feat(backend): automatisches taegliches SQLite-Online-Backup

server/backup.js

@@ -0,0 +1,34 @@
+const path = require('path');
+const fs = require('fs');
+const { db, DATA_DIR } = require('./db');
+
+const BACKUP_DIR = path.join(DATA_DIR, 'backups');
+const KEEP = 14;
+
+async function runBackup(now) {
+  fs.mkdirSync(BACKUP_DIR, { recursive: true });
+  const stamp = now.replace(/[:.]/g, '-');
+  const dest = path.join(BACKUP_DIR, `dienstplan-${stamp}.db`);
+  await db.backup(dest); // Online-Backup-API von SQLite — konsistent, ohne cp-Risiko
+  prune();
+  return dest;
+}
+
+function prune() {
+  const files = fs.readdirSync(BACKUP_DIR)
+    .filter(f => f.startsWith('dienstplan-') && f.endsWith('.db'))
+    .sort(); // ISO-abgeleiteter Stamp → lexikografisch == chronologisch
+  const excess = files.length - KEEP;
+  for (let i = 0; i < excess; i++) {
+    fs.unlinkSync(path.join(BACKUP_DIR, files[i]));
+  }
+}
+
+function scheduleBackups() {
+  const tick = () => runBackup(new Date().toISOString())
+    .catch(e => console.error('Backup fehlgeschlagen:', e));
+  tick();
+  setInterval(tick, 24 * 60 * 60 * 1000);
+}
+
+module.exports = { runBackup, scheduleBackups, BACKUP_DIR };