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Documentation Index

Fetch the complete documentation index at: https://docs.prefect.io/llms.txt

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prefect.task_engine

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Functions

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run_task_sync 

run_task_sync(task: 'Task[P, R]', task_run_id: Optional[UUID] = None, task_run: Optional[TaskRun] = None, parameters: Optional[dict[str, Any]] = None, wait_for: Optional['OneOrManyFutureOrResult[Any]'] = None, return_type: Literal['state', 'result'] = 'result', dependencies: Optional[dict[str, set[RunInput]]] = None, context: Optional[dict[str, Any]] = None) -> Union[R, State, None]

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run_task_async 

run_task_async(task: 'Task[P, R]', task_run_id: Optional[UUID] = None, task_run: Optional[TaskRun] = None, parameters: Optional[dict[str, Any]] = None, wait_for: Optional['OneOrManyFutureOrResult[Any]'] = None, return_type: Literal['state', 'result'] = 'result', dependencies: Optional[dict[str, set[RunInput]]] = None, context: Optional[dict[str, Any]] = None) -> Union[R, State, None]

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run_generator_task_sync 

run_generator_task_sync(task: 'Task[P, R]', task_run_id: Optional[UUID] = None, task_run: Optional[TaskRun] = None, parameters: Optional[dict[str, Any]] = None, wait_for: Optional['OneOrManyFutureOrResult[Any]'] = None, return_type: Literal['state', 'result'] = 'result', dependencies: Optional[dict[str, set[RunInput]]] = None, context: Optional[dict[str, Any]] = None) -> Generator[R, None, None]

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run_generator_task_async 

run_generator_task_async(task: 'Task[P, R]', task_run_id: Optional[UUID] = None, task_run: Optional[TaskRun] = None, parameters: Optional[dict[str, Any]] = None, wait_for: Optional['OneOrManyFutureOrResult[Any]'] = None, return_type: Literal['state', 'result'] = 'result', dependencies: Optional[dict[str, set[RunInput]]] = None, context: Optional[dict[str, Any]] = None) -> AsyncGenerator[R, None]

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run_task 

run_task(task: 'Task[P, Union[R, Coroutine[Any, Any, R]]]', task_run_id: Optional[UUID] = None, task_run: Optional[TaskRun] = None, parameters: Optional[dict[str, Any]] = None, wait_for: Optional['OneOrManyFutureOrResult[Any]'] = None, return_type: Literal['state', 'result'] = 'result', dependencies: Optional[dict[str, set[RunInput]]] = None, context: Optional[dict[str, Any]] = None) -> Union[R, State, None, Coroutine[Any, Any, Union[R, State, None]]]
Runs the provided task. Args:
  • task: The task to run
  • task_run_id: The ID of the task run; if not provided, a new task run will be created
  • task_run: The task run object; if not provided, a new task run will be created
  • parameters: The parameters to pass to the task
  • wait_for: A list of futures to wait for before running the task
  • return_type: The return type to return; either “state” or “result”
  • dependencies: A dictionary of task run inputs to use for dependency tracking
  • context: A dictionary containing the context to use for the task run; only required if the task is running on in a remote environment
Returns:
  • The result of the task run

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Classes

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TaskRunTimeoutError

Raised when a task run exceeds its timeout.

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BaseTaskRunEngine

Methods:

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compute_transaction_key 

compute_transaction_key(self) -> Optional[str]

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handle_rollback 

handle_rollback(self, txn: Transaction) -> None

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is_cancelled 

is_cancelled(self) -> bool

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is_running 

is_running(self) -> bool
Whether or not the engine is currently running a task.

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log_finished_message 

log_finished_message(self) -> None

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record_terminal_state_timing 

record_terminal_state_timing(self, state: State) -> None

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state 

state(self) -> State

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SyncTaskRunEngine

Methods:

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asset_context 

asset_context(self)

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begin_run 

begin_run(self) -> None

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call_hooks 

call_hooks(self, state: Optional[State] = None) -> None

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call_task_fn 

call_task_fn(self, transaction: Transaction) -> Union[ResultRecord[Any], None, Coroutine[Any, Any, R], R]
Convenience method to call the task function. Returns a coroutine if the task is async.

