feat: Add native semantic logging support with property extraction

src/core/Akka.API.Tests/LogFormatSpec.cs

@@ -32,9 +32,9 @@ public DefaultLogFormatSpec() : base(CustomLoggerSetup())
     {
         _logger = (CustomLogger)Sys.Settings.StdoutLogger;
     }
-    
+
     private readonly CustomLogger _logger;
-    
+
     public class CustomLogger : StandardOutLogger
     {
         protected override void Log(object message)
@@ -44,13 +44,13 @@ protected override void Log(object message)
             {
                 _events.Add(e);
             }
-           
+
         }
-            
+
         private readonly ConcurrentBag<LogEvent> _events = new();
         public IReadOnlyCollection<LogEvent> Events => _events;
     }
-    
+
     public static ActorSystemSetup CustomLoggerSetup()
     {
         var hocon = @$"
@@ -115,6 +115,58 @@ await AwaitConditionAsync(() =>
         await Verifier.Verify(text);
     }
 
+    [Fact]
+    public async Task ShouldHandleSemanticLogEdgeCases()
+    {
+        // arrange
+        var filePath = Path.GetTempFileName();
+
+        // act
+        using (new OutputRedirector(filePath))
+        {
+            // Named properties
+            Sys.Log.Debug("User {UserId} logged in from {IpAddress}", 12345, "192.168.1.1");
+            Sys.Log.Info("Processing order {OrderId} for customer {CustomerId}", "ORD-001", "CUST-999");
+
+            // Positional properties (old style)
+            Sys.Log.Warning("Processing item {0} of {1}", 5, 10);
+
+            // Mixed types - use F2 instead of C for culture-independent output
+            Sys.Log.Info("Order total is ${Amount:F2} with {ItemCount} items", 123.45m, 3);
+
+            // Edge cases
+            Sys.Log.Debug("Empty template");
+            Sys.Log.Info("Single property {Value}", 42);
+            Sys.Log.Warning("Null value: {NullValue}", null);
+            Sys.Log.Error("Exception occurred for user {UserId}", 999);
+
+            // Special characters and escaping
+            Sys.Log.Debug("Path: {FilePath}, Size: {FileSize} bytes", @"C:\temp\file.txt", 1024);
+
+            // Boolean and date types - use explicit date format for culture-independent output
+            Sys.Log.Info("User {Username} is active: {IsActive}, joined on {JoinDate:yyyy-MM-dd}", "john.doe", true, DateTime.Parse("2024-01-15"));
+
+            // Long strings and alignment
+            Sys.Log.Debug("Request from {RemoteAddress} to endpoint {Endpoint} took {DurationMs}ms", "192.168.1.100:54321", "/api/v1/users", 250);
+
+            // force all logs to be received - wait for the last log message
+            await AwaitConditionAsync(() => Task.FromResult(_logger.Events.Any(e => e.Message.ToString()!.Contains("took 250ms"))), TimeSpan.FromSeconds(5));
+        }
+
+        // assert
+        // ReSharper disable once MethodHasAsyncOverload
+        var text = File.ReadAllText(filePath);
+
+        // need to sanitize the thread id and timestamps
+        text = SanitizeDateTime(text);
+        text = SanitizeThreadNumber(text);
+        text = SanitizeTestEventListener(text);
+        text = SanitizeDefaultLoggersStarted(text);
+        text = SanitizeCustomLoggerRemoved(text);
+
+        await Verifier.Verify(text);
+    }
+
     private static string SanitizeDefaultLoggersStarted(string logs)
     {
         var pattern = @"^.*Default Loggers started.*$\r?\n?";

