Add an AddApplicationInsightsTelemetryProcessor extension method

src/Microsoft.ApplicationInsights.AspNetCore/Extensions/ApplicationInsightsExtensions.cs

@@ -180,6 +180,19 @@ namespace Microsoft.Extensions.DependencyInjection
             return services;
         }
 
+        /// <summary>
+        /// Adds an Application Insights Telemetry Processor into a service collection via a <see cref="ITelemetryProcessorFactory"/>.
+        /// </summary>
+        /// <typeparam name="T">Type of the telemetry processor to add.</typeparam>
+        /// <param name="services">The <see cref="IServiceCollection"/> instance.</param>
+        /// <returns>
+        /// The <see cref="IServiceCollection"/>.
+        /// </returns>
+        public static IServiceCollection AddApplicationInsightsTelemetryProcessor<T>(this IServiceCollection services) where T : ITelemetryProcessor
+        {
+            return services.AddSingleton<ITelemetryProcessorFactory>(new TelemetryProcessorFactory<T>());
+        }
+
         /// <summary>
         /// Adds Application Insight specific configuration properties to <see cref="IConfigurationBuilder"/>.
         /// </summary>

src/Microsoft.ApplicationInsights.AspNetCore/Implementation/TelemetryProcessorFactory.cs

@@ -0,0 +1,22 @@
+namespace Microsoft.ApplicationInsights.AspNetCore
+{
+    using System;
+    using Microsoft.ApplicationInsights.Extensibility;
+
+    /// <summary>
+    /// A generic factory for telemetry processors of a given type.
+    /// </summary>
+    /// <typeparam name="T">The type of telemetry processor created by this factory.</typeparam>
+    internal class TelemetryProcessorFactory<T> : ITelemetryProcessorFactory where T : ITelemetryProcessor
+    {
+        /// <summary>
+        /// Creates an instance of the telemetry processor, passing the
+        /// next <see cref="ITelemetryProcessor"/> in the call chain to
+        /// its constructor.
+        /// </summary>
+        public ITelemetryProcessor Create(ITelemetryProcessor next)
+        {
+            return (ITelemetryProcessor)Activator.CreateInstance(typeof(T), args: next);
+        }
+    }
+}

test/Microsoft.ApplicationInsights.AspNetCore.Tests/Extensions/ApplicationInsightsExtensionsTests.cs

@@ -348,7 +348,7 @@ namespace Microsoft.Extensions.DependencyInjection.Test
             public static void RegistersTelemetryConfigurationFactoryMethodThatPopulatesItWithTelemetryProcessorFactoriesFromContainer()
             {
                 var services = ApplicationInsightsExtensionsTests.GetServiceCollectionWithContextAccessor();
-                services.AddSingleton<ITelemetryProcessorFactory>(new MockTelemetryProcessorFactory((next) => new FakeTelemetryProcessor(next)));
+                services.AddApplicationInsightsTelemetryProcessor<FakeTelemetryProcessor>();
 
                 services.AddApplicationInsightsTelemetry(new ConfigurationBuilder().Build());
 
@@ -590,17 +590,5 @@ namespace Microsoft.Extensions.DependencyInjection.Test
             {
             }
         }
-
-        private class MockTelemetryProcessorFactory: ITelemetryProcessorFactory
-        {
-            public Func<ITelemetryProcessor, ITelemetryProcessor> Factory { get; set; }
-
-            public MockTelemetryProcessorFactory(Func<ITelemetryProcessor, ITelemetryProcessor> factory)
-            {
-                this.Factory = factory;
-            }
-
-            public ITelemetryProcessor Create(ITelemetryProcessor next) => Factory(next);
-        }
     }
 }