Merge pull request #1727 from rmcrackan/rmcrackan/log-init-db

Log initial db state, esp to capture books in trash

Source/AppScaffolding/LibationScaffolding.cs

@@ -225,6 +225,7 @@ public static class LibationScaffolding
 	private static void configureLogging(Configuration config)
 	{
 		config.ConfigureLogging();
+		DbContexts.TryEmitPendingInitialDatabaseStatistics();
 
 		// capture most Console.WriteLine() and write to serilog. See below tests for details.
 		// Some dependencies print helpful info via Console.WriteLine. We'd like to log it.

Source/ApplicationServices/DbContexts.cs

@@ -1,6 +1,9 @@
 using DataLayer;
 using LibationFileManager;
+using Serilog;
+using System;
 using System.Collections.Generic;
+using System.Threading;
 
 namespace ApplicationServices;
 
@@ -8,6 +11,24 @@ public static class DbContexts
 {
 	private static bool _sqliteDbValidated;
 
+	private static readonly object _initialDatabaseStatisticsCaptureLock = new();
+
+	/// <summary>
+	/// True after initial DB statistics were read and either written to Serilog or stored for <see cref="TryEmitPendingInitialDatabaseStatistics"/>.
+	/// False if capture has not run yet or the last attempt threw (a later <see cref="GetContext"/> may retry).
+	/// </summary>
+	private static bool _initialDatabaseStatisticsCaptured;
+
+	/// <summary>Shape of the initial DB statistics log event; edit here only when changing what is logged.</summary>
+	private sealed class InitialDatabaseStatistics
+	{
+		public required int LibraryBooksNotInTrash { get; init; }
+		public required int LibraryBooksInTrash { get; init; }
+		public required int BookRecords { get; init; }
+	}
+
+	private static InitialDatabaseStatistics? _pendingInitialDbStats;
+
 	/// <summary>Use for fully functional context, incl. SaveChanges(). For query-only, use the other method</summary>
 	public static LibationContext GetContext()
 	{
@@ -25,9 +46,59 @@ public static class DbContexts
 			_sqliteDbValidated = true;
 		}
 
+		TryCaptureInitialDatabaseStatistics(context);
+
 		return context;
 	}
 
+	private static void TryCaptureInitialDatabaseStatistics(LibationContext context)
+	{
+		lock (_initialDatabaseStatisticsCaptureLock)
+		{
+			if (_initialDatabaseStatisticsCaptured)
+				return;
+
+			try
+			{
+				var (notInTrash, inTrash) = context.GetLibraryBookCountsByTrashFlag();
+				var bookRecords = context.GetBookCount();
+
+				var stats = new InitialDatabaseStatistics
+				{
+					LibraryBooksNotInTrash = notInTrash,
+					LibraryBooksInTrash = inTrash,
+					BookRecords = bookRecords,
+				};
+
+				if (Configuration.Instance.SerilogInitialized)
+					LogInitialDatabaseStatistics(stats);
+				else
+					_pendingInitialDbStats = stats;
+
+				_initialDatabaseStatisticsCaptured = true;
+			}
+			catch (Exception ex)
+			{
+				if (Configuration.Instance.SerilogInitialized)
+					Log.Warning(ex, "Could not capture initial database statistics");
+			}
+		}
+	}
+
+	/// <summary>
+	/// Writes initial DB statistics that were captured before Serilog was configured (e.g. WinForms early library load).
+	/// Call once after <see cref="Configuration.ConfigureLogging"/>.
+	/// </summary>
+	public static void TryEmitPendingInitialDatabaseStatistics()
+	{
+		var pending = Interlocked.Exchange(ref _pendingInitialDbStats, null);
+		if (pending is not null)
+			LogInitialDatabaseStatistics(pending);
+	}
+
+	private static void LogInitialDatabaseStatistics(InitialDatabaseStatistics stats) =>
+		Log.Logger.Information("Initial database statistics. {@DbStats}", stats);
+
 	/// <summary>Use for full library querying. No lazy loading</summary>
 	public static List<LibraryBook> GetLibrary_Flat_NoTracking(bool includeParents = false)
 	{

Source/DataLayer/QueryObjects/BookQueries.cs

@@ -16,6 +16,10 @@ public static class BookQueries
 			.AsNoTrackingWithIdentityResolution()
 			.GetBook(productId);
 
+	/// <summary>Total rows in <see cref="LibationContext.Books"/> (no related entities loaded).</summary>
+	public static int GetBookCount(this LibationContext context)
+		=> context.Books.AsNoTracking().Count();
+
 	public static Book? GetBook(this IQueryable<Book> books, string productId)
 		=> books
 			.GetBooks()

Source/DataLayer/QueryObjects/LibraryBookQueries.cs

@@ -62,6 +62,13 @@ public static class LibraryBookQueries
 			.Where(lb => lb.IsDeleted || lb.Book.ContentType == ContentType.Parent)
 			.getLibrary()
 			.ToList();
+
+		/// <summary>Counts <see cref="LibraryBook"/> rows by <see cref="LibraryBook.IsDeleted"/> (no related entities loaded).</summary>
+		public (int NotInTrash, int InTrash) GetLibraryBookCountsByTrashFlag()
+		{
+			var q = context.LibraryBooks.AsNoTracking();
+			return (q.Count(lb => !lb.IsDeleted), q.Count(lb => lb.IsDeleted));
+		}
 	}
 
 	extension(IQueryable<LibraryBook> library)