Clear Metadata dictonary. Move Metadata to last.

Clear Metadata dictionary when clearing metrics after flush. Move metadata node serialization to bottom, and try add, if it fails ignore. Add tests

Author: hjgraca

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

@@ -1,12 +1,12 @@
 /*
  * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
- * 
+ *
  * Licensed under the Apache License, Version 2.0 (the "License").
  * You may not use this file except in compliance with the License.
  * A copy of the License is located at
- * 
+ *
  *  http://aws.amazon.com/apache2.0
- * 
+ *
  * or in the "license" file accompanying this file. This file is distributed
  * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
  * express or implied. See the License for the specific language governing
@@ -29,7 +29,7 @@ public class Metadata
     /// </summary>
     public Metadata()
     {
-        CloudWatchMetrics = new List<MetricDirective> {new()};
+        CloudWatchMetrics = new List<MetricDirective> { new() };
         CustomMetadata = new Dictionary<string, object>();
     }
 
@@ -66,6 +66,7 @@ public Metadata()
     internal void ClearMetrics()
     {
         _metricDirective.Metrics.Clear();
+        CustomMetadata?.Clear();
     }
 
     /// <summary>
@@ -158,7 +159,7 @@ internal List<MetricDefinition> GetMetrics()
     /// <param name="value">Metadata value</param>
     internal void AddMetadata(string key, object value)
     {
-        CustomMetadata.Add(key, value);
+        CustomMetadata.TryAdd(key, value);
     }
 
     /// <summary>

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

@@ -43,14 +43,14 @@ public Dictionary<string, object> MetricData
             var targetMembers = new Dictionary<string, object>();
 
             foreach (var dimension in AWS.ExpandAllDimensionSets()) targetMembers.Add(dimension.Key, dimension.Value);
-
-            foreach (var metadata in AWS.CustomMetadata) targetMembers.Add(metadata.Key, metadata.Value);
-
+            
             foreach (var metricDefinition in AWS.GetMetrics())
             {
                 var values = metricDefinition.Values;
                 targetMembers.Add(metricDefinition.Name, values.Count == 1 ? values[0] : values);
             }
+            
+            foreach (var metadata in AWS.CustomMetadata) targetMembers.TryAdd(metadata.Key, metadata.Value);
 
             return targetMembers;
         }

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

@@ -546,7 +546,47 @@ public void WhenMetricsAndMetadataAdded_ValidateOutput()
             var result = consoleOut.ToString();
 
             // Assert
-            Assert.Contains("CloudWatchMetrics\":[{\"Namespace\":\"dotnet-powertools-test\",\"Metrics\":[{\"Name\":\"Time\",\"Unit\":\"Milliseconds\"}],\"Dimensions\":[[\"Service\"],[\"functionVersion\"]]}]},\"Service\":\"testService\",\"functionVersion\":\"$LATEST\",\"env\":\"dev\",\"Time\":100.7}"
+            Assert.Contains("CloudWatchMetrics\":[{\"Namespace\":\"dotnet-powertools-test\",\"Metrics\":[{\"Name\":\"Time\",\"Unit\":\"Milliseconds\"}],\"Dimensions\":[[\"Service\"],[\"functionVersion\"]]}]},\"Service\":\"testService\",\"functionVersion\":\"$LATEST\",\"Time\":100.7,\"env\":\"dev\"}"
+                , result);
+
+            // Reset
+            handler.ResetForTest();
+        }
+        
+        [Fact]
+        public void When_Metrics_And_Metadata_Added_With_Same_Key_Should_Only_Write_Metrics()
+        {
+            // Arrange
+            var methodName = Guid.NewGuid().ToString();
+            var consoleOut = new StringWriter();
+            Console.SetOut(consoleOut);
+            var configurations = Substitute.For<IPowertoolsConfigurations>();
+
+            var metrics = new Metrics(
+                configurations,
+                nameSpace: "dotnet-powertools-test",
+                service: "testService"
+            );
+
+            var handler = new MetricsAspectHandler(
+                metrics,
+                false
+            );
+
+            var eventArgs = new AspectEventArgs { Name = methodName };
+
+            // Act 
+            handler.OnEntry(eventArgs);
+            Metrics.AddDimension("functionVersion", "$LATEST");
+            Metrics.AddMetric("Time", 100.7, MetricUnit.Milliseconds);
+            Metrics.AddMetadata("Time", "dev");
+            handler.OnExit(eventArgs);
+
+            var result = consoleOut.ToString();
+
+            // Assert
+            // No Metadata key was added
+            Assert.Contains("CloudWatchMetrics\":[{\"Namespace\":\"dotnet-powertools-test\",\"Metrics\":[{\"Name\":\"Time\",\"Unit\":\"Milliseconds\"}],\"Dimensions\":[[\"Service\"],[\"functionVersion\"]]}]},\"Service\":\"testService\",\"functionVersion\":\"$LATEST\",\"Time\":100.7}"
                 , result);
 
             // Reset

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

@@ -0,0 +1,44 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+using System.Globalization;
+using System.Threading.Tasks;
+
+namespace AWS.Lambda.Powertools.Metrics.Tests.Handlers;
+
+public class FunctionHandler
+{
+    [Metrics(Namespace = "ns", Service = "svc")]
+    public async Task<string> HandleSameKey(string input)
+    {
+        Metrics.AddMetric("MyMetric", 1);
+        Metrics.AddMetadata("MyMetric", "meta");
+
+        await Task.Delay(1);
+
+        return input.ToUpper(CultureInfo.InvariantCulture);
+    }
+    
+    [Metrics(Namespace = "ns", Service = "svc")]
+    public async Task<string> HandleTestSecondCall(string input)
+    {
+        Metrics.AddMetric("MyMetric", 1);
+        Metrics.AddMetadata("MyMetadata", "meta");
+        
+        await Task.Delay(1);
+
+        return input.ToUpper(CultureInfo.InvariantCulture);
+    }
+}

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

@@ -0,0 +1,52 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+using System.Threading.Tasks;
+using Xunit;
+
+namespace AWS.Lambda.Powertools.Metrics.Tests.Handlers;
+
+[Collection("Sequential")]
+public class FunctionHandlerTests
+{
+    [Fact]
+    public async Task When_Metrics_Add_Metadata_Same_Key_Should_Ignore_Metadata()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var handler = new FunctionHandler();
+        
+        // Act
+        var exception = await Record.ExceptionAsync( () => handler.HandleSameKey("whatever"));
+        
+        // Assert
+        Assert.Null(exception);
+    }
+    
+    [Fact]
+    public async Task When_Metrics_Add_Metadata_Second_Invocation_Should_Not_Throw_Exception()
+    {
+        // Arrange
+        Metrics.ResetForTest();
+        var handler = new FunctionHandler();
+
+        // Act
+        var exception = await Record.ExceptionAsync( () => handler.HandleTestSecondCall("whatever"));
+        Assert.Null(exception);
+        
+        exception = await Record.ExceptionAsync( () => handler.HandleTestSecondCall("whatever"));
+        Assert.Null(exception);
+    }
+}