feat(backup): VACUUM INTO snapshot core (create/list/prune) + config + off-box hook

2026-06-20 02:21:22 +02:00
parent 4b44996aac
commit 48bcd69031
3 changed files with 155 additions and 0 deletions
@@ -0,0 +1,84 @@
+import Database from 'better-sqlite3';
+import fs from 'node:fs';
+import path from 'node:path';
+import { execFile } from 'node:child_process';
+import { config } from '../config.js';
+
+export type SnapshotReason = 'pre-migration' | 'scheduled' | 'manual';
+
+export interface SnapshotInfo {
+  path: string;
+  reason: SnapshotReason;
+  bytes: number;
+  mtimeMs: number;
+}
+
+const REASONS: SnapshotReason[] = ['pre-migration', 'scheduled', 'manual'];
+
+function ensureDir(): string {
+  fs.mkdirSync(config.backup.dir, { recursive: true });
+  return config.backup.dir;
+}
+
+function timestamp(): string {
+  // 2026-06-20T14:03:09.123Z -> 20260620T140309123 (ms precision keeps names unique
+  // and sortable; VACUUM INTO throws if the target file already exists).
+  return new Date().toISOString().replace(/[-:.]/g, '').replace(/Z$/, '');
+}
+
+/** Synchronous, WAL-safe snapshot via VACUUM INTO. Returns the absolute path. */
+export function createSnapshot(db: Database.Database, reason: SnapshotReason): string {
+  const dir = ensureDir();
+  const ts = timestamp();
+  // VACUUM INTO throws if the target already exists. Millisecond precision keeps
+  // names unique under normal use, but tight loops can collide within the same
+  // millisecond — append a disambiguating counter on collision to guarantee a
+  // free, sortable path.
+  let file = path.join(dir, `backspace-${ts}-${reason}.db`);
+  for (let n = 1; fs.existsSync(file); n++) {
+    file = path.join(dir, `backspace-${ts}-${String(n).padStart(3, '0')}-${reason}.db`);
+  }
+  db.prepare('VACUUM INTO ?').run(file);
+  runOffsite(file);
+  return file;
+}
+
+function runOffsite(snapshotPath: string): void {
+  const cmd = config.backup.offsiteCmd;
+  if (!cmd) return;
+  // Best-effort: failures are logged, never fatal.
+  execFile('/bin/sh', ['-c', `${cmd} "$1"`, 'sh', snapshotPath], (err, _stdout, stderr) => {
+    if (err) console.error(`[backup] off-box hook failed: ${err.message} ${stderr ?? ''}`);
+  });
+}
+
+export function listSnapshots(): SnapshotInfo[] {
+  if (!fs.existsSync(config.backup.dir)) return [];
+  return fs.readdirSync(config.backup.dir)
+    .filter(f => f.endsWith('.db'))
+    .map((f): SnapshotInfo | null => {
+      const reason = REASONS.find(r => f.endsWith(`-${r}.db`));
+      if (!reason) return null;
+      const full = path.join(config.backup.dir, f);
+      const st = fs.statSync(full);
+      return { path: full, reason, bytes: st.size, mtimeMs: st.mtimeMs };
+    })
+    .filter((s): s is SnapshotInfo => s !== null)
+    .sort((a, b) => b.mtimeMs - a.mtimeMs);
+}
+
+export function pruneSnapshots(): void {
+  const keep: Record<SnapshotReason, number> = {
+    'pre-migration': config.backup.keepPreMigration,
+    scheduled: config.backup.keepScheduled,
+    manual: config.backup.keepManual,
+  };
+  for (const reason of REASONS) {
+    const ofReason = listSnapshots().filter(s => s.reason === reason); // newest-first
+    for (const stale of ofReason.slice(keep[reason])) {
+      try { fs.unlinkSync(stale.path); } catch (err) {
+        console.error(`[backup] failed to prune ${stale.path}: ${(err as Error).message}`);
+      }
+    }
+  }
+}