Implement manual log file rotating and culling

Dalamud.Injector/EntryPoint.cs

@@ -128,12 +128,58 @@ namespace Dalamud.Injector
             levelSwitch.MinimumLevel = LogEventLevel.Information;
 #endif
 
+            CullLogFile(logPath, 1 * 1024 * 1024);
+
             Log.Logger = new LoggerConfiguration()
                 .WriteTo.Async(a => a.File(logPath))
                 .MinimumLevel.ControlledBy(levelSwitch)
                 .CreateLogger();
         }
 
+        private static void CullLogFile(string logPath, int cullingFileSize)
+        {
+            try
+            {
+                var bufferSize = 4096;
+
+                var logFile = new FileInfo(logPath);
+
+                if (!logFile.Exists)
+                    logFile.Create();
+
+                if (logFile.Length <= cullingFileSize)
+                    return;
+
+                var amountToCull = logFile.Length - cullingFileSize;
+
+                if (amountToCull < bufferSize)
+                    return;
+
+                using var reader = new BinaryReader(logFile.Open(FileMode.Open, FileAccess.Read, FileShare.ReadWrite));
+                using var writer = new BinaryWriter(logFile.Open(FileMode.Open, FileAccess.Write, FileShare.ReadWrite));
+
+                reader.BaseStream.Seek(amountToCull, SeekOrigin.Begin);
+
+                var read = -1;
+                var total = 0;
+                var buffer = new byte[bufferSize];
+                while (read != 0)
+                {
+                    read = reader.Read(buffer, 0, buffer.Length);
+                    writer.Write(buffer, 0, read);
+                    total += read;
+                }
+
+                writer.BaseStream.SetLength(total);
+            }
+            catch (Exception ex)
+            {
+                var caption = "XIVLauncher Error";
+                var message = $"Log cull threw an exception: {ex.Message}\n{ex.StackTrace ?? string.Empty}";
+                _ = MessageBoxW(IntPtr.Zero, message, caption, MessageBoxType.IconError | MessageBoxType.Ok);
+            }
+        }
+
         private static Process GetProcess(string arg)
         {
             Process process;

Dalamud/EntryPoint.cs

@@ -12,6 +12,8 @@ using Serilog;
 using Serilog.Core;
 using Serilog.Events;
 
+using static Dalamud.NativeFunctions;
+
 namespace Dalamud
 {
     /// <summary>
@@ -43,11 +45,16 @@ namespace Dalamud
         /// <param name="info">The <see cref="DalamudStartInfo"/> containing information needed to initialize Dalamud.</param>
         private static void RunThread(DalamudStartInfo info)
         {
+            // Setup logger
+            var levelSwitch = InitLogging(info.WorkingDirectory);
+
             // Load configuration first to get some early persistent state, like log level
             var configuration = DalamudConfiguration.Load(info.ConfigurationPath);
 
-            // Setup logger
+            // Set the appropriate logging level from the configuration
-            var levelSwitch = InitLogging(info.WorkingDirectory, configuration);
+#if !DEBUG
+            levelSwitch.MinimumLevel = configuration.LogLevel;
+#endif
 
             // Log any unhandled exception.
             AppDomain.CurrentDomain.UnhandledException += OnUnhandledException;
@@ -88,23 +95,22 @@ namespace Dalamud
             }
         }
 
-        private static LoggingLevelSwitch InitLogging(string baseDirectory, DalamudConfiguration configuration)
+        private static LoggingLevelSwitch InitLogging(string baseDirectory)
         {
 #if DEBUG
             var logPath = Path.Combine(baseDirectory, "dalamud.log");
+            var oldPath = Path.Combine(baseDirectory, "dalamud.log.old");
 #else
             var logPath = Path.Combine(baseDirectory, "..", "..", "..", "dalamud.log");
+            var oldPath = Path.Combine(baseDirectory, "..", "..", "..", "dalamud.log.old");
 #endif
 
-            var levelSwitch = new LoggingLevelSwitch();
+            CullLogFile(logPath, oldPath, 1 * 1024 * 1024);
+            CullLogFile(oldPath, null, 10 * 1024 * 1024);
 
-#if DEBUG
+            var levelSwitch = new LoggingLevelSwitch(LogEventLevel.Verbose);
-            levelSwitch.MinimumLevel = LogEventLevel.Verbose;
-#else
-            levelSwitch.MinimumLevel = configuration.LogLevel;
-#endif
             Log.Logger = new LoggerConfiguration()
-                   .WriteTo.Async(a => a.File(logPath, fileSizeLimitBytes: 5 * 1024 * 1024, rollOnFileSizeLimit: true))
+                .WriteTo.Async(a => a.File(logPath))
                 .WriteTo.Sink(SerilogEventSink.Instance)
                 .MinimumLevel.ControlledBy(levelSwitch)
                 .CreateLogger();
@@ -112,6 +118,73 @@ namespace Dalamud
             return levelSwitch;
         }
 
+        private static void CullLogFile(string logPath, string? oldPath, int cullingFileSize)
+        {
+            try
+            {
+                var bufferSize = 4096;
+
+                var logFile = new FileInfo(logPath);
+
+                if (!logFile.Exists)
+                    logFile.Create();
+
+                if (logFile.Length <= cullingFileSize)
+                    return;
+
+                var amountToCull = logFile.Length - cullingFileSize;
+
+                if (amountToCull < bufferSize)
+                    return;
+
+                if (oldPath != null)
+                {
+                    var oldFile = new FileInfo(oldPath);
+
+                    if (!oldFile.Exists)
+                        oldFile.Create();
+
+                    using var reader = new BinaryReader(logFile.Open(FileMode.Open, FileAccess.Read));
+                    using var writer = new BinaryWriter(oldFile.Open(FileMode.Append, FileAccess.Write));
+
+                    var read = -1;
+                    var total = 0;
+                    var buffer = new byte[bufferSize];
+                    while (read != 0 && total < amountToCull)
+                    {
+                        read = reader.Read(buffer, 0, buffer.Length);
+                        writer.Write(buffer, 0, read);
+                        total += read;
+                    }
+                }
+
+                {
+                    using var reader = new BinaryReader(logFile.Open(FileMode.Open, FileAccess.Read, FileShare.ReadWrite));
+                    using var writer = new BinaryWriter(logFile.Open(FileMode.Open, FileAccess.Write, FileShare.ReadWrite));
+
+                    reader.BaseStream.Seek(amountToCull, SeekOrigin.Begin);
+
+                    var read = -1;
+                    var total = 0;
+                    var buffer = new byte[bufferSize];
+                    while (read != 0)
+                    {
+                        read = reader.Read(buffer, 0, buffer.Length);
+                        writer.Write(buffer, 0, read);
+                        total += read;
+                    }
+
+                    writer.BaseStream.SetLength(total);
+                }
+            }
+            catch (Exception ex)
+            {
+                var caption = "XIVLauncher Error";
+                var message = $"Log cull threw an exception: {ex.Message}\n{ex.StackTrace ?? string.Empty}";
+                _ = MessageBoxW(IntPtr.Zero, message, caption, MessageBoxType.IconError | MessageBoxType.Ok);
+            }
+        }
+
         private static void OnUnhandledException(object sender, UnhandledExceptionEventArgs args)
         {
             switch (args.ExceptionObject)