Added Category to ApplicationFailureException (#483)

Fixes #448

Author: maciejdudko

src/Temporalio/Converters/DefaultFailureConverter.cs

@@ -155,6 +155,7 @@ appExc.Details as OutboundFailureDetails
                             appDet.Count == 0
                                 ? null
                                 : new() { Payloads_ = { appDet.Details.Select(conv.ToPayload) } },
+                        Category = appExc.Category,
                     };
                     if (appExc.NextRetryDelay != null)
                     {

src/Temporalio/Exceptions/ApplicationFailureException.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Temporalio.Api.Enums.V1;
 using Temporalio.Api.Failure.V1;
 
 namespace Temporalio.Exceptions
@@ -25,18 +26,21 @@ public class ApplicationFailureException : FailureException
         /// <param name="nonRetryable">If true, marks the exception as non-retryable.</param>
         /// <param name="details">Collection of details to serialize into the exception.</param>
         /// <param name="nextRetryDelay">Override the next retry delay with this value.</param>
+        /// <param name="category">Error category.</param>
         public ApplicationFailureException(
             string message,
             string? errorType = null,
             bool nonRetryable = false,
             IReadOnlyCollection<object?>? details = null,
-            TimeSpan? nextRetryDelay = null)
+            TimeSpan? nextRetryDelay = null,
+            ApplicationErrorCategory category = ApplicationErrorCategory.Unspecified)
             : base(message)
         {
             ErrorType = errorType;
             NonRetryable = nonRetryable;
             Details = new OutboundFailureDetails(details ?? Array.Empty<object?>());
             NextRetryDelay = nextRetryDelay;
+            Category = category;
         }
 
         /// <summary>
@@ -50,19 +54,22 @@ public ApplicationFailureException(
         /// <param name="nonRetryable">If true, marks the exception as non-retryable.</param>
         /// <param name="details">Collection of details to serialize into the exception.</param>
         /// <param name="nextRetryDelay">Override the next retry delay with this value.</param>
+        /// <param name="category">Error category.</param>
         public ApplicationFailureException(
             string message,
             Exception? inner,
             string? errorType = null,
             bool nonRetryable = false,
             IReadOnlyCollection<object?>? details = null,
-            TimeSpan? nextRetryDelay = null)
+            TimeSpan? nextRetryDelay = null,
+            ApplicationErrorCategory category = ApplicationErrorCategory.Unspecified)
             : base(message, inner)
         {
             ErrorType = errorType;
             NonRetryable = nonRetryable;
             Details = new OutboundFailureDetails(details);
             NextRetryDelay = nextRetryDelay;
+            Category = category;
         }
 
         /// <summary>
@@ -84,6 +91,7 @@ internal protected ApplicationFailureException(
             NonRetryable = info.NonRetryable;
             Details = new InboundFailureDetails(converter, info.Details?.Payloads_);
             NextRetryDelay = info.NextRetryDelay?.ToTimeSpan();
+            Category = info.Category;
         }
 
         /// <summary>
@@ -109,5 +117,10 @@ internal protected ApplicationFailureException(
         /// Gets the next retry delay override if any was set.
         /// </summary>
         public TimeSpan? NextRetryDelay { get; protected init; }
+
+        /// <summary>
+        /// Gets the error category.
+        /// </summary>
+        public ApplicationErrorCategory Category { get; protected init; }
     }
 }

src/Temporalio/Worker/ActivityWorker.cs

@@ -10,6 +10,7 @@
 using Google.Protobuf.WellKnownTypes;
 using Microsoft.Extensions.Logging;
 using Temporalio.Activities;
+using Temporalio.Api.Enums.V1;
 using Temporalio.Client;
 using Temporalio.Common;
 using Temporalio.Converters;
@@ -459,10 +460,22 @@ await Task.WhenAll(tsk.Start.Input.Select(p =>
             }
             catch (Exception e)
             {
-                act.Context.Logger.LogWarning(
-                    e,
-                    "Completing activity {ActivityType} as failed",
-                    act.Context.Info.ActivityType);
+                // Downgrade log level to DEBUG for benign application errors.
+                if ((e as ApplicationFailureException)?.Category == ApplicationErrorCategory.Benign)
+                {
+                    act.Context.Logger.LogDebug(
+                        e,
+                        "Completing activity {ActivityType} as failed (benign)",
+                        act.Context.Info.ActivityType);
+                }
+                else
+                {
+                    act.Context.Logger.LogWarning(
+                        e,
+                        "Completing activity {ActivityType} as failed",
+                        act.Context.Info.ActivityType);
+                }
+
                 completion.Result.Failed = new()
                 {
                     Failure_ = await dataConverter.ToFailureAsync(e).ConfigureAwait(false),

tests/Temporalio.Tests/Client/WorkflowHandleTests.cs

@@ -45,6 +45,23 @@ await Client.ExecuteWorkflowAsync(
         Assert.Equal("Some Details", appErr.Details.ElementAt<string>(0));
     }
 
+    [Fact]
+    public async Task GetResultAsync_BenignFailure_Throws()
+    {
+        var err = await Assert.ThrowsAsync<Exceptions.WorkflowFailedException>(async () =>
+        {
+            var arg = new KSWorkflowParams(new KSAction(
+                Error: new(Message: "Some Message", Details: "Some Details", IsBenign: true)));
+            await Client.ExecuteWorkflowAsync(
+                (IKitchenSinkWorkflow wf) => wf.RunAsync(arg),
+                new(id: $"workflow-{Guid.NewGuid()}", taskQueue: Env.KitchenSinkWorkerTaskQueue));
+        });
+        var appErr = Assert.IsType<Exceptions.ApplicationFailureException>(err.InnerException);
+        Assert.Equal("Some Message", appErr.Message);
+        Assert.Equal("Some Details", appErr.Details.ElementAt<string>(0));
+        Assert.Equal(ApplicationErrorCategory.Benign, appErr.Category);
+    }
+
     [Fact]
     public async Task GetResultAsync_NotFoundWorkflow_Throws()
     {

tests/Temporalio.Tests/IKitchenSinkWorkflow.cs

@@ -66,7 +66,8 @@ public record KSResultAction(
 public record KSErrorAction(
     [property: JsonPropertyName("message")] string? Message = null,
     [property: JsonPropertyName("details")] object? Details = null,
-    [property: JsonPropertyName("attempt")] bool Attempt = false);
+    [property: JsonPropertyName("attempt")] bool Attempt = false,
+    [property: JsonPropertyName("is_benign")] bool IsBenign = false);
 
 public record KSContinueAsNewAction(
     [property: JsonPropertyName("while_above_zero")] int? WhileAboveZero = null,

tests/Temporalio.Tests/KitchenSinkWorkflow.cs

@@ -1,3 +1,5 @@
+using Temporalio.Api.Enums.V1;
+
 namespace Temporalio.Tests;
 
 using System.Threading.Tasks;
@@ -76,7 +78,9 @@ public class KitchenSinkWorkflow
                 details = new[] { action.Error.Details };
             }
             throw new ApplicationFailureException(
-                action.Error.Message ?? string.Empty, details: details);
+                action.Error.Message ?? string.Empty,
+                details: details,
+                category: action.Error.IsBenign ? ApplicationErrorCategory.Benign : ApplicationErrorCategory.Unspecified);
         }
         else if (action.ContinueAsNew != null)
         {