How to mark an Activity error as benign in .NET
Set the category parameter to ApplicationErrorCategory.Benign when throwing an ApplicationFailureException to mark an Activity error as benign.
activities: error handling
6 notes, read out of this brain and free to use. Each one was extracted from a source and is re-checked against its exam.
Benign exception example in .NET
```csharp using Temporalio.Activities; using Temporalio.Api.Enums.V1; using Temporalio.Exceptions; public class MyActivities { [Activity] public async Task<string> MyActivityAsync() { try { return await CallExternalServiceAsync(); } catch (Exception e) { // Mark this error as benign since it's expected throw new ApplicationFailureException( "Service is down", inner: e, category: ApplicationErrorCategory.Benign); } } } ``` This example shows how to throw an ApplicationFailureException with ApplicationErrorCategory.Benign for an expected service unavailability error.
Benign exceptions reduce noise in logs and metrics
When activities return errors that are expected or not severe, they can create noise in logs, metrics, and OpenTelemetry traces. Marking these errors as benign excludes them from observability data while still handling them in workflow logic.
Mark errors as benign using NewApplicationErrorWithOptions
To mark an error as benign in Go, use temporal.NewApplicationErrorWithOptions and set the Category field to temporal.ApplicationErrorCategoryBenign in the ApplicationErrorOptions.
Benign exceptions effects on activity observability
Benign errors have activity failure logs downgraded to DEBUG level, do not emit activity failure metrics, and do not set the OpenTelemetry failure status to ERROR.
Code example: marking an activity error as benign
import ( "go.temporal.io/sdk/activity" "go.temporal.io/sdk/temporal" ) func MyActivity(ctx context.Context) (string, error) { result, err := callExternalService() if err != nil { // Mark this error as benign since it's expected return "", temporal.NewApplicationErrorWithOptions( err.Error(), "", temporal.ApplicationErrorOptions{ Category: temporal.ApplicationErrorCategoryBenign, }, ) } return result, nil }