feat: automated daily SQLite database backups with retention

New DatabaseBackupHostedService + SqliteDatabaseBackupRunner: - daily VACUUM INTO snapshot to <Data:Root>/backups (safe with WAL) - catch-up backup at startup when none exists from the last 24h - retention pruning (Backups:RetainCount, default 14) - warns and stays idle on MySQL/MariaDB where external backups apply Production previously had no automated database backup on Linux (the /api/backup endpoint is Windows-DPAPI-only). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-02 21:49:58 +02:00
parent e352aaeaac
commit 999d6e05e7
6 changed files with 298 additions and 0 deletions
@@ -0,0 +1,110 @@
+using Microsoft.Data.Sqlite;
+
+namespace JobTrackerApi.Services
+{
+    public interface IDatabaseBackupRunner
+    {
+        string BackupsRoot { get; }
+        bool IsSupported { get; }
+
+        /// <summary>Creates one backup file and prunes old ones. Returns the backup path, or null when unsupported.</summary>
+        Task<string?> RunOnceAsync(CancellationToken ct);
+
+        DateTime? GetLatestBackupUtc();
+    }
+
+    public sealed class SqliteDatabaseBackupRunner : IDatabaseBackupRunner
+    {
+        public const string BackupFilePrefix = "jobtracker_backup_";
+
+        private readonly ILogger<SqliteDatabaseBackupRunner> _logger;
+        private readonly string _connectionString;
+        private readonly int _retainCount;
+
+        public string BackupsRoot { get; }
+        public bool IsSupported { get; }
+
+        public SqliteDatabaseBackupRunner(IConfiguration cfg, AppPaths paths, ILogger<SqliteDatabaseBackupRunner> logger)
+        {
+            _logger = logger;
+
+            var provider = (cfg["Database:Provider"] ?? "sqlite").Trim().ToLowerInvariant();
+            var cs = cfg.GetConnectionString("JobTracker");
+            if (string.IsNullOrWhiteSpace(cs))
+            {
+                cs = $"Data Source={paths.GetDbPath()}";
+                provider = "sqlite";
+            }
+
+            _connectionString = cs;
+            IsSupported = provider == "sqlite";
+            BackupsRoot = Path.Combine(paths.DataRoot, "backups");
+            _retainCount = Math.Clamp(cfg.GetValue("Backups:RetainCount", 14), 1, 365);
+        }
+
+        // Test-friendly constructor.
+        public SqliteDatabaseBackupRunner(string connectionString, string backupsRoot, int retainCount, ILogger<SqliteDatabaseBackupRunner> logger)
+        {
+            _logger = logger;
+            _connectionString = connectionString;
+            IsSupported = true;
+            BackupsRoot = backupsRoot;
+            _retainCount = Math.Clamp(retainCount, 1, 365);
+        }
+
+        public async Task<string?> RunOnceAsync(CancellationToken ct)
+        {
+            if (!IsSupported)
+            {
+                _logger.LogWarning("Automated backups only support the SQLite provider. Configure external backups for MySQL/MariaDB.");
+                return null;
+            }
+
+            Directory.CreateDirectory(BackupsRoot);
+
+            var target = Path.Combine(BackupsRoot, $"{BackupFilePrefix}{DateTime.UtcNow:yyyyMMdd_HHmmss}.db");
+            if (File.Exists(target)) File.Delete(target);
+
+            await using (var connection = new SqliteConnection(_connectionString))
+            {
+                await connection.OpenAsync(ct);
+                await using var command = connection.CreateCommand();
+                // VACUUM INTO produces a consistent, compacted snapshot without blocking writers (WAL).
+                command.CommandText = $"VACUUM INTO '{target.Replace("'", "''")}'";
+                await command.ExecuteNonQueryAsync(ct);
+            }
+
+            _logger.LogInformation("Database backup written: {File}.", target);
+            PruneOldBackups();
+            return target;
+        }
+
+        public DateTime? GetLatestBackupUtc()
+        {
+            if (!Directory.Exists(BackupsRoot)) return null;
+            var latest = ListBackups().FirstOrDefault();
+            return latest?.LastWriteTimeUtc;
+        }
+
+        private void PruneOldBackups()
+        {
+            foreach (var stale in ListBackups().Skip(_retainCount))
+            {
+                try
+                {
+                    stale.Delete();
+                    _logger.LogInformation("Pruned old database backup: {File}.", stale.Name);
+                }
+                catch (IOException ex)
+                {
+                    _logger.LogWarning(ex, "Could not prune old database backup {File}.", stale.Name);
+                }
+            }
+        }
+
+        private IOrderedEnumerable<FileInfo> ListBackups()
+            => new DirectoryInfo(BackupsRoot)
+                .EnumerateFiles($"{BackupFilePrefix}*.db")
+                .OrderByDescending(f => f.LastWriteTimeUtc);
+    }
+}