src/core/Akka.API.Tests/verify/CoreAPISpec.ApproveCore.DotNet.verified.txt

@@ -3472,6 +3472,17 @@ namespace Akka.Event
         public abstract Akka.Event.LogLevel LogLevel();
         public override string ToString() { }
     }
+    [System.Runtime.CompilerServices.NullableAttribute(0)]
+    public class static LogEventExtensions
+    {
+        public static System.Collections.Generic.IEnumerable<object> GetParameters(this Akka.Event.LogEvent evt) { }
+        public static System.Collections.Generic.IReadOnlyList<string> GetPropertyNames(this Akka.Event.LogEvent evt) { }
+        public static string GetTemplate(this Akka.Event.LogEvent evt) { }
+        public static bool TryGetProperties(this Akka.Event.LogEvent evt, [System.Runtime.CompilerServices.NullableAttribute(new byte[] {
+                2,
+                1,
+                1})] out System.Collections.Generic.IReadOnlyDictionary<string, object> properties) { }
+    }
     public abstract class LogFilterBase : Akka.Actor.INoSerializationVerificationNeeded, Akka.Event.IDeadLetterSuppression
     {
         protected LogFilterBase() { }
@@ -3531,6 +3542,8 @@ namespace Akka.Event
         protected readonly Akka.Event.ILogMessageFormatter Formatter;
         public LogMessage(Akka.Event.ILogMessageFormatter formatter, string format) { }
         public string Format { get; }
+        public System.Collections.Generic.IReadOnlyList<string> PropertyNames { get; }
+        public System.Collections.Generic.IReadOnlyDictionary<string, object> GetProperties() { }
         [Akka.Annotations.InternalApiAttribute()]
         public abstract System.Collections.Generic.IEnumerable<object> Parameters();
         [Akka.Annotations.InternalApiAttribute()]
@@ -3708,6 +3721,12 @@ namespace Akka.Event
         public override Akka.Event.LogFilterType FilterType { get; }
         public override Akka.Event.LogFilterDecision ShouldKeepMessage(Akka.Event.LogEvent content, [System.Runtime.CompilerServices.NullableAttribute(2)] string expandedMessage = null) { }
     }
+    public sealed class SemanticLogMessageFormatter : Akka.Event.ILogMessageFormatter
+    {
+        public static readonly Akka.Event.SemanticLogMessageFormatter Instance;
+        public string Format(string format, params object[] args) { }
+        public string Format(string format, System.Collections.Generic.IEnumerable<object> args) { }
+    }
     public class StandardOutLogger : Akka.Event.MinimalLogger
     {
         public StandardOutLogger() { }

src/core/Akka.API.Tests/verify/CoreAPISpec.ApproveCore.Net.verified.txt

@@ -3483,6 +3483,17 @@ namespace Akka.Event
         public abstract Akka.Event.LogLevel LogLevel();
         public override string ToString() { }
     }
+    [System.Runtime.CompilerServices.NullableAttribute(0)]
+    public class static LogEventExtensions
+    {
+        public static System.Collections.Generic.IEnumerable<object> GetParameters(this Akka.Event.LogEvent evt) { }
+        public static System.Collections.Generic.IReadOnlyList<string> GetPropertyNames(this Akka.Event.LogEvent evt) { }
+        public static string GetTemplate(this Akka.Event.LogEvent evt) { }
+        public static bool TryGetProperties(this Akka.Event.LogEvent evt, [System.Runtime.CompilerServices.NullableAttribute(new byte[] {
+                2,
+                1,
+                1})] out System.Collections.Generic.IReadOnlyDictionary<string, object> properties) { }
+    }
     public abstract class LogFilterBase : Akka.Actor.INoSerializationVerificationNeeded, Akka.Event.IDeadLetterSuppression
     {
         protected LogFilterBase() { }
@@ -3542,6 +3553,8 @@ namespace Akka.Event
         protected readonly Akka.Event.ILogMessageFormatter Formatter;
         public LogMessage(Akka.Event.ILogMessageFormatter formatter, string format) { }
         public string Format { get; }
+        public System.Collections.Generic.IReadOnlyList<string> PropertyNames { get; }
+        public System.Collections.Generic.IReadOnlyDictionary<string, object> GetProperties() { }
         [Akka.Annotations.InternalApiAttribute()]
         public abstract System.Collections.Generic.IEnumerable<object> Parameters();
         [Akka.Annotations.InternalApiAttribute()]
@@ -3717,6 +3730,12 @@ namespace Akka.Event
         public override Akka.Event.LogFilterType FilterType { get; }
         public override Akka.Event.LogFilterDecision ShouldKeepMessage(Akka.Event.LogEvent content, [System.Runtime.CompilerServices.NullableAttribute(2)] string expandedMessage = null) { }
     }
+    public sealed class SemanticLogMessageFormatter : Akka.Event.ILogMessageFormatter
+    {
+        public static readonly Akka.Event.SemanticLogMessageFormatter Instance;
+        public string Format(string format, params object[] args) { }
+        public string Format(string format, System.Collections.Generic.IEnumerable<object> args) { }
+    }
     public class StandardOutLogger : Akka.Event.MinimalLogger
     {
         public StandardOutLogger() { }

src/core/Akka.API.Tests/verify/DefaultLogFormatSpec.ShouldHandleSemanticLogEdgeCases.DotNet.verified.txt

