From b624b2b4afd8b3930507b849411fc4b2c740d3a0 Mon Sep 17 00:00:00 2001
From: Sipke Schoorstra <sipkeschoorstra@outlook.com>
Date: Fri, 14 Mar 2025 23:37:46 +0100
Subject: [PATCH] Refactor error span handling with prioritization and
 predicates

Introduce `Order` property and `CanHandle` method in `IErrorSpanHandler` to enable prioritized and conditional processing of error spans. Update handler implementations to utilize these properties and streamline logic. This enhances flexibility and improves the extensibility of error span handling.
---
 .../Abstractions/ErrorSpanHandlerBase.cs                 | 2 ++
 .../Elsa.OpenTelemetry/Contracts/IErrorSpanHandler.cs    | 3 ++-
 .../Handlers/DefaultErrorSpanHandler.cs                  | 9 +++++----
 .../Handlers/FaultExceptionErrorSpanHandler.cs           | 6 +++---
 .../OpenTelemetryTracingActivityExecutionMiddleware.cs   | 6 ++++--
 5 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/modules/Elsa.OpenTelemetry/Abstractions/ErrorSpanHandlerBase.cs b/src/modules/Elsa.OpenTelemetry/Abstractions/ErrorSpanHandlerBase.cs
index 420936119..06e77bd4f 100644
--- a/src/modules/Elsa.OpenTelemetry/Abstractions/ErrorSpanHandlerBase.cs
+++ b/src/modules/Elsa.OpenTelemetry/Abstractions/ErrorSpanHandlerBase.cs
@@ -5,5 +5,7 @@ namespace Elsa.OpenTelemetry.Abstractions;
 
 public abstract class ErrorSpanHandlerBase : IErrorSpanHandler
 {
+    public virtual float Order => 0;
+    public abstract bool CanHandle(ErrorSpanContext context);
     public abstract void Handle(ErrorSpanContext context);
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.OpenTelemetry/Contracts/IErrorSpanHandler.cs b/src/modules/Elsa.OpenTelemetry/Contracts/IErrorSpanHandler.cs
index d15c3dee4..70b16f645 100644
--- a/src/modules/Elsa.OpenTelemetry/Contracts/IErrorSpanHandler.cs
+++ b/src/modules/Elsa.OpenTelemetry/Contracts/IErrorSpanHandler.cs
@@ -1,10 +1,11 @@
-using Elsa.OpenTelemetry.Abstractions;
 using Elsa.OpenTelemetry.Models;
 
 namespace Elsa.OpenTelemetry.Contracts;
 
 public interface IErrorSpanHandler
 {
+    float Order { get; }
+    bool CanHandle(ErrorSpanContext context);
     void Handle(ErrorSpanContext context);
 }
 
diff --git a/src/modules/Elsa.OpenTelemetry/Handlers/DefaultErrorSpanHandler.cs b/src/modules/Elsa.OpenTelemetry/Handlers/DefaultErrorSpanHandler.cs
index a3003ba35..aac9fbae9 100644
--- a/src/modules/Elsa.OpenTelemetry/Handlers/DefaultErrorSpanHandler.cs
+++ b/src/modules/Elsa.OpenTelemetry/Handlers/DefaultErrorSpanHandler.cs
@@ -5,11 +5,12 @@ namespace Elsa.OpenTelemetry.Handlers;
 
 public class DefaultErrorSpanHandler : ErrorSpanHandlerBase
 {
+    public override float Order => 100000;
+    
+    public override bool CanHandle(ErrorSpanContext context) => context.Exception != null;
+
     public override void Handle(ErrorSpanContext context)
     {
-        if (context.Exception is null)
-            return;
-        
-        context.Span.AddException(context.Exception);
+        context.Span.AddException(context.Exception!);
     }
 }
\ No newline at end of file
diff --git a/src/modules/Elsa.OpenTelemetry/Handlers/FaultExceptionErrorSpanHandler.cs b/src/modules/Elsa.OpenTelemetry/Handlers/FaultExceptionErrorSpanHandler.cs
index 301b2b78d..9403e20e9 100644
--- a/src/modules/Elsa.OpenTelemetry/Handlers/FaultExceptionErrorSpanHandler.cs
+++ b/src/modules/Elsa.OpenTelemetry/Handlers/FaultExceptionErrorSpanHandler.cs
@@ -6,11 +6,11 @@ namespace Elsa.OpenTelemetry.Handlers;
 
 public class FaultExceptionErrorSpanHandler : ErrorSpanHandlerBase
 {
+    public override bool CanHandle(ErrorSpanContext context) => context.Exception is FaultException;
+
     public override void Handle(ErrorSpanContext context)
     {
-        if (context.Exception is not FaultException faultException)
-            return;
-
+        var faultException = (FaultException)context.Exception!;
         var span = context.Span;
         var tags = new Dictionary<string, object?>
         {
diff --git a/src/modules/Elsa.OpenTelemetry/Middleware/OpenTelemetryTracingActivityExecutionMiddleware.cs b/src/modules/Elsa.OpenTelemetry/Middleware/OpenTelemetryTracingActivityExecutionMiddleware.cs
index 60a2acd46..e11106912 100644
--- a/src/modules/Elsa.OpenTelemetry/Middleware/OpenTelemetryTracingActivityExecutionMiddleware.cs
+++ b/src/modules/Elsa.OpenTelemetry/Middleware/OpenTelemetryTracingActivityExecutionMiddleware.cs
@@ -46,9 +46,11 @@ public class OpenTelemetryTracingActivityExecutionMiddleware(ActivityMiddlewareD
             span.SetStatus(ActivityStatusCode.Error);
             span.SetTag("activity.incidents", true);
 
-            var errorSpanHandlers = context.GetServices<IErrorSpanHandler>();
             var errorSpanHandlerContext = new ErrorSpanContext(span, context.Exception);
-
+            var errorSpanHandlers = context.GetServices<IErrorSpanHandler>()
+                .OrderBy(x => x.Order)
+                .Where(x => x.CanHandle(errorSpanHandlerContext));
+            
             foreach (var handler in errorSpanHandlers)
                 handler.Handle(errorSpanHandlerContext);
         }