

* Enable metrics provider

examples/Example.Elastic.OpenTelemetry.Worker/Example.Elastic.OpenTelemetry.Worker.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Hosting" Version="8.0.0" />
+    <PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.7.0" />
   </ItemGroup>
 
   <ItemGroup>

examples/Example.Elastic.OpenTelemetry.Worker/Program.cs

@@ -5,7 +5,7 @@
 
 var builder = Host.CreateApplicationBuilder(args);
 
-builder.AddElasticOpenTelemetry("CustomActivitySource");
+builder.AddElasticOpenTelemetry("CustomActivitySource", "CustomMeter");
 
 builder.Services.AddHostedService<Worker>();
 

examples/Example.Elastic.OpenTelemetry.Worker/Worker.cs

@@ -2,40 +2,44 @@
 // 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 System.Diagnostics.Metrics;
 
 namespace Example.Elastic.OpenTelemetry.Worker;
 
-public class Worker : BackgroundService
+public class Worker(ILogger<Worker> logger) : BackgroundService
 {
-	private readonly ILogger<Worker> _logger;
+	private readonly ILogger<Worker> _logger = logger;
 
 	private static readonly HttpClient HttpClient = new();
 	private const string ActivitySourceName = "CustomActivitySource";
 	private static readonly ActivitySource ActivitySource = new(ActivitySourceName, "1.0.0");
-
-	public Worker(ILogger<Worker> logger) => _logger = logger;
+	private static readonly Meter Meter = new("CustomMeter");
+	private static readonly Counter<int> Counter = Meter.CreateCounter<int>("invocations",
+		null, null, [KeyValuePair.Create<string, object?>("label1", "value1")]);
 
 	protected override async Task ExecuteAsync(CancellationToken stoppingToken)
 	{
-		while (!stoppingToken.IsCancellationRequested)
-		{
-			_logger.LogInformation("Sending request... ");
+		_logger.LogInformation("Sending request... ");
 
-			using (var activity = ActivitySource.StartActivity("DoingStuff", ActivityKind.Internal))
-			{
-				activity?.SetTag("CustomTag", "TagValue");
+		using (var activity = ActivitySource.StartActivity("DoingStuff", ActivityKind.Internal))
+		{
+			activity?.SetTag("CustomTag", "TagValue");
+
+			if (Counter.Enabled)
+				Counter.Add(1);
 
-				await Task.Delay(100, stoppingToken);
-				var response = await HttpClient.GetAsync("http://elastic.co", stoppingToken);
-				await Task.Delay(50, stoppingToken);
+			_logger.LogInformation("Sending request... ");
 
-				if (response.StatusCode == System.Net.HttpStatusCode.OK)
-					activity?.SetStatus(ActivityStatusCode.Ok);
-				else
-					activity?.SetStatus(ActivityStatusCode.Error);
-			}
+			await Task.Delay(100, stoppingToken);
+			var response = await HttpClient.GetAsync("http://elastic.co", stoppingToken);
+			await Task.Delay(50, stoppingToken);
 
-			await Task.Delay(5000, stoppingToken);
+			if (response.StatusCode == System.Net.HttpStatusCode.OK)
+				activity?.SetStatus(ActivityStatusCode.Ok);
+			else
+				activity?.SetStatus(ActivityStatusCode.Error);
 		}
+
+		await Task.Delay(5000, stoppingToken);
 	}
-}
+}

src/Elastic.OpenTelemetry/AgentBuilder.cs

@@ -22,14 +22,9 @@ namespace Elastic.OpenTelemetry;
 /// </summary>
 public class AgentBuilder
 {
-	private readonly MeterProviderBuilder _meterProvider =
-		Sdk.CreateMeterProviderBuilder()
-			.AddProcessInstrumentation()
-			.AddRuntimeInstrumentation()
-			.AddHttpClientInstrumentation();
-
 	private readonly string[] _activitySourceNames = [];
 	private Action<TracerProviderBuilder> _tracerProviderBuilderAction = tpb => { };
+	private Action<MeterProviderBuilder> _meterProviderBuilderAction = mpb => { };
 	private Action<ResourceBuilder>? _resourceBuilderAction = rb => { };
 	private Action<OtlpExporterOptions>? _otlpExporterConfiguration;
 	private string? _otlpExporterName;
@@ -144,6 +139,42 @@ public AgentBuilder ConfigureTracer(Action<ResourceBuilder> configureResourceBui
 		return this;
 	}
 
