Feature request: support per-task ack strategy

[vvanglro]

Hi, I would like to propose support for configuring the acknowledgement strategy at the task level.

Currently, ack_type appears to be configured globally at the worker/receiver level through the CLI, for example:

taskiq worker app.broker:broker --ack-type when_saved

This works well as a global worker policy, but it would be useful if individual tasks could override the ack behavior.

Use case

Different tasks in the same worker may have different reliability requirements.

For example:

• Some lightweight or idempotent tasks can be acknowledged early with when_received.
• Some critical tasks should only be acknowledged after execution or result persistence, such as when_executed or when_saved.
• Splitting these tasks into multiple brokers, queues, or workers works, but it adds operational complexity.

Proposed API

One possible API could be:

@broker.task(ack_type="when_saved")
async def critical_task(...):
    ...

@broker.task(ack_type="when_received")
async def best_effort_task(...):
    ...

Or using an enum:

from taskiq import AckType

@broker.task(ack_type=AckType.WHEN_SAVED)
async def critical_task(...):
    ...

@broker.task(ack_type=AckType.WHEN_RECEIVED)
async def best_effort_task(...):
    ...

Expected behavior

The worker could use the task-level ack_type when present, and fall back to the worker-level/default ack_type otherwise.

A possible precedence could be:

1. task-level ack_type
2. worker-level --ack-type
3. taskiq default ack behavior

Broker compatibility

I understand that acknowledgement behavior is currently handled by the receiver rather than by the task itself, and that not all brokers support acknowledgements.

So this feature could perhaps apply only to ack-capable brokers, or be validated/ignored depending on broker capabilities.

For example, this would be useful with Redis Streams in taskiq-redis, where acknowledgements are supported.

Question

Would the maintainers be open to supporting per-task ack strategies?