SEBWIN-301: Implemented service log file persistence in user directory.

SafeExamBrowser.Configuration/ConfigurationData/DataValues.cs

@@ -68,6 +68,8 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 			appConfig.SebUriScheme = "seb";
 			appConfig.SebUriSchemeSecure = "sebs";
 			appConfig.ServiceAddress = $"{BASE_ADDRESS}/service";
+			appConfig.ServiceEventName = $@"Global\{nameof(SafeExamBrowser)}-{Guid.NewGuid()}";
+			appConfig.ServiceLogFilePath = Path.Combine(logFolder, $"{logFilePrefix}_Service.log");
 
 			return appConfig;
 		}

SafeExamBrowser.Contracts/Configuration/AppConfig.cs

@@ -121,6 +121,11 @@ namespace SafeExamBrowser.Contracts.Configuration
 		/// </summary>
 		public string ServiceEventName { get; set; }
 
+		/// <summary>
+		/// The file path under which the log for the current session of the service component is to be stored.
+		/// </summary>
+		public string ServiceLogFilePath { get; set; }
+
 		/// <summary>
 		/// Creates a shallow clone.
 		/// </summary>

SafeExamBrowser.Logging/LogFileWriter.cs

@@ -29,11 +29,11 @@ namespace SafeExamBrowser.Logging
 
 		public void Initialize()
 		{
-			var logFolder = Path.GetDirectoryName(filePath);
+			var directory = Path.GetDirectoryName(filePath);
 
-			if (!Directory.Exists(logFolder))
+			if (!Directory.Exists(directory))
 			{
-				Directory.CreateDirectory(logFolder);
+				Directory.CreateDirectory(directory);
 			}
 		}
 

SafeExamBrowser.Service/CompositionRoot.cs

@@ -46,7 +46,7 @@ namespace SafeExamBrowser.Service
 			bootstrapOperations.Enqueue(new CommunicationHostOperation(serviceHost, logger));
 			bootstrapOperations.Enqueue(new ServiceEventCleanupOperation(logger, sessionContext));
 
-			sessionOperations.Enqueue(new SessionInitializationOperation(logger, serviceHost, sessionContext));
+			sessionOperations.Enqueue(new SessionInitializationOperation(logger, CreateLogWriter, serviceHost, sessionContext));
 			// TODO: sessionOperations.Enqueue(new RegistryOperation());
 			//       sessionOperations.Enqueue(new WindowsUpdateOperation());
 			sessionOperations.Enqueue(new SessionActivationOperation(logger, sessionContext));
@@ -81,5 +81,14 @@ namespace SafeExamBrowser.Service
 			logger.Subscribe(logFileWriter);
 			logFileWriter.Initialize();
 		}
+
+		private ILogObserver CreateLogWriter(string filePath)
+		{
+			var writer = new LogFileWriter(new DefaultLogFormatter(), filePath);
+
+			writer.Initialize();
+
+			return writer;
+		}
 	}
 }

SafeExamBrowser.Service/Operations/ServiceEventCleanupOperation.cs

@@ -33,10 +33,10 @@ namespace SafeExamBrowser.Service.Operations
 
 		public OperationResult Revert()
 		{
-			if (sessionContext.EventWaitHandle != null)
+			if (sessionContext.ServiceEvent != null)
 			{
 				logger.Info("Closing service event...");
-				sessionContext.EventWaitHandle.Close();
+				sessionContext.ServiceEvent.Close();
 				logger.Info("Service event successfully closed.");
 			}
 

SafeExamBrowser.Service/Operations/SessionActivationOperation.cs

@@ -22,7 +22,7 @@ namespace SafeExamBrowser.Service.Operations
 
 		public override OperationResult Perform()
 		{
-			var success = Context.EventWaitHandle.Set();
+			var success = Context.ServiceEvent.Set();
 
 			if (success)
 			{

SafeExamBrowser.Service/Operations/SessionInitializationOperation.cs

@@ -6,6 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System;
 using System.Security.AccessControl;
 using System.Security.Principal;
 using System.Threading;
@@ -18,16 +19,25 @@ namespace SafeExamBrowser.Service.Operations
 	internal class SessionInitializationOperation : SessionOperation
 	{
 		private ILogger logger;
+		private Func<string, ILogObserver> createLogWriter;
 		private IServiceHost serviceHost;
+		private ILogObserver sessionWriter;
 
