feat: Implement simple in-memory Serilog sink.

src/Agent/NewRelic/Agent/Core/Logging/InMemorySink.cs

@@ -0,0 +1,43 @@
+// Copyright 2020 New Relic, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+using System;
+using Serilog.Configuration;
+using Serilog;
+using Serilog.Core;
+using Serilog.Events;
+using System.Collections.Concurrent;
+
+namespace NewRelic.Agent.Core.Logging
+{
+    public class InMemorySink : ILogEventSink, IDisposable
+    {
+        private static readonly InMemorySink _instance = new InMemorySink();
+
+        public readonly ConcurrentQueue<LogEvent> LogEvents;
+
+        public static InMemorySink Instance
+        {
+            get
+            {
+                return _instance;
+            }
+        }
+
+        protected InMemorySink()
+        {
+            LogEvents = new ConcurrentQueue<LogEvent>();
+        }
+
+        public void Emit(LogEvent logEvent)
+        {
+            LogEvents.Enqueue(logEvent);
+        }
+
+        public void Dispose()
+        {
+            while (LogEvents.TryDequeue(out _))
+            { }
+        }
+    }
+}

src/Agent/NewRelic/Agent/Core/Logging/LoggerBootstrapper.cs

@@ -10,6 +10,7 @@
 using Serilog.Core;
 using Serilog.Formatting;
 using Logger = NewRelic.Agent.Core.Logging.Logger;
+using NewRelic.Agent.Core.Logging;
 
 namespace NewRelic.Agent.Core
 {
@@ -53,11 +54,9 @@ public static void Initialize()
                 .Enrich.With(new ThreadIdEnricher())
                 .Enrich.With(new ProcessIdEnricher())
                 .MinimumLevel.Information()
-                .ConfigureInMemoryLogSink()
+                .ConfigureInMemoryLogSink();
                 // TODO: implement event log sink
-                //.ConfigureEventLogSink()
-                // TODO: Remove console log sink when in-memory sink is implemented
-                .ConfigureConsoleSink();
+                //.ConfigureEventLogSink();
 
             // set the global Serilog logger to our startup logger instance, this gets replaced when ConfigureLogger() is called
             Serilog.Log.Logger = startupLoggerConfig.CreateLogger();
@@ -103,13 +102,12 @@ public static void ConfigureLogger(ILogConfig config)
 
         private static void EchoInMemoryLogsToConfiguredLogger(Serilog.ILogger configuredLogger)
         {
-            // TODO: copy logs from inMemory logger and emit them to Serilog.Log.Logger
-            // possible example:
-            //foreach (LogEvent logEvent in InMemorySink.Instance.LogEvents)
-            //{
-            //    configuredLogger.Write(logEvent.Level, logEvent.Exception, logEvent.MessageTemplate.Render(logEvent.Properties));
-            //}
-            //InMemorySink.Instance.Dispose();
+            while (InMemorySink.Instance.LogEvents.TryDequeue(out var logEvent))
+            {
+                configuredLogger.Write(logEvent);
+            }
+
+            InMemorySink.Instance.Dispose();
         }
 
         /// <summary>
@@ -133,9 +131,14 @@ private static void SetupLogLevel(ILogConfig config)
 
         private static LoggerConfiguration ConfigureInMemoryLogSink(this LoggerConfiguration loggerConfiguration)
         {
-            // TODO Configure the (yet-to-be-implemented) in-memory sink
-
-            return loggerConfiguration;
+            // formatter not needed since this will be pushed to other sinks for output.
+            return loggerConfiguration
+                .WriteTo.Logger(configuration =>
+                {
+                    configuration
+                        .ExcludeAuditLog()
+                        .WriteTo.Sink(InMemorySink.Instance);
+                });
         }
 
         // TODO: Implement EventLog support, see commented package reference in Core.csproj

tests/Agent/UnitTests/Core.UnitTest/NewRelic.Agent.Core.FromLegacy/AgentLoggerTest.cs

@@ -11,6 +11,7 @@
 using log4net.Appender;
 using log4net.Core;
 using System.IO;
+using NewRelic.Agent.Core.Logging;
 
 namespace NewRelic.Agent.Core
 {
@@ -368,7 +369,38 @@ public static void Logging_sets_threadid_property_for_LogException()
             Assert.AreEqual(log4net.ThreadContext.Properties["threadid"], Thread.CurrentThread.ManagedThreadId);
         }
 
+        #region InMemorySink Tests
 
+        [Test]
+        public static void InMemorySink_IsStartupLogger()
+        {
+            ILogConfig config = GetLogConfig("all");
+            LoggerBootstrapper.Initialize();
+
+            // Write a log message to global Serilog logger
+            Serilog.Log.Logger.Information("InMemorySink log");
+
+            // Check that the log message was stored in the InMemorySink
+            Assert.AreEqual(1, InMemorySink.Instance.LogEvents.Count);
+        }
+
+        [Test]
+        public static void InMemorySink_ReplacedBy_AgentLogger()
+        {
+            ILogConfig config = GetLogConfig("all");
+            LoggerBootstrapper.Initialize();
+
+            // Configure the real agent logger and replace the start up logger
+            LoggerBootstrapper.ConfigureLogger(config);
+
+            // Write a log message to global Serilog logger
+            Serilog.Log.Logger.Information("InMemorySink log");
+
+            // Check that the log message was not stored in the InMemorySink
+            Assert.AreEqual(0, InMemorySink.Instance.LogEvents.Count);
+        }
+
+        #endregion
 
         static private ILogConfig GetLogConfig(string logLevel)
         {