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prefect.concurrency.sync

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Functions

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concurrency

concurrency(names: Union[str, list[str]], occupy: int = 1, timeout_seconds: Optional[float] = None, max_retries: Optional[int] = None, lease_duration: float = 300, strict: bool = False, holder: 'Optional[ConcurrencyLeaseHolder]' = None, raise_on_lease_renewal_failure: Optional[bool] = None) -> Generator[None, None, None]

• names: The names of the concurrency limits to acquire slots from.
• occupy: The number of slots to acquire and hold from each limit.
• timeout_seconds: The number of seconds to wait for the slots to be acquired before raising a TimeoutError. A timeout of None will wait indefinitely.
• max_retries: The maximum number of retries to acquire the concurrency slots.
• lease_duration: The duration of the lease for the acquired slots in seconds.
• strict: A boolean specifying whether to raise an error if the concurrency limit does not exist. Defaults to False.
• holder: A dictionary containing information about the holder of the concurrency slots. Typically includes ‘type’ and ‘id’ keys.
• raise_on_lease_renewal_failure: Controls whether to terminate execution when lease renewal fails. When None (default), follows the strict parameter for backward compatibility. Set to False to allow long-running tasks to continue even if a transient lease renewal error occurs. Set to True to terminate execution immediately on renewal failure.

• TimeoutError: If the slots are not acquired within the given timeout.
• ConcurrencySlotAcquisitionError: If the concurrency limit does not exist and strict is True.

from prefect.concurrency.sync import concurrency

def resource_heavy():
    with concurrency("test", occupy=1):
        print("Resource heavy task")

def main():
    resource_heavy()

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rate_limit

rate_limit(names: Union[str, list[str]], occupy: int = 1, timeout_seconds: Optional[float] = None, strict: bool = False) -> None

• names: The names of the concurrency limits to acquire slots from.
• occupy: The number of slots to acquire and hold from each limit.
• timeout_seconds: The number of seconds to wait for the slots to be acquired before raising a TimeoutError. A timeout of None will wait indefinitely.
• strict: A boolean specifying whether to raise an error if the concurrency limit does not exist. Defaults to False.

• TimeoutError: If the slots are not acquired within the given timeout.
• ConcurrencySlotAcquisitionError: If the concurrency limit does not exist and strict is True.