[otlp] Add foundation for signal-specific envvars

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/OtlpExporterOptionsConfigurationType.cs

@@ -0,0 +1,17 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#nullable enable
+
+namespace OpenTelemetry.Exporter;
+
+[Flags]
+internal enum OtlpExporterOptionsConfigurationType
+{
+#pragma warning disable SA1602 // Enumeration items should be documented
+    Default,
+    Logs,
+    Metrics,
+    Traces,
+#pragma warning restore SA1602 // Enumeration items should be documented
+}

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/OtlpSpecConfigDefinitions.cs

@@ -0,0 +1,34 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+namespace OpenTelemetry.Exporter;
+
+/// <summary>
+/// Contains spec environment variable key definitions for OpenTelemetry Protocol (OTLP) exporter.
+/// </summary>
+/// <remarks>
+/// Specification: <see href="https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/exporter.md"/>.
+/// </remarks>
+internal static class OtlpSpecConfigDefinitions
+{
+    public const string DefaultEndpointEnvVarName = "OTEL_EXPORTER_OTLP_ENDPOINT";
+    public const string DefaultHeadersEnvVarName = "OTEL_EXPORTER_OTLP_HEADERS";
+    public const string DefaultTimeoutEnvVarName = "OTEL_EXPORTER_OTLP_TIMEOUT";
+    public const string DefaultProtocolEnvVarName = "OTEL_EXPORTER_OTLP_PROTOCOL";
+
+    public const string LogsEndpointEnvVarName = "OTEL_EXPORTER_OTLP_LOGS_ENDPOINT";
+    public const string LogsHeadersEnvVarName = "OTEL_EXPORTER_OTLP_LOGS_HEADERS";
+    public const string LogsTimeoutEnvVarName = "OTEL_EXPORTER_OTLP_LOGS_TIMEOUT";
+    public const string LogsProtocolEnvVarName = "OTEL_EXPORTER_OTLP_LOGS_PROTOCOL";
+
+    public const string MetricsEndpointEnvVarName = "OTEL_EXPORTER_OTLP_METRICS_ENDPOINT";
+    public const string MetricsHeadersEnvVarName = "OTEL_EXPORTER_OTLP_METRICS_HEADERS";
+    public const string MetricsTimeoutEnvVarName = "OTEL_EXPORTER_OTLP_METRICS_TIMEOUT";
+    public const string MetricsProtocolEnvVarName = "OTEL_EXPORTER_OTLP_METRICS_PROTOCOL";
+    public const string MetricsTemporalityPreferenceEnvVarName = "OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE";
+
+    public const string TracesEndpointEnvVarName = "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT";
+    public const string TracesHeadersEnvVarName = "OTEL_EXPORTER_OTLP_TRACES_HEADERS";
+    public const string TracesTimeoutEnvVarName = "OTEL_EXPORTER_OTLP_TRACES_TIMEOUT";
+    public const string TracesProtocolEnvVarName = "OTEL_EXPORTER_OTLP_TRACES_PROTOCOL";
+}

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpExporterOptions.cs

@@ -17,21 +17,25 @@ namespace OpenTelemetry.Exporter;
 
 /// <summary>
 /// OpenTelemetry Protocol (OTLP) exporter options.
-/// OTEL_EXPORTER_OTLP_ENDPOINT, OTEL_EXPORTER_OTLP_HEADERS, OTEL_EXPORTER_OTLP_TIMEOUT, OTEL_EXPORTER_OTLP_PROTOCOL
-/// environment variables are parsed during object construction.
 /// </summary>
+/// <remarks>
+/// Note: OTEL_EXPORTER_OTLP_ENDPOINT, OTEL_EXPORTER_OTLP_HEADERS,
+/// OTEL_EXPORTER_OTLP_TIMEOUT, and OTEL_EXPORTER_OTLP_PROTOCOL environment
+/// variables are parsed during object construction.
+/// </remarks>
 public class OtlpExporterOptions
 {
+    internal const string DefaultGrpcEndpoint = "http://localhost:4317";
+    internal const string DefaultHttpEndpoint = "http://localhost:4318";
+    internal const OtlpExportProtocol DefaultOtlpExportProtocol = OtlpExportProtocol.Grpc;
+
     internal static readonly KeyValuePair<string, string>[] StandardHeaders = new KeyValuePair<string, string>[]
     {
         new KeyValuePair<string, string>("User-Agent", GetUserAgentString()),
     };
 
     internal readonly Func<HttpClient> DefaultHttpClientFactory;
 
