Run scheduled backups in an isolated subprocess

scripts/scheduled-backup.ts

@@ -0,0 +1,16 @@
+import { Database } from 'bun:sqlite';
+import { createBackup, latestBackupTime, type BackupConfig } from '../src/ops/backups';
+
+const path = process.argv[2];
+if (!path || !process.argv[3]) throw new Error('Expected database path and backup configuration');
+const config = JSON.parse(process.argv[3]) as BackupConfig;
+const latest = latestBackupTime(config);
+if (latest && Date.now() - latest < config.intervalMs) console.log(JSON.stringify({ timestamp: latest, created: false }));
+else {
+  const db = new Database(path, { readonly: true, strict: true });
+  try {
+    db.exec('PRAGMA busy_timeout=5000');
+    createBackup(db, config);
+    console.log(JSON.stringify({ timestamp: latestBackupTime(config), created: true }));
+  } finally { db.close(); }
+}

src/index.ts

@@ -15,6 +15,7 @@ if (process.env.NODE_ENV !== "production") {
 }
 
 const backups = process.env.NODE_ENV === "production" ? startBackups(sqlite, backupConfig(databasePath)) : undefined;
+await backups?.ready;
 if (import.meta.hot) import.meta.hot.dispose(() => backups?.stop());
 
 const reminders = process.env.NODE_ENV === "production" ? startReminders(db, { token: readDiscordSharingConfig().token, origin: readAuthConfig().origin, commandsAvailable: /^[a-f\d]{64}$/i.test(process.env.DISCORD_PUBLIC_KEY ?? "") && Boolean(readAuthConfig().clientId) }) : undefined;

src/ops/backups.test.ts

@@ -35,6 +35,7 @@ test("WAL snapshots restore committed progress, revoke sessions, replicate, and
     expect(readdirSync(config.replica!)).toHaveLength(2);
     expect(readdirSync(config.directory)).toContain("keep.txt");
     const runner = startBackups(f.sqlite, config);
+    await runner.ready;
     expect(runner.state.failed).toBe(false); expect(runner.state.lastSuccess).toBeGreaterThan(0); runner.stop();
   } finally { f.close(); rmSync(directory, { recursive: true, force: true }); }
 });
@@ -71,3 +72,47 @@ test("backup and restore CLIs work against a live database without overwriting i
     expect(f.sqlite.query('SELECT count(*) AS n FROM sessions').get()).toEqual({ n: 2 });
   } finally { f.close(); rmSync(directory, { recursive: true, force: true }); }
 });
+
+test('scheduled backups yield to the event loop, retain WAL data, and verify replicas', async () => {
+  const directory = mkdtempSync(join(tmpdir(), 'minabot-async-backup-'));
+  const path = join(directory, 'live.sqlite'), f = fixture(path);
+  let runner: ReturnType<typeof startBackups> | undefined;
+  try {
+    f.sqlite.exec('PRAGMA journal_mode=WAL');
+    await f.json('/habits', 'POST', { name: 'Async snapshot', method: 'manual' }, 201);
+    const config = backupConfig(path, { BACKUP_REPLICA_DIR: 'replica' });
+    mkdirSync(config.replica!);
+    let yielded = false;
+    const timer = new Promise<void>(resolve => setTimeout(() => { yielded = true; resolve(); }, 0));
+    runner = startBackups(path, config);
+    expect(runner.state.lastSuccess).toBe(0);
+    await runner.ready;
+    expect(yielded).toBe(true); await timer;
+    expect(runner.state.failed).toBe(false);
+    expect(runner.state.lastSuccess).toBeGreaterThan(0);
+    const snapshots = readdirSync(config.directory).filter(file => file.endsWith('.sqlite'));
+    expect(snapshots).toHaveLength(1);
+    const check = new Database(join(config.replica!, snapshots[0]!), { readonly: true });
+    try { expect(check.query('SELECT count(*) AS n FROM habits').get()).toEqual({ n: 1 }); } finally { check.close(); }
+    await runner.tick();
+    expect(readdirSync(config.directory).filter(file => file.endsWith('.sqlite'))).toHaveLength(1);
+  } finally { runner?.stop(); f.close(); rmSync(directory, { recursive: true, force: true }); }
+});
+
+test('scheduled backup ticks coalesce, expose failure and recovery, and stop admitting work', async () => {
+  const config = backupConfig('/tmp/test-only.sqlite', {});
+  let calls = 0, release!: (value: number) => void;
+  const run = async () => { calls++; return new Promise<number>(resolve => { release = resolve; }); };
+  const runner = startBackups('/tmp/test-only.sqlite', config, run);
+  expect(runner.tick()).toBe(runner.ready);
+  expect(calls).toBe(1);
+  release(123); await runner.ready;
+  expect(runner.state.lastSuccess).toBe(123);
+  const second = runner.tick(); expect(calls).toBe(2);
+  runner.stop(); release(456); await second;
+  await runner.tick(); expect(calls).toBe(2);
+  const failed = startBackups('/tmp/test-only.sqlite', config, async () => { throw new Error('test failure'); });
+  await failed.ready; expect(failed.state.failed).toBe(true); failed.stop();
+  const disabled = startBackups('/tmp/test-only.sqlite', { ...config, enabled: false }, run);
+  await disabled.ready; expect(calls).toBe(2); disabled.stop();
+});

