Tasks, Jobs & Messages

In the world of asynchronous processing, terms like "task", "job", and "message" are often used interchangeably. Let's clarify these concepts and explain how Taskhook uses them.

Key differences

While there's significant overlap in how these terms are used across different systems, here's how they're typically distinguished:

Messages

Messages represent pure data transfer between systems. They're typically:

• Lightweight and focused on communication
• Often part of event-driven architectures
• Usually processed in a fire-and-forget manner
• Examples: Notifications, events, alerts

Tasks

Tasks represent discrete units of work with clear completion criteria:

• Single, well-defined operation
• Usually stateless
• Often idempotent
• Examples: Image resizing, email sending, data validation

Jobs

Jobs represent higher-level business processes:

• May consist of multiple tasks
• Often stateful
• Usually tied to business logic
• Examples: User onboarding, report generation, data migration

To summarize, of the three, messages are most clearly a separate concept, as they're focused on communication rather than processing. Tasks and jobs are more closely related, with tasks being more implementation-focused and jobs being more business-focused.

How Taskhook uses these terms

At Taskhook, we use the term "task" at API level because our focus is on discrete, well-defined units of work that:

• Have clear success/failure criteria
• Can be retried independently
• Are processed via HTTP callbacks
• Maintain minimal state

Real-world examples

Let's look at how these concepts map to real applications:

Message-style usage

// Event notification
await client.tasks.create({
  target: 'https://api.yourapp.com/webhooks/user-events',
  payload: {
    type: 'user.created',
    userId: '123',
    timestamp: '2024-02-01T12:00:00Z',
  },
})

Task-style usage

// Image processing
await client.tasks.create({
  target: 'https://api.yourapp.com/tasks/resize-image',
  payload: {
    imageId: '456',
    dimensions: { width: 800, height: 600 },
    format: 'webp',
  },
})

Job-style usage

// Report generation
await client.tasks.create({
  target: 'https://api.yourapp.com/jobs/generate-report',
  payload: {
    reportId: '789',
    type: 'monthly-analytics',
    parameters: {
      month: '2024-01',
      format: 'pdf',
      sections: ['revenue', 'users', 'engagement'],
    },
  },
})

Practical implications

When designing your system with Taskhook:

1. Message queues: Use tasks with minimal payloads and immediate execution
2. Task queues: Use tasks with specific payloads and retry policies
3. Job queues: Use tasks with rich payloads, subtasks, state management, and workflow logic

The key is understanding that while these concepts have different meanings that can vary from source to source, systems like Taskhook provide flexible primitives that can be used to implement any of these patterns.

Next steps

Now that you understand these core concepts, learn more about:

• Task Properties to see what data you can include
• Retry Behavior for reliability patterns
• Best Practices for system design