Added CorrelationId Property and method

Author: hjgraca

libraries/src/AWS.Lambda.Powertools.Logging/Logger.Scope.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using AWS.Lambda.Powertools.Logging.Internal;
 using AWS.Lambda.Powertools.Logging.Internal.Helpers;
 
 namespace AWS.Lambda.Powertools.Logging;
@@ -13,6 +14,22 @@ public static partial class Logger
     /// <value>The scope.</value>
     private static IDictionary<string, object> Scope { get; } = new Dictionary<string, object>(StringComparer.Ordinal);
 
+    /// <summary>
+    ///     Gets the correlation identifier from the log context.
+    /// </summary>
+    /// <value>The correlation identifier, or null if not set.</value>
+    public static string CorrelationId
+    {
+        get
+        {
+            if (Scope.TryGetValue(LoggingConstants.KeyCorrelationId, out var value))
+            {
+                return value?.ToString();
+            }
+            return null;
+        }
+    }
+
     /// <summary>
     ///     Appending additional key to the log context.
     /// </summary>

libraries/src/AWS.Lambda.Powertools.Logging/PowertoolsLoggerExtensions.cs

@@ -170,6 +170,16 @@ public static void Log(this ILogger logger, LogLevel logLevel, Exception excepti
 
     #endregion
 
+    /// <summary>
+    ///     Gets the correlation identifier from the log context.
+    /// </summary>
+    /// <param name="logger">The logger instance.</param>
+    /// <returns>The correlation identifier, or null if not set.</returns>
+    public static string GetCorrelationId(this ILogger logger)
+    {
+        return Logger.CorrelationId;
+    }
+
     /// <summary>
     ///     Appending additional key to the log context.
     /// </summary>

libraries/tests/AWS.Lambda.Powertools.Logging.Tests/Attributes/LoggingAttributeTest.cs

@@ -357,6 +357,53 @@ public void When_Setting_SamplingRate_Should_Add_Key()
             ));
         }
 
+        [Fact]
+        public void CorrelationId_Property_Should_Return_CorrelationId()
+        {
+            // Arrange
+            var correlationId = Guid.NewGuid().ToString();
+            
+            // Act
+            _testHandlers.CorrelationCloudWatchEventCustomPath(new CloudWatchEvent<CwEvent>
+            {
+                Detail = new CwEvent
+                {
+                    CorrelationId = correlationId
+                }
+            });
+            
+            // Assert - Static Logger property
+            Assert.Equal(correlationId, Logger.CorrelationId);
+        }
+        
+        [Fact]
+        public void CorrelationId_Extension_Should_Return_CorrelationId_Via_ILogger()
+        {
+            // Arrange
+            var correlationId = Guid.NewGuid().ToString();
+            
+            // Act
+            _testHandlers.CorrelationIdExtensionTest(new CloudWatchEvent<CwEvent>
+            {
+                Detail = new CwEvent
+                {
+                    CorrelationId = correlationId
+                }
+            });
+            
+            // Assert - The test handler will verify the extension method works
+            Assert.Equal(correlationId, Logger.CorrelationId);
+        }
+        
+        [Fact]
+        public void CorrelationId_Should_Return_Null_When_Not_Set()
+        {
+            // Arrange - no correlation ID set
+            
+            // Act & Assert
+            Assert.Null(Logger.CorrelationId);
+        }
+        
         [Fact]
         public void When_Setting_Service_Should_Update_Key()
         {

libraries/tests/AWS.Lambda.Powertools.Logging.Tests/Handlers/TestHandlers.cs

@@ -71,6 +71,20 @@ public void CorrelationCloudWatchEventCustomPath(CloudWatchEvent<CwEvent> cwEven
     {
     }
 
+    [Logging(CorrelationIdPath = "/detail/correlationId")]
+    public void CorrelationIdExtensionTest(CloudWatchEvent<CwEvent> cwEvent)
+    {
+        // Test that the ILogger extension method works
+        var logger = Microsoft.Extensions.Logging.LoggerFactory.Create(builder => { }).CreateLogger(nameof(TestHandlers));
+        var correlationIdFromExtension = logger.GetCorrelationId();
+        
+        // Verify it matches the static property
+        if (correlationIdFromExtension != Logger.CorrelationId)
+        {
+            throw new Exception("Extension method returned different value than static property");
+        }
+    }
+
     [Logging(CorrelationIdPath = "/headers/my_request_id_header")]
     public void CorrelationIdFromString(TestObject testObject)
     {