Task States

Common task state progressions:

Success: scheduled → queued → processing → completed
Retry Success: scheduled → queued → processing → retrying → ... → processing → completed
Failed: scheduled → queued → processing → retrying → ... → abandoned
Cancelled: scheduled → cancelled
Expired: scheduled → expired

Notification Events

Available notification events:

• task.queued: Task is queued for execution
• task.processing: Task execution started
• task.completed: Task completed successfully
• task.failed: Task failed after all retries
• task.expired: Task expired before execution
• task.cancelled: Task was cancelled
• group.first_failed: First failure in a group task
• group.all_completed: All group tasks completed
• group.all_failed: All group tasks failed
• group.partial_completion: Some tasks completed, some failed

If no events are specified, notifications are sent for all events.

When using group tasks (target: "group:name"), these additional events provide detailed status updates:

1. group.first_failed: First task failure in the group
2. group.all_completed: All tasks in the group have completed (success or failure)
3. group.all_failed: All tasks in the group have failed
4. group.partial_completion: Some tasks completed successfully, others failed
5. group.task_cancelled: A task in the group was cancelled
6. group.task_expired: A task in the group expired

Each group event includes the group_info object with current completion statistics.