Async Task Queue Toolkit: Task Queue Patterns Guide

Task Queue Patterns Guide Practical patterns and best practices for building reliable async task queues in production. Delivery Guarantees At-Least-Once Delivery The default mode for this toolkit. A task may be delivered more than once if: The worker crashes after starting execution but before acknowledgment A network partition occurs between the worker and Redis The visibility timeout expires before the task completes # Tasks are acknowledged AFTER successful execution await handler ( * msg . args , ** msg . kwargs ) await broker . ack ( msg . task_id ) # Only after success When to use: Most workloads where occasional duplicate processing is acceptable (sending emails, updating caches, writing to idempotent APIs). Exactly-Once Semantics True exactly-once delivery is impossible in distributed systems, but you can achieve exactly-once processing through idempotency: @task ( retries = 3 ) async def process_payment ( payment_id : str , amount : float ) -> dict : """ Process a payment exac