feat(metrics): enhance documentation for Cold Start Function Name dim…

…ension and update test classes
aws-powertools · Feb 25, 2025 · 75ac8ef · 75ac8ef
1 parent 97dc991
commit 75ac8ef
Show file tree

Hide file tree

Showing 5 changed files with 70 additions and 4 deletions.
diff --git a/docs/core/metrics-v2.md b/docs/core/metrics-v2.md
@@ -657,7 +657,7 @@ By default it will skip all previously defined dimensions including default dime
         Metrics.PushSingleMetric("SingleMetric", 1, MetricUnit.Count, defaultDimensions: Metrics.DefaultDimensions );
         ...
     ```
-=== "Default Dimensions Options / Builder patterns .cs"
+=== "Default Dimensions Options / Builder patterns"
 
     ```csharp hl_lines="9-13 18"
     using AWS.Lambda.Powertools.Metrics;
@@ -682,6 +682,54 @@ By default it will skip all previously defined dimensions including default dime
         ...
     ```
 
+### Cold start Function Name dimension
+
+In cases where you want to customize the `FunctionName` dimension in Cold Start metrics.
+
+This is useful where you want to maintain the same name in case of auto generated handler names (cdk, top-level statement functions, etc.)
+
+Example:
+
+=== "In decorator"
+
+    ```csharp hl_lines="5"
+    using AWS.Lambda.Powertools.Metrics;
+
+    public class Function {
+
+      [Metrics(FunctionName = "MyFunctionName", Namespace = "ExampleApplication", Service = "Booking")]
+      public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigProxyEvent, ILambdaContext context)
+      {
+        Metrics.AddMetric("SuccessfulBooking", 1, MetricUnit.Count);
+        ...
+      }
+    ```
+=== "Configure / Builder patterns"
+
+    ```csharp hl_lines="12"
+    using AWS.Lambda.Powertools.Metrics;
+
+    public class Function {
+      
+      public Function()
+      {
+        Metrics.Configure(options =>
+        {
+            options.Namespace = "dotnet-powertools-test";
+            options.Service = "testService";
+            options.CaptureColdStart = true;
+            options.FunctionName = "MyFunctionName";
+        });
+      }
+
+      [Metrics]
+      public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigProxyEvent, ILambdaContext context)
+      {
+        Metrics.AddMetric("SuccessfulBooking", 1, MetricUnit.Count);
+        ...
+      }
+    ```
+
 ## AspNetCore
 
 ### Installation

diff --git a/libraries/src/AWS.Lambda.Powertools.Metrics/InternalsVisibleTo.cs b/libraries/src/AWS.Lambda.Powertools.Metrics/InternalsVisibleTo.cs
@@ -15,4 +15,5 @@
 
 using System.Runtime.CompilerServices;
 
-[assembly: InternalsVisibleTo("AWS.Lambda.Powertools.Metrics.Tests")]
+[assembly: InternalsVisibleTo("AWS.Lambda.Powertools.Metrics.Tests")]
+[assembly: InternalsVisibleTo("AWS.Lambda.Powertools.Metrics.AspNetCore.Tests")]
diff --git a/libraries/tests/AWS.Lambda.Powertools.Metrics.AspNetCore.Tests/MetricsFilterTests.cs b/libraries/tests/AWS.Lambda.Powertools.Metrics.AspNetCore.Tests/MetricsFilterTests.cs
@@ -6,8 +6,15 @@
 
 namespace AWS.Lambda.Powertools.Metrics.AspNetCore.Tests;
 
-public class MetricsFilterTests
+[Collection("Sequential")]
+public class MetricsFilterTests : IDisposable
 {
+    public void Dispose()
+    {
+        MetricsHelper.ResetColdStart();
+        MetricsAspect.ResetForTest();
+    }
+
     private readonly IMetrics _metrics;
     private readonly EndpointFilterInvocationContext _context;
     private readonly ILambdaContext _lambdaContext;

diff --git a/libraries/tests/AWS.Lambda.Powertools.Metrics.AspNetCore.Tests/MetricsHelperTests.cs b/libraries/tests/AWS.Lambda.Powertools.Metrics.AspNetCore.Tests/MetricsHelperTests.cs
@@ -8,8 +8,15 @@
 
 namespace AWS.Lambda.Powertools.Metrics.AspNetCore.Tests;
 
-public class MetricsHelperTests
+[Collection("Sequential")]
+public class MetricsHelperTests : IDisposable
 {
+    public void Dispose()
+    {
+        MetricsHelper.ResetColdStart();
+        MetricsAspect.ResetForTest();
+    }
+
     [Fact]
     public async Task CaptureColdStartMetrics_WhenEnabled_ShouldPushMetric()
     {

diff --git a/.../tests/AWS.Lambda.Powertools.Metrics.AspNetCore.Tests/MetricsMiddlewareExtensionsTests.cs b/.../tests/AWS.Lambda.Powertools.Metrics.AspNetCore.Tests/MetricsMiddlewareExtensionsTests.cs
@@ -7,16 +7,19 @@
 
 namespace AWS.Lambda.Powertools.Metrics.AspNetCore.Tests;
 
+[Collection("Sequential")]
 public class MetricsMiddlewareExtensionsTests : IDisposable
 {
     public MetricsMiddlewareExtensionsTests()
     {
         MetricsHelper.ResetColdStart();
+        MetricsAspect.ResetForTest();
     }
 
     public void Dispose()
     {
         MetricsHelper.ResetColdStart();
+        MetricsAspect.ResetForTest();
     }
 
     [Fact]