chore: Metrics PushSingleMetric default dimensions

docs/core/metrics-v2.md

@@ -602,6 +602,30 @@ CloudWatch EMF uses the same dimensions across all your metrics. Use **`PushSing
 
 === "Function.cs"
 
+    ```csharp hl_lines="8-13"
+    using AWS.Lambda.Powertools.Metrics;
+
+    public class Function {
+
+      [Metrics(Namespace = ExampleApplication, Service = "Booking")]
+      public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigProxyEvent, ILambdaContext context)
+      {
+        Metrics.PushSingleMetric(
+                    metricName: "ColdStart",
+                    value: 1,
+                    unit: MetricUnit.Count,
+                    nameSpace: "ExampleApplication",
+                    service: "Booking");
+        ...
+    ```
+
+By default it will skip all previously defined dimensions including default dimensions. Use `dimensions` argument if you want to reuse default dimensions or specify custom dimensions from a dictionary.
+
+- `Metrics.DefaultDimensions`: Reuse default dimensions when using static Metrics
+- `Options.DefaultDimensions`: Reuse default dimensions when using Builder or Configure patterns
+
+=== "New Default Dimensions.cs"
+
     ```csharp hl_lines="8-17"
     using AWS.Lambda.Powertools.Metrics;
 
@@ -622,6 +646,47 @@ CloudWatch EMF uses the same dimensions across all your metrics. Use **`PushSing
                     });
         ...
     ```
+=== "Default Dimensions static.cs"
+
+    ```csharp hl_lines="8-12"
+    using AWS.Lambda.Powertools.Metrics;
+
+    public class Function {
+
+      [Metrics(Namespace = ExampleApplication, Service = "Booking")]
+      public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigProxyEvent, ILambdaContext context)
+      {
+         Metrics.SetDefaultDimensions(new Dictionary<string, string> 
+        {
+            { "Default", "SingleMetric" }
+        });
+        Metrics.PushSingleMetric("SingleMetric", 1, MetricUnit.Count, dimensions: Metrics.DefaultDimensions );
+        ...
+    ```
+=== "Default Dimensions Options / Builder patterns .cs"
+
+    ```csharp hl_lines="9-13 18"
+    using AWS.Lambda.Powertools.Metrics;
+
+    public MetricsnBuilderHandler(IMetrics metrics = null)
+    {
+        _metrics = metrics ?? new MetricsBuilder()
+            .WithCaptureColdStart(true)
+            .WithService("testService")
+            .WithNamespace("dotnet-powertools-test")
+            .WithDefaultDimensions(new Dictionary<string, string>
+            {
+                { "Environment", "Prod1" },
+                { "Another", "One" }
+            }).Build();
+    }
+
+    public void HandlerSingleMetricDimensions()
+    {
+        _metrics.PushSingleMetric("SuccessfulBooking", 1, MetricUnit.Count, dimensions: _metrics.Options.DefaultDimensions);
+    }
+        ...
+    ```
 
 ## AspNetCore
 

libraries/src/AWS.Lambda.Powertools.Metrics/Metrics.cs

@@ -36,6 +36,21 @@ public static IMetrics Instance
         get => _instance ?? new Metrics(PowertoolsConfigurations.Instance, consoleWrapper: new ConsoleWrapper());
         private set => _instance = value;
     }
+
+    /// <summary>
+    /// Gets DefaultDimensions
+    /// </summary>
+    public static Dictionary<string, string> DefaultDimensions => Instance.Options.DefaultDimensions;
+
+    /// <summary>
+    /// Gets Namespace
+    /// </summary>
+    public static string Namespace => Instance.Options.Namespace;
+
+    /// <summary>
+    /// Gets Service 
+    /// </summary>
+    public static string Service => Instance.Options.Service;
 
     /// <inheritdoc />
     public MetricsOptions Options => _options ??

