Task Drivers

Task drivers handle the persistence and scheduling of your tasks. The tasks plugin supports multiple drivers to fit different deployment scenarios and requirements.

Available Drivers

SQLite Driver (Development)

The SQLite driver provides persistent, file-based task scheduling. It's perfect for development environments and single-instance applications with job recovery on restart.

Pros:

• Persistent job storage
• Jobs recoverable on restart
• No external dependencies
• Lightweight and reliable

Cons:

• Single instance only
• No distributed scheduling support
• Intended for development use

Usage:

import { SQLiteDriver } from '@commandkit/tasks/sqlite';
import { setDriver } from '@commandkit/tasks';

setDriver(new SQLiteDriver('./tasks.db'));

BullMQ Driver (Production)

The BullMQ driver provides robust, distributed task scheduling using Redis as the backend. It's ideal for production environments with multiple bot instances.

Pros:

• Distributed scheduling across multiple instances
• Persistent task storage
• Built-in retry mechanisms
• Production-ready with Redis

Cons:

• Requires Redis server
• More complex setup
• Additional dependency

Installation:

npm install bullmq

Usage:

import { BullMQDriver } from '@commandkit/tasks/bullmq';
import { setDriver } from '@commandkit/tasks';

setDriver(
  new BullMQDriver({
    host: 'localhost',
    port: 6379,
  }),
);

Advanced Redis Configuration:

const driver = new BullMQDriver({
  host: 'redis.example.com',
  port: 6379,
  password: 'your-password',
  tls: true,
  retryDelayOnFailover: 100,
  maxRetriesPerRequest: 3,
});

Setting Up Drivers

Basic Setup

Configure your driver before the tasks plugin loads:

import { tasks } from '@commandkit/tasks';
import { SQLiteDriver } from '@commandkit/tasks/sqlite';
import { setDriver } from '@commandkit/tasks';

// Set up the driver
setDriver(new SQLiteDriver('./tasks.db'));

export default {
  plugins: [tasks()],
};

Environment-Specific Configuration

import { tasks } from '@commandkit/tasks';
import { SQLiteDriver } from '@commandkit/tasks/sqlite';
import { BullMQDriver } from '@commandkit/tasks/bullmq';
import { setDriver } from '@commandkit/tasks';
import { COMMANDKIT_IS_DEV } from 'commandkit';

// Choose driver based on environment
if (COMMANDKIT_IS_DEV) {
  setDriver(new SQLiteDriver('./tasks.db'));
} else {
  setDriver(
    new BullMQDriver({
      host: process.env.REDIS_HOST || 'localhost',
      port: parseInt(process.env.REDIS_PORT || '6379'),
      password: process.env.REDIS_PASSWORD,
    }),
  );
}

export default {
  plugins: [tasks()],
};

Driver Comparison

Feature	SQLite	BullMQ
Setup Complexity	Simple	Moderate
Dependencies	None	bullmq, Redis
Persistence	File-based	Redis
Distributed	No	Yes
Job Recovery	Yes	Yes
Production Ready	Development	Yes
Memory Usage	Low	Moderate

Choosing the Right Driver

Use SQLite when:

• You're developing locally
• You want persistent job storage during development
• You have a single bot instance
• You need job recovery on restart

Use BullMQ when:

• You have multiple bot instances
• You need distributed task scheduling
• You're deploying to production
• You need advanced features like retries and monitoring

Custom Drivers

You can create your own driver by implementing the TaskDriver interface:

import { TaskDriver, TaskRunner } from '@commandkit/tasks';
import { TaskData } from '@commandkit/tasks';

class CustomDriver implements TaskDriver {
  private runner: TaskRunner | null = null;

  async create(task: TaskData): Promise<string> {
    // Implement your scheduling logic
    const id = await this.scheduler.schedule(task);
    return id;
  }

  async delete(task: string): Promise<void> {
    // Implement your deletion logic
    await this.scheduler.cancel(task);
  }

  async setTaskRunner(runner: TaskRunner): Promise<void> {
    this.runner = runner;
  }
}

// Use your custom driver
setDriver(new CustomDriver());

Next Steps

• Dynamic Tasks - Learn how to create tasks on-demand
• Advanced Patterns - Best practices for task management