prefect.task_worker

Functions

should_try_to_read_parameters ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

should_try_to_read_parameters(task: Task[P, R], task_run: TaskRun) -> bool

Determines whether a task run should read parameters from the result store.

create_status_server ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L427" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

create_status_server(task_worker: TaskWorker) -> FastAPI

aserve ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L452" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

aserve(*tasks: Task[P, R]) -> None

Serve the provided tasks so that their runs may be submitted to and executed in the engine. Tasks do not need to be within a flow run context to be submitted. You must .submit the same task object that you pass to serve.

Args:

• - tasks: A list of tasks to serve. When a scheduled task run is found for a given task, the task run will be submitted to the engine for execution.
• - limit: The maximum number of tasks that can be run concurrently. Defaults to 10. Pass None to remove the limit.
• - status_server_port: An optional port on which to start an HTTP server exposing status information about the task worker. If not provided, no status server will run.
• - timeout: If provided, the task worker will exit after the given number of seconds. Defaults to None, meaning the task worker will run indefinitely.

serve ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L555" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

serve(*tasks: Task[P, R]) -> None

Serve the provided tasks so that their runs may be submitted to and executed in the engine. Tasks do not need to be within a flow run context to be submitted. You must .submit the same task object that you pass to serve.

Args:

• - tasks: A list of tasks to serve. When a scheduled task run is found for a given task, the task run will be submitted to the engine for execution.
• - limit: The maximum number of tasks that can be run concurrently. Defaults to 10. Pass None to remove the limit.
• - status_server_port: An optional port on which to start an HTTP server exposing status information about the task worker. If not provided, no status server will run.
• - timeout: If provided, the task worker will exit after the given number of seconds. Defaults to None, meaning the task worker will run indefinitely.

store_parameters ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L604" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

store_parameters(result_store: ResultStore, identifier: UUID, parameters: dict[str, Any]) -> None

Store parameters for a task run in the result store.

Args:

• result_store: The result store to store the parameters in.
• identifier: The identifier of the task run.
• parameters: The parameters to store.

read_parameters ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L633" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

read_parameters(result_store: ResultStore, identifier: UUID) -> dict[str, Any]

Read parameters for a task run from the result store.

Args:

• result_store: The result store to read the parameters from.
• identifier: The identifier of the task run.

Returns:

• The parameters for the task run.

Classes

StopTaskWorker ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L62" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Raised when the task worker is stopped.

TaskWorker ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L80" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

This class is responsible for serving tasks that may be executed in the background by a task runner via the traditional engine machinery.

When start() is called, the task worker will open a websocket connection to a server-side queue of scheduled task runs. When a scheduled task run is found, the scheduled task run is submitted to the engine for execution with a minimal EngineContext so that the task run can be governed by orchestration rules.

Args:

• - tasks: A list of tasks to serve. These tasks will be submitted to the engine when a scheduled task run is found.
• - limit: The maximum number of tasks that can be run concurrently. Defaults to 10. Pass None to remove the limit.

Methods:

astart ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L177" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

astart(self, timeout: Optional[float] = None) -> None

Starts a task worker, which runs the tasks provided in the constructor.

Args:

• timeout: If provided, the task worker will exit after the given number of seconds. Defaults to None, meaning the task worker will run indefinitely.

astop ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L219" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

astop(self) -> None

Stops the task worker's polling cycle.

available_tasks ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L165" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

available_tasks(self) -> Optional[int]

client_id ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L141" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

client_id(self) -> str

current_tasks ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L157" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

current_tasks(self) -> Optional[int]

execute_task_run ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L399" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

execute_task_run(self, task_run: TaskRun) -> None

Execute a task run in the task worker.

handle_sigterm ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L168" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

handle_sigterm(self, signum: int, frame: object) -> None

Shuts down the task worker when a SIGTERM is received.

limit ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L153" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

limit(self) -> Optional[int]

start ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L207" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

start(self, timeout: Optional[float] = None) -> None

Starts a task worker, which runs the tasks provided in the constructor.

Args:

• timeout: If provided, the task worker will exit after the given number of seconds. Defaults to None, meaning the task worker will run indefinitely.

started ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L149" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

started(self) -> bool

started_at ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L145" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

started_at(self) -> Optional[DateTime]

stop ^{<a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/task_worker.py#L233" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

stop(self) -> None

Stops the task worker's polling cycle.