Description
The ASP.NET Core exception handler middleware, UseExceptionHandler(), is responsible for catching and processing unhandled exceptions from ASP.NET Core requests.
In .NET 8, we introduced IExceptionHandler. Implementations of IExceptionHandler are registered with dependency injection and invoked by the middleware. An implementation can return true from IExceptionHandler.TryHandleAsync to indicate that the exception has been handled. The middleware stops processing the exception once it has been handled.
In .NET 10, we're changing the default behavior so that the middleware no longer records diagnostics for exceptions handled by IExceptionHandler.
Version
.NET 10 Preview 7
Previous behavior
The exception handler middleware recorded diagnostics about exceptions handled by IExceptionHandler.
The exception diagnostics are:
- Logging
UnhandledException to ILogger.
- Writing the
Microsoft.AspNetCore.Diagnostics.HandledException event to EventSource.
- Adding the
error.type tag to the http.server.request.duration metric.
New behavior
If IExceptionHandler.TryHandleAsync returns true, then exception diagnostics are no longer recorded by default.
Type of breaking change
Reason for change
ASP.NET Core users have given feedback that the previous behavior was undesirable. Their IExceptionHandler implementation reported that the exception was handled, but the error handling middleware still recorded the error in the app's telemetry.
We are changing ASP.NET Core to follow the behavior expected by users by suppressing diagnostics when IExceptionHandler handles the exception. We're also adding configuration options to customize exception diagnostics behavior if needed.
Recommended action
If you want handled exceptions to continue recording telemetry, you can use the new ExceptionHandlerOptions.SuppressDiagnosticsCallback option:
app.UseExceptionHandler(new ExceptionHandlerOptions
{
SuppressDiagnosticsCallback = context => false;
});The context passed to the callback includes information about the exception, the request, and whether the exception was handled. Returning false from the callback indicates that diagnostics shouldn't be suppressed. This restores the previous behavior.
References
Affected APIs
UseExceptionHandler()IExceptionHandler
Description
The ASP.NET Core exception handler middleware,
UseExceptionHandler(), is responsible for catching and processing unhandled exceptions from ASP.NET Core requests.In .NET 8, we introduced
IExceptionHandler. Implementations ofIExceptionHandlerare registered with dependency injection and invoked by the middleware. An implementation can returntruefromIExceptionHandler.TryHandleAsyncto indicate that the exception has been handled. The middleware stops processing the exception once it has been handled.In .NET 10, we're changing the default behavior so that the middleware no longer records diagnostics for exceptions handled by
IExceptionHandler.Version
.NET 10 Preview 7
Previous behavior
The exception handler middleware recorded diagnostics about exceptions handled by
IExceptionHandler.The exception diagnostics are:
UnhandledExceptiontoILogger.Microsoft.AspNetCore.Diagnostics.HandledExceptionevent toEventSource.error.typetag to thehttp.server.request.durationmetric.New behavior
If
IExceptionHandler.TryHandleAsyncreturnstrue, then exception diagnostics are no longer recorded by default.Type of breaking change
Reason for change
ASP.NET Core users have given feedback that the previous behavior was undesirable. Their
IExceptionHandlerimplementation reported that the exception was handled, but the error handling middleware still recorded the error in the app's telemetry.We are changing ASP.NET Core to follow the behavior expected by users by suppressing diagnostics when
IExceptionHandlerhandles the exception. We're also adding configuration options to customize exception diagnostics behavior if needed.Recommended action
If you want handled exceptions to continue recording telemetry, you can use the new
ExceptionHandlerOptions.SuppressDiagnosticsCallbackoption:The context passed to the callback includes information about the exception, the request, and whether the exception was handled. Returning
falsefrom the callback indicates that diagnostics shouldn't be suppressed. This restores the previous behavior.References
Affected APIs
UseExceptionHandler()IExceptionHandler