+	/// <summary>
+	/// TODO
+	/// </summary>
+	public AgentBuilder ConfigureMeter(params string[] activitySourceNames)
+	{
+		MeterInternal(null, activitySourceNames);
+		return this;
+	}
+
+	/// <summary>
+	/// TODO
+	/// </summary>
+	public AgentBuilder ConfigureMeter(Action<ResourceBuilder> configureResourceBuilder)
+	{
+		MeterInternal(configureResourceBuilder, null);
+		return this;
+	}
+
+	/// <summary>
+	/// TODO
+	/// </summary>
+	public AgentBuilder ConfigureMeter(Action<ResourceBuilder> configureResourceBuilder, params string[] activitySourceNames)
+	{
+		MeterInternal(configureResourceBuilder, activitySourceNames);
+		return this;
+	}
+
+	/// <summary>
+	/// TODO
+	/// </summary>
+	public AgentBuilder ConfigureMeter(Action<ResourceBuilder> configureResourceBuilder, string activitySourceName)
+	{
+		MeterInternal(configureResourceBuilder, [activitySourceName]);
+		return this;
+	}
+
 	/// <summary>
 	/// TODO
 	/// </summary>
@@ -161,6 +192,26 @@ public AgentBuilder ConfigureTracer(Action<TracerProviderBuilder> configure)
 		return this;
 	}
 
+	/// <summary>
+	/// TODO
+	/// </summary>
+	public AgentBuilder ConfigureMeter(Action<MeterProviderBuilder> configure)
+	{
+		ArgumentNullException.ThrowIfNull(configure);
+		_meterProviderBuilderAction += configure;
+		return this;
+	}
+
+	private AgentBuilder MeterInternal(Action<ResourceBuilder>? configureResourceBuilder = null, string[]? activitySourceNames = null)
+	{
+		_resourceBuilderAction = configureResourceBuilder;
+
+		if (activitySourceNames is not null)
+			_meterProviderBuilderAction += mpb => mpb.AddMeter(activitySourceNames);
+
+		return this;
+	}
+
 	private AgentBuilder TracerInternal(Action<ResourceBuilder>? configureResourceBuilder = null, string[]? activitySourceNames = null)
 	{
 		_resourceBuilderAction = configureResourceBuilder;
@@ -183,7 +234,13 @@ public IAgent Build()
 
 		Log(AgentBuilderBuiltTracerProviderEvent);
 
-		var agent = tracerProvider is not null ? new Agent(_diagnosticSourceSubscription, tracerProvider) : new Agent(_diagnosticSourceSubscription);
+		var meterProviderBuilder = Sdk.CreateMeterProviderBuilder();
+		MeterProviderBuilderAction.Invoke(meterProviderBuilder);
+		var meterProvider = meterProviderBuilder.Build();
+
+		Log(AgentBuilderBuiltMeterProviderEvent);
+
+		var agent = new Agent(_diagnosticSourceSubscription, tracerProvider, meterProvider);
 
 		Log(AgentBuilderBuiltAgentEvent);
 
@@ -207,7 +264,8 @@ public IServiceCollection Register(IServiceCollection serviceCollection)
 			.AddSingleton<IAgent>(new Agent(_diagnosticSourceSubscription))
 			.AddSingleton<LoggerResolver>()
 			.AddOpenTelemetry()
-				.WithTracing(TracerProviderBuilderAction);
+				.WithTracing(TracerProviderBuilderAction)
+				.WithMetrics(MeterProviderBuilderAction);
 
 		Log(AgentBuilderRegisteredDistroServicesEvent);
 
@@ -236,6 +294,30 @@ public IServiceCollection Register(IServiceCollection serviceCollection)
 			tracerProviderBuilder.AddOtlpExporter(_otlpExporterName, _otlpExporterConfiguration);
 		};
 