@@ -0,0 +1,11 @@
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] User 12345 logged in from 192.168.1.1
+[INFO][DateTime][Thread 0001][ActorSystem(test)] Processing order ORD-001 for customer CUST-999
+[WARNING][DateTime][Thread 0001][ActorSystem(test)] Processing item 5 of 10
+[INFO][DateTime][Thread 0001][ActorSystem(test)] Order total is $123.45 with 3 items
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] Empty template
+[INFO][DateTime][Thread 0001][ActorSystem(test)] Single property 42
+[WARNING][DateTime][Thread 0001][ActorSystem(test)] Null value: {NullValue}
+[ERROR][DateTime][Thread 0001][ActorSystem(test)] Exception occurred for user 999
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] Path: C:\temp\file.txt, Size: 1024 bytes
+[INFO][DateTime][Thread 0001][ActorSystem(test)] User john.doe is active: True, joined on 2024-01-15
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] Request from 192.168.1.100:54321 to endpoint /api/v1/users took 250ms

src/core/Akka.API.Tests/verify/DefaultLogFormatSpec.ShouldHandleSemanticLogEdgeCases.Net.verified.txt

@@ -0,0 +1,11 @@
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] User 12345 logged in from 192.168.1.1
+[INFO][DateTime][Thread 0001][ActorSystem(test)] Processing order ORD-001 for customer CUST-999
+[WARNING][DateTime][Thread 0001][ActorSystem(test)] Processing item 5 of 10
+[INFO][DateTime][Thread 0001][ActorSystem(test)] Order total is $123.45 with 3 items
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] Empty template
+[INFO][DateTime][Thread 0001][ActorSystem(test)] Single property 42
+[WARNING][DateTime][Thread 0001][ActorSystem(test)] Null value: {NullValue}
+[ERROR][DateTime][Thread 0001][ActorSystem(test)] Exception occurred for user 999
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] Path: C:\temp\file.txt, Size: 1024 bytes
+[INFO][DateTime][Thread 0001][ActorSystem(test)] User john.doe is active: True, joined on 2024-01-15
+[DEBUG][DateTime][Thread 0001][ActorSystem(test)] Request from 192.168.1.100:54321 to endpoint /api/v1/users took 250ms

src/core/Akka.TestKit/EventFilter/Internal/EventFilterBase.cs

@@ -87,8 +87,26 @@ protected virtual void OnEventMatched(LogEvent logEvent)
     /// <returns>TBD</returns>
     protected bool InternalDoMatch(string src, object? msg)
     {
+        // Check source matcher first (fast path)
+        if (!_sourceMatcher.IsMatch(src))
+            return false;
+
+        // For semantic logging support, try matching against both the formatted message
+        // and the unformatted template pattern
+        if (msg is LogMessage logMessage)
+        {
+            // Try matching against the template pattern first (e.g., "User {UserId} logged in")
+            if (_messageMatcher.IsMatch(logMessage.Format))
+                return true;
+
+            // Fall back to matching the formatted message (e.g., "User 12345 logged in")
+            var formattedMsg = logMessage.ToString() ?? "null";
+            return _messageMatcher.IsMatch(formattedMsg);
+        }
+
+        // Non-semantic logging or legacy messages
         var msgstr = msg == null ? "null" : msg.ToString() ?? "null";
-        return _sourceMatcher.IsMatch(src) && _messageMatcher.IsMatch(msgstr);
+        return _messageMatcher.IsMatch(msgstr);
     }
 
     /// <summary>

src/core/Akka.Tests/Configuration/ConfigurationSpec.cs

@@ -50,7 +50,7 @@ public void The_default_configuration_file_contain_all_configuration_properties(
             settings.LogDeadLetters.ShouldBe(10);
             settings.LogDeadLettersDuringShutdown.ShouldBeFalse();
             settings.LogDeadLettersSuspendDuration.ShouldBe(TimeSpan.FromMinutes(5));
-            settings.LogFormatter.Should().BeOfType<DefaultLogMessageFormatter>();
+            settings.LogFormatter.Should().BeOfType<SemanticLogMessageFormatter>();
 
             settings.ProviderClass.ShouldBe(typeof (LocalActorRefProvider).FullName);
             settings.SupervisorStrategyClass.ShouldBe(typeof (DefaultSupervisorStrategy).FullName);