[Resources.Azure] Add App Service account and resource group attributes

src/OpenTelemetry.Resources.Azure/AppServiceResourceDetector.cs

@@ -35,7 +35,20 @@ public Resource Detect()
                     new(ResourceSemanticConventions.AttributeCloudPlatform, ResourceAttributeConstants.AzureAppServicePlatformValue),
                 };
 
-                var azureResourceUri = GetAzureResourceURI(websiteSiteName);
+                var websiteResourceGroup = Environment.GetEnvironmentVariable(ResourceAttributeConstants.AppServiceResourceGroupEnvVar);
+                if (!string.IsNullOrEmpty(websiteResourceGroup))
+                {
+                    attributeList.Add(new(ResourceAttributeConstants.AzureResourceGroupName, websiteResourceGroup));
+                }
+
+                var websiteOwnerName = Environment.GetEnvironmentVariable(ResourceAttributeConstants.AppServiceOwnerNameEnvVar);
+                var subscriptionId = GetSubscriptionId(websiteOwnerName);
+                if (subscriptionId is { Length: > 0 })
+                {
+                    attributeList.Add(new(ResourceSemanticConventions.AttributeCloudAccount, subscriptionId));
+                }
+
+                var azureResourceUri = GetAzureResourceURI(websiteSiteName, websiteResourceGroup, subscriptionId);
                 if (azureResourceUri != null)
                 {
                     attributeList.Add(new(ResourceSemanticConventions.AttributeCloudResourceId, azureResourceUri));
@@ -63,20 +76,28 @@ public Resource Detect()
         return Resource.Empty;
     }
 
-    private static string? GetAzureResourceURI(string websiteSiteName)
+    private static string? GetAzureResourceURI(string websiteSiteName, string? websiteResourceGroup, string? subscriptionId)
+    {
+        return string.IsNullOrEmpty(websiteResourceGroup) || string.IsNullOrEmpty(subscriptionId)
+            ? null
+            : $"/subscriptions/{subscriptionId}/resourceGroups/{websiteResourceGroup}/providers/Microsoft.Web/sites/{websiteSiteName}";
+    }
+
+    private static string? GetSubscriptionId(string? websiteOwnerName)
     {
-        var websiteResourceGroup = Environment.GetEnvironmentVariable(ResourceAttributeConstants.AppServiceResourceGroupEnvVar);
-        var websiteOwnerName = Environment.GetEnvironmentVariable(ResourceAttributeConstants.AppServiceOwnerNameEnvVar) ?? string.Empty;
+        // WEBSITE_OWNER_NAME typically has the form
+        // "<subscription-id>+<resource-group>-<region>webspace".
+        // See https://learn.microsoft.com/azure/app-service/reference-app-settings#app-environment
+        if (websiteOwnerName == null)
+        {
+            return null;
+        }
 
 #if NET
         var index = websiteOwnerName.IndexOf('+', StringComparison.Ordinal);
 #else
         var index = websiteOwnerName.IndexOf("+", StringComparison.Ordinal);
 #endif
-        var subscriptionId = index > 0 ? websiteOwnerName.Substring(0, index) : websiteOwnerName;
-
-        return string.IsNullOrEmpty(websiteResourceGroup) || string.IsNullOrEmpty(subscriptionId)
-            ? null
-            : $"/subscriptions/{subscriptionId}/resourceGroups/{websiteResourceGroup}/providers/Microsoft.Web/sites/{websiteSiteName}";
+        return index > 0 ? websiteOwnerName.Substring(0, index) : websiteOwnerName;
     }
 }

src/OpenTelemetry.Resources.Azure/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Add `cloud.account.id` and `azure.resource_group.name` attributes to the Azure
+  App Service resource detector.
+  ([#5138](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/5138))
+
 ## 1.18.0-beta.1
 
 Released 2026-Aug-21

src/OpenTelemetry.Resources.Azure/README.md

@@ -51,6 +51,8 @@ using var loggerFactory = LoggerFactory.Create(builder =>
 | Attribute                   | Description                                                                                                                                                                                               |
 | --------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | azure.app.service.stamp     | The specific "stamp" cluster within Azure where the App Service is running, e.g., "waws-prod-sn1-001".                                                                                                    |
+| azure.resource_group.name   | The Azure resource group from `WEBSITE_RESOURCE_GROUP`. Emitted when the environment variable is non-empty.                                                                                               |
+| cloud.account.id            | The Azure subscription ID parsed from `WEBSITE_OWNER_NAME`. Emitted when the environment variable is non-empty.                                                                                           |
 | cloud.platform              | The cloud platform. Here, it's always "azure_app_service".                                                                                                                                                |
 | cloud.provider              | The cloud service provider. In this context, it's always "azure".                                                                                                                                         |
 | cloud.resource_id           | The Azure Resource Manager URI uniquely identifying the Azure App Service. Typically in the format "/subscriptions/{subscriptionId}/resourceGroups/{groupName}/providers/Microsoft.Web/sites/{siteName}". |

src/OpenTelemetry.Resources.Azure/ResourceAttributeConstants.cs

@@ -7,6 +7,7 @@ internal sealed class ResourceAttributeConstants
 {
     // AppService resource attributes
     internal const string AzureAppServiceStamp = "azure.app.service.stamp";
+    internal const string AzureResourceGroupName = "azure.resource_group.name";
 
