Add MinimumEventLevel to Sentry.Log4Net and convert events below it to breadcrumbs

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Features
 
 - Added Sampling Decision to Trace Envelope Header ([#2495](https://github.com/getsentry/sentry-dotnet/pull/2495))
+- Add MinimumEventLevel to Sentry.Log4Net and convert events below it to breadcrumbs ([#2505](https://github.com/getsentry/sentry-dotnet/pull/2505))
 
 ### Fixes
 

samples/Sentry.Samples.Log4Net/Program.cs

@@ -26,6 +26,10 @@ private static void Main()
         // Does not result in an event in Sentry
         Log.Debug("Debug message which is not sent.");
 
+        // app.config sets MinimumEventLevel to ERROR, so every below that level is added as a breadcrumb.
+        Log.Info("Info message which is added as a breadcrumb.");
+        Log.Error("Error message which is sent as an event.");
+
         try
         {
             DoWork();

samples/Sentry.Samples.Log4Net/app.config

@@ -18,6 +18,9 @@
       <!--Sends the log event Identity value as the user-->
       <SendIdentity value="true" />
       <Environment value="dev" />
+      <!--If MinimumEventLevel is specified, every event above threshold
+      and below MinimumEventLevel will be added as a breadcrumb.-->
+      <MinimumEventLevel value="ERROR" />
       <threshold value="INFO" />
     </appender>
     <root>

src/Sentry.Log4Net/LevelMapping.cs

@@ -15,4 +15,18 @@ internal static class LevelMapping
             _ => null
         };
     }
+
+    public static BreadcrumbLevel? ToBreadcrumbLevel(this LoggingEvent loggingLevel)
+    {
+        return loggingLevel.Level switch
+        {
+            var l when l == Level.Fatal || l == Level.Emergency => BreadcrumbLevel.Critical,
+            var l when l == Level.Alert || l == Level.Critical || l == Level.Severe || l == Level.Error => BreadcrumbLevel.Error,
+            var l when l == Level.Warn => BreadcrumbLevel.Warning,
+            var l when l == Level.Notice || l == Level.Info => BreadcrumbLevel.Info,
+            var l when l == Level.Debug || l == Level.Verbose || l == Level.Trace || l == Level.Finer || l == Level.Finest ||
+                       l == Level.Fine || l == Level.All => BreadcrumbLevel.Debug,
+            _ => null
+        };
+    }
 }

src/Sentry.Log4Net/SentryAppender.cs

@@ -32,6 +32,12 @@ internal static readonly SdkVersion NameAndVersion
     /// </summary>
     public string? Environment { get; set; }
 
+    /// <summary>
+    /// Lowest level required for a log message to become an event.
+    /// Every level above threshold and below this level will become a breadcrumb.
+    /// </summary>
+    public Level? MinimumEventLevel { get; set; }
+
     /// <summary>
     /// log4net SDK name.
     /// </summary>
@@ -79,6 +85,20 @@ protected override void Append(LoggingEvent loggingEvent)
         }
 
         var exception = loggingEvent.ExceptionObject ?? loggingEvent.MessageObject as Exception;
+
+        if (MinimumEventLevel is not null && loggingEvent.Level < MinimumEventLevel)
+        {
+            var message = !string.IsNullOrWhiteSpace(loggingEvent.RenderedMessage) ? loggingEvent.RenderedMessage : string.Empty;
+            var category = loggingEvent.LoggerName;
+            var level = loggingEvent.ToBreadcrumbLevel();
+            IDictionary<string, string> data = GetLoggingEventProperties(loggingEvent)
+                .Where(kvp => kvp.Value != null)
+                .ToDictionary(kvp => kvp.Key, kvp => kvp.Value!.ToString());
+
+            _hub.AddBreadcrumb(message, category, type: null, data, level ?? default);
+            return;
+        }
+
         var evt = new SentryEvent(exception)
         {
             Logger = loggingEvent.LoggerName,

test/Sentry.Log4Net.Tests/ApiApprovalTests.Run.Core3_1.verified.txt

@@ -1,11 +1,12 @@
-[assembly: System.CLSCompliant(true)]
+[assembly: System.CLSCompliant(true)]
 namespace Sentry.Log4Net
 {
     public class SentryAppender : log4net.Appender.AppenderSkeleton
     {
         public SentryAppender() { }
         public string? Dsn { get; set; }
         public string? Environment { get; set; }
+        public log4net.Core.Level? MinimumEventLevel { get; set; }
         public bool SendIdentity { get; set; }
         protected override void Append(log4net.Core.LoggingEvent loggingEvent) { }
         protected override void OnClose() { }

test/Sentry.Log4Net.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt

@@ -6,6 +6,7 @@ namespace Sentry.Log4Net
         public SentryAppender() { }
         public string? Dsn { get; set; }
         public string? Environment { get; set; }
+        public log4net.Core.Level? MinimumEventLevel { get; set; }
         public bool SendIdentity { get; set; }
         protected override void Append(log4net.Core.LoggingEvent loggingEvent) { }
         protected override void OnClose() { }

