Merge pull request #208 from amirkaws/amirkaws-cold-start-capture-warning-bug-fix

fix: ColdStart capture warning

Author: sliedig

examples/Metrics/src/HelloWorld/Function.cs

@@ -74,8 +74,7 @@ public Function(IDynamoDBContext dynamoDbContext, HttpClient httpClient)
     /// <returns>API Gateway Proxy response</returns>
     [Logging(LogEvent = true)]
     [Metrics(CaptureColdStart = true)]
-    public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigwProxyEvent,
-        ILambdaContext context)
+    public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigwProxyEvent, ILambdaContext context)
     {
         var requestContextRequestId = apigwProxyEvent.RequestContext.RequestId;
 

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

@@ -78,8 +78,14 @@ public void OnExit(AspectEventArgs eventArgs)
     /// <param name="eventArgs">Aspect Arguments</param>
     public void OnEntry(AspectEventArgs eventArgs)
     {
-        if (!_isColdStart || !_captureColdStartEnabled) return;
-
+        if (!_isColdStart)
+            return;
+        
+        _isColdStart = false;
+        
+        if (!_captureColdStartEnabled) 
+            return;
+        
         var nameSpace = _metrics.GetNamespace();
         var service = _metrics.GetService();
         Dictionary<string, string> dimensions = null;
@@ -102,8 +108,6 @@ public void OnEntry(AspectEventArgs eventArgs)
             service,
             dimensions
         );
-
-        _isColdStart = false;
     }
 
     /// <summary>

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

@@ -45,6 +45,11 @@ public class Metrics : IMetrics
     ///     If true, Powertools will throw an exception on empty metrics when trying to flush
     /// </summary>
     private readonly bool _raiseOnEmptyMetrics;
+    
+    /// <summary>
+    ///     The capture cold start enabled
+    /// </summary>
+    private readonly bool _captureColdStartEnabled;
 
     /// <summary>
     ///     Creates a Metrics object that provides features to send metrics to Amazon Cloudwatch using the Embedded metric
@@ -55,14 +60,16 @@ public class Metrics : IMetrics
     /// <param name="nameSpace">Metrics Namespace Identifier</param>
     /// <param name="service">Metrics Service Name</param>
     /// <param name="raiseOnEmptyMetrics">Instructs metrics validation to throw exception if no metrics are provided</param>
+    /// <param name="captureColdStartEnabled">Instructs metrics capturing the ColdStart is enabled</param>
     internal Metrics(IPowertoolsConfigurations powertoolsConfigurations, string nameSpace = null, string service = null,
-        bool raiseOnEmptyMetrics = false)
+        bool raiseOnEmptyMetrics = false, bool captureColdStartEnabled = false)
     {
         if (_instance != null) return;
 
         _instance = this;
         _powertoolsConfigurations = powertoolsConfigurations;
         _raiseOnEmptyMetrics = raiseOnEmptyMetrics;
+        _captureColdStartEnabled = captureColdStartEnabled;
         _context = InitializeContext(nameSpace, service, null);
     }
 
@@ -80,7 +87,7 @@ void IMetrics.AddMetric(string key, double value, MetricUnit unit)
     {
         if (string.IsNullOrWhiteSpace(key))
             throw new ArgumentNullException(
-                "'AddMetric' method requires a valid metrics key. 'Null' or empty values are not allowed.");
+                $"'AddMetric' method requires a valid metrics key. 'Null' or empty values are not allowed.");
 
         if (value < 0) {
             throw new ArgumentException(
@@ -132,7 +139,7 @@ void IMetrics.AddDimension(string key, string value)
     {
         if (string.IsNullOrWhiteSpace(key))
             throw new ArgumentNullException(
-                "'AddDimension' method requires a valid dimension key. 'Null' or empty values are not allowed.");
+                $"'AddDimension' method requires a valid dimension key. 'Null' or empty values are not allowed.");
 