     // Azure VM resource attributes
     internal const string AzureVmScaleSetName = "azure.vm.scaleset.name";

test/OpenTelemetry.Resources.Azure.Tests/AzureResourceDetectorTests.cs

@@ -104,7 +104,9 @@ public void AppServiceResourceDetectorReturnsResourceWithAttributes()
             Assert.StartsWith("https://opentelemetry.io/schemas/", resource.SchemaUrl);
 
             var expectedResourceUri = "/subscriptions/testtestSubscriptionId/resourceGroups/testResourceGroup/providers/Microsoft.Web/sites/sitename";
+            Assert.Contains(new KeyValuePair<string, object>(ResourceSemanticConventions.AttributeCloudAccount, "testtestSubscriptionId"), resource.Attributes);
             Assert.Contains(new KeyValuePair<string, object>(ResourceSemanticConventions.AttributeCloudResourceId, expectedResourceUri), resource.Attributes);
+            Assert.Contains(new KeyValuePair<string, object>(ResourceAttributeConstants.AzureResourceGroupName, "testResourceGroup"), resource.Attributes);
             Assert.Contains(new KeyValuePair<string, object>(ResourceSemanticConventions.AttributeServiceName, "sitename"), resource.Attributes);
 
             foreach (var kvp in AppServiceResourceDetector.AppServiceResourceAttributes)
@@ -114,6 +116,42 @@ public void AppServiceResourceDetectorReturnsResourceWithAttributes()
         }
     }
 
+    [Fact]
+    public void AppServiceResourceDetectorUsesUnseparatedOwnerNameAsCloudAccount()
+    {
+        var resource = DetectAppServiceResource("subscription-without-separator", null);
+
+        Assert.Contains(
+            new KeyValuePair<string, object>(ResourceSemanticConventions.AttributeCloudAccount, "subscription-without-separator"),
+            resource.Attributes);
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceAttributeConstants.AzureResourceGroupName);
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceSemanticConventions.AttributeCloudResourceId);
+    }
+
+    [Fact]
+    public void AppServiceResourceDetectorEmitsResourceGroupWithoutCloudAccount()
+    {
+        var resource = DetectAppServiceResource(null, "testResourceGroup");
+
+        Assert.Contains(
+            new KeyValuePair<string, object>(ResourceAttributeConstants.AzureResourceGroupName, "testResourceGroup"),
+            resource.Attributes);
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceSemanticConventions.AttributeCloudAccount);
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceSemanticConventions.AttributeCloudResourceId);
+    }
+
+    [Theory]
+    [InlineData("", null)]
+    [InlineData(null, "")]
+    public void AppServiceResourceDetectorSuppressesEmptyIdentityAttributes(string? websiteOwnerName, string? websiteResourceGroup)
+    {
+        var resource = DetectAppServiceResource(websiteOwnerName, websiteResourceGroup);
+
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceSemanticConventions.AttributeCloudAccount);
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceAttributeConstants.AzureResourceGroupName);
+        Assert.DoesNotContain(resource.Attributes, attribute => attribute.Key == ResourceSemanticConventions.AttributeCloudResourceId);
+    }
+
     [Fact]
     public void TestAzureVmResourceDetector()
     {
@@ -277,4 +315,19 @@ public void CustomServiceNameAfterAppServiceDetectorOverridesDetectorValue()
                 resource.Attributes);
         }
     }
+
+    private static Resource DetectAppServiceResource(string? websiteOwnerName, string? websiteResourceGroup)
+    {
+        var environment = new Dictionary<string, string?>
+        {
+            [ResourceAttributeConstants.AppServiceSiteNameEnvVar] = "sitename",
+            [ResourceAttributeConstants.AppServiceOwnerNameEnvVar] = websiteOwnerName,
+            [ResourceAttributeConstants.AppServiceResourceGroupEnvVar] = websiteResourceGroup,
+        };
+
+        using (EnvironmentVariableScope.Create(environment))
+        {
+            return ResourceBuilder.CreateEmpty().AddAzureAppServiceDetector().Build();
+        }
+    }
 }