[FileBasedConfiguration] Resource Detectors

docs/config.md

@@ -45,6 +45,37 @@ with environment variables taking precedence over `App.config` or `Web.config` f
      `SiteName\VirtualPath` ex: `MySite\MyApp`
      - If that is not the case it will use the name of the application [entry Assembly](https://learn.microsoft.com/en-us/dotnet/api/system.reflection.assembly.getentryassembly?view=net-7.0).
 
+4. File-based Configuration (Experimental)
+
+    > **Status:** [Experimental](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/versioning-and-stability.md)
+    > For more information about the OpenTelemetry configuration specification, see:
+    > **[File-based configuration documentation](https://opentelemetry.io/docs/specs/otel/configuration/sdk/)**  
+
+    You can configure OpenTelemetry using a YAML file. This method is disabled
+    by default and must be explicitly enabled.
+
+    To enable file-based configuration, set the following environment variable:
+
+    ```bash
+    OTEL_EXPERIMENTAL_FILE_BASED_CONFIGURATION_ENABLED=true
+    ```
+
+    By default, the value is false.
+
+    You can also specify the configuration file path (default: config.yaml):
+
+    ```bash
+    OTEL_EXPERIMENTAL_CONFIG_FILE=/path/to/config.yaml
+    ```
+
+    In your config file you can use environment variables in the format `${ENVIRONMENT_VARIABLE}`
+    instead of a fixed value.
+
+    You can also use `${ENVIRONMENT_VARIABLE:-value}`, where `value` is the fallback if the
+    environment variable is empty or not set.
+
+    See [configuration examples](#configuration-examples)
+
 By default we recommend using environment variables for configuration.
 However, if given setting supports it, then:
 
@@ -503,3 +534,40 @@ instead.
 |----------------------------------|-------------------------------------------------------------------------|------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------|
 | `OTEL_DOTNET_AUTO_LOG_DIRECTORY` | Directory of the .NET Tracer logs.                                      | *See the previous note on default paths* | [Experimental](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/versioning-and-stability.md) |
 | `OTEL_LOG_LEVEL`                 | SDK log level. (supported values: `none`,`error`,`warn`,`info`,`debug`) | `info`                                   | [Stable](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/versioning-and-stability.md)       |
+
+## Configuration Examples
+
+### Resource Configuration
+
+You can configure resource attributes directly in YAML or via the
+`OTEL_RESOURCE_ATTRIBUTES` environment variable.
+
+``` yaml
+resource:
+# Configure resource attributes. Entries have higher priority than entries from .resource.attributes_list.
+# Entries must contain .name and .value, and may optionally include .type. If an entry's .type omitted or null, string is used.
+# The .value's type must match the .type. Values for .type include: string, bool, int, double, string_array, bool_array, int_array, double_array.
+  attributes:
+    - name: service.name
+      value: unknown_service
+      type: string
+  # Alternatively, configure via a comma-separated list (same format as OTEL_RESOURCE_ATTRIBUTES).
+  attributes_list: ${OTEL_RESOURCE_ATTRIBUTES}
+```  
+
+### Resource Detectors Configuration
+
+For more details and updates, see: [Resource Detectors list and documentation](https://opentelemetry.io/docs/zero-code/dotnet/configuration/#resource-detectors)
+
+``` yaml
+resource:
+  detection/development:
+    detectors:
+      azureappservice: # Detects Azure App Service resource information
+      container:       # Detects container resource info (container.* attributes) [Core only]
+      host:            # Detects host resource info (host.* attributes)
+      operatingsystem: # Detects OS-level attributes (os.*)
+      process:         # Detects process-level attributes (process.*)
+      processruntime:  # Detects process runtime attributes (process.runtime.*)
+      service:         # Detects service.name and service.instance.id
+```

src/OpenTelemetry.AutoInstrumentation/Configurations/FileBasedConfiguration/DetectionDevelopment.cs

@@ -0,0 +1,16 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+using Vendors.YamlDotNet.Serialization;
+
+namespace OpenTelemetry.AutoInstrumentation.Configurations.FileBasedConfiguration;
+
+internal class DetectionDevelopment
+{
+    /// <summary>
+    /// Gets or sets the configuration for resource detectors.
+    /// If omitted or null, no resource detectors are enabled.
+    /// </summary>
+    [YamlMember(Alias = "detectors")]
+    public DotNetDetectors? Detectors { get; set; }
+}

src/OpenTelemetry.AutoInstrumentation/Configurations/FileBasedConfiguration/DotNetDetectors.cs

