Use OtlpExportProtocol for OTLP options

CHANGELOG.md

@@ -6,7 +6,7 @@ This project follows semantic versioning. Release tags use `vMAJOR.MINOR.PATCH`.
 
 ## [Unreleased]
 
-No unreleased changes.
+- Changed `OtlpOptions.Protocol` from a string to the nullable OpenTelemetry `OtlpExportProtocol` enum.
 
 ## [1.0.0] - 2026-05-24
 

Directory.Packages.props

@@ -1,54 +1,58 @@
-<Project>
-  <PropertyGroup>
-    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
-    <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
-  </PropertyGroup>
-  <ItemGroup Label="Versioning + SourceLink (library-side)">
-    <PackageVersion Include="Atya.Governance.CodeQuality" Version="1.0.0" />
-    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.300" />
-    <PackageVersion Include="MinVer" Version="7.0.0" />
-  </ItemGroup>
-  <ItemGroup Label="Testing">
-    <PackageVersion Include="Atya.Governance.Testing" Version="1.0.0" />
-    <PackageVersion Include="Castle.Core" Version="5.2.1" />
-    <PackageVersion Include="coverlet.collector" Version="10.0.1" />
-    <PackageVersion Include="coverlet.msbuild" Version="10.0.1" />
-    <PackageVersion Include="FluentAssertions" Version="8.10.0" />
-    <PackageVersion Include="Microsoft.Extensions.Hosting" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Options" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
-    <PackageVersion Include="Newtonsoft.Json" Version="13.0.4" />
-    <PackageVersion Include="NSubstitute" Version="5.3.0" />
-    <PackageVersion Include="NSubstitute.Analyzers.CSharp" Version="1.0.17" />
-    <PackageVersion Include="xunit" Version="2.9.3" />
-    <PackageVersion Include="xunit.analyzers" Version="1.27.0" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
-  </ItemGroup>
-  <ItemGroup Label="Benchmarking">
-    <PackageVersion Include="BenchmarkDotNet" Version="0.15.8" />
-  </ItemGroup>
-  <ItemGroup Label="Runtime + integrations">
-    <PackageVersion Include="Atya.Diagnostics.Observation" Version="1.0.0" />
-    <PackageVersion Include="Atya.Foundation.Guards" Version="1.0.0" />
-    <PackageVersion Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Configuration.Binder" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Diagnostics.Abstractions" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.FileProviders.Abstractions" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Hosting.Abstractions" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Logging" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Logging.Console" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Logging.Configuration" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.8" />
-    <PackageVersion Include="OpenTelemetry" Version="1.15.3" />
-    <PackageVersion Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.15.3" />
-    <PackageVersion Include="OpenTelemetry.Extensions.Hosting" Version="1.15.3" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.15.2" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.EntityFrameworkCore" Version="1.15.1-beta.1" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.GrpcNetClient" Version="1.15.1-beta.1" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.Http" Version="1.15.1" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.Runtime" Version="1.15.1" />
-    <PackageVersion Include="OpenTelemetry.Instrumentation.SqlClient" Version="1.15.2" />
-  </ItemGroup>
-</Project>
+<Project>
+  <PropertyGroup>
+    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+    <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
+  </PropertyGroup>
+
+  <ItemGroup Label="Versioning + SourceLink (library-side)">
+    <PackageVersion Include="Atya.Governance.CodeQuality" Version="1.0.0" />
+    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.300" />
+    <PackageVersion Include="MinVer" Version="7.0.0" />
+  </ItemGroup>
+
+  <ItemGroup Label="Testing">
+    <PackageVersion Include="Atya.Governance.Testing" Version="1.0.0" />
+    <PackageVersion Include="Castle.Core" Version="5.2.1" />
+    <PackageVersion Include="coverlet.collector" Version="10.0.1" />
+    <PackageVersion Include="coverlet.msbuild" Version="10.0.1" />
+    <PackageVersion Include="FluentAssertions" Version="8.10.0" />
+    <PackageVersion Include="Microsoft.Extensions.Hosting" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Options" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+    <PackageVersion Include="Newtonsoft.Json" Version="13.0.4" />
+    <PackageVersion Include="NSubstitute" Version="5.3.0" />
+    <PackageVersion Include="NSubstitute.Analyzers.CSharp" Version="1.0.17" />
+    <PackageVersion Include="xunit" Version="2.9.3" />
+    <PackageVersion Include="xunit.analyzers" Version="1.27.0" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
+  </ItemGroup>
+
+  <ItemGroup Label="Benchmarking">
+    <PackageVersion Include="BenchmarkDotNet" Version="0.15.8" />
+  </ItemGroup>
+
+  <ItemGroup Label="Runtime + integrations">
+    <PackageVersion Include="Atya.Diagnostics.Observation" Version="1.0.0" />
+    <PackageVersion Include="Atya.Foundation.Guards" Version="1.0.0" />
+    <PackageVersion Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Configuration.Binder" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Diagnostics.Abstractions" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.FileProviders.Abstractions" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Hosting.Abstractions" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Logging" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Logging.Console" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Logging.Configuration" Version="10.0.8" />
+    <PackageVersion Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="10.0.8" />
+    <PackageVersion Include="OpenTelemetry" Version="1.15.3" />
+    <PackageVersion Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.15.3" />
+    <PackageVersion Include="OpenTelemetry.Extensions.Hosting" Version="1.15.3" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.15.2" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.EntityFrameworkCore" Version="1.15.1-beta.1" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.GrpcNetClient" Version="1.15.1-beta.1" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.Http" Version="1.15.1" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.Runtime" Version="1.15.1" />
+    <PackageVersion Include="OpenTelemetry.Instrumentation.SqlClient" Version="1.15.2" />
+  </ItemGroup>
+</Project>