-    private const string DefaultGrpcEndpoint = "http://localhost:4317";
-    private const string DefaultHttpEndpoint = "http://localhost:4318";
-    private const OtlpExportProtocol DefaultOtlpExportProtocol = OtlpExportProtocol.Grpc;
     private const string UserAgentProduct = "OTel-OTLP-Exporter-Dotnet";
 
     private Uri endpoint;
@@ -40,39 +44,27 @@ public class OtlpExporterOptions
     /// Initializes a new instance of the <see cref="OtlpExporterOptions"/> class.
     /// </summary>
     public OtlpExporterOptions()
-        : this(new ConfigurationBuilder().AddEnvironmentVariables().Build(), new())
+        : this(OtlpExporterOptionsConfigurationType.Default)
+    {
+    }
+
+    internal OtlpExporterOptions(
+        OtlpExporterOptionsConfigurationType configurationType)
+        : this(
+              configuration: new ConfigurationBuilder().AddEnvironmentVariables().Build(),
+              configurationType,
+              defaultBatchOptions: new())
     {
     }
 
     internal OtlpExporterOptions(
         IConfiguration configuration,
+        OtlpExporterOptionsConfigurationType configurationType,
         BatchExportActivityProcessorOptions defaultBatchOptions)
     {
-        Debug.Assert(configuration != null, "configuration was null");
         Debug.Assert(defaultBatchOptions != null, "defaultBatchOptions was null");
 
-        if (configuration.TryGetUriValue(OtlpExporterSpecEnvVarKeyDefinitions.DefaultEndpointEnvVarName, out var endpoint))
-        {
-            this.endpoint = endpoint;
-        }
-
-        if (configuration.TryGetStringValue(OtlpExporterSpecEnvVarKeyDefinitions.DefaultHeadersEnvVarName, out var headers))
-        {
-            this.Headers = headers;
-        }
-
-        if (configuration.TryGetIntValue(OtlpExporterSpecEnvVarKeyDefinitions.DefaultTimeoutEnvVarName, out var timeout))
-        {
-            this.TimeoutMilliseconds = timeout;
-        }
-
-        if (configuration.TryGetValue<OtlpExportProtocol>(
-            OtlpExporterSpecEnvVarKeyDefinitions.DefaultProtocolEnvVarName,
-            OtlpExportProtocolParser.TryParse,
-            out var protocol))
-        {
-            this.Protocol = protocol;
-        }
+        this.ApplyConfiguration(configuration, configurationType);
 
         this.HttpClientFactory = this.DefaultHttpClientFactory = () =>
         {
@@ -98,7 +90,7 @@ public Uri Endpoint
         {
             if (this.endpoint == null)
             {
-                this.endpoint = this.Protocol == OtlpExportProtocol.Grpc
+                return this.Protocol == OtlpExportProtocol.Grpc
                     ? new Uri(DefaultGrpcEndpoint)
                     : new Uri(DefaultHttpEndpoint);
             }
@@ -195,8 +187,42 @@ internal static OtlpExporterOptions CreateOtlpExporterOptions(
         string name)
         => new(
             configuration,
+            OtlpExporterOptionsConfigurationType.Default,
             serviceProvider.GetRequiredService<IOptionsMonitor<BatchExportActivityProcessorOptions>>().Get(name));
 
