Cron Scheduler Expert

Cron & Scheduler Expert (2026 Edition)

English | Bahasa Indonesia

English

Orchestration & Integration

Connects and orchestrates with relevant domain skills like brainstorming, zero-to-prod-orchestrator, and project-context-mapper to ensure cohesive execution.

Description

Production-grade guide for implementing scheduled tasks, cron jobs, and recurring background work in modern web applications. Covers Vercel Cron Jobs, Cloudflare Workers Cron Triggers, Inngest scheduled functions, node-cron, BullMQ repeatable jobs, distributed cron locking (Redis-based), timezone-aware scheduling, and common use cases (cleanup jobs, report generation, health checks, subscription renewals).

Trigger Conditions

Activate this skill when:

• Setting up scheduled/recurring tasks (daily reports, cleanup, health checks).
• Configuring Vercel Cron Jobs or Cloudflare Workers Cron Triggers.
• Implementing subscription renewal checks or billing cycle jobs.
• Building data aggregation or ETL pipelines on a schedule.
• Needing distributed cron locking to prevent duplicate execution.
• Scheduling email digests or notification batches.

Platform Selection Guide

Recommendation: Use Vercel Cron for Next.js apps on Vercel. Use Inngest for complex multi-step scheduled workflows. Use BullMQ repeatable jobs for self-hosted environments.

1. Vercel Cron Jobs

// vercel.json
{
  "crons": [
    {
      "path": "/api/cron/daily-cleanup",
      "schedule": "0 3 * * *"
    },
    {
      "path": "/api/cron/hourly-health-check",
      "schedule": "0 * * * *"
    },
    {
      "path": "/api/cron/weekly-report",
      "schedule": "0 9 * * 1"
    }
  ]
}

// app/api/cron/daily-cleanup/route.ts
import { NextResponse } from 'next/server';

export async function GET(request: Request) {
  // Verify the request is from Vercel Cron (not public)
  const authHeader = request.headers.get('authorization');
  if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  try {
    // Cleanup expired sessions
    const deletedSessions = await db.delete(sessions)
      .where(lt(sessions.expiresAt, new Date()));

    // Cleanup orphaned uploads (older than 24h, not linked to any record)
    const deletedUploads = await db.delete(uploads)
      .where(and(
        isNull(uploads.linkedRecordId),
        lt(uploads.createdAt, new Date(Date.now() - 86400000)),
      ));

    return NextResponse.json({
      ok: true,
      cleaned: { sessions: deletedSessions.rowCount, uploads: deletedUploads.rowCount },
    });
  } catch (error) {
    console.error('Daily cleanup failed:', error);
    return NextResponse.json({ ok: false, error: 'Cleanup failed' }, { status: 500 });
  }
}

export const runtime = 'nodejs';
export const maxDuration = 60; // Allow up to 60s for cleanup

2. Inngest Scheduled Functions

// inngest/functions/weekly-report.ts
import { inngest } from '@/lib/inngest';

export const weeklyReportJob = inngest.createFunction(
  {
    id: 'weekly-usage-report',
    name: 'Generate Weekly Usage Report',
  },
  { cron: 'TZ=Asia/Jakarta 0 9 * * 1' }, // Every Monday 9 AM WIB
  async ({ step }) => {
    // Step 1: Gather data
    const metrics = await step.run('gather-metrics', async () => {
      return await db.query.usageMetrics.findMany({
        where: gte(usageMetrics.createdAt, subDays(new Date(), 7)),
      });
    });

    // Step 2: Generate report
    const report = await step.run('generate-report', async () => {
      return generateWeeklyReport(metrics);
    });

    // Step 3: Send to admins
    await step.run('send-report', async () => {
      const admins = await db.query.users.findMany({
        where: eq(users.role, 'admin'),
      });
      for (const admin of admins) {
        await emailQueue.add('weekly-report', { to: admin.email, report });
      }
    });

    return { sent: true, reportId: report.id };
  },
);

3. BullMQ Repeatable Jobs

// queues/scheduled-jobs.ts
import { Queue, Worker } from 'bullmq';

const scheduledQueue = new Queue('scheduled', {
  connection: { host: process.env.REDIS_HOST },
});

// Add repeatable jobs on startup
export async function registerScheduledJobs() {
  // Daily cleanup at 3 AM
  await scheduledQueue.add('daily-cleanup', {}, {
    repeat: { pattern: '0 3 * * *', tz: 'Asia/Jakarta' },
    jobId: 'daily-cleanup', // Prevent duplicates on restart
  });

