From 31d7735997fa0d8d8f4dc41fe43381f5f6f00cb0 Mon Sep 17 00:00:00 2001
From: Maxwell Weru <mburumaxwell@gmail.com>
Date: Thu, 16 May 2024 05:41:27 +0300
Subject: [PATCH] Resolving `TelemetryClient` in
 `ActivitySourceDependencyCollector` should be on need (#252)

`IHostedService` implementations may be invoked before the `TelemetryClient` is available. This change makes it possible to use `ActivitySourceDependencyCollector` in such scenarios instead of crashing.
---
 .../ActivitySourceDependencyCollector.cs               | 10 +++++++---
 .../IServiceCollectionExtensions.cs                    |  2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/Tingle.AspNetCore.ApplicationInsights/ActivitySourceDependencyCollector.cs b/src/Tingle.AspNetCore.ApplicationInsights/ActivitySourceDependencyCollector.cs
index aa4c116..c4e1b49 100644
--- a/src/Tingle.AspNetCore.ApplicationInsights/ActivitySourceDependencyCollector.cs
+++ b/src/Tingle.AspNetCore.ApplicationInsights/ActivitySourceDependencyCollector.cs
@@ -1,5 +1,6 @@
 using Microsoft.ApplicationInsights;
 using Microsoft.ApplicationInsights.DataContracts;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using System.Diagnostics;
 
@@ -8,13 +9,13 @@ namespace Tingle.AspNetCore.ApplicationInsights;
 // See https://github.com/microsoft/ApplicationInsights-dotnet/issues/1427
 internal class ActivitySourceDependencyCollector : IHostedService
 {
-    private readonly TelemetryClient client;
+    private readonly IServiceProvider serviceProvider;
     private readonly IDictionary<string, ActivitySamplingResult> activities;
     private readonly ActivityListener? listener;
 
-    public ActivitySourceDependencyCollector(TelemetryClient client, IDictionary<string, ActivitySamplingResult> activities)
+    public ActivitySourceDependencyCollector(IServiceProvider serviceProvider, IDictionary<string, ActivitySamplingResult> activities)
     {
-        this.client = client ?? throw new ArgumentNullException(nameof(client));
+        this.serviceProvider = serviceProvider ?? throw new ArgumentNullException(nameof(serviceProvider));
         this.activities = activities ?? throw new ArgumentNullException(nameof(activities));
 
         if (activities.Count > 0)
@@ -34,6 +35,9 @@ public ActivitySourceDependencyCollector(TelemetryClient client, IDictionary<str
 
     internal void ActivityStopped(Activity activity)
     {
+        var client = serviceProvider.GetService<TelemetryClient>();
+        if (client is null) return;
+
         // extensibility point - can chain more telemetry extraction methods here
         var telemetry = ExtractDependencyTelemetry(activity);
         if (telemetry == null)
diff --git a/src/Tingle.AspNetCore.ApplicationInsights/IServiceCollectionExtensions.cs b/src/Tingle.AspNetCore.ApplicationInsights/IServiceCollectionExtensions.cs
index 8d8aef4..ca5f247 100644
--- a/src/Tingle.AspNetCore.ApplicationInsights/IServiceCollectionExtensions.cs
+++ b/src/Tingle.AspNetCore.ApplicationInsights/IServiceCollectionExtensions.cs
@@ -62,6 +62,6 @@ public static IServiceCollection AddActivitySourceDependencyCollector(this IServ
     public static IServiceCollection AddActivitySourceDependencyCollector(this IServiceCollection services,
                                                                           IDictionary<string, ActivitySamplingResult> activities)
     {
-        return services.AddHostedService(p => ActivatorUtilities.CreateInstance<ActivitySourceDependencyCollector>(p, [activities]));
+        return services.AddHostedService(p => new ActivitySourceDependencyCollector(p, activities));
     }
 }