fix(platforms): address remaining review feedback

Author: niemyjski

src/Platforms/Exceptionless.Extensions.Hosting/ExceptionlessExtensions.cs

@@ -4,6 +4,7 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
+using System.Linq;
 
 namespace Exceptionless {
     public static class ExceptionlessExtensions {
@@ -116,7 +117,13 @@ public static IServiceCollection AddExceptionless(this IServiceCollection servic
         }
 
         private static IServiceCollection AddExceptionlessLifetimeService(this IServiceCollection services) {
-            services.TryAddEnumerable(ServiceDescriptor.Singleton<IHostedService, ExceptionlessLifetimeService>());
+            if (services.Any(descriptor => descriptor.ServiceType == typeof(ExceptionlessLifetimeService)))
+                return services;
+
+            services.AddSingleton<ExceptionlessLifetimeService>();
+            services.AddSingleton<IHostedService>(sp => sp.GetRequiredService<ExceptionlessLifetimeService>());
+            services.AddSingleton<IHostedLifecycleService>(sp => sp.GetRequiredService<ExceptionlessLifetimeService>());
+
             return services;
         }
     }

src/Platforms/Exceptionless.NLog/ExceptionlessTarget.cs

@@ -28,15 +28,17 @@ public ExceptionlessTarget() {
         protected override void InitializeTarget() {
             base.InitializeTarget();
 
-            foreach (var field in Fields) {
-                if (field == null)
-                    throw new NLogConfigurationException("Exceptionless field configuration cannot be null.");
+            if (Fields != null) {
+                foreach (var field in Fields) {
+                    if (field == null)
+                        throw new NLogConfigurationException("Exceptionless field configuration cannot be null.");
 
-                if (String.IsNullOrWhiteSpace(field.Name))
-                    throw new NLogConfigurationException("Exceptionless field name is required.");
+                    if (String.IsNullOrWhiteSpace(field.Name))
+                        throw new NLogConfigurationException("Exceptionless field name is required.");
 
-                if (field.Layout == null)
-                    throw new NLogConfigurationException($"Exceptionless field '{field.Name}' must define a layout.");
+                    if (field.Layout == null)
+                        throw new NLogConfigurationException($"Exceptionless field '{field.Name}' must define a layout.");
+                }
             }
 
             string apiKey = RenderLogEvent(ApiKey, LogEventInfo.CreateNullEvent());
@@ -80,10 +82,12 @@ protected override void Write(LogEventInfo logEvent) {
             string userIdentityName = RenderLogEvent(UserIdentityName, logEvent);
             builder.Target.SetUserIdentity(userIdentity, userIdentityName);
 
-            foreach (var field in Fields) {
-                string renderedField = RenderLogEvent(field.Layout, logEvent);
-                if (!String.IsNullOrWhiteSpace(renderedField))
-                    builder.AddObject(renderedField, field.Name);
+            if (Fields != null) {
+                foreach (var field in Fields) {
+                    string renderedField = RenderLogEvent(field.Layout, logEvent);
+                    if (!String.IsNullOrWhiteSpace(renderedField))
+                        builder.AddObject(renderedField, field.Name);
+                }
             }
 
             builder.Submit();

test/Exceptionless.Tests/Platforms/HostingExtensionsTests.cs

@@ -17,9 +17,17 @@ public void AddExceptionless_WhenCalled_RegistersClientAndLifetimeService() {
 
             // Assert
             Assert.Contains(builder.Services, descriptor => descriptor.ServiceType == typeof(ExceptionlessClient));
-            Assert.Contains(builder.Services, descriptor =>
-                descriptor.ServiceType == typeof(IHostedService) &&
-                descriptor.ImplementationType == typeof(ExceptionlessLifetimeService));
+            Assert.Single(builder.Services, descriptor => descriptor.ServiceType == typeof(ExceptionlessLifetimeService));
+            Assert.Single(builder.Services, descriptor => descriptor.ServiceType == typeof(IHostedService));
+            Assert.Single(builder.Services, descriptor => descriptor.ServiceType == typeof(IHostedLifecycleService));
+
+            using var serviceProvider = builder.Services.BuildServiceProvider();
+            Assert.Same(
+                serviceProvider.GetRequiredService<IHostedService>(),
+                serviceProvider.GetRequiredService<IHostedLifecycleService>());
+            Assert.Same(
+                serviceProvider.GetRequiredService<ExceptionlessLifetimeService>(),
+                serviceProvider.GetRequiredService<IHostedService>());
         }
 
         [Fact]
@@ -32,9 +40,9 @@ public void UseExceptionless_WhenCalledTwice_DoesNotRegisterDuplicateLifetimeSer
             builder.UseExceptionless();
 
             // Assert
-            Assert.Single(builder.Services, descriptor =>
-                descriptor.ServiceType == typeof(IHostedService) &&
-                descriptor.ImplementationType == typeof(ExceptionlessLifetimeService));
+            Assert.Single(builder.Services, descriptor => descriptor.ServiceType == typeof(ExceptionlessLifetimeService));
+            Assert.Single(builder.Services, descriptor => descriptor.ServiceType == typeof(IHostedService));
+            Assert.Single(builder.Services, descriptor => descriptor.ServiceType == typeof(IHostedLifecycleService));
         }
     }
 }