  // Every 5 minutes: health check
  await scheduledQueue.add('health-check', {}, {
    repeat: { every: 5 * 60 * 1000 }, // 5 minutes in ms
    jobId: 'health-check',
  });

  // Monthly: subscription renewal check (1st of each month at midnight)
  await scheduledQueue.add('subscription-renewal', {}, {
    repeat: { pattern: '0 0 1 * *', tz: 'Asia/Jakarta' },
    jobId: 'subscription-renewal',
  });
}

// Worker
const worker = new Worker('scheduled', async (job) => {
  switch (job.name) {
    case 'daily-cleanup':
      await performDailyCleanup();
      break;
    case 'health-check':
      await performHealthCheck();
      break;
    case 'subscription-renewal':
      await checkSubscriptionRenewals();
      break;
  }
}, { connection: { host: process.env.REDIS_HOST } });

4. Distributed Cron Locking (Redis)

// lib/cron-lock.ts
import { Redis } from 'ioredis';

const redis = new Redis(process.env.REDIS_URL!);

/**
 * Acquire a distributed lock to prevent duplicate cron execution
 * across multiple server instances.
 */
export async function acquireCronLock(
  jobName: string,
  ttlSeconds: number = 300,
): Promise<boolean> {
  const lockKey = `cron-lock:${jobName}`;
  // SET NX (only if not exists) with TTL
  const result = await redis.set(lockKey, Date.now().toString(), 'EX', ttlSeconds, 'NX');
  return result === 'OK';
}

export async function releaseCronLock(jobName: string): Promise<void> {
  await redis.del(`cron-lock:${jobName}`);
}

// Usage in cron handler
export async function GET(request: Request) {
  const locked = await acquireCronLock('daily-cleanup', 300);
  if (!locked) {
    return Response.json({ skipped: true, reason: 'Already running on another instance' });
  }

  try {
    await performDailyCleanup();
    return Response.json({ ok: true });
  } finally {
    await releaseCronLock('daily-cleanup');
  }
}

Common Cron Patterns

Common Pitfalls to Avoid

Integration with Other Skills

• async-queue-temporal-expert — BullMQ repeatable jobs, Inngest scheduled functions
• cloud-hosting-expert — Vercel Cron, Cloudflare Workers Cron configuration
• saas-billing — Subscription renewal checks, billing cycle jobs
• email-notification-expert — Scheduled email digests, daily summaries
• data-telemetry-expert — Scheduled metric aggregation and reporting
• logging-error-tracking-expert — Cron job failure monitoring

Bahasa Indonesia

Integrasi Orkestrasi

Terhubung dan mengorkestrasi skill domain yang relevan seperti brainstorming, zero-to-prod-orchestrator, dan project-context-mapper untuk memastikan eksekusi yang kohesif.

Deskripsi

Panduan tingkat produksi untuk mengimplementasikan tugas terjadwal, cron job, dan pekerjaan latar belakang berulang di aplikasi web modern. Mencakup Vercel Cron Jobs, Cloudflare Workers Cron Triggers, Inngest scheduled functions, node-cron, BullMQ repeatable jobs, distributed cron locking (berbasis Redis), penjadwalan sadar zona waktu, dan kasus penggunaan umum (pembersihan data, pembuatan laporan, health check, perpanjangan langganan).

Kondisi Pemicu

Aktifkan skill ini ketika:

• Menyiapkan tugas terjadwal/berulang (laporan harian, pembersihan, health check).
• Mengonfigurasi Vercel Cron Jobs atau Cloudflare Workers Cron Triggers.
• Mengimplementasikan pemeriksaan perpanjangan langganan atau siklus billing.
• Membangun pipeline agregasi data atau ETL pada jadwal tertentu.
• Membutuhkan penguncian cron terdistribusi untuk mencegah eksekusi duplikat.

Integrasi dengan Skill Lain

• async-queue-temporal-expert — BullMQ repeatable jobs, Inngest scheduled functions
• cloud-hosting-expert — Konfigurasi Vercel Cron, Cloudflare Workers Cron
• saas-billing — Pemeriksaan perpanjangan langganan, siklus billing
• email-notification-expert — Digest email terjadwal, ringkasan harian
• data-telemetry-expert — Agregasi metrik terjadwal dan pelaporan