> ## Documentation Index
> Fetch the complete documentation index at: https://prefect-bd373955-codex-docket-background-task-ha.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# task_delivery
# `prefect.server.task_delivery`
Durable delivery of deferred task runs to TaskWorkers.
## Functions
### `schedule_task_run_delivery`
```python theme={null}
schedule_task_run_delivery(task_run: schemas.core.TaskRun) -> None
```
Schedule a deferred task run for delivery through Docket.
### `deliver_task_run`
```python theme={null}
deliver_task_run(task_run: schemas.core.TaskRun, visibility_timeout_seconds: float, kind: str, max_size: int, perpetual: Perpetual = Perpetual(), docket: Docket = CurrentDocket()) -> None
```
Offer a task run until a TaskWorker acknowledges it.
### `task_run_delivery_lifespan`
```python theme={null}
task_run_delivery_lifespan(docket: Docket) -> AsyncGenerator[TaskRunDeliveryManager, None]
```
Configure deferred task delivery for an API process.
## Classes
### `TaskDeliveryUnavailable`
Raised when task delivery has not been configured.
### `TaskRunDelivery`
### `TaskRunSubscription`
A TaskWorker subscription to one or more task-key queues.
**Methods:**
#### `acknowledge`
```python theme={null}
acknowledge(self, delivery: TaskRunDelivery) -> None
```
Acknowledge a task run accepted by the connected TaskWorker.
#### `receive`
```python theme={null}
receive(self, timeout: float = 1) -> TaskRunDelivery
```
Receive a task run matching this subscription.
### `TaskRunDeliveryManager`
Schedules Docket executions and creates keyed TaskWorker subscriptions.
**Methods:**
#### `active`
```python theme={null}
active(cls) -> 'TaskRunDeliveryManager'
```
#### `publish`
```python theme={null}
publish(self, task_run: schemas.core.TaskRun) -> None
```
#### `reconcile`
```python theme={null}
reconcile(self, task_run: schemas.core.TaskRun) -> bool
```
Restore delivery for a deferred task run if its execution is absent.
#### `schedule`
```python theme={null}
schedule(self, task_run: schemas.core.TaskRun) -> None
```
#### `subscribe`
```python theme={null}
subscribe(self, task_keys: list[str]) -> TaskRunSubscription
```