benchmarks/OpenTelemetry.Benchmarks/Program.cs

@@ -4,6 +4,7 @@
 using BenchmarkDotNet.Order;
 using BenchmarkDotNet.Running;
 using Microsoft.Extensions.DependencyInjection;
+using OpenTelemetry.Exporter;
 
 namespace OpenTelemetry.Benchmarks;
 
@@ -88,7 +89,7 @@ private static void ConfigureFull(OpenTelemetryOptions options)
         options.Instrumentations.Runtime.Enabled = true;
         options.Exporters.Otlp.Enabled = true;
         options.Exporters.Otlp.Endpoint = "http://localhost:4317";
-        options.Exporters.Otlp.Protocol = "grpc";
+        options.Exporters.Otlp.Protocol = OtlpExportProtocol.Grpc;
         options.Exporters.Otlp.Headers["x-benchmark"] = "opentelemetry";
     }
 }

src/OpenTelemetry/Internal/OpenTelemetryOptionsValidator.cs

@@ -4,6 +4,7 @@
 using Atya.Diagnostics.OpenTelemetry.Options;
 using Atya.Foundation.Guards;
 using Microsoft.Extensions.Options;
+using OpenTelemetry.Exporter;
 
 namespace Atya.Diagnostics.OpenTelemetry.Internal;
 
@@ -43,10 +44,11 @@ public ValidateOptionsResult Validate(string? name, OpenTelemetryOptions options
                 $"OpenTelemetryOptions.Exporters.Otlp.Endpoint '{options.Exporters.Otlp.Endpoint}' is not a valid absolute URI.");
         }
 
-        if (!OtlpExporterConfigurator.IsSupportedProtocol(options.Exporters.Otlp.Protocol))
+        if (options.Exporters.Otlp.Protocol is { } protocol &&
+            !Enum.IsDefined(typeof(OtlpExportProtocol), protocol))
         {
             return ValidateOptionsResult.Fail(
-                "OpenTelemetryOptions.Exporters.Otlp.Protocol must be either 'grpc' or 'http/protobuf'.");
+                "OpenTelemetryOptions.Exporters.Otlp.Protocol must be a defined OtlpExportProtocol value.");
         }
 
         foreach (var header in options.Exporters.Otlp.Headers)

src/OpenTelemetry/Internal/OtlpExporterConfigurator.cs

@@ -23,9 +23,17 @@ public static void Apply(OtlpExporterOptions otlp, OtlpOptions options)
             otlp.Endpoint = new Uri(options.Endpoint);
         }
 
-        if (!string.IsNullOrWhiteSpace(options.Protocol))
+        if (options.Protocol is { } protocol)
         {
-            otlp.Protocol = ParseProtocol(options.Protocol);
+            if (!Enum.IsDefined(typeof(OtlpExportProtocol), protocol))
+            {
+                throw new ArgumentOutOfRangeException(
+                    nameof(options),
+                    protocol,
+                    "OTLP protocol must be a defined OtlpExportProtocol value.");
+            }
+
+            otlp.Protocol = protocol;
         }
 
         if (options.Headers.Count > 0)
@@ -34,33 +42,4 @@ public static void Apply(OtlpExporterOptions otlp, OtlpOptions options)
         }
     }
 
