Feature/backup on migration (#13754)

* Added generalised backup for migrations

* Added backup strategy to MigrateLibraryDb

* Added missing namespace

* Fix merge issues

* Fixed style issue

* change fast backup key to timestamp

* Update src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/SqliteDatabaseProvider.cs

* Update Fields

* applied review comments

2 files changed, 51 insertions, 0 deletions

diff --git a/src/Jellyfin.Database/Jellyfin.Database.Implementations/IJellyfinDatabaseProvider.cs b/src/Jellyfin.Database/Jellyfin.Database.Implementations/IJellyfinDatabaseProvider.cs
index 074016553..566b521dd 100644
--- a/src/Jellyfin.Database/Jellyfin.Database.Implementations/IJellyfinDatabaseProvider.cs
+++ b/src/Jellyfin.Database/Jellyfin.Database.Implementations/IJellyfinDatabaseProvider.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
@@ -45,4 +46,20 @@ public interface IJellyfinDatabaseProvider
     /// <param name="cancellationToken">The token that will be used to abort the operation.</param>
     /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
     Task RunShutdownTask(CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Runs a full Database backup that can later be restored to.
+    /// </summary>
+    /// <param name="cancellationToken">A cancelation token.</param>
+    /// <returns>A key to identify the backup.</returns>
+    /// <exception cref="NotImplementedException">May throw an NotImplementException if this operation is not supported for this database.</exception>
+    Task<string> MigrationBackupFast(CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Restores a backup that has been previously created by <see cref="MigrationBackupFast(CancellationToken)"/>.
+    /// </summary>
+    /// <param name="key">The key to the backup from which the current database should be restored from.</param>
+    /// <param name="cancellationToken">A cancelation token.</param>
+    /// <returns>A <see cref="Task"/> representing the result of the asynchronous operation.</returns>
+    Task RestoreBackupFast(string key, CancellationToken cancellationToken);
 }
diff --git a/src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/SqliteDatabaseProvider.cs b/src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/SqliteDatabaseProvider.cs
index d9eb0ae7a..e818c3524 100644
--- a/src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/SqliteDatabaseProvider.cs
+++ b/src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/SqliteDatabaseProvider.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -16,6 +17,7 @@ namespace Jellyfin.Database.Providers.Sqlite;
 [JellyfinDatabaseProviderKey("Jellyfin-SQLite")]
 public sealed class SqliteDatabaseProvider : IJellyfinDatabaseProvider
 {
+    private const string BackupFolderName = "SQLiteBackups";
     private readonly IApplicationPaths _applicationPaths;
     private readonly ILogger<SqliteDatabaseProvider> _logger;
 
@@ -84,4 +86,36 @@ public sealed class SqliteDatabaseProvider : IJellyfinDatabaseProvider
     {
         configurationBuilder.Conventions.Add(_ => new DoNotUseReturningClauseConvention());
     }
+
+    /// <inheritdoc />
+    public Task<string> MigrationBackupFast(CancellationToken cancellationToken)
+    {
+        var key = DateTime.UtcNow.ToString("yyyyMMddhhmmss", CultureInfo.InvariantCulture);
+        var path = Path.Combine(_applicationPaths.DataPath, "jellyfin.db");
+        var backupFile = Path.Combine(_applicationPaths.DataPath, BackupFolderName);
+        if (!Directory.Exists(backupFile))
+        {
+            Directory.CreateDirectory(backupFile);
+        }
+
+        backupFile = Path.Combine(_applicationPaths.DataPath, $"{key}_jellyfin.db");
+        File.Copy(path, backupFile);
+        return Task.FromResult(key);
+    }
+
+    /// <inheritdoc />
+    public Task RestoreBackupFast(string key, CancellationToken cancellationToken)
+    {
+        var path = Path.Combine(_applicationPaths.DataPath, "jellyfin.db");
+        var backupFile = Path.Combine(_applicationPaths.DataPath, BackupFolderName, $"{key}_jellyfin.db");
+
+        if (!File.Exists(backupFile))
+        {
+            _logger.LogCritical("Tried to restore a backup that does not exist.");
+            return Task.CompletedTask;
+        }
+
+        File.Copy(backupFile, path, true);
+        return Task.CompletedTask;
+    }
 }