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/EMFValidationTests.cs

@@ -176,6 +176,32 @@ public void When_PushSingleMetric_With_Namespace()
             Assert.Contains("\"CloudWatchMetrics\":[{\"Namespace\":\"ExampleApplication\",\"Metrics\":[{\"Name\":\"SingleMetric\",\"Unit\":\"Count\",\"StorageResolution\":1}],\"Dimensions\":[[\"Default\"]]}]},\"Default\":\"SingleMetric\",\"SingleMetric\":1}", metricsOutput);
         }
 
+        [Trait("Category", "SchemaValidation")]
+        [Fact]
+        public void When_PushSingleMetric_With_No_DefaultDimensions()
+        {
+            // Act
+            _handler.PushSingleMetricNoDefaultDimensions();
+
+            var metricsOutput = _consoleOut.ToString();
+
+            // Assert
+            Assert.Contains("\"CloudWatchMetrics\":[{\"Namespace\":\"ExampleApplication\",\"Metrics\":[{\"Name\":\"SingleMetric\",\"Unit\":\"Count\"}],\"Dimensions\":[[]]}]},\"SingleMetric\":1}", metricsOutput);
+        }
+
+        [Trait("Category", "SchemaValidation")]
+        [Fact]
+        public void When_PushSingleMetric_With_DefaultDimensions()
+        {
+            // Act
+            _handler.PushSingleMetricDefaultDimensions();
+
+            var metricsOutput = _consoleOut.ToString();
+
+            // Assert
+            Assert.Contains("\"CloudWatchMetrics\":[{\"Namespace\":\"ExampleApplication\",\"Metrics\":[{\"Name\":\"SingleMetric\",\"Unit\":\"Count\"}],\"Dimensions\":[[\"Default\"]]}]},\"Default\":\"SingleMetric\",\"SingleMetric\":1}", metricsOutput);
+        }
+
         [Trait("Category", "SchemaValidation")]
         [Fact]
         public void When_PushSingleMetric_With_Env_Namespace()

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/Handlers/FunctionHandler.cs

@@ -63,6 +63,22 @@ public void PushSingleMetricWithNamespace()
             });
     }
 
+    [Metrics(Namespace = "ExampleApplication")]
+    public void PushSingleMetricNoDefaultDimensions()
+    {
+        Metrics.PushSingleMetric("SingleMetric", 1, MetricUnit.Count);
+    }
+
+    [Metrics(Namespace = "ExampleApplication")]
+    public void PushSingleMetricDefaultDimensions()
+    {
+        Metrics.SetDefaultDimensions(new Dictionary<string, string> 
+        {
+            { "Default", "SingleMetric" }
+        });
+        Metrics.PushSingleMetric("SingleMetric", 1, MetricUnit.Count, dimensions: Metrics.DefaultDimensions );
+    }
+
     [Metrics]
     public void PushSingleMetricWithEnvNamespace()
     {
@@ -218,4 +234,10 @@ public void HandlerRaiseOnEmptyMetrics()
     {
 
     }
+
+    [Metrics(Namespace = "ns", Service = "svc", CaptureColdStart = true)]
+    public void HandleOnlyDimensionsInColdStart(ILambdaContext context)
+    {
+        Metrics.AddMetric("MyMetric", 1);
+    }
 }

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/Handlers/FunctionHandlerTests.cs

@@ -270,7 +270,7 @@ public void When_RaiseOnEmptyMetrics_And_NoMetrics_Should_ThrowException()
         var exception = Assert.Throws<SchemaValidationException>(() => _handler.HandlerRaiseOnEmptyMetrics());
         Assert.Equal("No metrics have been provided.", exception.Message);
     }
-    
+
     [Fact]
     public void Handler_With_Builder_Should_Raise_Empty_Metrics()
     {
@@ -282,6 +282,66 @@ public void Handler_With_Builder_Should_Raise_Empty_Metrics()
         Assert.Equal("No metrics have been provided.", exception.Message);
     }
 
+    [Fact]
+    public void Handler_With_Builder_Push_Single_Metric_No_Dimensions()
+    {
+        // Arrange
+        var handler = new MetricsnBuilderHandler();
+
+        // Act
+        handler.HandlerSingleMetric();
+
+        // Get the output and parse it
+        var metricsOutput = _consoleOut.ToString();
+
+        Assert.Contains(
+            "\"CloudWatchMetrics\":[{\"Namespace\":\"dotnet-powertools-test\",\"Metrics\":[{\"Name\":\"SuccessfulBooking\",\"Unit\":\"Count\"}],\"Dimensions\":[[]]}]},\"SuccessfulBooking\":1}",
+            metricsOutput);
+    }
+
+    [Fact]
+    public void Handler_With_Builder_Push_Single_Metric_Dimensions()
+    {
+        // Arrange
+        var handler = new MetricsnBuilderHandler();
+
+        // Act
+        handler.HandlerSingleMetricDimensions();
+
+        // Get the output and parse it
+        var metricsOutput = _consoleOut.ToString();
+
+        Assert.Contains(
