[Instrumentation.Hangfire] Added support for custom job display names (…

…#756)

* Added support for custom job display names

* Move JOB prefix to DisplayNameFunc.

* Added entry to CHANGELOG.md

* Fixed missing period in API docs.

src/OpenTelemetry.Instrumentation.Hangfire/.publicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -1,4 +1,6 @@
 OpenTelemetry.Trace.HangfireInstrumentationOptions
+OpenTelemetry.Trace.HangfireInstrumentationOptions.DisplayNameFunc.get -> System.Func<Hangfire.BackgroundJob, string>
+OpenTelemetry.Trace.HangfireInstrumentationOptions.DisplayNameFunc.set -> void
 OpenTelemetry.Trace.HangfireInstrumentationOptions.HangfireInstrumentationOptions() -> void
 OpenTelemetry.Trace.HangfireInstrumentationOptions.RecordException.get -> bool
 OpenTelemetry.Trace.HangfireInstrumentationOptions.RecordException.set -> void

src/OpenTelemetry.Instrumentation.Hangfire/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+* Add support for custom job display names
+  ([#756](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/756))
+
 ## 1.0.0-beta.3
 
 Released 2022-Oct-26

src/OpenTelemetry.Instrumentation.Hangfire/HangfireInstrumentationOptions.cs

@@ -14,6 +14,10 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+using Hangfire;
+using OpenTelemetry.Instrumentation.Hangfire.Implementation;
+
 namespace OpenTelemetry.Trace;
 
 /// <summary>
@@ -28,4 +32,12 @@ public class HangfireInstrumentationOptions
     /// https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/exceptions.md.
     /// </remarks>
     public bool RecordException { get; set; }
+
+    /// <summary>
+    /// Gets or sets a delegate used to format the job name.
+    /// </summary>
+    /// <remarks>
+    /// Defaults to <c>{backgroundJob.Job.Type.Name}.{backgroundJob.Job.Method.Name}</c>.
+    /// </remarks>
+    public Func<BackgroundJob, string> DisplayNameFunc { get; set; } = HangfireInstrumentation.DefaultDisplayNameFunc;
 }

src/OpenTelemetry.Instrumentation.Hangfire/Implementation/HangfireInstrumentation.cs

@@ -14,6 +14,8 @@
 // limitations under the License.
 // </copyright>
 
+using Hangfire;
+
 namespace OpenTelemetry.Instrumentation.Hangfire.Implementation;
 
 using System;
@@ -41,4 +43,10 @@ internal static class HangfireInstrumentation
     /// The activity source.
     /// </summary>
     internal static readonly ActivitySource ActivitySource = new(ActivitySourceName, Version.ToString());
+
+    /// <summary>
+    /// The default display name delegate.
+    /// </summary>
+    internal static readonly Func<BackgroundJob, string> DefaultDisplayNameFunc =
+        backgroundJob => $"JOB {backgroundJob.Job.Type.Name}.{backgroundJob.Job.Method.Name}";
 }

src/OpenTelemetry.Instrumentation.Hangfire/Implementation/HangfireInstrumentationJobFilterAttribute.cs

@@ -14,6 +14,9 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+using Hangfire;
+
 namespace OpenTelemetry.Instrumentation.Hangfire.Implementation;
 
 using System.Collections.Generic;
@@ -56,7 +59,10 @@ public void OnPerforming(PerformingContext performingContext)
 
         if (activity != null)
         {
-            activity.DisplayName = $"JOB {performingContext.BackgroundJob.Job.Type.Name}.{performingContext.BackgroundJob.Job.Method.Name}";
+            Func<BackgroundJob, string> displayNameFunc =
+                this.options.DisplayNameFunc ?? HangfireInstrumentation.DefaultDisplayNameFunc;
+
+            activity.DisplayName = displayNameFunc(performingContext.BackgroundJob);
 
             if (activity.IsAllDataRequested)
             {

test/OpenTelemetry.Instrumentation.Hangfire.Tests/HangfireInstrumentationJobFilterAttributeTests.cs

@@ -128,6 +128,27 @@ public async Task Should_Create_Activity_Without_Exception_Event_When_Job_Failed
         Assert.Empty(activity.Events);
     }
 
+    [Fact]
+    public async Task Should_Create_Activity_With_Custom_DisplayName()
+    {
+        // Arrange
+        var exportedItems = new List<Activity>();
+        using var tel = Sdk.CreateTracerProviderBuilder()
+            .AddHangfireInstrumentation(options => options.DisplayNameFunc = backgroundJob => $"JOB {backgroundJob.Id}")
+            .AddInMemoryExporter(exportedItems)
+            .Build();
+
+        // Act
+        var jobId = BackgroundJob.Enqueue<TestJob>(x => x.Execute());
+        await this.WaitJobProcessedAsync(jobId, 5);
+
+        // Assert
+        Assert.Single(exportedItems, i => i.GetTagItem("job.id") as string == jobId);
+        var activity = exportedItems.Single(i => i.GetTagItem("job.id") as string == jobId);
+        Assert.Contains($"JOB {jobId}", activity.DisplayName);
+        Assert.Equal(ActivityKind.Internal, activity.Kind);
+    }
+
     private async Task WaitJobProcessedAsync(string jobId, int timeToWaitInSeconds)
     {
         var timeout = DateTime.Now.AddSeconds(timeToWaitInSeconds);