@@ -0,0 +1,71 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+using System.Reflection;
+using Vendors.YamlDotNet.Serialization;
+
+namespace OpenTelemetry.AutoInstrumentation.Configurations.FileBasedConfiguration;
+
+internal class DotNetDetectors
+{
+    /// <summary>
+    /// Gets or sets the Azure App Service detector configuration.
+    /// </summary>
+    [YamlMember(Alias = "azureappservice")]
+    public object? AzureAppService { get; set; }
+
+#if NET
+    /// <summary>
+    /// Gets or sets the container detector configuration.
+    /// </summary>
+    [YamlMember(Alias = "container")]
+    public object? Container { get; set; }
+#endif
+
+    /// <summary>
+    /// Gets or sets the host detector configuration.
+    /// </summary>
+    [YamlMember(Alias = "host")]
+    public object? Host { get; set; }
+
+    /// <summary>
+    /// Gets or sets the operating system detector configuration.
+    /// </summary>
+    [YamlMember(Alias = "operatingsystem")]
+    public object? OperatingSystem { get; set; }
+
+    /// <summary>
+    /// Gets or sets the process detector configuration.
+    /// </summary>
+    [YamlMember(Alias = "process")]
+    public object? Process { get; set; }
+
+    /// <summary>
+    /// Gets or sets the process runtime detector configuration.
+    /// </summary>
+    [YamlMember(Alias = "processruntime")]
+    public object? ProcessRuntime { get; set; }
+
+    /// <summary>
+    /// Returns the list of enabled resource detectors.
+    /// </summary>
+    public IReadOnlyList<ResourceDetector> GetEnabledResourceDetectors()
+    {
+        var enabled = new List<ResourceDetector>();
+        var properties = typeof(DotNetDetectors).GetProperties(BindingFlags.Instance | BindingFlags.Public);
+
+        foreach (var prop in properties)
+        {
+            var value = prop.GetValue(this);
+            if (value != null)
+            {
+                if (Enum.TryParse<ResourceDetector>(prop.Name, out var resourceDetector))
+                {
+                    enabled.Add(resourceDetector);
+                }
+            }
+        }
+
+        return enabled;
+    }
+}

src/OpenTelemetry.AutoInstrumentation/Configurations/FileBasedConfiguration/ResourceConfiguration.cs

@@ -19,6 +19,12 @@ internal class ResourceConfiguration
     [YamlMember(Alias = "attributes_list")]
     public string? AttributesList { get; set; }
 
+    /// <summary>
+    /// Gets or sets the detection development configuration.
+    /// </summary>
+    [YamlMember(Alias = "detection/development")]
+    public DetectionDevelopment? DetectionDevelopment { get; set; }
+
     public List<KeyValuePair<string, object>> ParseAttributes()
     {
         var resourceAttributesWithPriority = new Dictionary<string, object>();

src/OpenTelemetry.AutoInstrumentation/Configurations/ResourceSettings.cs

@@ -37,6 +37,6 @@ protected override void OnLoadFile(YamlConfiguration configuration)
 
         Resources = configuration.Resource?.ParseAttributes() ?? [];
 
-        // TODO initialize EnabledDetectors from file configuration
+        EnabledDetectors = configuration.Resource?.DetectionDevelopment?.Detectors?.GetEnabledResourceDetectors() ?? [];
     }
 }

test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/FileBasedTestHelper.cs

@@ -0,0 +1,32 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+using System.Reflection;
+using Vendors.YamlDotNet.Core;
+using Vendors.YamlDotNet.Serialization;
+using Xunit;
+
+namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased;
+
+internal static class FileBasedTestHelper
+{
+    public static void MoveParserToScalar(IParser parser)
+    {
+        parser.MoveNext(); // StreamStart
+        parser.MoveNext(); // DocumentStart
+        parser.MoveNext(); // Scalar
+    }
+
+    public static void AssertAliasPropertyExists<T>(T obj, string alias)
+    {
+        Assert.NotNull(obj);
+
+        var prop = typeof(T).GetProperties()
+                            .FirstOrDefault(p => p.GetCustomAttribute<YamlMemberAttribute>()?.Alias == alias);
+
+        Assert.NotNull(prop);
+
+        var value = prop.GetValue(obj);
+        Assert.NotNull(value);
+    }
+}

test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/FilebasedGeneralSettingsTests.cs → test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/FilebasedResourceSettingsTests.cs

@@ -7,7 +7,7 @@
 
 namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased;
 
-public class FilebasedGeneralSettingsTests
+public class FilebasedResourceSettingsTests
 {
     [Fact]
     public void LoadFile_MergesBaseAndCustomResourceAttributes()
@@ -97,4 +97,40 @@ public void LoadFile_AttributesListOverwrittenByAttributes()
 