         _context.AddDimension(key, value);
     }
@@ -150,7 +157,7 @@ void IMetrics.AddMetadata(string key, object value)
     {
         if (string.IsNullOrWhiteSpace(key))
             throw new ArgumentNullException(
-                "'AddMetadata' method requires a valid metadata key. 'Null' or empty values are not allowed.");
+                $"'AddMetadata' method requires a valid metadata key. 'Null' or empty values are not allowed.");
 
         _context.AddMetadata(key, value);
     }
@@ -168,7 +175,7 @@ void IMetrics.SetDefaultDimensions(Dictionary<string, string> defaultDimensions)
         foreach (var item in defaultDimensions)
             if (string.IsNullOrWhiteSpace(item.Key) || string.IsNullOrWhiteSpace(item.Value))
                 throw new ArgumentNullException(
-                    "'SetDefaultDimensions' method requires a valid key pair. 'Null' or empty values are not allowed.");
+                    $"'SetDefaultDimensions' method requires a valid key pair. 'Null' or empty values are not allowed.");
 
         _context.SetDefaultDimensions(DictionaryToList(defaultDimensions));
     }
@@ -197,8 +204,9 @@ void IMetrics.Flush(bool metricsOverflow)
         }
         else
         {
-            Console.WriteLine(
-                "##WARNING## Metrics and Metadata have not been specified. No data will be sent to Cloudwatch Metrics.");
+            if (!_captureColdStartEnabled)
+                Console.WriteLine(
+                    "##WARNING## Metrics and Metadata have not been specified. No data will be sent to Cloudwatch Metrics.");
         }
     }
 
@@ -230,7 +238,7 @@ void IMetrics.PushSingleMetric(string metricName, double value, MetricUnit unit,
     {
         if (string.IsNullOrWhiteSpace(metricName))
             throw new ArgumentNullException(
-                "'PushSingleMetric' method requires a valid metrics key. 'Null' or empty values are not allowed.");
+                $"'PushSingleMetric' method requires a valid metrics key. 'Null' or empty values are not allowed.");
 
         using var context = InitializeContext(nameSpace, service, defaultDimensions);
         context.AddMetric(metricName, value, unit);

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

@@ -139,7 +139,8 @@ public class MetricsAttribute : MethodAspectAttribute
             PowertoolsConfigurations.Instance,
             Namespace,
             Service,
-            RaiseOnEmptyMetrics
+            RaiseOnEmptyMetrics,
+            CaptureColdStart
         );
 
     /// <summary>

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

@@ -34,19 +34,21 @@ public void WhenCaptureColdStart_CreateSeparateBlob()
             // Arrange
             var methodName = Guid.NewGuid().ToString();
             var consoleOut = new StringWriter();
+            const bool captureColdStartEnabled = true;
             Console.SetOut(consoleOut);
 
             var configurations = new Mock<IPowertoolsConfigurations>();
 
             var logger = new Metrics(
                 configurations.Object,
                 nameSpace: "dotnet-powertools-test",
-                service: "testService"
+                service: "testService",
+                captureColdStartEnabled: captureColdStartEnabled
             );
 
             var handler = new MetricsAspectHandler(
                 logger,
-                true
+                captureColdStartEnabled
             );
 
             var eventArgs = new AspectEventArgs { Name = methodName };
@@ -74,19 +76,21 @@ public void WhenCaptureColdStartEnabled_ValidateExists()
             // Arrange
             var methodName = Guid.NewGuid().ToString();
             var consoleOut = new StringWriter();
+            const bool captureColdStartEnabled = true;
             Console.SetOut(consoleOut);
 
             var configurations = new Mock<IPowertoolsConfigurations>();
 
             var logger = new Metrics(
                 configurations.Object,
                 nameSpace: "dotnet-powertools-test",
-                service: "testService"
+                service: "testService",
+                captureColdStartEnabled: captureColdStartEnabled
             );
 
             var handler = new MetricsAspectHandler(
                 logger,
-                true
+                captureColdStartEnabled
             );
 
             var eventArgs = new AspectEventArgs { Name = methodName };