NLogLoggerFactory - Emulate Microsoft LoggerFactory by returning same…

… ILogger instance (#380)
NLog · Jan 21, 2020 · 3f07a9c · 3f07a9c
1 parent ab088e2
commit 3f07a9c
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Showing 3 changed files with 35 additions and 1 deletion.
diff --git a/src/NLog.Extensions.Logging/Logging/NLogLogger.cs b/src/NLog.Extensions.Logging/Logging/NLogLogger.cs
@@ -402,6 +402,12 @@ private bool IsEnabled(LogLevel logLevel)
             return _logger.IsEnabled(logLevel);
         }
 
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return LoggerName;
+        }
+
         /// <summary>
         /// Convert log level to NLog variant.
         /// </summary>

diff --git a/src/NLog.Extensions.Logging/Logging/NLogLoggerFactory.cs b/src/NLog.Extensions.Logging/Logging/NLogLoggerFactory.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using Microsoft.Extensions.Logging;
 using NLog.Common;
 
@@ -9,6 +10,8 @@ namespace NLog.Extensions.Logging
     /// </summary>
     public class NLogLoggerFactory : ILoggerFactory
     {
+        private readonly Dictionary<string, Microsoft.Extensions.Logging.ILogger> _loggers = new Dictionary<string, Microsoft.Extensions.Logging.ILogger>(StringComparer.Ordinal);
+
         private readonly NLogLoggerProvider _provider;
 
         /// <summary>
@@ -66,7 +69,15 @@ protected virtual void Dispose(bool disposing)
         /// <returns>The <see cref="T:Microsoft.Extensions.Logging.ILogger" />.</returns>
         public Microsoft.Extensions.Logging.ILogger CreateLogger(string categoryName)
         {
-            return _provider.CreateLogger(categoryName);
+            lock (_loggers)
+            {
+                if (!_loggers.TryGetValue(categoryName, out var logger))
+                {
+                    logger = _provider.CreateLogger(categoryName);
+                    _loggers[categoryName] = logger;
+                }
+                return logger;
+            }
         }
 
         /// <summary>

diff --git a/test/NLog.Extensions.Logging.Tests/Logging/NLogLoggerFactoryTests.cs b/test/NLog.Extensions.Logging.Tests/Logging/NLogLoggerFactoryTests.cs
@@ -56,5 +56,22 @@ public void AddProvider_StateUnderTest_ExpectedBehavior()
             // Assert
             Assert.Single(logFactory.Configuration.FindTargetByName<Targets.MemoryTarget>("output").Logs);
         }
+
+        [Fact]
+        public void CreateLogger_SameName_ReturnsSameInstanceTest()
+        {
+            // Arrange
+            var loggerFactory = new NLogLoggerFactory();
+            string loggerName = "namespace.class1";
+
+            // Act
+            var result1 = loggerFactory.CreateLogger(loggerName);
+            var result2 = loggerFactory.CreateLogger(loggerName);
+
+            // Assert
+            Assert.NotNull(result1);
+            Assert.Equal(loggerName, result1.ToString());
+            Assert.Same(result1, result2);
+        }
     }
 }