         Assert.Equal("fromAttributes", result["key1"]);
     }
+
+    [Fact]
+    public void GetEnabledResourceDetector_ReturnsCorrectEnabledDetectors()
+    {
+        var detectors = new DotNetDetectors
+        {
+            AzureAppService = new object(),
+            Host = new object(),
+            OperatingSystem = null,
+            Process = new object(),
+            ProcessRuntime = null
+        };
+
+#if NET
+        detectors.Container = new object();
+#endif
+
+        var result = detectors.GetEnabledResourceDetectors();
+
+        var expected = new List<ResourceDetector>
+        {
+            ResourceDetector.AzureAppService,
+            ResourceDetector.Host,
+            ResourceDetector.Process
+        };
+
+#if NET
+        expected.Add(ResourceDetector.Container);
+#endif
+
+        Assert.Equal(expected.Count, result.Count);
+        foreach (var detector in expected)
+        {
+            Assert.Contains(detector, result);
+        }
+    }
 }

test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/Files/TestFile.yaml

@@ -5,3 +5,12 @@ resource:
     - name: service.name
       value: unknown_service
   attributes_list:
+  detection/development:
+    detectors:
+      azureappservice:
+      container:
+      host:
+      operatingsystem:
+      process:
+      processruntime:
+

test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBasedConfiguration/Parser/ConditionalDeserializerTests.cs → test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/Parser/ConditionalDeserializerTests.cs

@@ -2,12 +2,13 @@
 // SPDX-License-Identifier: Apache-2.0
 
 using OpenTelemetry.AutoInstrumentation.Configurations.FileBasedConfiguration.Parser;
+using OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased;
 using Vendors.YamlDotNet.Core;
 using Vendors.YamlDotNet.Serialization;
 using Xunit;
 using YamlParser = Vendors.YamlDotNet.Core.Parser;
 
-namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBasedConfiguration.Parser;
+namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased.Parser;
 
 public class ConditionalDeserializerTests
 {

test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBasedConfiguration/Parser/EnvVarTypeConverterTests.cs → test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/Parser/EnvVarTypeConverterTests.cs

@@ -5,7 +5,7 @@
 using Xunit;
 using YamlParser = Vendors.YamlDotNet.Core.Parser;
 
-namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBasedConfiguration.Parser;
+namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased.Parser;
 
 public class EnvVarTypeConverterTests
 {

test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/ParserTests.cs → test/OpenTelemetry.AutoInstrumentation.Tests/Configurations/FileBased/Parser/ParserTests.cs

@@ -1,18 +1,18 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-using OpenTelemetry.AutoInstrumentation.Configurations.FileBasedConfiguration.Parser;
 using Xunit;
+using YamlParser = OpenTelemetry.AutoInstrumentation.Configurations.FileBasedConfiguration.Parser.Parser;
 
-namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased;
+namespace OpenTelemetry.AutoInstrumentation.Tests.Configurations.FileBased.Parser;
 
 [Collection("Non-Parallel Collection")]
 public class ParserTests
 {
     [Fact]
     public void Parse_FullConfigYaml_ShouldPopulateModelCorrectly()
     {
-        var config = Parser.ParseYaml("Configurations/FileBased/Files/TestFile.yaml");
+        var config = YamlParser.ParseYaml("Configurations/FileBased/Files/TestFile.yaml");
 
         Assert.NotNull(config);
 
@@ -28,6 +28,26 @@ public void Parse_FullConfigYaml_ShouldPopulateModelCorrectly()
 
         Assert.NotNull(config.Resource.AttributesList);
         Assert.Empty(config.Resource.AttributesList);
+        Assert.NotNull(config.Resource.DetectionDevelopment);
+
+#if NET
+        string[] expectedDetecors = [
+            "azureappservice", "container", "host", "operatingsystem", "process", "processruntime"
+                ];
+#endif
+#if NETFRAMEWORK
+        string[] expectedDetecors = [
+            "azureappservice", "host", "operatingsystem", "process", "processruntime"
+                ];
+#endif
+
+        var detectors = config.Resource.DetectionDevelopment.Detectors;
+        Assert.NotNull(detectors);
+
+        foreach (var alias in expectedDetecors)
+        {
+            FileBasedTestHelper.AssertAliasPropertyExists(detectors, alias);
+        }
     }
 
     [Fact]
@@ -37,7 +57,7 @@ public void Parse_EnvVarYaml_ShouldPopulateModelCompletely()
         Environment.SetEnvironmentVariable("OTEL_SERVICE_NAME", "my‑service");
         Environment.SetEnvironmentVariable("OTEL_RESOURCE_ATTRIBUTES", "key=value");
 
-        var config = Parser.ParseYaml("Configurations/FileBased/Files/TestFileEnvVars.yaml");
+        var config = YamlParser.ParseYaml("Configurations/FileBased/Files/TestFileEnvVars.yaml");
 
         Assert.Equal("1.0-rc.1", config.FileFormat);
         var serviceAttr = config.Resource?.Attributes?.First(a => a.Name == "service.name");