+            "\"CloudWatchMetrics\":[{\"Namespace\":\"dotnet-powertools-test\",\"Metrics\":[{\"Name\":\"SuccessfulBooking\",\"Unit\":\"Count\"}],\"Dimensions\":[[\"Service\",\"Environment\",\"Another\"]]}]},\"Service\":\"testService\",\"Environment\":\"Prod1\",\"Another\":\"One\",\"SuccessfulBooking\":1}",
+            metricsOutput);
+    }
+
+    [Fact]
+    public void Dimension_Only_Set_In_Cold_Start()
+    {
+        // Arrange
+        var handler = new FunctionHandler();
+
+        // Act
+        handler.HandleOnlyDimensionsInColdStart(new TestLambdaContext
+        {
+            FunctionName = "My_Function_Name"
+        });
+
+        // Get the output and parse it
+        var metricsOutput = _consoleOut.ToString();
+
+        // Assert cold start
+        Assert.Contains(
+            "\"CloudWatchMetrics\":[{\"Namespace\":\"ns\",\"Metrics\":[{\"Name\":\"ColdStart\",\"Unit\":\"Count\"}],\"Dimensions\":[[\"Service\",\"FunctionName\"]]}]},\"Service\":\"svc\",\"FunctionName\":\"My_Function_Name\",\"ColdStart\":1}",
+            metricsOutput);
+
+        // Assert successful add metric without dimensions
+        Assert.Contains(
+            "\"CloudWatchMetrics\":[{\"Namespace\":\"ns\",\"Metrics\":[{\"Name\":\"MyMetric\",\"Unit\":\"None\"}],\"Dimensions\":[[\"Service\"]]}]},\"Service\":\"svc\",\"MyMetric\":1}",
+            metricsOutput);
+    }
+
     public void Dispose()
     {
         Metrics.ResetForTest();

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/Handlers/MetricsnBuilderHandler.cs

@@ -32,4 +32,14 @@ public void Handler(ILambdaContext context)
     public void HandlerEmpty()
     {
     }
+
+    public void HandlerSingleMetric()
+    {
+        _metrics.PushSingleMetric("SuccessfulBooking", 1, MetricUnit.Count);
+    }
+
+    public void HandlerSingleMetricDimensions()
+    {
+        _metrics.PushSingleMetric("SuccessfulBooking", 1, MetricUnit.Count, dimensions: _metrics.Options.DefaultDimensions);
+    }
 }

libraries/tests/AWS.Lambda.Powertools.Metrics.Tests/MetricsTests.cs

@@ -243,4 +243,82 @@ public void When_ColdStart_And_DefaultDimensions_Is_Null_Should_Only_Add_Service
             Arg.Is<string>(s => s.Contains("\"CloudWatchMetrics\":[{\"Namespace\":\"dotnet-powertools-test\",\"Metrics\":[{\"Name\":\"ColdStart\",\"Unit\":\"Count\"}],\"Dimensions\":[[\"FunctionName\"]]}]},\"FunctionName\":\"TestFunction\",\"ColdStart\":1}"))
         );
     }
+
+    [Fact]
+    public void Namespace_Should_Return_OptionsNamespace()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var metricsMock = Substitute.For<IMetrics>();
+        var optionsMock = new MetricsOptions
+        {
+            Namespace = "TestNamespace"
+        };
+
+        metricsMock.Options.Returns(optionsMock);
+        Metrics.UseMetricsForTests(metricsMock);
+
+        // Act
+        var result = Metrics.Namespace;
+
+        // Assert
+        Assert.Equal("TestNamespace", result);
+    }
+
+    [Fact]
+    public void Service_Should_Return_OptionsService()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var metricsMock = Substitute.For<IMetrics>();
+        var optionsMock = new MetricsOptions
+        {
+            Service = "TestService"
+        };
+
+        metricsMock.Options.Returns(optionsMock);
+        Metrics.UseMetricsForTests(metricsMock);
+
+        // Act
+        var result = Metrics.Service;
+
+        // Assert
+        Assert.Equal("TestService", result);
+    }
+
+    [Fact]
+    public void Namespace_Should_Return_Null_When_Not_Set()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var metricsMock = Substitute.For<IMetrics>();
+        var optionsMock = new MetricsOptions();
+
+        metricsMock.Options.Returns(optionsMock);
+        Metrics.UseMetricsForTests(metricsMock);
+
+        // Act
+        var result = Metrics.Namespace;
+
+        // Assert
+        Assert.Null(result);
+    }
+
+    [Fact]
+    public void Service_Should_Return_Null_When_Not_Set()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var metricsMock = Substitute.For<IMetrics>();
+        var optionsMock = new MetricsOptions();
+
+        metricsMock.Options.Returns(optionsMock);
+        Metrics.UseMetricsForTests(metricsMock);
+
+        // Act
+        var result = Metrics.Service;
+
+        // Assert
+        Assert.Null(result);
+    }
 }