+    internal void ApplyConfigurationUsingSpecificationEnvVars(
+        IConfiguration configuration,
+        string endpointEnvVarKey,
+        bool appendSignalPathToEndpoint,
+        string protocolEnvVarKey,
+        string headersEnvVarKey,
+        string timeoutEnvVarKey)
+    {
+        if (configuration.TryGetUriValue(endpointEnvVarKey, out var endpoint))
+        {
+            this.endpoint = endpoint;
+            this.AppendSignalPathToEndpoint = appendSignalPathToEndpoint;
+        }
+
+        if (configuration.TryGetValue<OtlpExportProtocol>(
+            protocolEnvVarKey,
+            OtlpExportProtocolParser.TryParse,
+            out var protocol))
+        {
+            this.Protocol = protocol;
+        }
+
+        if (configuration.TryGetStringValue(headersEnvVarKey, out var headers))
+        {
+            this.Headers = headers;
+        }
+
+        if (configuration.TryGetIntValue(timeoutEnvVarKey, out var timeout))
+        {
+            this.TimeoutMilliseconds = timeout;
+        }
+    }
+
     private static string GetUserAgentString()
     {
         try
@@ -210,4 +236,60 @@ private static string GetUserAgentString()
             return UserAgentProduct;
         }
     }
+
+    private void ApplyConfiguration(
+        IConfiguration configuration,
+        OtlpExporterOptionsConfigurationType configurationType)
+    {
+        Debug.Assert(configuration != null, "configuration was null");
+
+        // Note: When using the "AddOtlpExporter" extensions configurationType
+        // never has a value other than "Default" because OtlpExporterOptions is
+        // shared by all signals and there is no way to differentiate which
+        // signal is being constructed.
+        if (configurationType == OtlpExporterOptionsConfigurationType.Default)
+        {
+            this.ApplyConfigurationUsingSpecificationEnvVars(
+                configuration!,
+                OtlpSpecConfigDefinitions.DefaultEndpointEnvVarName,
+                appendSignalPathToEndpoint: true,
+                OtlpSpecConfigDefinitions.DefaultProtocolEnvVarName,
+                OtlpSpecConfigDefinitions.DefaultHeadersEnvVarName,
+                OtlpSpecConfigDefinitions.DefaultTimeoutEnvVarName);
+        }
+        else if (configurationType == OtlpExporterOptionsConfigurationType.Logs)
+        {
+            this.ApplyConfigurationUsingSpecificationEnvVars(
+                configuration!,
+                OtlpSpecConfigDefinitions.LogsEndpointEnvVarName,
+                appendSignalPathToEndpoint: false,
+                OtlpSpecConfigDefinitions.LogsProtocolEnvVarName,
+                OtlpSpecConfigDefinitions.LogsHeadersEnvVarName,
+                OtlpSpecConfigDefinitions.LogsTimeoutEnvVarName);
+        }
+        else if (configurationType == OtlpExporterOptionsConfigurationType.Metrics)
+        {
+            this.ApplyConfigurationUsingSpecificationEnvVars(
+                configuration!,
+                OtlpSpecConfigDefinitions.MetricsEndpointEnvVarName,
+                appendSignalPathToEndpoint: false,
+                OtlpSpecConfigDefinitions.MetricsProtocolEnvVarName,
+                OtlpSpecConfigDefinitions.MetricsHeadersEnvVarName,
+                OtlpSpecConfigDefinitions.MetricsTimeoutEnvVarName);
+        }
+        else if (configurationType == OtlpExporterOptionsConfigurationType.Traces)
+        {
+            this.ApplyConfigurationUsingSpecificationEnvVars(
+                configuration!,
+                OtlpSpecConfigDefinitions.TracesEndpointEnvVarName,
+                appendSignalPathToEndpoint: false,
+                OtlpSpecConfigDefinitions.TracesProtocolEnvVarName,
+                OtlpSpecConfigDefinitions.TracesHeadersEnvVarName,
+                OtlpSpecConfigDefinitions.TracesTimeoutEnvVarName);
+        }
+        else
+        {
+            throw new NotSupportedException($"OtlpExporterOptionsConfigurationType '{configurationType}' is not supported.");
+        }
+    }
 }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpMetricExporterExtensions.cs

@@ -63,7 +63,7 @@ public static MeterProviderBuilder AddOtlpExporter(
             services.AddOptions<MetricReaderOptions>(finalOptionsName).Configure<IConfiguration>(
                 (readerOptions, config) =>
                 {
-                    var otlpTemporalityPreference = config[OtlpExporterSpecEnvVarKeyDefinitions.MetricsTemporalityPreferenceEnvVarName];
+                    var otlpTemporalityPreference = config[OtlpSpecConfigDefinitions.MetricsTemporalityPreferenceEnvVarName];
                     if (!string.IsNullOrWhiteSpace(otlpTemporalityPreference)
                         && Enum.TryParse<MetricReaderTemporalityPreference>(otlpTemporalityPreference, ignoreCase: true, out var enumValue))
                     {
@@ -140,7 +140,7 @@ public static MeterProviderBuilder AddOtlpExporter(
             services.AddOptions<MetricReaderOptions>(finalOptionsName).Configure<IConfiguration>(
                 (readerOptions, config) =>
                 {
-                    var otlpTemporalityPreference = config[OtlpExporterSpecEnvVarKeyDefinitions.MetricsTemporalityPreferenceEnvVarName];
+                    var otlpTemporalityPreference = config[OtlpSpecConfigDefinitions.MetricsTemporalityPreferenceEnvVarName];
                     if (!string.IsNullOrWhiteSpace(otlpTemporalityPreference)
                         && Enum.TryParse<MetricReaderTemporalityPreference>(otlpTemporalityPreference, ignoreCase: true, out var enumValue))
                     {

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/BaseOtlpHttpExportClientTests.cs

@@ -21,7 +21,7 @@ public void ValidateOtlpHttpExportClientEndpoint(string optionEndpoint, string e
     {
         try
         {
-            Environment.SetEnvironmentVariable(OtlpExporterSpecEnvVarKeyDefinitions.DefaultEndpointEnvVarName, endpointEnvVar);
+            Environment.SetEnvironmentVariable(OtlpSpecConfigDefinitions.DefaultEndpointEnvVarName, endpointEnvVar);
 
             OtlpExporterOptions options = new() { Protocol = OtlpExportProtocol.HttpProtobuf };
 
@@ -35,7 +35,7 @@ public void ValidateOtlpHttpExportClientEndpoint(string optionEndpoint, string e
         }
         finally
         {
-            Environment.SetEnvironmentVariable(OtlpExporterSpecEnvVarKeyDefinitions.DefaultEndpointEnvVarName, null);
+            Environment.SetEnvironmentVariable(OtlpSpecConfigDefinitions.DefaultEndpointEnvVarName, null);
         }
     }