Task

Tasks enable scheduled background job execution in Raindrop applications. They use standard Unix cron expressions to define when code should run automatically.

Each Task executes at the times specified by its cron schedule. When a Task execution fails, there’s no automatic retry mechanism. The Task will run again at the next scheduled time. Tasks have a maximum execution time of 5 minutes (300,000ms CPU walltime).

Tasks provide a reliable way to run maintenance operations, data processing, or periodic updates without manual intervention.

Creating

Configure a Task in your raindrop.manifest file with a cron expression:

application "demo-app" {
  task "demo-task" {
    type = "cron"
    cron = "0 2 * * *"  # Daily at 2 AM UTC
  }
}

Accessing

Access your Task through environment bindings in your service code:

import { Task, Event } from 'raindrop';

export default class DemoTask extends Task<Env> {
  async handle(event: Event): Promise<void> {
    // Task execution logic here
    console.log(`Task executed at ${new Date(event.scheduledTime)}`);
  }
}

Core Concepts

Main Interfaces

• Task<Env> - Abstract base class for processing scheduled events
• Event - Represents scheduled event data with timing information

Data Types

Event

interface Event {
  /** The value of the Cron Trigger that started the ScheduledEvent */
  cron: string;
  /** The type of event. This will always return "scheduled" */
  type: 'scheduled';
  /** The time the ScheduledEvent was scheduled to be executed in milliseconds since January 1, 1970, UTC */
  scheduledTime: number;
}

Task

abstract class Task<Env> {
  ctx: ExecutionContext;  // Runtime execution context
  env: Env;              // Environment bindings

  abstract handle(event: Event): Promise<void>;  // Required implementation method
}

System Limits

• Maximum execution time: 300,000ms (5 minutes) CPU walltime
• No automatic retry mechanism on failures

handle

Input

event: Event  // Scheduled event information

Output

Promise<void>  // Async completion

Example

Process scheduled events with timing information:

export default class BackupTask extends Task<Env> {
  async handle(event: Event): Promise<void> {
    // Log execution details
    const executionTime = new Date(event.scheduledTime);
    console.log(`Backup started at ${executionTime}`);

    // Perform backup operations
    await this.performBackup();
  }

  private async performBackup(): Promise<void> {
    // Backup implementation
  }
}