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can_retry 

can_retry(self, exc_or_state: Exception | State[R]) -> bool

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client 

client(self) -> SyncPrefectClient

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handle_crash 

handle_crash(self, exc: BaseException) -> None

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handle_exception 

handle_exception(self, exc: Exception) -> None

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handle_retry 

handle_retry(self, exc_or_state: Exception | State[R]) -> bool
Handle any task run retries.
  • If the task has retries left, and the retry condition is met, set the task to retrying and return True.
  • If the task has a retry delay, place in AwaitingRetry state with a delayed scheduled time.
  • If the task has no retries left, or the retry condition is not met, return False.

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handle_success 

handle_success(self, result: R, transaction: Transaction) -> Union[ResultRecord[R], None, Coroutine[Any, Any, R], R]

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handle_timeout 

handle_timeout(self, exc: TimeoutError) -> None

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initialize_run 

initialize_run(self, task_run_id: Optional[UUID] = None, dependencies: Optional[dict[str, set[RunInput]]] = None) -> Generator[Self, Any, Any]
Enters a client context and creates a task run if needed.

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result 

result(self, raise_on_failure: bool = True) -> 'Union[R, State, None]'

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run_context 

run_context(self)

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set_state 

set_state(self, state: State[R], force: bool = False) -> State[R]

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setup_run_context 

setup_run_context(self, client: Optional[SyncPrefectClient] = None)

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start 

start(self, task_run_id: Optional[UUID] = None, dependencies: Optional[dict[str, set[RunInput]]] = None) -> Generator[None, None, None]

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transaction_context 

transaction_context(self) -> Generator[Transaction, None, None]

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wait_until_ready 

wait_until_ready(self) -> None
Sync version: Waits until the scheduled time (if its the future), then enters Running.

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AsyncTaskRunEngine

Methods:

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asset_context 

asset_context(self)

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begin_run 

begin_run(self) -> None

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call_hooks 

call_hooks(self, state: Optional[State] = None) -> None

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call_task_fn 

call_task_fn(self, transaction: AsyncTransaction) -> Union[ResultRecord[Any], None, Coroutine[Any, Any, R], R]
Convenience method to call the task function. Returns a coroutine if the task is async.

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can_retry 

can_retry(self, exc_or_state: Exception | State[R]) -> bool

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client 

client(self) -> PrefectClient

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handle_crash 

handle_crash(self, exc: BaseException) -> None

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handle_exception 

handle_exception(self, exc: Exception) -> None

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handle_retry 

handle_retry(self, exc_or_state: Exception | State[R]) -> bool
Handle any task run retries.
  • If the task has retries left, and the retry condition is met, set the task to retrying and return True.
  • If the task has a retry delay, place in AwaitingRetry state with a delayed scheduled time.
  • If the task has no retries left, or the retry condition is not met, return False.

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handle_success 

handle_success(self, result: R, transaction: AsyncTransaction) -> Union[ResultRecord[R], None, Coroutine[Any, Any, R], R]

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handle_timeout 

handle_timeout(self, exc: TimeoutError) -> None

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initialize_run 

initialize_run(self, task_run_id: Optional[UUID] = None, dependencies: Optional[dict[str, set[RunInput]]] = None) -> AsyncGenerator[Self, Any]
Enters a client context and creates a task run if needed.

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result 

result(self, raise_on_failure: bool = True) -> 'Union[R, State, None]'

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run_context 

run_context(self)

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set_state 

set_state(self, state: State, force: bool = False) -> State

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setup_run_context 

setup_run_context(self, client: Optional[PrefectClient] = None)

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start 

start(self, task_run_id: Optional[UUID] = None, dependencies: Optional[dict[str, set[RunInput]]] = None) -> AsyncGenerator[None, None]

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transaction_context 

transaction_context(self) -> AsyncGenerator[AsyncTransaction, None]

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wait_until_ready 

wait_until_ready(self) -> None
Waits until the scheduled time (if its the future), then enters Running.