move metrics instanciation to aspect. reset test after run

Author: hjgraca

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

@@ -39,13 +39,17 @@ public class MetricsAspect
     /// </summary>
     private bool _clearLambdaContext;
 
-    private IMetrics _metricsInstance;
+    /// <summary>
+    ///     Gets the metrics instance.
+    /// </summary>
+    /// <value>The metrics instance.</value>
+    private static IMetrics _metricsInstance;
 
     static MetricsAspect()
     {
         _isColdStart = true;
     }
-    
+
     /// <summary>
     /// Runs before the execution of the method marked with the Metrics Attribute
     /// </summary>
@@ -66,13 +70,18 @@ public void Before(
         [Argument(Source.ReturnType)] Type returnType,
         [Argument(Source.Triggers)] Attribute[] triggers)
     {
-        
         // Before running Function
-        
+
         var trigger = triggers.OfType<MetricsAttribute>().First();
-        
-        _metricsInstance = trigger.MetricsInstance;
-        
+
+        _metricsInstance ??= new Metrics(
+            PowertoolsConfigurations.Instance,
+            trigger.Namespace,
+            trigger.Service,
+            trigger.RaiseOnEmptyMetrics,
+            trigger.CaptureColdStart
+        );
+
         var eventArgs = new AspectEventArgs
         {
             Instance = instance,
@@ -112,25 +121,27 @@ public void Before(
             );
         }
     }
-    
+
     /// <summary>
     /// OnExit runs after the execution of the method marked with the Metrics Attribute
     /// </summary>
     [Advice(Kind.After)]
-    public void Exit() {
+    public void Exit()
+    {
         _metricsInstance.Flush();
         if (_clearLambdaContext)
             PowertoolsLambdaContext.Clear();
     }
-    
-    
+
+
     /// <summary>
     /// Reset the aspect for testing purposes.
     /// </summary>
-     internal static void ResetForTest()
-     {
-         _isColdStart = true;
-         Metrics.ResetForTest();
-         PowertoolsLambdaContext.Clear();
-     }
+    internal static void ResetForTest()
+    {
+        _metricsInstance = null;
+        _isColdStart = true;
+        Metrics.ResetForTest();
+        PowertoolsLambdaContext.Clear();
+    }
 }

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

@@ -130,16 +130,4 @@ public class MetricsAttribute : Attribute
     /// </summary>
     /// <value><c>true</c> if [raise on empty metrics]; otherwise, <c>false</c>.</value>
     public bool RaiseOnEmptyMetrics { get; set; }
-
-    /// <summary>
-    ///     Gets the metrics instance.
-    /// </summary>
-    /// <value>The metrics instance.</value>
-    internal IMetrics MetricsInstance => new Metrics(
-            PowertoolsConfigurations.Instance,
-            Namespace,
-            Service,
-            RaiseOnEmptyMetrics,
-            CaptureColdStart
-        );
 }

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

@@ -5,7 +5,7 @@
 namespace AWS.Lambda.Powertools.Metrics.Tests.Handlers;
 
 [Collection("Sequential")]
-public sealed class ExceptionFunctionHandlerTests
+public sealed class ExceptionFunctionHandlerTests : IDisposable
 {
     [Fact]
     public async Task Stack_Trace_Included_When_Decorator_Present()
@@ -51,4 +51,9 @@ public async Task Decorator_In_Non_Handler_Method_Does_Not_Throw_Exception()
         var tracedException = await Record.ExceptionAsync(Handle);
         Assert.Null(tracedException);
     }
+
+    public void Dispose()
+    {
+        MetricsAspect.ResetForTest();
+    }
 }

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

@@ -13,13 +13,14 @@
  * permissions and limitations under the License.
  */
 
+using System;
 using System.Threading.Tasks;
 using Xunit;
 
 namespace AWS.Lambda.Powertools.Metrics.Tests.Handlers;
 
 [Collection("Sequential")]
-public class FunctionHandlerTests
+public class FunctionHandlerTests : IDisposable
 {
     [Fact]
     public async Task When_Metrics_Add_Metadata_Same_Key_Should_Ignore_Metadata()
@@ -61,4 +62,9 @@ public async Task When_Metrics_Add_Metadata_FromMultipleThread_Should_Not_Throw_
         var exception = await Record.ExceptionAsync(() => handler.HandleMultipleThreads("whatever"));
         Assert.Null(exception);
     }
+
+    public void Dispose()
+    {
+        MetricsAspect.ResetForTest();
+    }
 }