src/ops/backups.ts

@@ -82,18 +82,40 @@ export function restoreBackup(source: string, destination: string) {
   } finally { if (existsSync(temporary)) unlinkSync(temporary); }
   return destination;
 }
-export function startBackups(database: Database, config: BackupConfig) {
-  const state = { enabled: config.enabled, lastSuccess: 0, failed: false };
-  if (!config.enabled) return { state, stop() {} };
-  const tick = () => {
-    try {
-      const latest = latestBackupTime(config);
-      if (latest && Date.now() - latest < config.intervalMs) { state.lastSuccess = latest; state.failed = false; return; }
-      createBackup(database, config); state.lastSuccess = Date.now(); state.failed = false;
-      console.log(JSON.stringify({ event: "backup_completed", timestamp: new Date().toISOString() }));
-    } catch { state.failed = true; console.error(JSON.stringify({ event: "backup_failed", timestamp: new Date().toISOString() })); }
-  };
-  tick();
-  const timer = setInterval(tick, 60000); timer.unref();
-  return { state, stop: () => clearInterval(timer) };
+/** Runs all filesystem and SQLite backup work in a separate Bun process. */
+export async function runScheduledBackup(database: string, config: BackupConfig): Promise<number> {
+  const source = new URL("../../scripts/scheduled-backup.ts", import.meta.url);
+  const built = new URL("../scripts/scheduled-backup.ts", import.meta.url);
+  const script = (existsSync(source) ? source : built).pathname;
+  const child = Bun.spawn([process.execPath, script, resolve(database), JSON.stringify(config)], {
+    stdout: "pipe", stderr: "ignore",
+  });
+  const [output, status] = await Promise.all([new Response(child.stdout).text(), child.exited]);
+  if (status !== 0) throw new Error("Scheduled backup process failed");
+  const { timestamp, created } = JSON.parse(output) as { timestamp: number; created: boolean };
+  if (!Number.isFinite(timestamp) || timestamp <= 0) throw new Error("Scheduled backup returned an invalid timestamp");
+  if (created) console.log(JSON.stringify({ event: "backup_completed", timestamp: new Date(timestamp).toISOString() }));
+  return timestamp;
+}
+export function startBackups(database: Database | string, config: BackupConfig, run = runScheduledBackup) {
+  const state = { enabled: config.enabled, lastSuccess: 0, failed: false };
+  let running: Promise<void> | undefined;
+  let stopped = false;
+  const tick = (): Promise<void> => {
+    if (stopped || !config.enabled) return Promise.resolve();
+    if (running) return running;
+    running = (async () => {
+      try {
+        const path = typeof database === 'string' ? database : database.filename;
+        if (!path || path === ':memory:') throw new Error('Scheduled backups require a file database');
+        state.lastSuccess = await run(path, config); state.failed = false;
+      } catch { state.failed = true; console.error(JSON.stringify({ event: "backup_failed", timestamp: new Date().toISOString() })); }
+    })().finally(() => { running = undefined; });
+    return running;
+  };
+  // Callers await readiness before accepting traffic, matching the original startup check.
+  const ready = tick();
+  const timer = config.enabled ? setInterval(() => { void tick(); }, 60000) : undefined;
+  timer?.unref();
+  return { state, ready, tick, stop: () => { stopped = true; clearInterval(timer); } };
 }