(#2124) Add ability to initialize without logging

This commit makes changes to the API initialization method to allow
Chocolatey to allow the initialization to happen without enabling
logging.
Additionally changes have been made to allow adding extra loggers to be
added without overriding the logging
to the applications main chocolatey.log file.

These changes were necessary to allow programs (like ChocolateyGUI)
to add its own logging infrastructure without disabling logging
to the main log file.

src/chocolatey/GetChocolatey.cs

@@ -18,6 +18,7 @@ namespace chocolatey
 {
     using System;
     using System.Collections.Generic;
+    using System.IO;
     using System.Reflection;
     using infrastructure.licensing;
     using SimpleInjector;
@@ -47,16 +48,21 @@ public static class Lets
     {
         private static readonly log4net.ILog _logger = LogManager.GetLogger(typeof(Lets));
 
-        private static GetChocolatey set_up()
+        private static GetChocolatey set_up(bool initializeLogging)
         {
             add_assembly_resolver();
 
-            return new GetChocolatey();
+            return new GetChocolatey(initializeLogging);
         }
 
         public static GetChocolatey GetChocolatey()
         {
-            return GlobalMutex.enter(() => set_up(), 10);
+            return GetChocolatey(initializeLogging: true);
+        }
+
+        public static GetChocolatey GetChocolatey(bool initializeLogging)
+        {
+            return GlobalMutex.enter(() => set_up(initializeLogging), 10);
         }
 
         private static ResolveEventHandler _handler = null;
@@ -122,12 +128,24 @@ public class GetChocolatey
         /// Initializes a new instance of the <see cref="GetChocolatey"/> class.
         /// </summary>
         public GetChocolatey()
+            : this(initializeLogging: true)
+        {
+        }
+
+        public GetChocolatey(bool initializeLogging)
         {
-            Log4NetAppenderConfiguration.configure(null, excludeLoggerNames: ChocolateyLoggers.Trace.to_string());
-            Bootstrap.initialize();
-            Log.InitializeWith(new AggregateLog(new List<ILog>() { new Log4NetLog(), _logSinkLogger }));
-            _license = License.validate_license();
             _container = SimpleInjectorContainer.Container;
+            if (initializeLogging)
+            {
+                string loggingLocation = ApplicationParameters.LoggingLocation;
+                var fileSystem = _container.GetInstance<IFileSystem>();
+                fileSystem.create_directory_if_not_exists(loggingLocation);
+
+                Log4NetAppenderConfiguration.configure(loggingLocation, excludeLoggerNames: ChocolateyLoggers.Trace.to_string());
+                Log.InitializeWith(new AggregateLog(new List<ILog>() { new Log4NetLog(), _logSinkLogger }));
+                "chocolatey".Log().Debug("XmlConfiguration is now operational");
+            }
+            _license = License.validate_license();
         }
 
         /// <summary>
@@ -137,8 +155,28 @@ public GetChocolatey()
         /// <returns>This <see cref="GetChocolatey"/> instance</returns>
         public GetChocolatey SetCustomLogging(ILog logger)
         {
-            Log.InitializeWith(logger, resetLoggers: false);
-            drain_log_sink(logger);
+            return SetCustomLogging(logger, logExistingMessages: true, addToExistingLoggers: false);
+        }
+
+        public GetChocolatey SetCustomLogging(ILog logger, bool logExistingMessages)
+        {
+            return SetCustomLogging(logger, logExistingMessages, addToExistingLoggers: false);
+        }
+
+        public GetChocolatey SetCustomLogging(ILog logger, bool logExistingMessages, bool addToExistingLoggers)
+        {
+            var aggregateLog = new AggregateLog(new List<ILog> { logger });
+            if (addToExistingLoggers)
+            {
+                aggregateLog = new AggregateLog(new List<ILog> { logger, Log.GetLoggerFor("chocolatey") });
+            }
+
+            Log.InitializeWith(aggregateLog, resetLoggers: false);
+            if (logExistingMessages)
+            {
+                drain_log_sink(logger);
+            }
+
             return this;
         }