fix: Log Warning instead of Error when ratelimited

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- The SDK now logs a `Warning` instead of an `Error` when being ratelimited ([#4927](https://github.com/getsentry/sentry-dotnet/pull/4927))
+
 ## 6.2.0-alpha.0
 
 ### Features

src/Sentry/Http/HttpTransportBase.cs

@@ -359,7 +359,8 @@ private void HandleFailure(HttpResponseMessage response, Envelope envelope)
         var eventId = envelope.TryGetEventId(_options.DiagnosticLogger);
 
         // Spare the overhead if level is not enabled
-        if (_options.DiagnosticLogger?.IsEnabled(SentryLevel.Error) is true && response.Content is { } content)
+        var minLogLevel = response.StatusCode == (HttpStatusCode)429 ? SentryLevel.Warning : SentryLevel.Error;
+        if (_options.DiagnosticLogger?.IsEnabled(minLogLevel) is true && response.Content is { } content)
         {
             if (HasJsonContent(content))
             {
@@ -428,7 +429,8 @@ private async Task HandleFailureAsync(HttpResponseMessage response, Envelope env
 
         var eventId = envelope.TryGetEventId(_options.DiagnosticLogger);
         // Spare the overhead if level is not enabled
-        if (_options.DiagnosticLogger?.IsEnabled(SentryLevel.Error) is true && response.Content is { } content)
+        var minLogLevel = response.StatusCode == (HttpStatusCode)429 ? SentryLevel.Warning : SentryLevel.Error;
+        if (_options.DiagnosticLogger?.IsEnabled(minLogLevel) is true && response.Content is { } content)
         {
             if (HasJsonContent(content))
             {
@@ -525,6 +527,12 @@ private void LogFailure(string responseString, HttpStatusCode responseStatusCode
             return;
         }
 
+        if (responseStatusCode == (HttpStatusCode)429)
+        {
+            LogRateLimited(eventId, responseString);
+            return;
+        }
+
         _options.LogError("{0}: Sentry rejected the envelope '{1}'. Status code: {2}. Error detail: {3}.",
             _typeName,
             eventId,
@@ -551,6 +559,15 @@ private void LogFailure(JsonElement responseJson, HttpStatusCode responseStatusC
             return;
         }
 
+        if (responseStatusCode == (HttpStatusCode)429)
+        {
+            var responseDetail = errorCauses.Length > 0
+                ? $"{errorMessage} ({string.Join(", ", errorCauses)})"
+                : errorMessage;
+            LogRateLimited(eventId, responseDetail);
+            return;
+        }
+
         _options.LogError("{0}: Sentry rejected the envelope '{1}'. Status code: {2}. Error detail: {3}. Error causes: {4}.",
             _typeName,
             eventId,
@@ -570,6 +587,18 @@ private void LogRequestTooLarge(SentryId? eventId, string responseDetail)
             responseDetail);
     }
 
+    private void LogRateLimited(SentryId? eventId, string responseDetail)
+    {
+        _options.LogWarning(
+            "{0}: Sentry rejected the envelope '{1}' due to rate limiting. " +
+            "This may indicate that you are sending too much data or have exceeded your quota. " +
+            "See https://docs.sentry.io/product/accounts/quotas/ for more information. " +
+            "Server response: {2}",
+            _typeName,
+            eventId,
+            responseDetail);
+    }
+
     private static bool HasJsonContent(HttpContent content) =>
         string.Equals(content.Headers.ContentType?.MediaType, "application/json",
             StringComparison.OrdinalIgnoreCase);

test/Sentry.Tests/Internals/Http/HttpTransportTests.cs

@@ -989,4 +989,87 @@ public async Task SendEnvelopeAsync_Response413_RecordsSendErrorDiscard()
         recorder.DiscardedEvents.Should().ContainKey(DiscardReason.SendError.WithCategory(DataCategory.Error));
         recorder.DiscardedEvents.Should().NotContainKey(DiscardReason.NetworkError.WithCategory(DataCategory.Error));
     }
+
+    [Fact]
+    public async Task SendEnvelopeAsync_Response429WithJsonMessage_LogsWarning()
+    {
+        // Arrange
+        const string expectedDetail = "Sentry dropped data due to a quota or internal rate limit being reached.";
+
+        var httpHandler = Substitute.For<MockableHttpMessageHandler>();
+
+        httpHandler.VerifiableSendAsync(Arg.Any<HttpRequestMessage>(), Arg.Any<CancellationToken>())
+            .Returns(_ => SentryResponses.GetJsonErrorResponse((HttpStatusCode)429, expectedDetail));
+
+        var logger = new InMemoryDiagnosticLogger();
+
+        var httpTransport = new HttpTransport(
+            new SentryOptions
+            {
+                Dsn = ValidDsn,
+                Debug = true,
+                DiagnosticLogger = logger
+            },
+            new HttpClient(httpHandler));
+
+        var envelope = Envelope.FromEvent(new SentryEvent());
+
+        // Act
+        await httpTransport.SendEnvelopeAsync(envelope);
+
+        // Assert
+        var warningEntry = logger.Entries.FirstOrDefault(e =>
+            e.Level == SentryLevel.Warning &&
+            e.Message.Contains("due to rate limiting"));
+
+        warningEntry.Should().NotBeNull();
+        warningEntry!.Message.Should().Contain("exceeded your quota");
+        warningEntry.Args[2].ToString().Should().Contain(expectedDetail);
+
+        // Should NOT have an error-level log for this
+        logger.Entries.Should().NotContain(e =>
+            e.Level == SentryLevel.Error &&
+            e.Message.Contains("Sentry rejected the envelope"));
+    }
+
+    [Fact]
+    public async Task SendEnvelopeAsync_Response429WithTextMessage_LogsWarning()
+    {
+        // Arrange
+        const string expectedMessage = "Rate limited";
+
+        var httpHandler = Substitute.For<MockableHttpMessageHandler>();
+
+        httpHandler.VerifiableSendAsync(Arg.Any<HttpRequestMessage>(), Arg.Any<CancellationToken>())
+            .Returns(_ => SentryResponses.GetTextErrorResponse((HttpStatusCode)429, expectedMessage));
+
+        var logger = new InMemoryDiagnosticLogger();
+
+        var httpTransport = new HttpTransport(
+            new SentryOptions
+            {
+                Dsn = ValidDsn,
+                Debug = true,
+                DiagnosticLogger = logger
+            },
+            new HttpClient(httpHandler));
+
+        var envelope = Envelope.FromEvent(new SentryEvent());
+
+        // Act
+        await httpTransport.SendEnvelopeAsync(envelope);
+
+        // Assert
+        var warningEntry = logger.Entries.FirstOrDefault(e =>
+            e.Level == SentryLevel.Warning &&
+            e.Message.Contains("due to rate limiting"));
+
+        warningEntry.Should().NotBeNull();
+        warningEntry!.Args[2].ToString().Should().Contain(expectedMessage);
+
+        // Should NOT have an error-level log for this
+        logger.Entries.Should().NotContain(e =>
+            e.Level == SentryLevel.Error &&
+            e.Message.Contains("Sentry rejected the envelope"));
+    }
 }