test/Sentry.Log4Net.Tests/ApiApprovalTests.Run.DotNet7_0.verified.txt

@@ -6,6 +6,7 @@ namespace Sentry.Log4Net
         public SentryAppender() { }
         public string? Dsn { get; set; }
         public string? Environment { get; set; }
+        public log4net.Core.Level? MinimumEventLevel { get; set; }
         public bool SendIdentity { get; set; }
         protected override void Append(log4net.Core.LoggingEvent loggingEvent) { }
         protected override void OnClose() { }

test/Sentry.Log4Net.Tests/ApiApprovalTests.Run.Net4_8.verified.txt

@@ -6,6 +6,7 @@ namespace Sentry.Log4Net
         public SentryAppender() { }
         public string? Dsn { get; set; }
         public string? Environment { get; set; }
+        public log4net.Core.Level? MinimumEventLevel { get; set; }
         public bool SendIdentity { get; set; }
         protected override void Append(log4net.Core.LoggingEvent loggingEvent) { }
         protected override void OnClose() { }

test/Sentry.Log4Net.Tests/SentryAppenderTests.cs

@@ -9,10 +9,14 @@ private class Fixture
         public IDisposable SdkDisposeHandle { get; set; } = Substitute.For<IDisposable>();
         public Func<string, IDisposable> InitAction { get; set; }
         public IHub Hub { get; set; } = Substitute.For<IHub>();
+        public Func<IHub> HubAccessor { get; set; }
+        public Scope Scope { get; } = new(new SentryOptions());
         public string Dsn { get; set; } = "dsn";
 
         public Fixture()
         {
+            HubAccessor = () => Hub;
+            Hub.ConfigureScope(Arg.Invoke(Scope));
             InitAction = s =>
             {
                 DsnReceivedOnInit = s;
@@ -125,6 +129,20 @@ public void Append_NullEvent_NoOp()
         sut.DoAppend(null as LoggingEvent);
     }
 
+    [Fact]
+    public void Append_BelowThreshold_DoesNotSendEvent()
+    {
+        var sut = _fixture.GetSut();
+        sut.Threshold = Level.Warn;
+        var evt = new LoggingEvent(new LoggingEventData
+        {
+            Level = Level.Info
+        });
+
+        sut.DoAppend(evt);
+        _fixture.Hub.DidNotReceiveWithAnyArgs().CaptureEvent(Arg.Any<SentryEvent>());
+    }
+
     [Fact]
     public void Append_ByDefault_DoesNotSetUser()
     {
@@ -291,6 +309,76 @@ public void Append_ConfiguredEnvironment()
             .CaptureEvent(Arg.Is<SentryEvent>(e => e.Environment == expected));
     }
 
+    [Fact]
+    public void MinimumEventLevel_DefaultsToNull()
+    {
+        var appender = new SentryAppender();
+        Assert.Null(appender.MinimumEventLevel);
+    }
+
+    [Fact]
+    public void DoAppend_BelowMinimumEventLevel_AddsBreadcrumb()
+    {
+        var sut = _fixture.GetSut();
+        sut.Threshold = Level.Debug;
+        sut.MinimumEventLevel = Level.Error;
+
+        const string expectedBreadcrumbMsg = "log4net breadcrumb";
+        var warnEvt = new LoggingEvent(new LoggingEventData
+        {
+            Level = Level.Warn,
+            Message = expectedBreadcrumbMsg
+        });
+        sut.DoAppend(warnEvt);
+
+        var breadcrumb = _fixture.Scope.Breadcrumbs.First();
+        Assert.Equal(expectedBreadcrumbMsg, breadcrumb.Message);
+    }
+
+    [Fact]
+    public void DoAppend_NullMinimumEventLevel_AddsEvent()
+    {
+        var sut = _fixture.GetSut();
+        sut.Threshold = Level.Debug;
+        sut.MinimumEventLevel = null;
+
+        const string expectedMessage = "log4net message";
+        var warnEvt = new LoggingEvent(new LoggingEventData
+        {
+            Level = Level.Warn,
+            Message = expectedMessage
+        });
+        sut.DoAppend(warnEvt);
+
+        // No breadcrumb is added.
+        Assert.Empty(_fixture.Scope.Breadcrumbs);
+        // Event is sent instead.
+        _ = _fixture.Hub.Received(1)
+            .CaptureEvent(Arg.Is<SentryEvent>(e => e.Message.Message == expectedMessage));
+    }
+
+    [Fact]
+    public void DoAppend_AboveMinimumEventLevel_AddsEvent()
+    {
+        var sut = _fixture.GetSut();
+        sut.Threshold = Level.Debug;
+        sut.MinimumEventLevel = Level.Warn;
+
+        const string expectedMessage = "log4net message";
+        var warnEvt = new LoggingEvent(new LoggingEventData
+        {
+            Level = Level.Error,
+            Message = expectedMessage
+        });
+        sut.DoAppend(warnEvt);
+
+        // No breadcrumb is added.
+        Assert.Empty(_fixture.Scope.Breadcrumbs);
+        // Event is sent instead.
+        _ = _fixture.Hub.Received(1)
+            .CaptureEvent(Arg.Is<SentryEvent>(e => e.Message.Message == expectedMessage));
+    }
+
     [Fact]
     public void Close_DisposesSdk()
     {