-		public SessionInitializationOperation(ILogger logger, IServiceHost serviceHost, SessionContext sessionContext) : base(sessionContext)
+		public SessionInitializationOperation(
+			ILogger logger,
+			Func<string, ILogObserver> createLogWriter,
+			IServiceHost serviceHost,
+			SessionContext sessionContext) : base(sessionContext)
 		{
 			this.logger = logger;
+			this.createLogWriter = createLogWriter;
 			this.serviceHost = serviceHost;
 		}
 
 		public override OperationResult Perform()
 		{
+			InitializeSessionWriter();
+
 			logger.Info("Initializing new session...");
 
 			serviceHost.AllowConnection = false;
@@ -35,16 +45,20 @@ namespace SafeExamBrowser.Service.Operations
 			logger.Info($" -> Runtime-ID: {Context.Configuration.AppConfig.RuntimeId}");
 			logger.Info($" -> Session-ID: {Context.Configuration.SessionId}");
 
-			InitializeEventWaitHandle();
+			InitializeServiceEvent();
 
 			return OperationResult.Success;
 		}
 
 		public override OperationResult Revert()
 		{
+			var success = true;
+
 			logger.Info("Finalizing current session...");
 
-			var success = Context.EventWaitHandle?.Set() == true;
+			if (Context.ServiceEvent != null)
+			{
+				success = Context.ServiceEvent.Set();
 
 				if (success)
 				{
@@ -54,14 +68,17 @@ namespace SafeExamBrowser.Service.Operations
 				{
 					logger.Error("Failed to inform runtime about session termination!");
 				}
+			}
 
 			Context.Configuration = null;
+			logger.Unsubscribe(sessionWriter);
+			sessionWriter = null;
 			serviceHost.AllowConnection = true;
 
 			return success ? OperationResult.Success : OperationResult.Failed;
 		}
 
-		private void InitializeEventWaitHandle()
+		private void InitializeServiceEvent()
 		{
 			var securityIdentifier = new SecurityIdentifier(WellKnownSidType.BuiltinUsersSid, null);
 			var accessRule = new EventWaitHandleAccessRule(securityIdentifier, EventWaitHandleRights.Synchronize, AccessControlType.Allow);
@@ -69,16 +86,22 @@ namespace SafeExamBrowser.Service.Operations
 
 			security.AddAccessRule(accessRule);
 
-			if (Context.EventWaitHandle != null)
+			if (Context.ServiceEvent != null)
 			{
 				logger.Info("Closing service event from previous session...");
-				Context.EventWaitHandle.Close();
+				Context.ServiceEvent.Close();
 				logger.Info("Service event successfully closed.");
 			}
 
 			logger.Info("Attempting to create new service event...");
-			Context.EventWaitHandle = new EventWaitHandle(false, EventResetMode.AutoReset, Context.Configuration.AppConfig.ServiceEventName, out _, security);
+			Context.ServiceEvent = new EventWaitHandle(false, EventResetMode.AutoReset, Context.Configuration.AppConfig.ServiceEventName, out _, security);
 			logger.Info("Service event successfully created.");
 		}
+
+		private void InitializeSessionWriter()
+		{
+			sessionWriter = createLogWriter.Invoke(Context.Configuration.AppConfig.ServiceLogFilePath);
+			logger.Subscribe(sessionWriter);
+		}
 	}
 }

SafeExamBrowser.Service/SessionContext.cs

@@ -24,6 +24,6 @@ namespace SafeExamBrowser.Service
 		/// <summary>
 		/// The global inter-process event used for status synchronization with the runtime component.
 		/// </summary>
-		internal EventWaitHandle EventWaitHandle { get; set; }
+		internal EventWaitHandle ServiceEvent { get; set; }
 	}
 }