+	private Action<MeterProviderBuilder> MeterProviderBuilderAction =>
+		builder =>
+		{
+			foreach (var source in _activitySourceNames)
+				builder.LogAndAddMeter(source);
+
+			builder
+				.AddProcessInstrumentation()
+				.AddRuntimeInstrumentation()
+				.AddHttpClientInstrumentation();
+
+			var action = _resourceBuilderAction;
+			action += b => b.AddDistroAttributes();
+			builder.ConfigureResource(action);
+
+			_meterProviderBuilderAction?.Invoke(builder);
+
+			builder.AddOtlpExporter(_otlpExporterName, o =>
+			{
+				o.ExportProcessorType = ExportProcessorType.Simple;
+				o.Protocol = OtlpExportProtocol.HttpProtobuf;
+			});
+		};
+
 	/// <summary>
 	/// TODO
 	/// </summary>

src/Elastic.OpenTelemetry/DependencyInjection/ServiceCollectionExtensions.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information
 using Elastic.OpenTelemetry;
 using Microsoft.Extensions.Hosting;
+using OpenTelemetry.Metrics;
 using OpenTelemetry.Trace;
 
 namespace Microsoft.Extensions.DependencyInjection;
@@ -32,6 +33,23 @@ public static IHostApplicationBuilder AddElasticOpenTelemetry(this IHostApplicat
 		return builder;
 	}
 
+	/// <summary>
+	/// TODO
+	/// </summary>
+	/// <param name="builder"></param>
+	/// <param name="configureTracerProvider"></param>
+	/// <param name="configureMeterProvider"></param>
+	/// <returns></returns>
+	public static IHostApplicationBuilder AddElasticOpenTelemetry(
+		this IHostApplicationBuilder builder,
+		Action<TracerProviderBuilder>? configureTracerProvider,
+		Action<MeterProviderBuilder>? configureMeterProvider)
+	{
+		builder.Services.AddElasticOpenTelemetry(configureTracerProvider, configureMeterProvider);
+		return builder;
+	}
+
+
 	/// <summary>
 	/// Adds the Elastic OpenTelemetry distribution to an application via the <see cref="IServiceCollection"/>.
 	/// </summary>
@@ -54,7 +72,21 @@ public static IServiceCollection AddElasticOpenTelemetry(this IServiceCollection
 	/// </summary>
 	/// <param name="serviceCollection"></param>
 	/// <param name="configureTracerProvider"></param>
+	/// <param name="configureMeterProvider"></param>
 	/// <returns></returns>
-	public static IServiceCollection AddElasticOpenTelemetry(this IServiceCollection serviceCollection, Action<TracerProviderBuilder> configureTracerProvider) =>
-		new AgentBuilder().ConfigureTracer(configureTracerProvider).Register(serviceCollection);
+	public static IServiceCollection AddElasticOpenTelemetry(
+		this IServiceCollection serviceCollection,
+		Action<TracerProviderBuilder>? configureTracerProvider,
+		Action<MeterProviderBuilder>? configureMeterProvider)
+	{
+		var builder = new AgentBuilder();
+
+		if (configureTracerProvider is not null)
+			builder.ConfigureTracer(configureTracerProvider);
+
+		if (configureMeterProvider is not null)
+			builder.ConfigureMeter(configureMeterProvider);
+
+		return builder.Register(serviceCollection);
+	}
 }

src/Elastic.OpenTelemetry/Diagnostics/ElasticDiagnosticLoggingObserver.cs

@@ -24,6 +24,10 @@ public void OnNext(KeyValuePair<string, object?> data)
 				AgentBuilderBuiltTracerProvider(data);
 				break;
 
+			case ElasticOpenTelemetryDiagnostics.AgentBuilderBuiltMeterProviderEvent:
+				AgentBuilderBuiltMeterProvider(data);
+				break;
+
 			case ElasticOpenTelemetryDiagnostics.AgentBuilderBuiltAgentEvent:
 				AgentBuilderBuiltAgent(data);
 				break;
@@ -52,6 +56,10 @@ public void OnNext(KeyValuePair<string, object?> data)
 				SourceAdded(data);
 				break;
 
+			case ElasticOpenTelemetryDiagnostics.MeterAddedEvent:
+				MeterAdded(data);
+				break;
+
 			default:
 				if (data.Value is DiagnosticEvent diagnostic)
 					_logFileWriter.LogUnhandledEvent(data.Key, diagnostic);
@@ -70,6 +78,12 @@ void AgentBuilderBuiltTracerProvider(KeyValuePair<string, object?> data)
 				_logFileWriter.LogAgentBuilderBuiltTracerProvider(diagnostic);
 		}
 