-    public static bool IsSupportedProtocol(string? protocol)
-    {
-        if (string.IsNullOrWhiteSpace(protocol))
-        {
-            return true;
-        }
-
-        return protocol.Equals("grpc", StringComparison.OrdinalIgnoreCase) ||
-            protocol.Equals("http/protobuf", StringComparison.OrdinalIgnoreCase);
-    }
-
-    private static OtlpExportProtocol ParseProtocol(string protocol)
-    {
-        var normalizedProtocol = Guard.AgainstNullOrWhiteSpace(protocol).Trim();
-
-        if (normalizedProtocol.Equals("grpc", StringComparison.OrdinalIgnoreCase))
-        {
-            return OtlpExportProtocol.Grpc;
-        }
-
-        if (normalizedProtocol.Equals("http/protobuf", StringComparison.OrdinalIgnoreCase))
-        {
-            return OtlpExportProtocol.HttpProtobuf;
-        }
-
-        throw new ArgumentException(
-            "OTLP protocol must be either 'grpc' or 'http/protobuf'.",
-            nameof(protocol));
-    }
 }

src/OpenTelemetry/Options/OtlpOptions.cs

@@ -1,6 +1,8 @@
 // <copyright file="OtlpOptions.cs" company="Atya">
 // Copyright (c) Atya. All rights reserved.
 // </copyright>
+using OpenTelemetry.Exporter;
+
 namespace Atya.Diagnostics.OpenTelemetry.Options;
 
 /// <summary>
@@ -20,10 +22,10 @@ public sealed class OtlpOptions
     public string? Endpoint { get; set; }
 
     /// <summary>
-    /// Gets or sets the OTLP transport protocol. Supported values: "grpc", "http/protobuf".
+    /// Gets or sets the OTLP transport protocol.
     /// When null, the OpenTelemetry SDK default is used.
     /// </summary>
-    public string? Protocol { get; set; }
+    public OtlpExportProtocol? Protocol { get; set; }
 
     /// <summary>
     /// Gets additional headers to include in OTLP export requests.

src/OpenTelemetry/PublicAPI.Shipped.txt

@@ -58,7 +58,7 @@ Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Endpoint.get -> string?
 Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Endpoint.set -> void
 Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Headers.get -> System.Collections.Generic.IDictionary<string!, string!>!
 Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.OtlpOptions() -> void
-Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Protocol.get -> string?
+*REMOVED*Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Protocol.get -> string?
 Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Protocol.set -> void
 static Microsoft.Extensions.DependencyInjection.OpenTelemetryServiceCollectionExtensions.AddAtyaOpenTelemetry(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services, Microsoft.Extensions.Configuration.IConfiguration! configuration, string! sectionName = "OpenTelemetry") -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.OpenTelemetryServiceCollectionExtensions.AddAtyaOpenTelemetry(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services, System.Action<Atya.Diagnostics.OpenTelemetry.Options.OpenTelemetryOptions!>? configure = null) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!

src/OpenTelemetry/PublicAPI.Unshipped.txt

@@ -1 +1,2 @@
 #nullable enable
+Atya.Diagnostics.OpenTelemetry.Options.OtlpOptions.Protocol.get -> OpenTelemetry.Exporter.OtlpExportProtocol?

src/OpenTelemetry/README.md

@@ -16,6 +16,7 @@ dotnet add package Atya.Diagnostics.OpenTelemetry
 
 ```csharp
 using Microsoft.Extensions.DependencyInjection;
+using OpenTelemetry.Exporter;
 
 services.AddAtyaOpenTelemetry(options =>
 {
@@ -38,7 +39,7 @@ services.AddAtyaOpenTelemetry(options =>
 
     options.Exporters.Otlp.Enabled = true;
     options.Exporters.Otlp.Endpoint = "http://otel-collector:4317";
-    options.Exporters.Otlp.Protocol = "grpc";
+    options.Exporters.Otlp.Protocol = OtlpExportProtocol.Grpc;
 });
 ```
 
