From cb4e11691f49b6aa15c16d2845ac3c5a63d0c842 Mon Sep 17 00:00:00 2001
From: Julian Verdurmen <304NotModified@users.noreply.github.com>
Date: Sat, 13 May 2017 16:55:24 +0200
Subject: [PATCH] small performance improvements for ServiceLocator

---
 .../AspNetEnvironmentLayoutRenderer.cs         | 14 ++++++++++++--
 .../AspNetLayoutRendererBase.cs                | 10 ++++++++++
 .../IISInstanceNameLayoutRenderer.cs           | 18 ++++++++++++++++--
 3 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/NLog.Web.AspNetCore/LayoutRenderers/AspNetEnvironmentLayoutRenderer.cs b/NLog.Web.AspNetCore/LayoutRenderers/AspNetEnvironmentLayoutRenderer.cs
index 2165c959..2356f32d 100644
--- a/NLog.Web.AspNetCore/LayoutRenderers/AspNetEnvironmentLayoutRenderer.cs
+++ b/NLog.Web.AspNetCore/LayoutRenderers/AspNetEnvironmentLayoutRenderer.cs
@@ -16,6 +16,10 @@ namespace NLog.Web.LayoutRenderers
     // ReSharper disable once InconsistentNaming
     public class AspNetEnvironmentLayoutRenderer : LayoutRenderer
     {
+        private static IHostingEnvironment _hostingEnvironment;
+
+        private static IHostingEnvironment HostingEnvironment => _hostingEnvironment ?? (_hostingEnvironment = ServiceLocator.ServiceProvider?.GetService<IHostingEnvironment>());
+        
         /// <summary>
         /// Append to target
         /// </summary>
@@ -23,8 +27,14 @@ public class AspNetEnvironmentLayoutRenderer : LayoutRenderer
         /// <param name="logEvent">Logging event.</param>
         protected override void Append(StringBuilder builder, LogEventInfo logEvent)
         {
-            var env = ServiceLocator.ServiceProvider?.GetService<IHostingEnvironment>();
-            builder.Append(env?.EnvironmentName);
+            builder.Append(HostingEnvironment?.EnvironmentName);
+        }
+
+        /// <inheritdoc />
+        protected override void CloseLayoutRenderer()
+        {
+            _hostingEnvironment = null;
+            base.CloseLayoutRenderer();
         }
     }
 }
diff --git a/NLog.Web.AspNetCore/LayoutRenderers/AspNetLayoutRendererBase.cs b/NLog.Web.AspNetCore/LayoutRenderers/AspNetLayoutRendererBase.cs
index b2b35e17..4411e096 100644
--- a/NLog.Web.AspNetCore/LayoutRenderers/AspNetLayoutRendererBase.cs
+++ b/NLog.Web.AspNetCore/LayoutRenderers/AspNetLayoutRendererBase.cs
@@ -85,6 +85,16 @@ protected override void Append(StringBuilder builder, LogEventInfo logEvent)
         /// <param name="logEvent">Logging event.</param>
         protected abstract void DoAppend(StringBuilder builder, LogEventInfo logEvent);
 
+#if NETSTANDARD_1plus
+
+/// <inheritdoc />
+        protected override void CloseLayoutRenderer()
+        {
+            _httpContextAccessor = null;
+            base.CloseLayoutRenderer();
+        }
+#endif
+
 
     }
 }
diff --git a/NLog.Web.AspNetCore/LayoutRenderers/IISInstanceNameLayoutRenderer.cs b/NLog.Web.AspNetCore/LayoutRenderers/IISInstanceNameLayoutRenderer.cs
index 94e9b656..56d21bb4 100644
--- a/NLog.Web.AspNetCore/LayoutRenderers/IISInstanceNameLayoutRenderer.cs
+++ b/NLog.Web.AspNetCore/LayoutRenderers/IISInstanceNameLayoutRenderer.cs
@@ -25,6 +25,12 @@ namespace NLog.Web.LayoutRenderers
     // ReSharper disable once InconsistentNaming
     public class IISInstanceNameLayoutRenderer : LayoutRenderer
     {
+#if NETSTANDARD_1plus
+        private static IHostingEnvironment _hostingEnvironment;
+
+        private static IHostingEnvironment HostingEnvironment => _hostingEnvironment ?? (_hostingEnvironment = ServiceLocator.ServiceProvider?.GetService<IHostingEnvironment>());
+#endif
+
         /// <summary>
         /// Append to target
         /// </summary>
@@ -35,13 +41,21 @@ protected override void Append(StringBuilder builder, LogEventInfo logEvent)
 
 
 #if NETSTANDARD_1plus
-            var env = ServiceLocator.ServiceProvider?.GetService<IHostingEnvironment>();
-            builder.Append(env?.ApplicationName);
+            builder.Append(HostingEnvironment?.ApplicationName);
 
 #else
             builder.Append(HostingEnvironment.SiteName);
 #endif
 
         }
+#if NETSTANDARD_1plus
+
+        /// <inheritdoc />
+        protected override void CloseLayoutRenderer()
+        {
+            _hostingEnvironment = null;
+            base.CloseLayoutRenderer();
+        }
+#endif
     }
 }