+		void AgentBuilderBuiltMeterProvider(KeyValuePair<string, object?> data)
+		{
+			if (data.Value is DiagnosticEvent diagnostic)
+				_logFileWriter.LogAgentBuilderBuiltMeterProvider(diagnostic);
+		}
+
 		void AgentBuilderBuiltAgent(KeyValuePair<string, object?> data)
 		{
 			if (data.Value is DiagnosticEvent diagnostic)
@@ -111,6 +125,12 @@ void SourceAdded(KeyValuePair<string, object?> data)
 			if (data.Value is DiagnosticEvent<AddSourcePayload> diagnostic)
 				_logFileWriter.LogSourceAdded(diagnostic);
 		}
+
+		void MeterAdded(KeyValuePair<string, object?> data)
+		{
+			if (data.Value is DiagnosticEvent<AddSourcePayload> diagnostic)
+				_logFileWriter.LogMeterAdded(diagnostic);
+		}
 	}
 
 	public void OnCompleted() { }

src/Elastic.OpenTelemetry/Diagnostics/ElasticOpenTelemetryDiagnostics.cs

@@ -39,6 +39,8 @@ public static void Log(string name, Func<DiagnosticEvent> createDiagnosticEvent)
 
 	public const string AgentBuilderBuiltTracerProviderEvent = "AgentBuilderBuiltTracerProvider";
 
+	public const string AgentBuilderBuiltMeterProviderEvent = "AgentBuilderBuiltMeterProvider";
+
 	public const string AgentBuilderRegisteredDistroServicesEvent = "RegisteredDistroServices";
 
 	public const string AgentBuilderBuiltAgentEvent = "AgentBuilderBuiltAgent";
@@ -49,6 +51,8 @@ public static void Log(string name, Func<DiagnosticEvent> createDiagnosticEvent)
 
 	public const string SourceAddedEvent = "SourceAdded";
 
+	public const string MeterAddedEvent = "MeterAdded";
+
 	public const string AgentBuildCalledMultipleTimesEvent = "AgentBuildCalledMultipleTimes";
 
 	public const string AgentSetAgentCalledMultipleTimesEvent = "AgentSetAgentCalledMultipleTimes";
@@ -65,6 +69,9 @@ public static void LogAgentBuilderInitialized(this LogFileWriter logFileWriter,
 	public static void LogAgentBuilderBuiltTracerProvider(this LogFileWriter logFileWriter, DiagnosticEvent diagnostic) =>
 		logFileWriter.WriteInfoLogLine(diagnostic, "AgentBuilder built TracerProvider.");
 
+	public static void LogAgentBuilderBuiltMeterProvider(this LogFileWriter logFileWriter, DiagnosticEvent diagnostic) =>
+	logFileWriter.WriteInfoLogLine(diagnostic, "AgentBuilder built MeterProvider.");
+
 	public static void LogAgentBuilderBuiltAgent(this LogFileWriter logFileWriter, DiagnosticEvent diagnostic) =>
 		logFileWriter.WriteInfoLogLine(diagnostic, "AgentBuilder built Agent.");
 
@@ -91,7 +98,13 @@ public static void LogProcessorAdded(this LogFileWriter logFileWriter, Diagnosti
 
 	public static void LogSourceAdded(this LogFileWriter logFileWriter, DiagnosticEvent<AddSourcePayload> diagnostic)
 	{
-		var message = $"Added '{diagnostic.Data.ActivitySourceName}' ActivitySource to '{diagnostic.Data.BuilderType.Name}'.";
+		var message = $"Added '{diagnostic.Data.Name}' ActivitySource to '{diagnostic.Data.BuilderType.Name}'.";
+		logFileWriter.WriteInfoLogLine(diagnostic, message);
+	}
+
+	public static void LogMeterAdded(this LogFileWriter logFileWriter, DiagnosticEvent<AddSourcePayload> diagnostic)
+	{
+		var message = $"Added '{diagnostic.Data.Name}' Meter to '{diagnostic.Data.BuilderType.Name}'.";
 		logFileWriter.WriteInfoLogLine(diagnostic, message);
 	}
 

src/Elastic.OpenTelemetry/Diagnostics/Payloads/AddSourcePayload.cs

@@ -3,4 +3,4 @@
 // See the LICENSE file in the project root for more information
 namespace Elastic.OpenTelemetry.Diagnostics;
 
-internal readonly record struct AddSourcePayload(string ActivitySourceName, Type BuilderType);
+internal readonly record struct AddSourcePayload(string Name, Type BuilderType);