@@ -81,7 +82,7 @@ Bind from the default `OpenTelemetry` configuration section:
       "Otlp": {
         "Enabled": true,
         "Endpoint": "http://otel-collector:4317",
-        "Protocol": "grpc",
+        "Protocol": "Grpc",
         "Headers": {
           "x-service": "orders"
         }
@@ -124,7 +125,7 @@ Options are validated through `Microsoft.Extensions.Options`. Invalid options fa
 - `ServiceName` cannot be null, empty, or whitespace.
 - `ActivitySources` and `Meters` cannot contain null, empty, or whitespace names.
 - OTLP `Endpoint`, when set, must be an absolute URI.
-- OTLP `Protocol`, when set, must be `grpc` or `http/protobuf`.
+- OTLP `Protocol`, when set, must be a defined `OtlpExportProtocol` value such as `Grpc` or `HttpProtobuf`.
 - OTLP header names cannot be empty and cannot contain `,` or `=`.
 - OTLP header values cannot be null and cannot contain `,`.
 

tests/OpenTelemetry.UnitTests/DependencyInjection/OpenTelemetryServiceCollectionExtensionsTests.cs

@@ -7,6 +7,7 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
+using OpenTelemetry.Exporter;
 
 namespace OpenTelemetry.UnitTests.DependencyInjection;
 
@@ -195,7 +196,7 @@ public void AddAtyaOpenTelemetry_Should_Register_OpenTelemetryOptions()
             options.Meters.Add("Orders.Business");
             options.Exporters.Otlp.Enabled = true;
             options.Exporters.Otlp.Endpoint = "http://localhost:4317";
-            options.Exporters.Otlp.Protocol = "grpc";
+            options.Exporters.Otlp.Protocol = OtlpExportProtocol.Grpc;
             options.Exporters.Otlp.Headers["authorization"] = "Bearer token";
             options.Instrumentations.AspNetCore.Enabled = true;
             options.Instrumentations.HttpClient.Enabled = true;
@@ -218,7 +219,7 @@ public void AddAtyaOpenTelemetry_Should_Register_OpenTelemetryOptions()
         _ = resolvedOptions.Meters.Should().ContainSingle("Orders.Business");
         _ = resolvedOptions.Exporters.Otlp.Enabled.Should().BeTrue();
         _ = resolvedOptions.Exporters.Otlp.Endpoint.Should().Be("http://localhost:4317");
-        _ = resolvedOptions.Exporters.Otlp.Protocol.Should().Be("grpc");
+        _ = resolvedOptions.Exporters.Otlp.Protocol.Should().Be(OtlpExportProtocol.Grpc);
         _ = resolvedOptions.Exporters.Otlp.Headers.Should().ContainKey("authorization");
         _ = resolvedOptions.Instrumentations.AspNetCore.Enabled.Should().BeTrue();
         _ = resolvedOptions.Instrumentations.HttpClient.Enabled.Should().BeTrue();
@@ -249,7 +250,7 @@ public void AddAtyaOpenTelemetry_Should_Bind_Options_From_Default_Configuration_
                 ["OpenTelemetry:Instrumentations:GrpcClient:Enabled"] = "true",
                 ["OpenTelemetry:Exporters:Otlp:Enabled"] = "true",
                 ["OpenTelemetry:Exporters:Otlp:Endpoint"] = "http://collector:4317",
-                ["OpenTelemetry:Exporters:Otlp:Protocol"] = "http/protobuf",
+                ["OpenTelemetry:Exporters:Otlp:Protocol"] = "HttpProtobuf",
                 ["OpenTelemetry:Exporters:Otlp:Headers:tenant"] = "billing",
             })
             .Build();
@@ -273,7 +274,7 @@ public void AddAtyaOpenTelemetry_Should_Bind_Options_From_Default_Configuration_
         _ = resolvedOptions.Instrumentations.GrpcClient.Enabled.Should().BeTrue();
         _ = resolvedOptions.Exporters.Otlp.Enabled.Should().BeTrue();
         _ = resolvedOptions.Exporters.Otlp.Endpoint.Should().Be("http://collector:4317");
-        _ = resolvedOptions.Exporters.Otlp.Protocol.Should().Be("http/protobuf");
+        _ = resolvedOptions.Exporters.Otlp.Protocol.Should().Be(OtlpExportProtocol.HttpProtobuf);
         _ = resolvedOptions.Exporters.Otlp.Headers.Should().Contain("tenant", "billing");
     }